Search

Background Intra-rectal artesunate has been developed as a potentially life-saving treatment of severe malaria in rural village settings where administration of parenteral antimalarial drugs is not possible. We studied the population pharmacokinetics of intra-rectal artesunate and the relationship with parasitological responses in patients with moderately severe falciparum malaria. Methods and Findings Adults and children in Africa and Southeast Asia with moderately severe malaria were recruited in two Phase II studies (12 adults from Southeast Asia and 11 children from Africa) with intensive sampling protocols, and three Phase III studies (44 children from Southeast Asia, and 86 children and 26 adults from Africa) with sparse sampling. All patients received 10 mg/kg artesunate as a single intra-rectal dose of suppositories. Venous blood samples were taken during a period of 24 h following dosing. Plasma artesunate and dihydroartemisinin (DHA, the main biologically active metabolite) concentrations were measured by high-performance liquid chromatography with electrochemical detection. The pharmacokinetic properties of DHA were determined using nonlinear mixed-effects modelling. Artesunate is rapidly hydrolysed in vivo to DHA, and this contributes the majority of antimalarial activity. For DHA, a one-compartment model assuming complete conversion from artesunate and first-order appearance and elimination kinetics gave the best fit to the data. The mean population estimate of apparent clearance (CL/F) was 2.64 (l/kg/h) with 66% inter-individual variability. The apparent volume of distribution (V/F) was 2.75 (l/kg) with 96% inter-individual variability. The estimated DHA population mean elimination half-life was 43 min. Gender was associated with increased mean CL/F by 1.14 (95% CI: 0.36–1.92) (l/kg/h) for a male compared with a female, and weight was positively associated with V/F. Larger V/Fs were observed for the patients requiring early rescue treatment compared with the remainder, independent of any confounders. No associations between the parasitological responses and the posterior individual estimates of V/F, CL/F, and AUC0–6h were observed. Conclusions The pharmacokinetic properties of DHA were affected only by gender and body weight. Patients with the lowest area under the DHA concentration curve did not have slower parasite clearance, suggesting that rectal artesunate is well absorbed in most patients with moderately severe malaria. However, a number of modelling assumptions were required due to the large intra- and inter-individual variability of the DHA concentrations., A study of the population pharmacokinetics of intra-rectal artesunate in patients with moderately severe falciparum malaria found the pharmacokinetic properties of dihydroartemisinin were affected only by gender and body weight., Editors' Summary Background. More than 40% of the world's population is at risk of malaria, a tropical parasitic disease that is transmitted between people by infected mosquitoes. Malaria parasites cause a 'flu-like illness that includes chills, fevers, headaches, and sometimes nausea and vomiting. If untreated, people with malaria can rapidly become anemic—the parasite destroys their red blood cells—or can develop complications that damage the brain and other organs. Severe malaria can be fatal and must be treated quickly. It has become a matter of great concern that the parasite has developed resistance to most of the drugs used to treat or prevent malaria. In the past few years, artemisinin derivatives have been shown to be an effective new form of treatment. Artemisinin derivatives are effective, rapid-acting antimalarial drugs—wormwood, the plant source of artemisinin, is an ancient Chinese cure for malaria. Artesunate, a water-soluble derivative of artemisinin, can be given as tablets or as injections. However, people with severe malaria often cannot take oral medicines, and in rural settings in the developing world, artesunate injections are usually impracticable. Consequently, rectal artesunate suppositories have been developed to provide first-line treatment of severe malaria in these settings. This simple dosing method can “buy” patients valuable time during which they can be moved to a hospital for further treatment. Why Was This Study Done? When treating severe malaria, it is important that every patient absorbs the antimalarial drug rapidly and efficiently into their blood. If even a small proportion of patients malabsorb the drug, many people could die. How the body processes a drug is known as pharmacokinetics, and although some pharmacokinetic studies have investigated how the body processes artesunate given in rectal suppositories, relatively little is know about the population pharmacokinetics of artesunate given this way. That is, the patient characteristics that affect the processing of intra-rectal artesunate are not known, and it is unclear whether a small proportion of the population might fail to absorb the drug given via this route. In this study, the researchers have developed and tested a population pharmacokinetic model for artesunate given rectally to children and adults with moderately severe malaria. What Did the Researchers Do and Find? The researchers took serial blood samples from nearly 200 patients with moderately severe malaria in Africa and Southeast Asia for the first 24 hours after they received a rectal artesunate suppository. They measured the levels of artesunate and dihydroartemisinin (DHA; the body rapidly converts artesunate to DHA, which kills the malaria parasites) in these samples and used these data to build a pharmacokinetic model for how the body processes. Averaged out across the patients, they calculated, for example, that half of the drug present absorbed was eliminated within 43 minutes. To find out whether any patient characteristics affected the pharmacokinetics of intra-rectal artesunate, the researchers used their model to estimate the clearance of DHA from the body and the ability of DHA to spread through the body (so-called apparent volume of distribution) for the study patients. This analysis showed that only gender and weight affected DHA pharmacokinetics. Finally, the researchers showed that how well the parasite was cleared from the patients was not related to these pharmacokinetic parameters, although the need for earlier rescue treatment was associated with a larger volume of distribution for DHA. Importantly, the parasitological response was not affected by the estimated cumulative amount of DHA absorbed into the blood during the first six hours after treatment. What Do These Findings Mean? The data presented in this study indicate that individual patients processed artesunate very differently in terms of how they absorbed the drug and how it spread around the body. Even so, the maximal effects of artesunate on the malaria parasite were achieved rapidly in nearly all the patients. This and other pharmacokinetic findings must be interpreted with caution, warn the researchers, because their model included many assumptions to allow, for example, for the variability of DHA concentrations both within individual patients and between patients. Nevertheless, the findings provide important clues about which patient characteristics might cause early treatment failure, and indicate that artesunate is sufficiently well absorbed via the rectal route in most patients to make artesunate suppositories a promising first-line treatment for moderately severe malaria. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030444. • World Health Organization links to general information on malaria plus specific information on rectal artesunate • MedlinePlus encyclopedia entry on malaria • US Centers for Disease Control and Prevention information on malaria for patients and professionals • Wikipedia pages on malaria and artemisinin (note that Wikipedia is a free online encyclopedia that anyone can edit)

Background Treatment of asymptomatic individuals, regardless of their malaria infection status, with regularly spaced therapeutic doses of antimalarial drugs has been proposed as a method for reducing malaria morbidity and mortality. This strategy, called intermittent preventive treatment (IPT), is currently employed for pregnant women and is being studied for infants (IPTi) as well. As with any drug-based intervention strategy, it is important to understand how implementation may affect the spread of drug-resistant parasites. This is a difficult issue to address experimentally because of the limited size and duration of IPTi trials as well as the intractability of distinguishing the spread of resistance due to conventional treatment of malaria episodes versus that due to IPTi when the same drug is used in both contexts. Methods and Findings Using a mathematical model, we evaluated the possible impact of treating individuals with antimalarial drugs at regular intervals regardless of their infection status. We translated individual treatment strategies and drug pharmacokinetics into parasite population dynamic effects and show that immunity, treatment rate, drug decay kinetics, and presumptive treatment rate are important factors in the spread of drug-resistant parasites. Our model predicts that partially resistant parasites are more likely to spread in low-transmission areas, but fully resistant parasites are more likely to spread under conditions of high transmission, which is consistent with some epidemiological observations. We were also able to distinguish between spread of resistance due to treatment of symptomatic infections and that due to IPTi. We showed that IPTi could accelerate the spread of resistant parasites, but this effect was only likely to be significant in areas of low or unstable transmission. Conclusions The results presented here demonstrate the importance of considering both the half-life of a drug and the existing level of resistance when choosing a drug for IPTi. Drugs to which little or no resistance exists are not advisable for IPT in high-transmission areas, but IPTi is not likely to significantly impact the spread of highly resistant parasites in areas where partial resistance is already established. IPTi is more likely to accelerate the spread of resistance in high-transmission areas than is IPT in adults (i.e., pregnant women)., A new malaria model predicts that deploying intermittent preventive treatment (IPT) in infancy could accelerate the spread of resistant parasites, but that this effect would be significant only in areas of low or unstable transmission.

Background Experimental animal data show that protection against severe acute respiratory syndrome coronavirus (SARS-CoV) infection with human monoclonal antibodies (mAbs) is feasible. For an effective immune prophylaxis in humans, broad coverage of different strains of SARS-CoV and control of potential neutralization escape variants will be required. Combinations of virus-neutralizing, noncompeting mAbs may have these properties. Methods and Findings Human mAb CR3014 has been shown to completely prevent lung pathology and abolish pharyngeal shedding of SARS-CoV in infected ferrets. We generated in vitro SARS-CoV variants escaping neutralization by CR3014, which all had a single P462L mutation in the glycoprotein spike (S) of the escape virus. In vitro experiments confirmed that binding of CR3014 to a recombinant S fragment (amino acid residues 318–510) harboring this mutation was abolished. We therefore screened an antibody-phage library derived from blood of a convalescent SARS patient for antibodies complementary to CR3014. A novel mAb, CR3022, was identified that neutralized CR3014 escape viruses, did not compete with CR3014 for binding to recombinant S1 fragments, and bound to S1 fragments derived from the civet cat SARS-CoV-like strain SZ3. No escape variants could be generated with CR3022. The mixture of both mAbs showed neutralization of SARS-CoV in a synergistic fashion by recognizing different epitopes on the receptor-binding domain. Dose reduction indices of 4.5 and 20.5 were observed for CR3014 and CR3022, respectively, at 100% neutralization. Because enhancement of SARS-CoV infection by subneutralizing antibody concentrations is of concern, we show here that anti-SARS-CoV antibodies do not convert the abortive infection of primary human macrophages by SARS-CoV into a productive one. Conclusions The combination of two noncompeting human mAbs CR3014 and CR3022 potentially controls immune escape and extends the breadth of protection. At the same time, synergy between CR3014 and CR3022 may allow for a lower total antibody dose to be administered for passive immune prophylaxis of SARS-CoV infection., Editors' Summary Background. Late in 2002, severe acute respiratory syndrome (SARS) emerged in the Guangdong province of China. In February 2003, an infected doctor from the province carried this new viral threat to human health to Hong Kong. Here, people staying in the same hotel caught the disease and took it to other countries. SARS was on the move, hitching lifts with international travellers. Because the virus responsible for SARS—SARS-CoV—spread by close person-to-person contact and killed 10% of the people it infected, health experts feared a world-wide epidemic. This was avoided by the World Health Organization issuing a global alert and warning against unnecessary travel to affected areas and by public-health officials isolating patients and their close contacts. By July 2003, the first SARS epidemic was over. 8,098 people had been infected; 774 people had died. Since then, sporadic cases of SARS have been contained locally. Why Was This Study Done? The first epidemic of SARS was caused by an animal virus that became adapted to spread between people. There is no reason this process won't be repeated. If it is, stringent quarantine measures could again prevent a global epidemic, but at considerable economic cost. What is needed is a way to prevent SARS developing in healthy people who have been exposed to SARS-CoV and to treat sick people so that they are less infectious and can fight the virus. In this study, researchers have been investigating “passive immunization” as a way to limit SARS epidemics. In passive immunization, short-term protection against illness is achieved by injecting antibodies—proteins that recognize specific molecules (called antigens) on foreign organisms such as bacteria and viruses and prevent those organisms from causing disease. Antibodies for passive immunization can be isolated from blood taken from people who have had SARS, or they can be manufactured as so-called “human monoclonal antibodies” in a laboratory. One of these human monoclonal antibodies—CR3014—had been previously made and shown to prevent lung damage in ferrets infected with SARS-CoV and to stop the infected animals from infecting others. But for effective disease prevention in people, a single monoclonal antibody might not be enough. There are strains of SARS-CoV that CR3014 does not recognize and therefore cannot act against. Also, the virus can alter the antigen recognized by CR3014 when it is grown at a low antibody concentration, producing so-called escape variants; if this happens CR3014 can no longer prevent these escape variants from killing human cells. What Did the Researchers Do and Find? The researchers tested how well a combination of two monoclonal antibodies controlled SARS-CoV killing of human cells. First, they showed that CR3014 escape variants all had the same small change in a part of the virus surface that interacts with human cells. CR3014 blocked this interaction in the parent SARS-CoV strain but not in the escape variants. They then made a new monoclonal antibody—CR3022—that prevented both the parent SARS-CoV stain and the CR3014 escape viruses from killing human cells. The two antibodies bound to neighboring parts of the virus surface, and both of them could bind at the same time. CR3022 also bound to surfaces of SARS-CoV strains to which CR3014 does not bind. And when they tried, the researchers could not generate any viral escape variants to which CR3022 was unable to bind. Finally, the effect of the two antibodies together on inhibition of SARS-CoV killing of human cells was more than the sum of their individual effects. What Do These Findings Mean? A combination of two (or more) human monoclonal antibodies that recognize different parts of the SARS-CoV surface that interacts with human cells might be a good way to immunize people passively against SARS-CoV. It might minimize the possibility of escape variants arising, broaden the range of virus strains against which protection is provided, and reduce the amount of antibody needed for effective protection. Before the approach is tried in people, it will have to be tested in animals—results from experiments done on human cells in dishes are not always replicated in whole animals or people. If the approach passes further tests, the hope is that passive immunization of people with SARS and their close contacts might reduce disease severity in infected people and reduce viral spread as effectively as dramatic quarantine measures Additional Information. Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030237. • Medline Plus pages on SARS • US Centers for Disease Control and Prevention information on SARS • US National Institute of Allergy and Infectious Diseases factsheet about research on SARS • Wikipedia page on SARS and monoclonal antibodies (note: Wikipedia is a free online encyclopedia that anyone can edit), Two human monoclonal antibodies that bind to different parts of the viral glycoprotein spike show synergistic effects in virus neutralization and suppress the emergence of resistant virus in vitro.

Colin Sutherland discusses a Policy Forum article that explores the design and standardization of pre-licensure phase III antimalarial treatment trials.

Background Envenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Few attempts have been made to quantify the burden, and recent estimates all suffer from the lack of an objective and reproducible methodology. In an attempt to provide an accurate, up-to-date estimate of the scale of the global problem, we developed a new method to estimate the disease burden due to snakebites. Methods and Findings The global estimates were based on regional estimates that were, in turn, derived from data available for countries within a defined region. Three main strategies were used to obtain primary data: electronic searching for publications on snakebite, extraction of relevant country-specific mortality data from databases maintained by United Nations organizations, and identification of grey literature by discussion with key informants. Countries were grouped into 21 distinct geographic regions that are as epidemiologically homogenous as possible, in line with the Global Burden of Disease 2005 study (Global Burden Project of the World Bank). Incidence rates for envenoming were extracted from publications and used to estimate the number of envenomings for individual countries; if no data were available for a particular country, the lowest incidence rate within a neighbouring country was used. Where death registration data were reliable, reported deaths from snakebite were used; in other countries, deaths were estimated on the basis of observed mortality rates and the at-risk population. We estimate that, globally, at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite. These figures may be as high as 1,841,000 envenomings and 94,000 deaths. Based on the fact that envenoming occurs in about one in every four snakebites, between 1.2 million and 5.5 million snakebites could occur annually. Conclusions Snakebites cause considerable morbidity and mortality worldwide. The highest burden exists in South Asia, Southeast Asia, and sub-Saharan Africa., Janaka de Silva and colleagues estimate that globally at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite., Editors' Summary Background. Of the 3,000 or so snake species that exist in the world, about 600 are venomous. Venomous snakes—which exist on every continent except Antarctica—immobilize their prey by injecting modified saliva (venom) that contains toxins into their prey's tissues through their fangs—specialized, hollow teeth. Snakes also use their venoms for self defense and will bite people who threaten, startle or provoke them. Snakebites caused by the families Viperidae (for example, pit vipers) and Elapidae (for example, kraits and cobras) are particularly dangerous to people. The potentially fatal effects of being “envenomed” (having venom injected) by these snakes include widespread bleeding, muscle paralysis, and tissue destruction (necrosis) around the bite site. Bites from these snakes can also cause permanent disability. For example, snakebite victims, who tend to be young and male, may have to have a limb amputated because of necrosis. The best treatment for any snakebite is to get the victim to a hospital as soon as possible where antivenoms (mixtures of antibodies that neutralize venoms) can be given. Why Was This Study Done? Although snakebites occur throughout the world, envenoming snakebites are thought to pose a particularly important yet largely neglected threat to public health. This is especially true in rural areas of tropical and subtropical countries where snakebites are common but where there is limited access to health care and to antivenoms. The true magnitude of the public-health threat posed by snakebites in these countries (and elsewhere in the world) is unknown, which makes it hard for public-health officials to optimize the prevention and treatment of snakebites in their respective countries. In this study, therefore, the researchers develop and apply a new method to estimate the global burden of snakebite. What Did the Researchers Do and Find? The researchers systematically searched the scientific literature for publications on snakebites and deaths from snakebites and extracted data on snakebite deaths in individual countries from the World Health Organization (WHO) mortality database. They also contacted Ministries of Health, National Poison Centers, and snakebite experts for unpublished information (“grey” literature) on snakebites. Together, these three approaches provided data on the number of snakebite envenomings and deaths for 135 and 162 countries, respectively. The researchers then grouped the 227 countries of the world into 21 geographical regions, each of which contained countries with similar population characteristics, and used the results of studies done in individual countries within each region to estimate the numbers of snakebite envenomings and deaths for each region. Finally, they added up these estimates to obtain an estimate of the global burden of snakebite. Using this method, the researchers estimate that, worldwide, at least 421,000 envenomings and 20,000 deaths from snakebite occur every year; the actual numbers, they suggest, could be as high as 1.8 million envenomings and 94,000 deaths. Their estimates also indicate that the highest burden of snakebite envenomings and death occurs in South and Southeast Asia and in sub-Saharan Africa, and that India is the country with the highest annual number of envenomings (81,000) and deaths (nearly 11,000). What Do These Findings Mean? These findings indicate that snakebites cause considerable illness and death around the world. Because of the careful methods used by the researchers, their global estimates of snakebite envenomings and deaths are probably more accurate than previous estimates. However, because the researchers had to make many assumptions in their calculations and because there are so few reliable data on the numbers of snakebites and deaths from the rural tropics, the true regional and global numbers of these events may differ substantially from the estimates presented here. In particular, the regional estimates for eastern sub-Saharan Africa, a region where snakebites are very common and where antivenoms are particularly hard to obtain, are likely to be inaccurate because they are based on a single study. The researchers, therefore, call for more studies on snakebite envenoming and deaths to be done to provide the information needed to deal effectively with this neglected public-health problem. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050218. This study is further discussed in a PLoS Medicine Perspective by Chippaux The MedlinePlus Medical Encyclopedia has a page on snakebites (in English and Spanish) The UK National Health Service Direct health encyclopedia has detailed information about all aspects of snakebites Wikipedia has pages on venomous snakes and on snakebites (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages) The World Health Organization provides information about antivenoms and about efforts to increase access to antivenoms in developing countries (available in several languages) A previous article in PLoS Medicine also discusses the neglected problem of snakebite envenoming: Gutiérrez JM, Theakston RDG, Warrell DA (2006) Confronting the Neglected Problem of Snake Bite Envenoming: The Need for a Global Partnership. PLoS Med 3(6): e150

Envenoming resulting from snakebites is an important public health problem in many tropical and subtropical countries. Few attempts have been made to quantify the burden, and recent estimates all suffer from the lack of an objective and reproducible methodology. In an attempt to provide an accurate, up-to-date estimate of the scale of the global problem, we developed a new method to estimate the disease burden due to snakebites.The global estimates were based on regional estimates that were, in turn, derived from data available for countries within a defined region. Three main strategies were used to obtain primary data: electronic searching for publications on snakebite, extraction of relevant country-specific mortality data from databases maintained by United Nations organizations, and identification of grey literature by discussion with key informants. Countries were grouped into 21 distinct geographic regions that are as epidemiologically homogenous as possible, in line with the Global Burden of Disease 2005 study (Global Burden Project of the World Bank). Incidence rates for envenoming were extracted from publications and used to estimate the number of envenomings for individual countries; if no data were available for a particular country, the lowest incidence rate within a neighbouring country was used. Where death registration data were reliable, reported deaths from snakebite were used; in other countries, deaths were estimated on the basis of observed mortality rates and the at-risk population. We estimate that, globally, at least 421,000 envenomings and 20,000 deaths occur each year due to snakebite. These figures may be as high as 1,841,000 envenomings and 94,000 deaths. Based on the fact that envenoming occurs in about one in every four snakebites, between 1.2 million and 5.5 million snakebites could occur annually.Snakebites cause considerable morbidity and mortality worldwide. The highest burden exists in South Asia, Southeast Asia, and sub-Saharan Africa.

Background The rectum is particularly vulnerable to HIV transmission having only a single protective layer of columnar epithelium overlying tissue rich in activated lymphoid cells; thus, unprotected anal intercourse in both women and men carries a higher risk of infection than other sexual routes. In the absence of effective prophylactic vaccines, increasing attention is being given to the use of microbicides and preventative antiretroviral (ARV) drugs. To prevent mucosal transmission of HIV, a microbicide/ARV should ideally act locally at and near the virus portal of entry. As part of an integrated rectal microbicide development programme, we have evaluated rectal application of the nucleotide reverse transcriptase (RT) inhibitor tenofovir (PMPA, 9-[(R)-2-(phosphonomethoxy) propyl] adenine monohydrate), a drug licensed for therapeutic use, for protective efficacy against rectal challenge with simian immunodeficiency virus (SIV) in a well-established and standardised macaque model. Methods and Findings A total of 20 purpose-bred Indian rhesus macaques were used to evaluate the protective efficacy of topical tenofovir. Nine animals received 1% tenofovir gel per rectum up to 2 h prior to virus challenge, four macaques received placebo gel, and four macaques remained untreated. In addition, three macaques were given tenofovir gel 2 h after virus challenge. Following intrarectal instillation of 20 median rectal infectious doses (MID50) of a noncloned, virulent stock of SIVmac251/32H, all animals were analysed for virus infection, by virus isolation from peripheral blood mononuclear cells (PBMC), quantitative proviral DNA load in PBMC, plasma viral RNA (vRNA) load by sensitive quantitative competitive (qc) RT-PCR, and presence of SIV-specific serum antibodies by ELISA. We report here a significant protective effect (p = 0.003; Fisher exact probability test) wherein eight of nine macaques given tenofovir per rectum up to 2 h prior to virus challenge were protected from infection (n = 6) or had modified virus outcomes (n = 2), while all untreated macaques and three of four macaques given placebo gel were infected, as were two of three animals receiving tenofovir gel after challenge. Moreover, analysis of lymphoid tissues post mortem failed to reveal sequestration of SIV in the protected animals. We found a strong positive association between the concentration of tenofovir in the plasma 15 min after rectal application of gel and the degree of protection in the six animals challenged with virus at this time point. Moreover, colorectal explants from non-SIV challenged tenofovir-treated macaques were resistant to infection ex vivo, whereas no inhibition was seen in explants from the small intestine. Tissue-specific inhibition of infection was associated with the intracellular detection of tenofovir. Intriguingly, in the absence of seroconversion, Gag-specific gamma interferon (IFN-γ)-secreting T cells were detected in the blood of four of seven protected animals tested, with frequencies ranging from 144 spot forming cells (SFC)/106 PBMC to 261 spot forming cells (SFC)/106 PBMC. Conclusions These results indicate that colorectal pretreatment with ARV drugs, such as tenofovir, has potential as a clinically relevant strategy for the prevention of HIV transmission. We conclude that plasma tenofovir concentration measured 15 min after rectal administration may serve as a surrogate indicator of protective efficacy. This may prove to be useful in the design of clinical studies. Furthermore, in vitro intestinal explants served as a model for drug distribution in vivo and susceptibility to virus infection. The finding of T cell priming following exposure to virus in the absence of overt infection is provocative. Further studies would reveal if a combined modality microbicide and vaccination strategy is feasible by determining the full extent of local immune responses induced and their protective potential., Martin Cranage and colleagues find that topical tenofovir gel can protect against rectal challenge with SIV in a macaque model, and can permit the induction of SIV-specific T cell responses., Editors' Summary Background. About 33 million people are now infected with the human immunodeficiency virus (HIV), which causes AIDS by killing immune system cells. As yet, there is no cure for AIDS, although HIV infections can be held in check with antiretroviral drugs. Also, despite years of research, there is no vaccine available that effectively protects people against HIV infection. So, to halt the AIDS epidemic, other ways of preventing the spread of HIV are being sought. For example, pre-exposure treatment (prophylaxis) with antiretroviral drugs is being investigated as a way to prevent HIV transmission. In addition, because HIV is often spread through heterosexual penile-to-vaginal sex with an infected partner, several vaginal microbicides (compounds that protect against HIV when applied inside the vagina) are being developed, some of which contain antiretroviral drugs. Why Was This Study Done? Because HIV can cross the membranes that line the mouth and the rectum (the lower end of the large intestine that connects to the anus) in addition to the membrane that lines the vagina, HIV transmission can also occur during oral and anal sex. The lining of the rectum in particular is extremely thin and overlies tissues rich in activated T cells (the immune system cells that HIV targets), so unprotected anal intercourse carries a high risk of HIV infection. Anal intercourse is common among men who have sex with men but is also more common in heterosexual populations than is generally thought. Tenofovir (an antiretroviral drug that counteracts HIV after it has entered human cells) given by mouth partly protects macaques against rectal infection with simian immunodeficiency virus (SIV; a virus that induces AIDS in monkeys and apes) so the researchers wanted to know whether this drug might be effective against rectal SIV infection if applied at the site where the virus enters the body. What Did the Researchers Do and Find? To answer this question, the researchers rectally infected several macaques with SIV up to 2 h after rectal application of a gel containing tenofovir, after rectal application of a gel not containing the drug, or after no treatment. In addition, a few animals were treated with the tenofovir gel after the viral challenge. Most of the animals given the tenofovir gel before the viral challenge were partly or totally protected from SIV infection, whereas all the untreated animals and most of those treated with the placebo gel or with the drug-containing gel after the viral challenge became infected with SIV. High blood levels of tenofovir 15 min after its rectal application correlated with protection from viral infection. The researchers also collected rectal and small intestine samples from tenofovir-treated macaques that had not been exposed to SIV and asked which samples were resistant to SIV infection in laboratory dishes. They found that only the rectal samples were resistant to infection and only rectal cells contained tenofovir. Finally, activated T cells that recognized an SIV protein were present in the blood of some of the animals that were protected from SIV infection by the tenofovir gel. What Do These Findings Mean? These findings, although based on experiments in only a few animals, suggest that rectal treatment with antiretroviral drugs before rectal exposure to HIV might prevent rectal HIV transmission in people. However, results from animal experiments do not always reflect what happens in people. Indeed, clinical trials of a potential vaginal microbicide that worked well in macaques were halted recently because women using the microbicide had higher rates of HIV infection than those using a control preparation. The finding that immune-system activation can occur in the absence of overt infection in animals treated with the tenofovir gel additionally suggests that a combination of a local antiretroviral/microbicide and vaccination might be a particularly effective way to prevent HIV transmission. However, because HIV targets activated T cells, viral rechallenge experiments must be done to check that the activated T cells induced by the virus in the presence of tenofovir do not increase the likelihood of infection upon re-exposure to HIV before this potential microbicide is tried in people. Additional Information Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050157. Read the accompanying PLoS Medicine Perspective by Florian Hladik An overview of HIV infection and AIDS is available from the US National Institute of Allergy and Infectious Diseases HIVInSite has comprehensive information on all aspects of HIV/AIDS, including an article on safer sex, which includes information on the risks associated with specific types of sex and on microbicides and other methods to prevent the sexual transmission of HIV Information on all aspects of HIV/AIDS is available from Avert, an international AIDS charity, including information on HIV prevention and on microbicides The World Health Organization has a fact sheet on microbicides The UK charity NAM also provides detailed information on microbicides PrEP Watch is a comprehensive information source on pre-exposure prophylaxis for HIV prevention Global Campaign for Microbicides is an international coalition of organisations dedicated to accelerating access to new HIV prevention options

Background Transmitted HIV-1 drug resistance can compromise initial antiretroviral therapy (ART); therefore, its detection is important for patient management. The absence of drug-associated selection pressure in treatment-naïve persons can cause drug-resistant viruses to decline to levels undetectable by conventional bulk sequencing (minority drug-resistant variants). We used sensitive and simple tests to investigate evidence of transmitted drug resistance in antiretroviral drug-naïve persons and assess the clinical implications of minority drug-resistant variants. Methods and Findings We performed a cross-sectional analysis of transmitted HIV-1 drug resistance and a case-control study of the impact of minority drug resistance on treatment response. For the cross-sectional analysis, we examined viral RNA from newly diagnosed ART-naïve persons in the US and Canada who had no detectable (wild type, n = 205) or one or more resistance-related mutations (n = 303) by conventional sequencing. Eight validated real-time PCR-based assays were used to test for minority drug resistance mutations (protease L90M and reverse transcriptase M41L, K70R, K103N, Y181C, M184V, and T215F/Y) above naturally occurring frequencies. The sensitive real-time PCR testing identified one to three minority drug resistance mutation(s) in 34/205 (17%) newly diagnosed persons who had wild-type virus by conventional genotyping; four (2%) individuals had mutations associated with resistance to two drug classes. Among 30/303 (10%) samples with bulk genotype resistance mutations we found at least one minority variant with a different drug resistance mutation. For the case-control study, we assessed the impact of three treatment-relevant drug resistance mutations at baseline from a separate group of 316 previously ART-naïve persons with no evidence of drug resistance on bulk genotype testing who were placed on efavirenz-based regimens. We found that 7/95 (7%) persons who experienced virologic failure had minority drug resistance mutations at baseline; however, minority resistance was found in only 2/221 (0.9%) treatment successes (Fisher exact test, p = 0.0038). Conclusions These data suggest that a considerable proportion of transmitted HIV-1 drug resistance is undetected by conventional genotyping and that minority mutations can have clinical consequences. With no treatment history to help guide therapies for drug-naïve persons, the findings suggest an important role for sensitive baseline drug resistance testing., Using real-time PCR to detect HIV resistance mutations present at low levels, Jeffrey Johnson and colleagues investigate prevalence and clinical implications of minority transmitted mutations., Editors' Summary Background Since the mid-1990s, several powerful antiretroviral drug combinations have been developed that have greatly improved the prognosis of HIV infection. All antiretroviral therapy (ART) regimens combine drugs that act against HIV in different ways (so-called different drug classes). Multiple drugs are necessary because HIV continually accumulates random changes (mutations) in its genetic material (genome). Some of these mutations make HIV resistant to individual antiretroviral drugs, so a mixture of drugs is needed to keep the virus in check. However, the efficacy of ART (which itself selects for drug-resistant variants by giving them a growth advantage over drug-sensitive variants) is substantially reduced when these variants account for more than about 20% of the viruses in an infected person. This level of variant virus can be detected in blood samples with a technique called bulk sequencing. In North America and Europe, where ART has been widely used for many years, around 20% of HIV-infected people who have taken ART themselves develop this level of drug-resistant virus, which can be transmitted by the same routes as nonresistant HIV (typically unprotected sexual intercourse or needle sharing). In such cases, the person acquiring drug-resistant HIV may experience treatment failure when drugs later fail to work against the resistant virus. In these countries, therefore, resistance testing by bulk sequencing is done routinely before ART is initiated to decide which antiviral drugs are likely to be effective. Why Was This Study Done? Several years usually elapse between the time a person becomes infected with HIV and the time he or she starts ART. During this time, the absence of selection pressure from antiviral drugs means that transmitted drug-resistant variants tend to decline to levels undetectable by bulk sequencing. These “minority drug-resistant variants” can be detected using other more sensitive tests but it is not known what proportion of HIV-infected people who have never taken ART carry minority drug-resistant variants (the “prevalence” of these variants). It is also unknown whether the presence of minority drug-resistant variants reduces the success of ART. In this paper, the researchers first report a “cross-sectional” study in North America using a sensitive assay to determine the prevalence of minority drug-resistant viruses among HIV-infected people who had never received ART. They then investigate whether minority drug-resistant variants have any impact on the effectiveness of ART in a “case-control” study. What Did the Researchers Do and Find? In their cross-sectional study, the researchers used a highly sensitive test for detecting mutations (called a real-time PCR-based assay) to look for low levels of viruses carrying any of eight major drug-resistance mutations in people with newly diagnosed HIV infection who reported no prior treatment with ART. Seventeen percent of the people who had only wild-type (nonmutated) virus by bulk sequencing (205 participants) were found, in fact, to carry low levels of virus variants with 1–3 drug-resistance mutations; 2% of them carried viruses resistant to two different drug classes (called multi-drug resistance). Among the people with resistance mutations detected by bulk sequencing (303 participants), 10% had at least one additional minority drug-resistant variant, often a viral variant that was resistant to a drug class different from that detected by bulk sequencing. In the case-control study, the researchers used their sensitive assays to measure the levels of viruses containing any of the three most common drug resistance mutations likely to affect viral responses to the antiretroviral drugs efavirenz and lamivudine in 316 people just before they started their first HIV treatment, which included these drugs. Of people for whom ART failed, 7% were infected with minority drug-resistant virus variants at baseline compared with only 0.9% of people for whom ART worked; this difference was statistically significant. What Do These Findings Mean? The findings of the cross-sectional study indicate that conventional bulk sequencing fails to detect a large proportion of transmitted HIV drug resistance and suggest that the transmission of drug-resistant variants from infectious ART-experienced people to ART-naïve individuals might not be uncommon. The findings of the case-control study suggest that the minority drug-resistant HIV variants may have clinical consequences. That is, the presence of such variants in individuals who have not previously taken ART may reduce the efficacy of some ART regimens. However, the number of participants meeting the criteria for analysis in the cross-sectional study was limited, and the association between minority resistance and treatment failure may have been influenced by other factors. Taken together, these findings suggest that, to ensure that first-line ART is as effective as possible, greater efforts should be made to prevent HIV transmission, whether from ART-experienced or ART-naive people. However, because data on minority drug-resistant virus are limited, more studies— particularly with recent populations—are needed before testing for these variants can be considered appropriate in the clinical management of newly diagnosed HIV infection. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050158. This study is further discussed in a PLoS Medicine Perspective by Steven G. Deeks Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS HIV InSite has comprehensive information on all aspects of HIV/AIDS, including links to fact sheets (in English, French, and Spanish) about antiretrovirals and information on genetic testing for HIV drug resistance NAM, a UK registered charity, provides information about all aspects of HIVand AIDS, including fact sheets on types of HIV drug, drug resistance, and resistance tests (in English, Spanish, French, Portuguese, and Russian) The US Centers for Disease Control and Prevention provides information on HIV/AIDS and on treatment (in English and Spanish)

The author discusses three new studies inPLoS Medicine that shed light on the mechanisms involved in apoptosis triggered by EGFR kinase inhibitors.

Spam, the term used to describe unsolicited e-mail received from an unknown sender without expressed consent of the recipient [1], has become a major problem for communications through the Internet. Since the delivery of the first spam message in 1978 [2], the volume of spam has grown tremendously. In January 2005, the percentage of all e-mails, worldwide, identified as spam was estimated at 73% [3]. Spammers (the name given to those who deliver spam) are motivated by the fact that a sufficiently large proportion of e-mail users are lured by their offers. In 2003, it was estimated that one-third of e-mail users had clicked on a Web link in a spam message, and 7% had ordered a product [4]. Despite the growing importance of spam for many industries and the public's strong interest in online health information, very little seems to be known about the relationship between spam and human health. Although it has been estimated that 10% of spam includes health-related offers [5], a search of MEDLINE on March 21, 2007, using the terms “spam,” “unsolicited e-mail,” or “junk e-mail” (limited to titles and abstracts, and using the search terms with and without a hyphen), failed to yield citations of original systematic studies on health-related spam. With this study, to our knowledge the first of its kind, we hope to start filling this gap.

Pharmacogenomics is one of the first clinical applications of the postgenomic era. It promises personalized medicine rather than the established “one size fits all” approach to drugs and dosages. The expected reduction in trial and error should ultimately lead to more efficient and safer drug therapy. In recent years, commercially available pharmacogenomic tests have been approved by the Food and Drug Administration (FDA), but their application in patient care remains very limited. More generally, the implementation of pharmacogenomics in routine clinical practice presents significant challenges. This article presents specific clinical examples of such challenges and discusses how obstacles to implementation of pharmacogenomic testing can be addressed., Jesse J. Swen and colleagues review the limited successes of pharmacogenomics (individualized drug dosing based on hereditary factors) and discuss the remaining challenges to its widespread clinical use.

Background Availability of an ultra-short-course drug regimen capable of curing patients with tuberculosis in 2 to 3 mo would significantly improve global control efforts. Because immediate prospects for novel treatment-shortening drugs remain uncertain, we examined whether better use of existing drugs could shorten the duration of treatment. Rifapentine is a long-lived rifamycin derivative currently recommended only in once-weekly continuation-phase regimens. Moxifloxacin is an 8-methoxyfluoroquinolone currently used in second-line regimens. Methods and Findings Using a well-established mouse model with a high bacterial burden and human-equivalent drug dosing, we compared the efficacy of rifapentine- and moxifloxacin-containing regimens with that of the standard daily short-course regimen based on rifampin, isoniazid, and pyrazinamide. Bactericidal activity was assessed by lung colony-forming unit counts, and sterilizing activity was assessed by the proportion of mice with culture-positive relapse after 2, 3, 4, and 6 mo of treatment. Here, we demonstrate that replacing rifampin with rifapentine and isoniazid with moxifloxacin dramatically increased the activity of the standard daily regimen. After just 2 mo of treatment, mice receiving rifapentine- and moxifloxacin-containing regimens were found to have negative lung cultures, while those given the standard regimen still harbored 3.17 log10 colony-forming units in the lungs (p < 0.01). No relapse was observed after just 3 mo of treatment with daily and thrice-weekly administered rifapentine- and moxifloxacin-containing regimens, whereas the standard daily regimen required 6 mo to prevent relapse in all mice. Conclusions Rifapentine should no longer be viewed solely as a rifamycin for once-weekly administration. Our results suggest that treatment regimens based on daily and thrice-weekly administration of rifapentine and moxifloxacin may permit shortening the current 6 mo duration of treatment to 3 mo or less. Such regimens warrant urgent clinical investigation., Eric Nuermberger and colleagues found that after two months of treatment, mice with lung cultures positive for tuberculosis that received daily doses of rifapentine- and moxifloxacin-containing regimens converted to negative lung cultures. This finding could make possible the development of shorter treatment regimens for humans., Editors' Summary Background. Every year, nearly 9 million people develop tuberculosis—a bacterial infection most commonly of the lungs—and about 2 million people die from the disease. Tuberculosis is caused by Mycobacterium tuberculosis, bacteria that are spread in airborne droplets when people with active tuberculosis sneeze or cough. Most infected people never become ill—their immune system successfully contains the infection. However, the bacteria remain dormant within the body and can cause disease years later if host immunity declines. Active tuberculosis can be cured by taking several antibiotics daily (for tuberculosis treatments, daily may mean five or seven times a week) for at least 6 mo. Combinations of drugs are needed to prevent the bacteria from developing resistance to the treatment, but also because of the complex biology of M. tuberculosis. During active tuberculosis, there are rapidly multiplying bacteria in the lungs but also less rapidly multiplying and near-dormant bacteria elsewhere in the body. Effective treatments contain a “bactericidal” drug such as isoniazid to kill the actively multiplying bacteria, a drug to kill the less actively multiplying bugs (for example, pyrazinamide), and a sterilizing drug (the most potent of which is rifampin) to kill the near-dormant bacteria and thus prevent the disease from recurring. Why Was This Study Done? Unfortunately, many patients fail to complete this treatment because it is long and complicated and because the drugs may have unpleasant side effects. Poor adherence to treatment contributes to the emergence of drug resistance and means that people stay infectious for longer and are more likely to have relapses. Consequently, it is hampering global efforts to control tuberculosis. A shorter course of treatment might improve matters, but many researchers believe that this will require the development of new drugs and, although there are several promising candidates, it will be several years before they can be used in patients. In this study, therefore, the researchers asked whether better use of existing drugs could shorten treatment times. In particular, they studied tuberculosis in animals to investigate whether a long-lived rifampin-like drug called rifapentine combined with moxifloxacin (an alternative to isoniazid) might shorten treatment times. What Did the Researchers Do and Find? The researchers used several different courses (“regimens”) of treatment containing rifapentine, moxifloxacin, and pyrazinamide, and the standard daily short-course regimen containing rifampin, isoniazid, and pyrazinamide to treat mice infected with M. tuberculosis. For each regimen, they measured its bactericidal activity by counting how many bacterial colonies could be grown from the lungs of the mice at specific times during the treatment, and its sterilizing activity by assessing the proportion of mice with any live bacteria in their lungs (a culture-positive relapse) after treatment completion. After 2 mo of treatment, the mice receiving the rifapentine- and moxifloxacin-containing regimens had negative lung cultures, a point not reached with the standard regimen until after 4 mo of treatment. Three months of treatment with daily or thrice-weekly rifapentine- and moxifloxacin-containing regimens was sufficient to prevent any culture-positive relapses, whereas the standard daily regimen had to be continued for 6 mo to achieve cure. Testing of additional drug combinations revealed that rifapentine is the most important drug in the new regimen and that simply replacing rifampin with rifapentine and retaining isoniazid also is sufficient to shorten the duration of therapy to 3 mo in this experimental model. What Do These Findings Mean? These findings provide the first evidence that replacing rifampin with rifapentine might halve the length of therapy needed to cure tuberculosis. They also indicate that it might be possible to give the drugs thrice-weekly rather than daily as in the current therapy. The World Health Organization recommends that all tuberculosis treatment is supervised (so-called directly observed therapy) to ensure treatment adherence, so a regimen that requires only three doses a week for 3 mo would greatly reduce the resources needed to treat tuberculosis as well as potentially improving treatment adherence. However, it should be emphasized that the current study is experimental, and there may be important differences between how mice and people respond to the proposed drug regimens, both in terms of cure rates and side effects. Nevertheless, these results strongly suggest that the safety, tolerability, and efficacy of tuberculosis treatment regimens containing rifapentine and pyrazinamide, combined with either moxifloxacin or isoniazid, should be evaluated in people as soon as possible. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040344. The MedlinePlus encyclopedia contains a page on tuberculosis (in English and Spanish) The US National Institute of Allergy and Infectious Diseases provides information on all aspects of tuberculosis The US Centers for Disease Control and Prevention provide several fact sheets and other information resources about tuberculosis, including information for patients and caregivers about treatment adherence The World Health Organization provides a 2007 report on global tuberculosis control (in English with key findings in French and Spanish), information on the Stop TB initiative, and a recent bulletin on tuberculosis treatment (in English with an abstract in French, Spanish, and Arabic)

Background Published pharmaceutical industry–sponsored trials are more likely than non-industry-sponsored trials to report results and conclusions that favor drug over placebo. Little is known about potential biases in drug–drug comparisons. This study examined associations between research funding source, study design characteristics aimed at reducing bias, and other factors that potentially influence results and conclusions in randomized controlled trials (RCTs) of statin–drug comparisons. Methods and Findings This is a cross-sectional study of 192 published RCTs comparing a statin drug to another statin drug or non-statin drug. Data on concealment of allocation, selection bias, blinding, sample size, disclosed funding source, financial ties of authors, results for primary outcomes, and author conclusions were extracted by two coders (weighted kappa 0.80 to 0.97). Univariate and multivariate logistic regression identified associations between independent variables and favorable results and conclusions. Of the RCTs, 50% (95/192) were funded by industry, and 37% (70/192) did not disclose any funding source. Looking at the totality of available evidence, we found that almost all studies (98%, 189/192) used only surrogate outcome measures. Moreover, study design weaknesses common to published statin–drug comparisons included inadequate blinding, lack of concealment of allocation, poor follow-up, and lack of intention-to-treat analyses. In multivariate analysis of the full sample, trials with adequate blinding were less likely to report results favoring the test drug, and sample size was associated with favorable conclusions when controlling for other factors. In multivariate analysis of industry-funded RCTs, funding from the test drug company was associated with results (odds ratio = 20.16 [95% confidence interval 4.37–92.98], p < 0.001) and conclusions (odds ratio = 34.55 [95% confidence interval 7.09–168.4], p < 0.001) that favor the test drug when controlling for other factors. Studies with adequate blinding were less likely to report statistically significant results favoring the test drug. Conclusions RCTs of head-to-head comparisons of statins with other drugs are more likely to report results and conclusions favoring the sponsor's product compared to the comparator drug. This bias in drug–drug comparison trials should be considered when making decisions regarding drug choice., Lisa Bero and colleagues found published trials comparing one statin with another were more likely to report results and conclusions favoring the sponsor's product than the comparison drug., Editors' Summary Background. Randomized controlled trials are generally considered to be the most reliable type of experimental study for evaluating the effectiveness of different treatments. Randomization involves the assignment of participants in the trial to different treatment groups by the play of chance. Properly done, this procedure means that the different groups are comparable at outset, reducing the chance that outside factors could be responsible for treatment effects seen in the trial. When done properly, randomization also ensures that the clinicians recruiting participants into the trial cannot know the treatment group to which a patient will end up being assigned. However, despite these advantages, a large number of factors can still result in bias creeping in. Bias comes about when the findings of research appear to differ in some systematic way from the true result. Other research studies have suggested that funding is a source of bias; studies sponsored by drug companies seem to more often favor the sponsor's drug than trials not sponsored by drug companies Why Was This Study Done? The researchers wanted to more precisely understand the impact of different possible sources of bias in the findings of randomized controlled trials. In particular, they wanted to study the outcomes of “head-to-head” drug comparison studies for one particular class of drugs, the statins. Drugs in this class are commonly prescribed to reduce the levels of cholesterol in blood amongst people who are at risk of heart and other types of disease. This drug class is a good example for studying the role of bias in drug–drug comparison trials, because these trials are extensively used in decision making by health-policy makers. What Did the Researchers Do and Find? This research study was based on searching PubMed, a biomedical literature database, with the aim of finding all randomized controlled trials of statins carried out between January 1999 and May 2005 (reference lists also were searched). Only trials which compared one statin to another statin or one statin to another type of drug were included. The researchers extracted the following information from each article: the study's source of funding, aspects of study design, the overall results, and the authors' conclusions. The results were categorized to show whether the findings were favorable to the test drug (the newer statin), inconclusive, or not favorable to the test drug. Aspects of each study's design were also categorized in relation to various features, such as how well the randomization was done (in particular, the degree to which the processes used would have prevented physicians from knowing which treatment a patient was likely to receive on enrollment); whether all participants enrolled in the trial were eventually analyzed; and whether investigators or participants knew what treatment an individual was receiving. One hundred and ninety-two trials were included in this study, and of these, 95 declared drug company funding; 23 declared government or other nonprofit funding while 74 did not declare funding or were not funded. Trials that were properly blinded (where participants and investigators did not know what treatment an individual received) were less likely to have conclusions favoring the test drug. However, large trials were more likely to favor the test drug than smaller trials. When looking specifically at the trials funded by drug companies, the researchers found various factors that predicted whether a result or conclusion favored the test drug. These included the impact of the journal publishing the results; the size of the trial; and whether funding came from the maker of the test drug. However, properly blinded trials were less likely to produce results favoring the test drug. Even once all other factors were accounted for, the funding source for the study was still linked with results and conclusions that favored the maker of the test drug. What Do These Findings Mean? This study shows that the type of sponsorship available for randomized controlled trials of statins was strongly linked to the results and conclusions of those studies, even when other factors were taken into account. However, it is not clear from this study why sponsorship has such a strong link to the overall findings. There are many possible reasons why this might be. Some people have suggested that drug companies may deliberately choose lower dosages for the comparison drug when they carry out “head-to-head” trials; this tactic is likely to result in the company's product doing better in the trial. Others have suggested that trials which produce unfavorable results are not published, or that unfavorable outcomes are suppressed. Whatever the reasons for these findings, the implications are important, and suggest that the evidence base relating to statins may be substantially biased. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040184. The James Lind Library has been created to help people understand fair tests of treatments in health care by illustrating how fair tests have developed over the centuries The International Committee of Medical Journal Editors has provided guidance regarding sponsorship, authorship, and accountability The CONSORT statement is a research tool that provides an evidence-based approach for reporting the results of randomized controlled trials Good Publication Practice guidelines provide standards for responsible publication of research sponsored by pharmaceutical companies Information from Wikipedia on Statins. Wikipedia is an internet encyclopedia anyone can edit

Background Epidermal growth factor receptor (EGFR) mutations are present in the majority of patients with non-small cell lung cancer (NSCLC) responsive to the EGFR tyrosine kinase inhibitors (TKIs) gefitinib or erlotinib. These EGFR-dependent tumors eventually become TKI resistant, and the common secondary T790M mutation accounts for half the tumors with acquired resistance to gefitinib. However, the key proapoptotic proteins involved in TKI-induced cell death and other secondary mutations involved in resistance remain unclear. The objective of this study was to identify the mechanism of EGFR TKI-induced apoptosis and secondary resistant mutations that affect this process. Methods and Findings To study TKI-induced cell death and mechanisms of resistance, we used lung cancer cell lines (with or without EGFR mutations), Ba/F3 cells stably transfected with EGFR mutation constructs, and tumor samples from a gefitinib-resistant patient. Here we show that up-regulation of the BH3-only polypeptide BIM (also known as BCL2-like 11) correlated with gefitinib-induced apoptosis in gefitinib-sensitive EGFR-mutant lung cancer cells. The T790M mutation blocked gefitinib-induced up-regulation of BIM and apoptosis. This blockade was overcome by the irreversible TKI CL-387,785. Knockdown of BIM by small interfering RNA was able to attenuate apoptosis induced by EGFR TKIs. Furthermore, from a gefitinib-resistant patient carrying the activating L858R mutation, we identified a novel secondary resistant mutation, L747S in cis to the activating mutation, which attenuated the up-regulation of BIM and reduced apoptosis. Conclusions Our results provide evidence that BIM is involved in TKI-induced apoptosis in sensitive EGFR-mutant cells and that both attenuation of the up-regulation of BIM and resistance to gefitinib-induced apoptosis are seen in models that contain the common EGFR T790M and the novel L747S secondary resistance mutations. These findings also suggest that induction of BIM may have a role in the treatment of TKI-resistant tumors., Susumu Kobayashi and colleagues provide evidence that the polypeptide BIM is involved in tyrosine kinase inhibitor (TKI)-induced apoptosis in sensitiveEGFR-mutant cells and suggest that induction of BIM may have a role in the treatment of TKI-resistant tumors., Editors' Summary Background. Most cases of lung cancer—the leading cause of cancer deaths worldwide—are “non-small cell lung cancer” (NSCLC). Many patients with NSCLC die within a year of their diagnosis, but recently, “targeted” therapies have increased the life expectancy of some of them. Like all cancers, NSCLC occurs when cells begin to divide uncontrollably because of changes (mutations) in their genes. Targeted therapies specifically attack these changes and, unlike standard chemotherapy drugs, kill cancer cells without damaging normal cells. The targeted drugs used to treat NSCLC are gefitinib and erlotinib, two epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). In normal cells, messenger proteins bind to EGFR and activate its tyrosine kinase, an enzyme that sticks phosphate groups on tyrosine (an amino acid) in other proteins. These “phosphorylated” proteins then tell the cell to divide. In some NSCLCs, EGFR drives uncontrolled cell division because its tyrosine kinase is mutated and the cancer becomes dependent on or “addicted” to EGFR signaling for its survival. TKI treatment can dramatically shrink this subset of NSCLCs, most of which lack a specific part of EGFR (the gene that encodes EGFR) or have the amino acid leucine instead of arginine at position 858 (an L858R mutation) of EGFR. Why Was This Study Done? TKI-sensitive NSCLCs eventually become resistant to TKIs because they acquire additional (secondary) mutations. In half of these TKI-resistant tumors, the additional mutation is replacement of threonine by methionine at position 790 (T790M) in EGFR. However, the mutations responsible for the remaining cases of TKI resistance are not known. In addition, little is known about how TKIs induce cell death other than that they induce a type of cell death called apoptosis. A better understanding of how TKIs kill tumor cells and how secondary mutations block their effects could reveal ways to enhance their action and improve the outcome for patients with NSCLC. In this study, the researchers have studied the mechanism of TKI-induced cell death and of resistance to TKIs. What Did the Researchers Do and Find? The researchers first measured the ability of gefitinib to cause apoptosis (genetically programmed cell death) in NSCLC cell lines (tumor cells adapted to grow indefinitely in dishes) that had the EGFR deletion, the L858R mutation, or normal EGFR. Gefitinib caused apoptosis only in cell lines with altered EGFR. Then they asked whether a proapoptotic protein called BIM (a member of the BCL2 family of pro- and antiapoptotic proteins) is involved in TKI-induced cell death—BIM is known to be involved in this process in leukemia (blood cancer) cells. Gefitinib treatment increased the expression of BIM in TKI-sensitive NSCLC cell lines and reduced the phosphorylation of BIM (which makes BIM more active). By contrast, blocking BIM expression using a technique called RNA interference reduced TKI-induced apoptosis in TKI-sensitive NSCLC cells. Furthermore, introduction of the T790M resistance mutation into these cells blocked gefitinib-induced up-regulation of BIM and apoptosis. Finally, the researchers identified a new TKI resistance mutation (L747S, substitution of serine for leucine at position 747) in a patient whose TKI-sensitive NSCLC had become resistant to gefitinib, and showed that this resistance mutation also reduced TKI-induced apoptosis in cells growing in dishes by interfering with BIM up-regulation. What Do These Findings Mean? These findings (and those reported by Gong et al. and Cragg et al.) show that BIM is required for TKI-induced apoptosis in EGFR mutant NSCLC cells. They also show that mutations that make TKI-sensitive cells resistant to these drugs reduce TKI-induced apoptosis by preventing the upregulation of BIM. These results were obtained by examining the behavior of established cell lines growing in dishes and need to be confirmed in cells freshly isolated from tumors and in tumors themselves. However, they suggest that the efficacy of TKIs could be increased by finding ways to increase BIM expression or to activate other proteins involved in apoptosis Such approaches might be particularly beneficial for patients with NSCLC whose initially TKI-sensitive tumors have acquired mutations that make them resistant to TKIs. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040315. Ingo Mellinghoff discusses this paper and two related ones in a perspective article US National Cancer Institute information for patients and professionals on lung cancer (in English and Spanish) Information for patients from Cancer Research UK on lung cancer, including information on treatment with TKIs CancerQuest information on all aspects of cancer from Emory University (in several languages) Wikipedia pages on apoptosis, epidermal growth factor receptor, and BCL2 proteins (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages) Information for patients from Cancerbackup on erlotinib and gefitinib

Background The catalytically active 66-kDa subunit of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) consists of DNA polymerase, connection, and ribonuclease H (RNase H) domains. Almost all known RT inhibitor resistance mutations identified to date map to the polymerase domain of the enzyme. However, the connection and RNase H domains are not routinely analysed in clinical samples and none of the genotyping assays available for patient management sequence the entire RT coding region. The British Columbia Centre for Excellence in HIV/AIDS (the Centre) genotypes clinical isolates up to codon 400 in RT, and our retrospective statistical analyses of the Centre's database have identified an N348I mutation in the RT connection domain in treatment-experienced individuals. The objective of this multidisciplinary study was to establish the in vivo relevance of this mutation and its role in drug resistance. Methods and Findings The prevalence of N348I in clinical isolates, the time taken for it to emerge under selective drug pressure, and its association with changes in viral load, specific drug treatment, and known drug resistance mutations was analysed from genotypes, viral loads, and treatment histories from the Centre's database. N348I increased in prevalence from below 1% in 368 treatment-naïve individuals to 12.1% in 1,009 treatment-experienced patients (p = 7.7 × 10−12). N348I appeared early in therapy and was highly associated with thymidine analogue mutations (TAMs) M41L and T215Y/F (p < 0.001), the lamivudine resistance mutations M184V/I (p < 0.001), and non-nucleoside RTI (NNRTI) resistance mutations K103N and Y181C/I (p < 0.001). The association with TAMs and NNRTI resistance mutations was consistent with the selection of N348I in patients treated with regimens that included both zidovudine and nevirapine (odds ratio 2.62, 95% confidence interval 1.43–4.81). The appearance of N348I was associated with a significant increase in viral load (p < 0.001), which was as large as the viral load increases observed for any of the TAMs. However, this analysis did not account for the simultaneous selection of other RT or protease inhibitor resistance mutations on viral load. To delineate the role of this mutation in RT inhibitor resistance, N348I was introduced into HIV-1 molecular clones containing different genetic backbones. N348I decreased zidovudine susceptibility 2- to 4-fold in the context of wild-type HIV-1 or when combined with TAMs. N348I also decreased susceptibility to nevirapine (7.4-fold) and efavirenz (2.5-fold) and significantly potentiated resistance to these drugs when combined with K103N. Biochemical analyses of recombinant RT containing N348I provide supporting evidence for the role of this mutation in zidovudine and NNRTI resistance and give some insight into the molecular mechanism of resistance. Conclusions This study provides the first in vivo evidence that treatment with RT inhibitors can select a mutation (i.e., N348I) outside the polymerase domain of the HIV-1 RT that confers dual-class resistance. Its emergence, which can happen early during therapy, may significantly impact on a patient's response to antiretroviral therapies containing zidovudine and nevirapine. This study also provides compelling evidence for investigating the role of other mutations in the connection and RNase H domains in virological failure., Analyzing HIV sequences from a Canadian cohort, Gilda Tachedjian and colleagues identify a common mutation in a little-studied domain of reverse transcriptase that confers resistance to two drug classes., Editors' Summary Background. In the 1980s, infection with the human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), was a death sentence. Although the first antiretroviral drugs (compounds that block HIV's life cycle) were developed quickly, single antiretrovirals only transiently suppress HIV infection. HIV rapidly accumulates random changes (mutations) in its genetic material, some of which make it drug resistant. Nowadays, there are many different antiretrovirals. Some inhibit the viral protease, an enzyme used to assemble new viruses. Others block reverse transcriptase (RT), which makes replicates of the genes of the virus. Nucleoside/nucleotide RT inhibitors (NRTIs; for example, zidovudine—also called AZT—and lamivudine) and non-nucleoside RT inhibitors (NNRTIs; for example, nevirapine and efavirenz) interfere with the activity of RT by binding to different sites in its so-called “DNA polymerase domain,” the part of the enzyme that constructs copies of the viral genes. Highly active antiretroviral therapy (HAART), which was introduced in the mid 1990s, combines several antiretrovirals (usually a protease inhibitor and two NRTIs or an NNRTI and two NRTIs) so that the replication of any virus that develops resistance to one drug is inhibited by the other drugs in the mix. When treated with HAART, HIV infection is usually a chronic, stable condition rather than a fatal disease. Why Was This Study Done? Unfortunately, HIV that is resistant to drugs still develops in some patients. To improve the prevention and management of drug resistance, a better understanding of the mutations that cause resistance is needed. Resistance to RT inhibitors usually involves mutations in the DNA polymerase domain that reduce the efficacy of NRTIs (including thymidine analogue mutations—also known as TAMs—and lamivudine-resistance mutations) and NNRTIs. Blood tests that detect these resistance mutations (genotype tests) have been used for several years to guide individualized selection of HIV drugs. Recently, however, mutations outside the DNA polymerase domain have also been implicated in resistance to RT inhibitors. In this study, the researchers have used data and samples collected since the mid 1990s by Canada's British Columbia Centre for Excellence in HIV/AIDS to investigate the clinical relevance of a mutation called N348I. This mutation changes an asparagine (a type of amino acid) to an isoleucine in a region of RT known as the connection domain. The researchers have also investigated how this mutation causes resistance to RT inhibitors in laboratory tests. What Did the Researchers Do and Find? The researchers analyzed the first two-thirds of the RT gene in viruses isolated from a large number of the Centre's patients. Virus carrying the N348I mutation was present in less than one in 100 patients whose HIV infection had never been treated, but in more than one in 10 treatment-experienced patients. The mutation appeared early in therapy, often in viruses that had TAMs, a lamivudine-resistance mutation called M184V/I, and/or NNRTI resistance mutations. Patients treated with zidovudine and nevirapine were 2.6 times more likely to have the N348I mutation than patients not treated with these drugs. Furthermore, the appearance of the N348I mutation often coincided with an increase in viral load, although other mutations that appeared at a similar time could have contributed to this increase. When the researchers introduced the N348I mutation into HIV growing in the laboratory, they found that it decreased the susceptibility of the virus to zidovudine and to NNRTIs. What Do These Findings Mean? These findings show that the treatment of patients with RT inhibitors can select a drug-resistant HIV variant that has a mutation outside the enzyme's DNA polymerase domain. Because this N348I mutation, which is commonly selected in vivo and has also been seen in other studies, confers resistance to two classes of RT inhibitors and can emerge early during therapy, it could have a large impact on patient responses to antiviral regimens that contain zidovudine and nevirapine. Although these findings do not show that the N348I mutation alone causes treatment failure, they may have implications for genotypic and phenotypic resistance testing, which is often used to guide treatment decisions. At present, genotype tests for resistance to RT inhibitors look for mutations only in the DNA polymerase domain of RT. This study is the first to demonstrate that it might be worth looking for the N348I mutation (and for other mutations outside the DNA polymerase domain) to improve the ability of genotypic and phenotypic resistance tests to predict treatment outcomes. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040335. Information is available from the US National Institute of Allergy and Infectious Diseases on HIV infection and AIDS HIV InSite has comprehensive information on all aspects of HIV/AIDS, including links to fact sheets (in English, French, and Spanish) about antiretrovirals, and chapters explaining antiretroviral resistance testing NAM, a UK registered charity, provides information about all aspects of HIV and AIDS, including fact sheets on types of HIV drugs, drug resistance, and resistance tests (in English, Spanish, French, Portuguese, and Russian) The US Centers for Disease Control and Prevention provides information on HIV/AIDS and on treatment (in English and Spanish) AIDSinfo, a service of the US Department of Health and Human Services provides information for patients on HIV and its treatment

Background Paracetamol (acetaminophen) poisoning is the leading cause of acute liver failure in Great Britain and the United States. Successful interventions to reduced harm from paracetamol poisoning are needed. To achieve this, the government of the United Kingdom introduced legislation in 1998 limiting the pack size of paracetamol sold in shops. Several studies have reported recent decreases in fatal poisonings involving paracetamol. We use interrupted time-series analysis to evaluate whether the recent fall in the number of paracetamol deaths is different to trends in fatal poisoning involving aspirin, paracetamol compounds, antidepressants, or nondrug poisoning suicide. Methods and Findings We calculated directly age-standardised mortality rates for paracetamol poisoning in England and Wales from 1993 to 2004. We used an ordinary least-squares regression model divided into pre- and postintervention segments at 1999. The model included a term for autocorrelation within the time series. We tested for changes in the level and slope between the pre- and postintervention segments. To assess whether observed changes in the time series were unique to paracetamol, we compared against poisoning deaths involving compound paracetamol (not covered by the regulations), aspirin, antidepressants, and nonpoisoning suicide deaths. We did this comparison by calculating a ratio of each comparison series with paracetamol and applying a segmented regression model to the ratios. No change in the ratio level or slope indicated no difference compared to the control series. There were about 2,200 deaths involving paracetamol. The age-standardised mortality rate rose from 8.1 per million in 1993 to 8.8 per million in 1997, subsequently falling to about 5.3 per million in 2004. After the regulations were introduced, deaths dropped by 2.69 per million (p = 0.003). Trends in the age-standardised mortality rate for paracetamol compounds, aspirin, and antidepressants were broadly similar to paracetamol, increasing until 1997 and then declining. Nondrug poisoning suicide also declined during the study period, but was highest in 1993. The segmented regression models showed that the age-standardised mortality rate for compound paracetamol dropped less after the regulations (p = 0.012) but declined more rapidly afterward (p = 0.031). However, age-standardised rates for aspirin and antidepressants fell in a similar way to paracetamol after the regulations. Nondrug poisoning suicide declined at a similar rate to paracetamol after the regulations were introduced. Conclusions Introduction of regulations to limit availability of paracetamol coincided with a decrease in paracetamol-poisoning mortality. However, fatal poisoning involving aspirin, antidepressants, and to a lesser degree, paracetamol compounds, also showed similar trends. This raises the question whether the decline in paracetamol deaths was due to the regulations or was part of a wider trend in decreasing drug-poisoning mortality. We found little evidence to support the hypothesis that the 1998 regulations limiting pack size resulted in a greater reduction in poisoning deaths involving paracetamol than occurred for other drugs or nondrug poisoning suicide., Analysis of mortality rates for paracetamol poisoning in England and Wales does not support the view that regulations limiting pack size have been responsible for a reduction in deaths., Editors' Summary Background. Paracetamol—known as acetaminophen in the United States—is a cheap and effective painkiller. It is widely used to relieve minor aches and pains as well as fevers and headaches. Recommended doses of paracetamol are considered safe in humans, but overdoses are toxic and can cause liver failure and death. Because this drug is very easy to get hold of, there are many overdoses each year, either accidental or deliberate. In the UK, paracetamol poisoning is the most common cause of acute liver failure. Toward the end of 1998, new laws were introduced in the UK to try to reduce the number of paracetamol overdoses. These laws said that pharmacies could not sell packs of paracetamol containing more than 32 tablets and other shops could not sell packs with more than 16 tablets. One of the reasons behind the introduction of this law was that many suicides are not preplanned and, therefore, if it was harder for people to get hold of or keep large quantities of tablets, they might be less likely to attempt suicide or accidentally overdose. Why Was This Study Done? Following the introduction of these new laws, the number of deaths caused by paracetamol overdose in the UK dropped. However, it is possible that the drop in deaths came about for a variety of different reasons and not just as a result of the new laws on paracetamol pack size. For example, the suicide rate might have been falling anyway due to other changes in society and the fall in death rate from paracetamol might just have been part of that trend. It is important to find out whether the legal changes that were introduced to address a public health problem did in fact bring about a change for the better. This knowledge would also be relevant to other countries that are considering similar changes. What Did the Researchers Do and Find? The researchers used data from the Office of National Statistics, which holds information on drug poisoning deaths in England and Wales. These data were then broken down by the type of drug that was mentioned on the death certificate. The researchers compared death rates involving the following drugs: paracetamol; paracetamol-containing compounds (which were not subject to the new pack size laws); aspirin; antidepressant drugs; and then finally non-drug poisoning suicides. The reason for comparing death rates involving paracetamol against death rates involving other drugs, or non-drug suicide, was that this method would allow the researchers to see if the drop in paracetamol deaths followed overall trends in the poisoning or suicide rates or not. If the paracetamol death rate dropped following introduction of the new laws but the rates of other types of poisoning or suicide did not, then there would be a link between the new laws and a fall in paracetamol suicides. The researchers compared these death data within specific time periods before the end of 1998 (when the new laws on paracetamol pack size were introduced) and after. Overall, there were nearly 2,200 deaths involving paracetamol between 1993 and 2004. The number of deaths per year involving paracetamol dropped substantially when comparing the periods of time before the end of 1998 and after it. However, the number of deaths per year involving any drug, and the non-drug suicides, also fell during this period of time. When comparing the trends for paracetamol deaths with other poisoning or suicide deaths, the researchers did not find any statistical evidence that the fall in paracetamol deaths was any different to the overall trend in poisoning or suicide death rates. What Do These Findings Mean? Although the paracetamol death rate fell immediately following the new laws on pack size, this study suggests the link might just be coincidence. The researchers could not find any data supporting the idea that the new laws caused a drop in paracetamol deaths. However, this was an observational study, not a true experimental one: the researchers here were clearly not able to set up equivalent “experimental” and “control” groups for comparison. It is very difficult to prove or disprove conclusively that new laws such as this are, or are not, effective. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040105 Information is available from Medline Plus about suicide Wikipedia has an entry on paracetamol (note that Wikipedia is an internet encyclopedia anyone can edit) Information about regulation of drugs in the UK is available from the Medicines and Healthcare Regulatory Agency The Office for National Statistics provides key economic and social data about the UK, and is involved in many other important projects

This article, which grew out of conversations between a former drug rep and a physician who researches pharmaceutical marketing, reveals the strategies used by reps to manipulate physician prescribing.

Background Mild cognitive impairment (MCI) refers to a transitional zone between normal ageing and dementia. Despite the uncertainty regarding the definition of MCI as a clinical entity, clinical trials have been conducted in the attempt to study the role of cholinesterase inhibitors (ChEIs) currently approved for symptomatic treatment of mild to moderate Alzheimer disease (AD), in preventing progression from MCI to AD. The objective of this review is to assess the effects of ChEIs (donepezil, rivastigmine, and galantamine) in delaying the conversion from MCI to Alzheimer disease or dementia. Methods and Findings The terms “donepezil”, “rivastigmine”, “galantamine”, and “mild cognitive impairment” and their variants, synonyms, and acronyms were used as search terms in four electronic databases (MEDLINE, EMBASE, Cochrane, PsycINFO) and three registers: the Cochrane Collaboration Trial Register, Current Controlled Trials, and ClinicalTrials.gov. Published and unpublished studies were included if they were randomized clinical trials published (or described) in English and conducted among persons who had received a diagnosis of MCI and/or abnormal memory function documented by a neuropsychological assessment. A standardized data extraction form was used. The reporting quality was assessed using the Jadad scale. Three published and five unpublished trials met the inclusion criteria (three on donepezil, two on rivastigmine, and three on galantamine). Enrolment criteria differed among the trials, so the study populations were not homogeneous. The duration of the trials ranged from 24 wk to 3 y. No significant differences emerged in the probability of conversion from MCI to AD or dementia between the treated groups and the placebo groups. The rate of conversion ranged from 13% (over 2 y) to 25% (over 3 y) among treated patients, and from 18% (over 2 y) to 28% (over 3 y) among those in the placebo groups. Only for two studies was it possible to derive point estimates of the relative risk of conversion: 0.85 (95% confidence interval 0.64–1.12), and 0.84 (0.57–1.25). Statistically significant differences emerged for three secondary end points. However, when adjusting for multiple comparisons, only one difference remained significant (i.e., the rate of atrophy in the whole brain). Conclusions The use of ChEIs in MCI was not associated with any delay in the onset of AD or dementia. Moreover, the safety profile showed that the risks associated with ChEIs are not negligible. The uncertainty regarding MCI as a clinical entity raises the question as to the scientific validity of these trials., A systematic review of trials of cholinesterase inhibitors for preventing transition of mild cognitive impairment (MCI) to dementia, conducted by Roberto Raschetti and colleagues, found no difference between treatment and control groups and concluded that uncertainty regarding the definition of MCI casts doubts on the validity of such trials., Editors' Summary Background. Worldwide, more than 24 million people have dementia, a group of brain disorders characterized by an irreversible decline in memory, problem solving, communication, and other “cognitive” functions. The commonest form of dementia is Alzheimer disease (AD). The risk of developing AD increases with age—AD is rare in people younger than 65 but about half of people over 85 years old have it. The earliest symptom of AD is usually difficulty in remembering new information. As the disease progresses, patients may become confused and have problems expressing themselves. Their behavior and personality can also change. In advanced AD, patients need help with daily activities like dressing and eating, and eventually lose their ability to recognize relatives and to communicate. There is no cure for AD but a class of drugs called “cholinesterase inhibitors” can sometimes temporarily slow the worsening of symptoms. Three cholinesterase inhibitors—donepezil, rivastigmine, and galantamine—are currently approved for use in mild-to-moderate AD. Why Was This Study Done? Some experts have questioned the efficacy of cholinesterase inhibitors in AD, but other experts and patient support groups have called for these drugs to be given to patients with a condition called mild cognitive impairment (MCI) as well as to those with mild AD. People with MCI have memory problems that are more severe than those normally seen in people of their age but no other symptoms of dementia. They are thought to have an increased risk of developing AD, but it is not known whether everyone with MCI eventually develops AD, and there is no standardized way to diagnose MCI. Despite these uncertainties, several clinical trials have investigated whether cholinesterase inhibitors prevent progression from MCI to AD. In this study, the researchers have assessed whether the results of these trials provide any evidence that cholinesterase inhibitors can prevent MCI progressing to AD. What Did the Researchers Do and Find? The researchers conducted a systematic review of the medical literature to find trials that had addressed this issue, which met criteria that they had defined clearly in advance of their search. They identified three published and five unpublished randomized controlled trials (studies in which patients randomly receive the test drug or an inactive placebo) that investigated the effect of cholinesterase inhibitors on the progression of MCI. The researchers obtained the results of six of these trials—four examined the effect of cholinesterase inhibitors on the conversion of MCI to clinically diagnosed AD or dementia (the primary end point); all six examined the effect of the drugs on several secondary end points (for example, individual aspects of cognitive function). None of the drugs produced a statistically significant difference (a difference that is unlikely to have happened by chance) in the probability of progression from MCI to AD. The only statistically significant secondary end point after adjustment for multiple comparisons (when many outcomes are considered, false positive results can occur unless specific mathematical techniques are used to prevent this problem) was a decrease in the rate of brain shrinkage associated with galantamine treatment. More patients treated with cholinesterase inhibitors dropped out of trials because of adverse effects than patients given placebo. Finally, in the one trial that reported all causes of deaths, one participant who received placebo and six who received galantamine died. What Do These Findings Mean? These findings suggest that the use of cholinesterase inhibitors is not associated with any delay in the onset of clinically diagnosed AD or dementia in people with MCI. They also show that the use of these drugs has no effect on most surrogate (substitute) indicators of AD but that the risks associated with their use are not negligible. However, because MCI has not yet been clearly defined as a clinical condition that precedes dementia, some (even many) of the patients enrolled into the trials that the researchers assessed may not actually have had MCI. Thus, further clinical trials are needed to clarify whether cholinesterase inhibitors can delay the progression of MCI to dementia, but these additional trials should not be done until the diagnosis of MCI has been standardized. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040338. An essay by Matthews and colleagues, in the October 2007 issue of PLoS Medicine, discusses how mild cognitive impairment is currently diagnosed The US Alzheimer's Association provides information about all aspects of Alzheimer disease, including fact sheets on treatments for Alzheimer disease and on mild cognitive impairment The UK Alzheimer's Society provides information for patients and caregivers on all aspects of dementia, including drug treatments and mild cognitive impairment The UK charity DIPEx provides short video clips of personal experiences of care givers of people with dementia

Background Loperamide is widely used in adults for acute diarrhea. However, its use in children has been discouraged by the World Health Organization and the American Academy of Pediatrics owing to concerns over safety and efficacy in young children. Methods and Findings To assess the efficacy and adverse effects of loperamide compared with placebo for acute diarrhea in children, we reviewed Medline, EMBase, the Cochrane Central Register of Controlled Trials, and bibliographies of known clinical trials and of review articles, and we also interviewed key investigators in the field. We undertook a systematic review and meta-analysis of randomized controlled trials of children younger than 12 y of age with acute diarrhea, comparing loperamide with placebo. Included trials reported data on diarrhea duration or severity, or provided data on adverse effects. Compared with patients who received placebo, patients allocated to loperamide were less likely to continue to have diarrhea at 24 h (prevalence ratio 0.66, 95% confidence interval [CI]: 0.57 to 0.78), had a shorter duration of diarrhea by 0.8 d (95% CI: 0.7 to 0.9 d), and had a lower count of stools at 24 h (0.84, 95% CI: 0.77 to 0.92). Results were similar when random-effects summaries were estimated. Serious adverse events, defined as ileus, lethargy, or death, were reported in eight out of 927 children allocated to loperamide (0.9%, 95% CI: 0.4% to 1.7%). Serious adverse events were not reported in any of the 764 children allocated to placebo (0%, 95% CI: 0% to 0.5%). Among the children allocated to loperamide, serious adverse events were reported only among children younger than 3 y. Conclusions In children who are younger than 3 y, malnourished, moderately or severely dehydrated, systemically ill, or have bloody diarrhea, adverse events outweigh benefits even at doses ≤0.25 mg/kg/d. In children who are older than 3 y with no/minimal dehydration, loperamide may be a useful adjunct to oral rehydration and early refeeding., In seriously ill children under 3 years of age with diarrhea the adverse effects of loperamide outweighed the benefits, but the drug could be useful as part of treatment for other children., Editors' Summary Background. While diarrhea is often thought of as a mild, inconvenient condition, it is estimated that, worldwide, 1.6–2.5 million children under 5 y old die each year from diarrhea, most of them in developing countries. Dehydration is the key factor in the deaths of these children. In richer countries, diarrhea is rarely deadly, but it has been calculated that, in the United States, the annual national health-care cost associated with the condition amounts to around US$1.5 billion. Some of the cost results from the purchase of anti-diarrheal drugs. Loperamide is one of the most widely used of these drugs. In most countries, it can be obtained without a prescription. The use of loperamide is intended to reduce the frequency of bowel movements, but taking it will not lead to rehydration, nor will it kill the infectious organisms responsible for the condition. Why Was This Study Done? The World Health Organization and other health authorities have concerns that loperamide may not be effective in young children and that it may not be safe. In the United States, the Food and Drug Administration approves its use for children older than 2 y of age. The researchers wanted to know whether loperamide could play a useful part in treating diarrhea in children. What Did the Researchers Do and Find? They did not do any new work with children suffering from diarrhea. Instead, they searched the medical literature for previously conducted trials involving the use of loperamide. They used these previously conducted trials to estimate whether use of loperamide influenced the duration of diarrhea or the number of diarrheal stools in children under 12 y of age. They also used these trials to examine adverse effects of loperamide. In total they found 13 studies that met the criteria they had set for inclusion in their study. More than 900 children in these studies had been given loperamide for their diarrhea; each trial also had a control group of children whose treatment did not include loperamide. Most of the children in the studies had only mild diarrhea. The researchers found that, compared with children in the control groups, those treated with loperamide were less likely to continue to have diarrhea 24 h later, had a shorter duration of diarrhea, and had a lower count of diarrheal stools. However, eight of the children given loperamide and none of the control group did have serious adverse effects. All those who had serious adverse effects were less than 3 y of age. What Do These Findings Mean? The researchers concluded that if a child is less than 3 y of age, malnourished, moderately or severely dehydrated, or has bloody diarrhea, the risk of adverse events from loperamide treatment outweighs the benefits, even at low doses. In other children, loperamide may be a useful part of treatment. However, they advise that rehydrating the child (by giving fluids orally) and progressively returning him or her to a normal diet should still be the main focus in the treatment of childhood diarrhea. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040098. For advice on the treatment of diarrhea, visit the Web sites of BestTreatments (produced by BMJ Publications) and of FamilyDoctor (produced by the American Academy of Family Physicians) The World Health Organization has a Web page about diarrhea that gives a global perspective on this major cause of childhood death UNICEF (the children's organization of the United Nations) includes diarrhea in its Facts for Life series, which aims to provide parents and other caregivers with the information they need to save and improve children's lives; the messages contained in Facts for Life are based on the latest scientific findings, but are presented in nontechnical language

Background Malaysia's stable health care system is facing challenges with increasing medicine costs. To investigate these issues a survey was carried out to evaluate medicine prices, availability, affordability, and the structure of price components. Methods and Findings The methodology developed by the World Health Organization (WHO) and Health Action International (HAI) was used. Price and availability data for 48 medicines was collected from 20 public sector facilities, 32 private sector retail pharmacies and 20 dispensing doctors in four geographical regions of West Malaysia. Medicine prices were compared with international reference prices (IRPs) to obtain a median price ratio. The daily wage of the lowest paid unskilled government worker was used to gauge the affordability of medicines. Price component data were collected throughout the supply chain, and markups, taxes, and other distribution costs were identified. In private pharmacies, innovator brand (IB) prices were 16 times higher than the IRPs, while generics were 6.6 times higher. In dispensing doctor clinics, the figures were 15 times higher for innovator brands and 7.5 for generics. Dispensing doctors applied high markups of 50%–76% for IBs, and up to 316% for generics. Retail pharmacy markups were also high—25%–38% and 100%–140% for IBs and generics, respectively. In the public sector, where medicines are free, availability was low even for medicines on the National Essential Drugs List. For a month's treatment for peptic ulcer disease and hypertension people have to pay about a week's wages in the private sector. Conclusions The free market by definition does not control medicine prices, necessitating price monitoring and control mechanisms. Markups for generic products are greater than for IBs. Reducing the base price without controlling markups may increase profits for retailers and dispensing doctors without reducing the price paid by end users. To increase access and affordability, promotion of generic medicines and improved availability of medicines in the public sector are required., Drug price and availability data were collected from West Malaysian public sector facilities, private sector retail pharmacies, and dispensing doctors. Mark-ups were higher on generic drugs than on innovator brands., Editors' Summary Background. The World Health Organization has said that one-third of the people of the world cannot access the medicines they need. An important reason for this problem is that prices are often too high for people or government-funded health systems to afford. In developing countries, most people who need medicines have to pay for them out of their own pockets. Where the cost of drugs is covered by health systems, spending on medicines is a major part of the total healthcare budget. Governments use a variety of approaches to try to control the cost of drugs and make sure that essential medicines are affordable and not overpriced. According to the theory of “free market economics,” the costs of goods and services are determined by interactions between buyers and sellers and not by government intervention. However, free market economics does not work well at containing the costs of medicines, particularly new medicines, because new medicines are protected by patent law, which legally prevents others from making, using, or selling the medicine for a particular period of time. Therefore, without government intervention, there is nothing to help to push down prices. Why Was This Study Done? Malaysia is a middle-income country with a relatively effective public health system, but it is facing a rapid rise in drug costs. In Malaysia, medicine prices are determined by free-market economics, without any control by government. Government hospitals are expected to provide drugs free, but a substantial proportion of medicines are paid for by patients who buy them directly from private pharmacies or prescribing doctors. There is evidence that Malaysian patients have difficulties accessing the drugs they need and that cost is an important factor. Therefore, the researchers who wrote this paper wanted to examine the cost of different medicines in Malaysia, and their availability and affordability from different sources. What Did the Researchers Do and Find? In this research project, 48 drugs were studied, of which 28 were part of a “core list” identified by the World Health Organization as “essential drugs” on the basis of the global burden of disease. The remaining 20 reflected health care needs in Malaysia itself. The costs of each medicine were collected from government hospitals, private pharmacies, and dispensing doctors in four different regions of Malaysia. Data were collected for the “innovator brand” (made by the original patent holder) and for “generic” brands (an equivalent drug to the innovator brand, produced by a different company once the innovator brand no longer has an exclusive patent). The medicine prices were compared against international reference prices (IRP), which are the average prices offered by not-for-profit drug companies to developing countries. Finally, the researchers also compared the cost of the drugs with daily wages, in order to work out their “affordability.” The researchers found that, irrespective of the source of medicines, prices were on average very much higher than the international reference price, ranging from 2.4 times the IRP for innovator brands accessed through public hospitals, to 16 times the IRP for innovator brands accessed through private pharmacies. The availability of medicines was also very poor, with only 25% of generic medicines available on average through the public sector. The affordability of many of the medicines studied was again very poor. For example, one month's supply of ranitidine (a drug for stomach ulcers) was equivalent to around three days' wages for a low-paid government worker, and one month's supply of fluoxetine (an antidepressant) would cost around 26 days' wages. What Do These Findings Mean? These results show that essential drugs are very expensive in Malaysia and are not universally available. Many people would not be able to pay for essential medicines. The cost of medicines in Malaysia seems to be much higher than in areas of India and Sri Lanka, although the researchers did not attempt to collect data in order to carry out an international comparison. It is possible that the high cost and low availability in Malaysia are the result of a lack of government regulation. Overall, the findings suggest that the government should set up mechanisms to prevent drug manufacturers from increasing prices too much and thus ensure greater access to essential medicines. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040082. Read a related PLoS Medicine Perspective article by Suzanne Hill Information is available from the World Health Organization on Improving Access to Medicines Information on medicine prices is available from Health Action International Wikipedia has an entry on Patent (a type of intellectual property that is normally used to prevent other companies from selling a newly invented medicine). (Wikipedia is an internet encyclopedia anyone can edit.) The Drugs for Neglected Diseases Initiative is an international collaboration between public organizations that aims to develop drugs for people suffering from neglected diseases

Background Somatic genetic CDKN2A, TP53, and DNA content abnormalities are common in many human cancers and their precursors, including esophageal adenocarcinoma (EA) and Barrett's esophagus (BE), conditions for which aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) have been proposed as possible chemopreventive agents; however, little is known about the ability of a biomarker panel to predict progression to cancer nor how NSAID use may modulate progression. We aimed to evaluate somatic genetic abnormalities with NSAIDs as predictors of EA in a prospective cohort study of patients with BE. Methods and Findings Esophageal biopsies from 243 patients with BE were evaluated at baseline for TP53 and CDKN2A (p16) alterations, tetraploidy, and aneuploidy using sequencing; loss of heterozygosity (LOH); methylation-specific PCR; and flow cytometry. At 10 y, all abnormalities, except CDKN2A mutation and methylation, contributed to EA risk significantly by univariate analysis, ranging from 17p LOH (relative risk [RR] = 10.6; 95% confidence interval [CI] 5.2–21.3, p < 0.001) to 9p LOH (RR = 2.6; 95% CI 1.1–6.0, p = 0.03). A panel of abnormalities including 17p LOH, DNA content tetraploidy and aneuploidy, and 9p LOH was the best predictor of EA (RR = 38.7; 95% CI 10.8–138.5, p < 0.001). Patients with no baseline abnormality had a 12% 10-y cumulative EA incidence, whereas patients with 17p LOH, DNA content abnormalities, and 9p LOH had at least a 79.1% 10-y EA incidence. In patients with zero, one, two, or three baseline panel abnormalities, there was a significant trend toward EA risk reduction among NSAID users compared to nonusers (p = 0.01). The strongest protective effect was seen in participants with multiple genetic abnormalities, with NSAID nonusers having an observed 10-y EA risk of 79%, compared to 30% for NSAID users (p < 0.001). Conclusions A combination of 17p LOH, 9p LOH, and DNA content abnormalities provided better EA risk prediction than any single TP53, CDKN2A, or DNA content lesion alone. NSAIDs are associated with reduced EA risk, especially in patients with multiple high-risk molecular abnormalities., In a ten-year study of people with Barrett's esophagus, nonsteroidal anti-inflamatory drugs were associated with reduced risk of esophageal adenocarcinoma, especially in patients with multiple high-risk molecular abnormalities., Editors' Summary Background. Normally, the cells in the human body divide only when extra cells are needed, after an injury, for example. Sometimes, however, cells accumulate genetic changes (mutations) that allow them to divide uncontrollably to form a disorganized mass or tumor. If these altered cells also acquire mutations that allow them to spread around the body, a malignant tumor or cancer results. Scientists have identified numerous genetic changes that occur in tumors and are now investigating whether these molecular abnormalities can be used as “biomarkers” to choose the best treatments for patients, to identify who will benefit from cancer-prevention strategies, to detect cancer early, and to predict which cancers are most likely to become life-threatening. This last application is particularly important for cancers with a well-defined premalignant stage. Because the cells in premalignant tissues have acquired some of the genetic changes required for cancer development, they are more likely to become malignant than normal cells. Barrett's esophagus, for example, is a premalignant disorder of the muscular tube that takes food from the mouth to the stomach. People with Barrett's esophagus are much more likely to develop esophageal cancer than the general population. Why Was This Study Done? Esophageal cancer is often incurable by the time it is detected, so it would be helpful to know which people with Barrett's esophagus are most likely to develop esophageal cancer—only 1 in 200 of them develop cancer each year. In this study, the researchers evaluated whether a panel of genetic alterations could identify this subset of patients. They also investigated whether the regular use of aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) affects the risk of developing esophageal cancer in people with Barrett's esophagus—other evidence suggests that NSAIDs may help to prevent several types of cancer, including esophageal cancer. What Did the Researchers Do and Find? The researchers took esophageal tissue samples from patients with Barrett's esophagus and looked for alterations in the genes encoding the tumor-suppressor proteins TP53 and CDKN2A. These proteins normally stop cells dividing but are often inactivated in cancer cells by mutation of one of the two gene copies that encode each of them and also loss of the other copy (so-called “loss of heterozygosity” or LOH). The researchers also looked for changes in the cellular DNA content of the samples (tumor cells often contain unusual amounts of DNA) and asked the study participants about their NSAID use before waiting to see which participants developed esophageal cancer. After 10 y, the participants whose tissue samples had LOH of the short arms (p) of Chromosome 17 or 9 (the sites of the genes encoding TP53 and CDKN2A, respectively), or an altered DNA content, were more likely to have developed esophageal cancer than those without these abnormalities; those whose samples contained all three abnormalities had the highest risk of developing esophageal cancer. Overall, just 12% of patients with no abnormalities but nearly 80% of patients with three abnormalities developed esophageal cancer. NSAID use reduced the risk of cancer development in all the participants, but its effect was greatest in those with three genetic abnormalities. What Do These Findings Mean? These findings suggest that the combined measurement of 17pLOH, 9pLOH, and cellular DNA content might be a powerful way to identify those patients with Barrett's esophagus who are most likely to develop esophageal cancer. They also suggest that NSAID use is associated with a reduced risk of esophageal cancer, particularly in patients with multiple genetic abnormalities. Because very few participants developed cancer during the study, these results need confirming in more patients. Also, the ability of NSAIDs to prevent the progression of Barrett's esophagus to esophageal cancer needs testing in multicenter randomized trials; the use of the panel of abnormalities described here to identify the people with Barrett's esophagus most at risk of developing esophageal cancer should facilitate such studies. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040067. CancerQuest information from Emory University (Atlanta, Georgia, United States) on cancer biology, including the role of tumor suppressor proteins US National Cancer Institute patient and physician information on esophageal cancer and its prevention MedlinePlus encyclopedia pages on Barrett's esophagus and esophageal cancer Cancerbackup (UK charity) patient information on esophageal cancer and Barrett's esophagus

Background Paracetamol (acetaminophen) poisoning is the leading cause of acute liver failure in Great Britain and the United States. Successful interventions to reduced harm from paracetamol poisoning are needed. To achieve this, the government of the United Kingdom introduced legislation in 1998 limiting the pack size of paracetamol sold in shops. Several studies have reported recent decreases in fatal poisonings involving paracetamol. We use interrupted time-series analysis to evaluate whether the recent fall in the number of paracetamol deaths is different to trends in fatal poisoning involving aspirin, paracetamol compounds, antidepressants, or nondrug poisoning suicide. Methods and Findings We calculated directly age-standardised mortality rates for paracetamol poisoning in England and Wales from 1993 to 2004. We used an ordinary least-squares regression model divided into pre- and postintervention segments at 1999. The model included a term for autocorrelation within the time series. We tested for changes in the level and slope between the pre- and postintervention segments. To assess whether observed changes in the time series were unique to paracetamol, we compared against poisoning deaths involving compound paracetamol (not covered by the regulations), aspirin, antidepressants, and nonpoisoning suicide deaths. We did this comparison by calculating a ratio of each comparison series with paracetamol and applying a segmented regression model to the ratios. No change in the ratio level or slope indicated no difference compared to the control series. There were about 2,200 deaths involving paracetamol. The age-standardised mortality rate rose from 8.1 per million in 1993 to 8.8 per million in 1997, subsequently falling to about 5.3 per million in 2004. After the regulations were introduced, deaths dropped by 2.69 per million (p = 0.003). Trends in the age-standardised mortality rate for paracetamol compounds, aspirin, and antidepressants were broadly similar to paracetamol, increasing until 1997 and then declining. Nondrug poisoning suicide also declined during the study period, but was highest in 1993. The segmented regression models showed that the age-standardised mortality rate for compound paracetamol dropped less after the regulations (p = 0.012) but declined more rapidly afterward (p = 0.031). However, age-standardised rates for aspirin and antidepressants fell in a similar way to paracetamol after the regulations. Nondrug poisoning suicide declined at a similar rate to paracetamol after the regulations were introduced. Conclusions Introduction of regulations to limit availability of paracetamol coincided with a decrease in paracetamol-poisoning mortality. However, fatal poisoning involving aspirin, antidepressants, and to a lesser degree, paracetamol compounds, also showed similar trends. This raises the question whether the decline in paracetamol deaths was due to the regulations or was part of a wider trend in decreasing drug-poisoning mortality. We found little evidence to support the hypothesis that the 1998 regulations limiting pack size resulted in a greater reduction in poisoning deaths involving paracetamol than occurred for other drugs or nondrug poisoning suicide.

Background The response to the next influenza pandemic will likely include extensive use of antiviral drugs (mainly oseltamivir), combined with other transmission-reducing measures. Animal and in vitro studies suggest that some strains of influenza may become resistant to oseltamivir while maintaining infectiousness (fitness). Use of antiviral agents on the scale anticipated for the control of pandemic influenza will create an unprecedented selective pressure for the emergence and spread of these strains. Nonetheless, antiviral resistance has received little attention when evaluating these plans. Methods and Findings We designed and analyzed a deterministic compartmental model of the transmission of oseltamivir-sensitive and -resistant influenza infections during a pandemic. The model predicts that even if antiviral treatment or prophylaxis leads to the emergence of a transmissible resistant strain in as few as 1 in 50,000 treated persons and 1 in 500,000 prophylaxed persons, widespread use of antivirals may strongly promote the spread of resistant strains at the population level, leading to a prevalence of tens of percent by the end of a pandemic. On the other hand, even in circumstances in which a resistant strain spreads widely, the use of antivirals may significantly delay and/or reduce the total size of the pandemic. If resistant strains carry some fitness cost, then, despite widespread emergence of resistance, antivirals could slow pandemic spread by months or more, and buy time for vaccine development; this delay would be prolonged by nondrug control measures (e.g., social distancing) that reduce transmission, or use of a stockpiled suboptimal vaccine. Surprisingly, the model suggests that such nondrug control measures would increase the proportion of the epidemic caused by resistant strains. Conclusions The benefits of antiviral drug use to control an influenza pandemic may be reduced, although not completely offset, by drug resistance in the virus. Therefore, the risk of resistance should be considered in pandemic planning and monitored closely during a pandemic., Emergence of oseltamivir-resistant influenza strains during a pandemic is likely given the heightened selective pressure if the drug is widely used. Marc Lipsitch and colleagues suggest that resistance would reduce but not completely offset the drug's benefits for pandemic control., Editors' Summary Background. Governments and health authorities worldwide are planning how they would best prepare for and deal with a future influenza pandemic. Seasonal influenza is thought to affect between 5% and 15% of the population worldwide each year. Most people who get influenza recover within a couple of weeks without lasting effects, but a small proportion of patients, mostly young children and elderly people, experience serious complications that can be fatal. An influenza pandemic happens when new variants of the influenza virus emerge against which little immunity exists in the general population. Pandemic influenza strains are transmitted more rapidly than seasonal strains, often sweep across several countries or continents, and make more people ill. There are drugs that can treat and prevent influenza. One of them, oseltamivir (Tamiflu) is an antiviral drug that works by preventing viral particles from being released by infected human cells. Stockpiling large amounts of oseltamivir and related drugs with the intent to treat a large fraction of the population is a key part of pandemic preparedness of many countries. However, it is known that influenza viruses can develop resistance to these drugs. Why Was This Study Done? It is not clear how the emergence of oseltamivir-resistant influenza strains would affect the course of any future influenza pandemic. Much research in this area has focused on how likely the new strains are to emerge in the first place, rather than on how they might spread once they had emerged. In the context of an influenza pandemic, antiviral drugs would be used in a large proportion of the population, likely driving the selection and spread of resistant viruses. For this study, the researchers wanted to estimate the likely impact of resistant strains during an influenza pandemic. What Did the Researchers Do and Find? These researchers set up a mathematical model (i.e., simulations done on a computer) to mimic the spread of influenza. They then fed a set of assumptions into the computer. These included information about the rate of transmission of influenza from one person to another; what proportion of people would receive antiviral drugs for prophylaxis or treatment; how likely the drugs would be to successfully treat or prevent infection; and in what proportion of people the virus might become resistant to drugs. The modeling led to three main predictions. First, it predicted that widespread use of antiviral drugs such as oseltamivir could quickly lead to the spread of resistant viruses, even if resistant strains emerged only rarely. Second, even with resistant strains circulating, prophylaxis and treatment with oseltamivir would still delay the spread of the pandemic and reduce its total size. Third, nondrug interventions (such as social isolation and school closures) would further reduce the number of cases, but a higher proportion of cases would be caused by resistant strains if these control measures were used. What Do These Findings Mean? These findings suggest that, in the event of a future influenza pandemic for which antiviral drugs are used, there is a risk of resistance emerging and resistant strains causing illness in a substantial number of people. This would counteract the benefits of antiviral drugs but not eliminate those benefits entirely. Like all modeling studies, this one relies on realistic assumptions being entered into the model, and it is hard to know closely the model will mimic a real-life situation until the properties of an actual pandemic strain are known. Most studies, including this one, suggest that in the event of a pandemic, antiviral drugs will have an overall beneficial impact on reducing death rates and adverse health outcomes. However, given the sizeable effects of resistance suggested here, its role should be considered in pandemic planning. This includes surveillance that can detect emergence and spread of resistant strains. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0040015. World Health Organization: information on pandemic preparedness World Health Organization: fact sheets on influenza Information from the UK Health Protection Agency on pandemic influenza US government website on both pandemic flu and avian flu (information provided by the US Department of Health and Human Services)

Background HIV protease inhibitor (PI) therapy results in the rapid selection of drug resistant viral variants harbouring one or two substitutions in the viral protease. To combat PI resistance development, two approaches have been developed. The first is to increase the level of PI in the plasma of the patient, and the second is to develop novel PI with high potency against the known PI-resistant HIV protease variants. Both approaches share the requirement for a considerable increase in the number of protease mutations to lead to clinical resistance, thereby increasing the genetic barrier. We investigated whether HIV could yet again find a way to become less susceptible to these novel inhibitors. Methods and Findings We have performed in vitro selection experiments using a novel PI with an increased genetic barrier (RO033-4649) and demonstrated selection of three viruses 4- to 8-fold resistant to all PI compared to wild type. These PI-resistant viruses did not have a single substitution in the viral protease. Full genomic sequencing revealed the presence of NC/p1 cleavage site substitutions in the viral Gag polyprotein (K436E and/or I437T/V) in all three resistant viruses. These changes, when introduced in a reference strain, conferred PI resistance. The mechanism leading to PI resistance is enhancement of the processing efficiency of the altered substrate by wild-type protease. Analysis of genotypic and phenotypic resistance profiles of 28,000 clinical isolates demonstrated the presence of these NC/p1 cleavage site mutations in some clinical samples (codon 431 substitutions in 13%, codon 436 substitutions in 8%, and codon 437 substitutions in 10%). Moreover, these cleavage site substitutions were highly significantly associated with reduced susceptibility to PI in clinical isolates lacking primary protease mutations. Furthermore, we used data from a clinical trial (NARVAL, ANRS 088) to demonstrate that these NC/p1 cleavage site changes are associated with virological failure during PI therapy. Conclusions HIV can use an alternative mechanism to become resistant to PI by changing the substrate instead of the protease. Further studies are required to determine to what extent cleavage site mutations may explain virological failure during PI therapy., Changes in the cleavage site of the Gag substrate for the HIV protease can convey resistance to protease inhibitors and might contribute to virologic failure during therapy that includes these drugs., Editors' Summary Background. Twenty-five years ago, infection with the human immunodeficiency virus (HIV)—the causative agent of AIDS—was a death sentence. However, drugs that attack various stages of the HIV life cycle were soon developed that, although not curing the infection, kept it in check when used in combination and greatly increased the life expectancy of people infected with HIV. Unfortunately, viruses resistant to these drugs have rapidly emerged and antiviral therapy now fails in many patients. The use of HIV protease inhibitors (PIs) in combination therapies, for example, has led to the stepwise selection of viral variants resistant to these drugs. Resistance is first acquired when the viral protease changes so that PIs no longer bind to it and inhibit it efficiently. These changes often reduce the efficiency with which the protease binds its substrates—polyproteins called Gag and GagPol that it chops up into smaller proteins to make new viral particles. So the next step is the accumulation of changes elsewhere in the protease that make it work better, and sometimes changes in its substrate that make it easier to cut; these compensatory changes do not directly affect viral resistance to PIs. Why Was This Study Done? To prevent viruses with resistance to PIs emerging, drug doses are kept high in patients and new PIs are being developed with high potency against known PI-resistant HIV variants. Both approaches set a “high genetic barrier” to the development of PI resistance by ensuring that HIV has to incorporate many changes in its protease to become resistant. But, the HIV genome naturally changes—mutates—very rapidly, so novel HIV variants could emerge that are less susceptible to the new potent PIs without the virus having to leap this high genetic barrier. In this study, the researchers have investigated whether HIV can find an alternative route to PI resistance that does not involve the introduction of multiple changes into its protease. What Did the Researchers Do and Find? The researchers took wild-type HIV and treated it in the laboratory with a new PI regimen that has a high genetic barrier. By gradually increasing its concentration, the researchers selected three viral populations that were able to grow in 4- to 8-fold higher concentrations of the PI than wild-type virus. None of these populations had mutations in the viral protease. Instead, they all had mutations near one of the sites—the NC/p1 site—where the protease normally cuts the Gag polyprotein. These mutations, the researchers report, enhanced the overall efficiency with which the wild-type protease cleaved the polyprotein, and a selection experiment with another PI showed that the development of PI resistance through alterations near the NC/p1 cleavage site was not unique to one PI. The researchers also investigated the potential clinical significance of this new drug resistance mechanism by looking for the same mutations in nearly 30,000 patient samples. Many of the samples did indeed have these mutations. Finally, they showed that mutations at the NC/p1 cleavage site were associated with virological failure (increased viral replication) during PI therapy in an ongoing clinical trial. What Do These Findings Mean? These results suggest that increased polyprotein processing because of mutations in the natural substrate of the HIV protease might be a new mechanism by which HIV can become resistant to PIs. This strategy, which occurs in the laboratory and in patients, allows HIV to develop PI resistance without the need for multiple changes in its protease and so avoids the high genetic barrier to resistance that new PIs provide. Clinical studies are now needed to test which of the mutations seen in this study contribute to virological failure, whether the degree of this failure is clinically relevant, and whether these substrate mutations enhance the effect of protease mutations. If the clinical importance of the new mechanism is confirmed, genetic examination of both the polyprotein and the protease will be needed when trying to figure out why a PI-containing therapy is failing in individual patients. Furthermore, it will be necessary to test whether this mechanism can contribute to the development of resistance when evaluating new drugs. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0040036. US National Institute of Allergy and Infectious Diseases factsheet on HIV infection and AIDS US Department of Health and Human Services information on AIDS US Centers for Disease Control and Prevention information on HIV/AIDS Aidsmap information on HIV and AIDS provided by the charity NAM BioAfrica, Bioinformatics for HIV Research, information on HIV-1 protease cleavage sites

This month's PLoS Medicine publishes a paper describing the results of a very early drug discovery study. The nature of early drug development is to identify many promising compounds, only a small number of which eventually make it into routine treatment. Consequently, there are many more papers reporting promising leads in early drug development than ones that report efficacy in large clinical trials. Because of this natural attrition, medical journals (including this one) are often reluctant to publish intriguing results from the early stages of drug discovery. However, PLoS Medicine occasionally does publish such reports, and the manuscript by Dominique Mazier and colleagues [1] in this issue is an example. What made us and our advisers select this paper above the many similar ones we receive? As editors, we ask several general questions about any submitted manuscript: how important is the research question (both globally and in relation to the journal's audience); what is the likelihood of the conclusions holding up over time (and when is it worth publishing preliminary results that would be important if confirmed but where confirmation is uncertain); and, for a highly selective general medical journal, do the results represent a substantial advance—be it in understanding pathogenesis, suggesting treatment options, or having implications for public health. More specifically, for drug development papers, questions we consider include: how substantial is the disease burden that the drug would treat; are any treatments currently available (or do the available treatments have serious limitations); has a novel or interesting mechanism been developed; (or was a novel system used in the development of the drug); and finally, is there a realistic path to clinical development? Malaria is clearly a topic of great relevance to PLoS Medicine's mission (of publishing papers on the diseases causing a high global burden of disease), and to our authors and readers. A substantial number of papers submitted to us concern malaria, and the 44 articles of all types on malaria that we have published have been cumulatively downloaded more than 100,000 times. The World Health Organization estimates that malaria is responsible for more than 1 million deaths per year, most of them young children living in Africa (see http://www.who.int/mediacentre/factsheets/fs094/en/). A recent PLoS Medicine paper by Mathers and Loncar [2] reported that malaria was the 12th leading cause of death worldwide in 2002. We also know there are substantial limitations of current treatments for malaria; resistance to antimalarial drugs is an increasing problem. Therefore, the development of a new drug, especially one targeting a stage of the parasite life cycle upon which very few other drugs act, is of great interest. The paper by Mazier and colleagues describes the very early stages of such a development by identifying a novel compound against the liver stage of malarial parasites. Before Plasmodium spp. can cause the symptoms of malaria by multiplying in the bloodstream, the parasites must pass through the liver. Most current drugs target the blood stages. Hopefully, one day malarial disease might be prevented by an effective vaccine, but it will probably be many years before a vaccine that works by killing parasites at the liver stages of development is available. Another option for prevention would be drugs that act in the few days between a mosquito's inoculation of a patient with sporozoites and the time when parasites escape from the liver and develop into the blood stages of disease. In severe infections, such as those caused by P. falciparum, all parasites are released from liver cells after a few days, leaving none behind. But some Plasmodium species (vivax and ovale) can remain in liver cells for months, only re-emerging after the first wave of blood-stage parasites has produced fevers and thus eluding drugs inactive against liver stages. In the paper published in this issue, Carraz and colleagues applied a methodology for screening compounds active against the liver stages of P. falciparum and identified an inhibitor from aqueous extracts of Madagascan plants growing in eastern rain forests. Few existing drugs kill liver stages of malarial parasites: two such drugs licensed at the moment are primaquine (an 8-aminoquinoline derivative) and the combination of atovaquone–proguanil. (Tafenoquine and bulaquine, structural relatives of primaquine, are not yet licensed.) A disadvantage of the 8-aminoquinolines is the toxicity caused by haemolysis of red blood cells in patients with some types of G6PD deficiency, a condition frequent in African populations. In addition to the actual discovery, the technical aspects of this paper are worthy of note. One problem that has beset drug discovery in malaria is the difficulty of culturing the liver stage of the parasite in vitro. The effectiveness of the 8-aminoquinoline derivatives in killing liver stages was discovered well before the first cultures of blood stage parasites became possible in 1976. Since then, several other stages of development have been cultured in vitro, but culturing these stages is technically more challenging than the blood stages. Hence, the work of Mazier and colleagues can also be seen as a technical achievement, as their screening depended on a source of sporozoites and primary hepatocyte cultures established from liver biopsies. Antimalarial efficacy of one plant, Strychnopsis thouarsii, was initially assayed by experiments on P. yoelii (a rodent malaria infection) cultured in mouse hepatocytes. An extract with antimalarial activity in the lower end of the micromolar range was further analysed and structural analysis of the active chemical found a morphinan core that was chemically modified to give N-cyclopentyl (NCP)-tazopsine. This semi-synthetic derivative was shown to have a higher selectivity for hepatic parasites, compared with blood stages, and was also less toxic to host cells than the parent compound. Further experiments showed that in vivo efficacy against sporozoite challenge with P. yoelii was confirmed and found to be best with NCP-tazopsine. Neither blood stages nor gametocytes were killed, confirming the unique hepatic selectivity of this class of antimalarials. One incidental but practical advantage of this selectivity of tazopsines, which is highlighted by the authors, is a diminished chance of selecting drug resistance because liver-stage parasites are much less numerous than blood-stage parasites. But, even having acknowledged this study's merits, one might still ask whether it is reasonable for a general medical journal to devote limited publication resources to such an early-phase drug study. We would argue that, as failure to produce an effective drug is a common event, we should be prepared to accept a fair amount of uncertainty in such papers, especially those presenting technical advances, whether or not the particular drug in question succeeds. And the compound that is the subject of this study has promise. Inhibitors of malaria not only have to cross multiple biological membranes to reach intra-hepatic parasites, but also have to elude metabolism and degradation by the very liver cells that host the parasite. Tazopsines have overcome some of these hurdles. The next stage of their development will be optimization of the chemically tractable lead inhibitor using screening for efficacy against liver stages of infection. Studies of tazopsines on P. vivax and P. ovale will also be of interest. A truly selective drug would be a very welcome tool in the rather limited current armamentarium against Plasmodium parasites. Gambling publication resources on such an outcome seems a reasonable decision.

Background Skin atrophy is a common manifestation of aging and is frequently accompanied by ulceration and delayed wound healing. With an increasingly aging patient population, management of skin atrophy is becoming a major challenge in the clinic, particularly in light of the fact that there are no effective therapeutic options at present. Methods and Findings Atrophic skin displays a decreased hyaluronate (HA) content and expression of the major cell-surface hyaluronate receptor, CD44. In an effort to develop a therapeutic strategy for skin atrophy, we addressed the effect of topical administration of defined-size HA fragments (HAF) on skin trophicity. Treatment of primary keratinocyte cultures with intermediate-size HAF (HAFi; 50,000–400,000 Da) but not with small-size HAF (HAFs; 400,000 Da) induced wild-type (wt) but not CD44-deficient (CD44−/−) keratinocyte proliferation. Topical application of HAFi caused marked epidermal hyperplasia in wt but not in CD44−/− mice, and significant skin thickening in patients with age- or corticosteroid-related skin atrophy. The effect of HAFi on keratinocyte proliferation was abrogated by antibodies against heparin-binding epidermal growth factor (HB-EGF) and its receptor, erbB1, which form a complex with a particular isoform of CD44 (CD44v3), and by tissue inhibitor of metalloproteinase-3 (TIMP-3). Conclusions Our observations provide a novel CD44-dependent mechanism for HA oligosaccharide-induced keratinocyte proliferation and suggest that topical HAFi application may provide an attractive therapeutic option in human skin atrophy., Mouse and human data suggest that topical application of intermediate-size hyaluronate fragments holds therapeutic potential for skin atrophy., Editors' Summary Background. Time wreaks many changes in the human body but the skin is where one of the first visible signs of aging—wrinkles—occurs. The skin consists of three main layers. The outermost layer is the epidermis. It is the thickness of a sheet of paper and forms a barrier that prevents the body losing water or infectious agents entering it. The cells in the epidermis are mainly keratinocytes. These specialized skin cells are continually produced at the base of the epidermis. From there, they move toward the skin's surface where they are shed. The middle layer is the dermis. It is about ten times thicker than the epidermis and contains the blood vessels that feed the skin, nerves, sebaceous glands, and hair follicles. The final, subcutaneous layer contains sweat glands, some hair follicles, blood vessels and fat. The dermis contains collagen fibers that support the skin and elastin fibers that provide flexibility. Human skin begins to age in early adulthood. By the time a person is 80 years old, their epidermis may be half its original thickness because of decreased keratinocyte proliferation. The dermis also thins, and loss of collagen and elastin fibers means that the skin becomes less elastic. The gradual loss of epidermis and dermis—skin atrophy—is clinically important because aging skin is more fragile and heals slower than young skin and is also prone to ulceration. Why Was This Study Done? No one knows why skin atrophy occurs, but it is becoming more common as people live longer, and there is no effective treatment for it. One characteristic of atrophic skin is that, compared to normal skin, it contains less hyaluronate (also called hyaluronan and hyaluronic acid)—a large carbohydrate component of the extracellular matrix, the material that surrounds cells. It also contains less CD44, a cell-surface protein that interacts with hyaluronate. This interaction can stimulate cell proliferation and migration. Given these observations, in this study the researchers have investigated whether treating atrophic skin with fragments of hyaluronate might counteract atrophy. What Did the Researchers Do and Find? The researchers isolated keratinocytes from normal mice and from CD44-deficient mice (CD44−/− mice) and treated them with different sized fragments of hyaluronate. Intermediate sized hyaluronate fragments (so-called HAFi) but not large or small fragments increased the proliferation of normal keratinocytes but not CD44−/− keratinocytes. This suggests that proliferation in response to HAFi is CD44-dependent. Similarly, a cream of HAFi applied to the backs of normal mice caused thickening of the epidermal layer but had no effect on CD44−/− mice. Finally, topical application of HAFi for one month caused skin thickening and clinical improvement in six people with skin atrophy but had no effect on normal human skin. The collagen, elastic fiber, and blood vessel content of the dermis also increased in treated patients. By using antibodies to block the function of various proteins, the researchers also discovered that heparin-binding epidermal growth factor (HB-EGF, a protein that stimulates keratinocyte proliferation), erbB1 (a cell-surface protein that binds HB-EGF), and matrix metalloproteinases (proteins that activate HB-EGF) are all required for the stimulation of keratinocyte proliferation by HAFi. What Do These Findings Mean? Taken together, these results provide the first indication that application of HAFi to atrophic skin might be useful therapeutically. The absence of any effect on normal human skin is reassuring but puzzling given the thickening seen in normal mouse skin, so this finding needs confirmation before hyaluronate fragments are used clinically. Longer trials in more people are also needed to characterize the clinical effects fully. Finally, the mechanism by which hyaluronate fragments have their effect needs to be studied in more depth. Such studies might reveal other potential therapeutic options for the treatment of skin atrophy. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030493. MedlinePlus encyclopedia entry on aging changes in skin US National Institute on Aging, patient information on skin care and aging American Academy of Dermatology, patient information on aging skin Information on CD44, the hyaluronan receptor, provided by Glycoforum a source of information on glycobiology Wikpedia pages on skin and on hyaluronan (note that Wikipedia is a free online encyclopedia that anyone can edit)

This Health in Action provides recommendations for improving education for health professionals about pharmaceutical and device promotion, which includes any activity that can increase sales of pharmaceuticals or devices. The recommendations were produced by an iterative E-mail discussion among representatives of four organizations: the American Medical Student Association, Healthy Skepticism Inc., No Free Lunch, and PharmAware (Box 1). Box 1. The Four Organizations Calling for Action American Medical Student Association (http://www.amsa.org) An association of nearly 60,000 doctors-in-training with aims including: improving health care and healthcare delivery to all people and promoting active improvement in medical education. Healthy Skepticism Inc. (http://www.healthyskepticism.org) An international organization aiming to improve health by reducing harm from misleading pharmaceutical promotion. No Free Lunch (http://www.nofreelunch.org, http://www.nofreelunch.uk, http://www.nograziepagoio.it) An international network aiming to improve patient care by encouraging health care providers to practice medicine on the basis of scientific evidence rather than on the basis of pharmaceutical promotion. PharmAware (http://www.pharmaware.co.uk) A group of British medical students who aim to change doctors' relationships with the pharmaceutical industry. We hope these recommendations will inform, stimulate, and support educators of health professionals to develop improved education about pharmaceutical and device promotion. We will survey educators to seek their views on these recommendations.

The new study by Boyle and colleagues provides important data on basic science mechanisms involved in pain and inflammation [1]. Their data, along with that from previous studies, provides further basic scientific evidence documenting p38–TNF-alpha interactions, and suggests that spinal p38 or spinal TNF-alpha blockade may have clinical relevance [1,2]. The present study documents that p38 activation may be occurring predominantly in microglia. The present study, therefore, joins other recent work which suggests the importance of p38-glial-TNF-alpha interactions in neuroinflammation and synaptic signaling [3–6]. This increasing evidence may have clinical relevance not only to arthritis pain, but also to the pathogenesis of various forms of neuropathic pain and Alzheimer disease [1–8]. Because the present study suggests that spinal delivery may be more effective than systemic delivery when attempting to intervene in spinally-mediated inflammatory mechanisms, the authors note the potential importance of developing compounds that may bypass the blood-brain barrier. The present author speculates that the rapid and significant clinical effects noted following perispinal administration of etanercept in small pilot studies suggest that perispinal administration of p38 inhibitors may also allow these compounds to reach the spinal cord and dorsal root ganglia in therapeutically effective amounts [7,8]. It is hypothesized that this may be possible via passage through the vertebral portion of the cerebrospinal venous system, and this may explain the efficacy of perispinal etanercept in the above cited studies [7–9]. Previous studies have documented that epidural administration of large molecules may result in delivery to the endoneurial space [10]. This evidence, along with the basic scientific evidence provided by the present study of the potential clinical importance of spinal delivery, supports consideration of investigation of this novel route of administration.

Background to the debate: Isotretinoin is an effective treatment for severe acne, a condition which can be physically, emotionally, and socially disabling. Because the drug is teratogenic, causing severe birth defects, women taking the drug are directed to avoid pregnancy. In the United States, a series of risk reduction programs have been implemented that aim to prevent pregnant women from taking the drug and to prevent women taking it from getting pregnant. The most recent, and most stringent, is an Internet-based, performance-linked system called iPLEDGE, which tries to ensure that the drug is dispensed only when there is documentary proof that the patient is not pregnant and is using two forms of birth control. Is iPLEDGE the best way to reduce isotretinoin birth defects, or is it an unproven and overly burdensome system?, Isotretinoin is an effective treatment for severe acne, but causes birth defects. Will iPLEDGE, the recently implemented US risk reduction program, reduce isotretinoin birth defects, or is it an unproven and overly burdensome system?

The authors review recent research on the molecular mechanisms of addiction and propose a new classification for addictive drugs.

In PLoS Medicine, volume 3, issue 8: DOI: 10.1371/journal.pmed.0030272 Under the section heading “Expected Death Toll during a Present-Day Mass Vaccination Campaign,” the numbers of expected deaths that were computed for a mass vaccination campaign were displayed as per million; they should be absolute numbers. The corrected text should be: “Under those assumptions, in the Netherlands mass vaccination with NYCBH would lead to 9.8 deaths (95% CI [0, 30]), mass vaccination with Lister to 55.1 deaths (95% CI [7, 182]), and mass vaccination with Bern would lead to 303.5 deaths (95% CI [19, 1093]). In Germany mass vaccination with NYCBH would lead to 46.2 deaths (95% CI [6, 142]), mass vaccination with Lister would lead to 268.5 deaths (95% CI [39, 875]), and mass vaccination with Bern would lead to 1,381 deaths (95% CI [94, 4909]).”

Background Somatic afferent input to the spinal cord from a peripheral inflammatory site can modulate the peripheral response. However, the intracellular signaling mechanisms in the spinal cord that regulate this linkage have not been defined. Previous studies suggest spinal cord p38 mitogen-activated protein (MAP) kinase and cytokines participate in nociceptive behavior. We therefore determined whether these pathways also regulate peripheral inflammation in rat adjuvant arthritis, which is a model of rheumatoid arthritis. Methods and Findings Selective blockade of spinal cord p38 MAP kinase by administering the p38 inhibitor SB203580 via intrathecal (IT) catheters in rats with adjuvant arthritis markedly suppressed paw swelling, inhibited synovial inflammation, and decreased radiographic evidence of joint destruction. The same dose of SB203580 delivered systemically had no effect, indicating that the effect was mediated by local concentrations in the neural compartment. Evaluation of articular gene expression by quantitative real-time PCR showed that spinal p38 inhibition markedly decreased synovial interleukin-1 and −6 and matrix metalloproteinase (MMP3) gene expression. Activation of p38 required tumor necrosis factor α (TNFα) in the nervous system because IT etanercept (a TNF inhibitor) given during adjuvant arthritis blocked spinal p38 phosphorylation and reduced clinical signs of adjuvant arthritis. Conclusions These data suggest that peripheral inflammation is sensed by the central nervous system (CNS), which subsequently activates stress-induced kinases in the spinal cord via a TNFα-dependent mechanism. Intracellular p38 MAP kinase signaling processes this information and profoundly modulates somatic inflammatory responses. Characterization of this mechanism could have clinical and basic research implications by supporting development of new treatments for arthritis and clarifying how the CNS regulates peripheral immune responses., Inhibition of p38 MAP kinase in the CNS reduces peripheral inflammation and joint destruction in arthritic rats., Editors' Summary Background. Rheumatoid arthritis is a disease marked by chronic inflammation, leading to joint pain and destruction. Pain and inflammation in the joints as well as other locations in the body (i.e., the “periphery”) are constantly monitored by the central nervous system (i.e., the brain and spinal cord). Scientists have long suspected that the central nervous system (CNS) can regulate inflammation and immune responses, but little is known about how the CNS does this. One potential player is a protein called p38 that is involved in a number of cellular processes critical to the development of rheumatoid arthritis. Several substances that block the action of p38 are effective in animal models of arthritis and are currently being tested in clinical trials in patients with rheumatoid arthritis. Originally, p38 was considered as a drug target that should mainly be blocked in the joints. But recent work has shown that pain in the periphery can lead to activation of p38 in the spinal cord, and that blocking p38 in the spinal cord might reduce peripheral pain. Why Was This Study Done? Based on the observation that p38 is activated in the CNS in response to peripheral pain, the researchers who did this study wondered whether it might be involved in the interaction between inflammation in the joints and the CNS. What Did the Researchers Do and Find? They induced inflammation in the joints of rats and then looked for responses in the spinal cord. They found that p38 was indeed activated in the spinal cord of these rats. This activation depended on another protein, called TNFα, which is another major regulator of inflammation. The scientists then blocked either p38 or the TNFα with drugs directly delivered to the spinal cord of the arthritic rats, they could substantially reduce inflammation, arthritis, and destruction of the joints, compared with rats that had undergone the same treatment but received no active drug. Treatment of arthritic rats with the same amount of drugs given directly under the skin (this is called “systemic treatment”) did not have any effect on the joints. What Do These Findings Mean? Blocking p38 and TNFα by giving drugs systemically is known to have beneficial effects in animal models and human patients with rheumatoid arthritis. However, the drugs tested in patients to date also have side effects. Given that much lower doses were needed to achieve beneficial effects in the rats when the drugs were administered directly into the spinal cord, it is possible that spinal cord administration might reduce the side effects (and possibly the costs) of the drugs without compromising the benefits to the patients. If future studies confirm that the action of these drugs on the CNS is essential to achieve a response even when administered as a systemic treatment, designing drugs that get into the CNS easier might improve the effectiveness and/or make it possible to use lower doses systemically. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030338. MedlinePlus entry on rheumatoid arthritis Rheumatoid arthritis pages from the US National Institute of Arthritis and Musculoskeletal and Skin Diseases Rheumatoid Arthritis fact sheet from the American College of Rheumatology Description Wikipedia entry on rheumatoid arthritis (note: Wikipedia is a free online encyclopedia that anyone can edit)

Recent regulatory warnings about adverse behavioural effects of antidepressants in susceptible individuals have raised the profile of these issues with clinicians, patients, and the public. We review available clinical trial data on paroxetine and sertraline and pharmacovigilance studies of paroxetine and fluoxetine, and outline a series of medico-legal cases involving antidepressants and violence. Both clinical trial and pharmacovigilance data point to possible links between these drugs and violent behaviours. The legal cases outlined returned a variety of verdicts that may in part have stemmed from different judicial processes. Many jurisdictions appear not to have considered the possibility that a prescription drug may induce violence. The association of antidepressant treatment with aggression and violence reported here calls for more clinical trial and epidemiological data to be made available and for good clinical descriptions of the adverse outcomes of treatment. Legal systems are likely to continue to be faced with cases of violence associated with the use of psychotropic drugs, and it may fall to the courts to demand access to currently unavailable data. The problem is international and calls for an international response.

Background Age-related macular degeneration (AMD) is the leading cause of blindness in people over 50 y of age in at least three continents. Choroidal neovascularization (CNV) is the process by which abnormal blood vessels develop underneath the retina. CNV develops in 10% of patients with AMD but accounts for up to 90% of the blindness from AMD. Although the precise etiology of CNV in AMD remains unknown, the macrophage component of the inflammatory response, which has been shown to promote tumor growth and support atherosclerotic plaque formation, is thought to stimulate aberrant angiogenesis in blinding eye diseases. The current theory is that macrophage infiltration promotes the development of neovascularization in CNV. Methods and Findings We examined the role of macrophages in a mouse model of CNV. IL-10 −/− mice, which have increased inflammation in response to diverse stimuli, have significantly reduced CNV with increased macrophage infiltrates compared to wild type. Prevention of macrophage entry into the eye promoted neovascularization while direct injection of macrophages significantly inhibited CNV. Inhibition by macrophages was mediated by the TNF family death molecule Fas ligand (CD95-ligand). Conclusions Immune vascular interactions can be highly complex. Normal macrophage function is critical in controlling pathologic neovascularization in the eye. IL-10 regulates macrophage activity in the eye and is an attractive therapeutic target in order to suppress or inhibit CNV in AMD that can otherwise lead to blindness., Apte and colleagues examined the role of macrophages in a mouse model of choroidal neovascularization, and showed that normal macrophage function is critical in controlling pathologic neovascularization in the eye., Editors' Summary Background. The most common cause of poor eyesight in later life in the developed world is known as age-related macular degeneration (AMD). The macula is the central part of the retina (the film-like membrane at the back of the eye), which is the most sensitive and important for sharp central vision. There are two types of advanced AMD: so-called wet, or neovascular, AMD (neovascular means “new vessel”) and dry, or geographic atrophy, AMD (atrophy means “to waste away”). Wet AMD occurs when abnormal, fragile new blood vessels grow under the macula behind the retina. These blood vessels often leak blood and fluid, which lift the macula. Dry AMD occurs as the light-sensitive cells in the macula (the rods and cones) break down. To study this disease further, researchers use animal models. One such animal model is made by using a laser to damage the back of the eye in a mouse, which causes the formation of new vessels. Various treatments can then be tested to see if they have any effect on the damage. Why Was This Study Done? One theory about AMD is that the immune system may be involved in determining how severe the damage at the back of the eye is, and how much new vessel formation occurs. The researchers wanted to look at the effect of the immune system on AMD, in particular, the effect of one type of cell called a macrophage, and a substance, IL-10, that is secreted from bone marrow cells and that affects how these macrophages work. What Did the Researchers Do and Find? The researchers used a mouse strain in which IL-10 was absent, induced damage in the eyes that mimicked AMD, and then looked at what role macrophages had in the eye abnormalities. They found that in the eyes of mice that lacked IL-10, there was reduced new vessel formation and increased numbers of macrophages compared to mice that had normal amounts of IL-10. Also, preventing macrophages from getting into the eyes of such mice by injecting IL-10 into the eyes made the new vessel formation worse, while direct injection of macrophages made it better. What Do These Findings Mean? Although animal models cannot completely replicate disease in humans, they can give us an idea of how diseases might come about and suggest possible treatment strategies. It is possible that inhibiting the effect of IL-10, or other strategies that make macrophages more efficient in the eye, may be a useful treatment for AMD. In a related Perspective (DOI: 10.1371/journal.pmed.0030364), Susan Lightman and Virginia Calder discuss the findings further, including suggesting new experiments that will need to be done as a next step. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030310. MedlinePlus encyclopedia entry on macular degeneration National Institutes of Health Senior Health page of information on AMD National Eye Institute AMD fact page

In PLoS Medicine, volume 3, issue 6: DOI: 10.1371/journal.pmed.0030197 In the first paragraph of the section The Epidemic of Counterfeit Artesunate in Southeast Asia, the sentence “Counterfeit artesunate continues to circulate on a vast scale in mainland Southeast Asia, where between 38% and 52% of “artesunate” blister packs sampled contain no active ingredient [1–5]” should be “Counterfeit artesunate continues to circulate on a vast scale in mainland Southeast Asia, where between 38% and 53% of “artesunate” blister packs sampled contain no active ingredient [1–5].”

Metabolomics (also referred to as metabonomics) is the comprehensive study of the metabolome, the repertoire of biochemicals (or small molecules) present in cells, tissue, and body fluids. The study of metabolism at the global or “-omics” level is a new but rapidly growing field that has the potential to have an impact upon medical practice [1–4]. At the center of metabolomics is the concept that an individual's metabolic state is a close representation of the individual's overall health status. This metabolic state reflects what has been encoded by the genome and modified by environmental factors. Today, clinicians capture only a very small part of the information contained in the metabolome, as revealed by a defined set of blood chemistry analyses to define health and disease states. Examples include measuring glucose to monitor diabetes and measuring cholesterol for cardiovascular health. Such a narrow chemical analysis could potentially be replaced in the future with a metabolic signature that captures global biochemical changes in disease and upon treatment. Such metabolic signatures could provide: (1) prognostic, diagnostic, and surrogate markers for a disease state; (2) the ability to subclassify disease; (3) biomarkers for drug response phenotypes (pharmacometabolomics); and (4) information about mechanisms of disease. Indeed, sophisticated metabolomic analytical platforms and informatics tools have recently been developed that make it possible to define initial metabolic signatures for several diseases [5–12].

Background Large quantities of smallpox vaccine have been stockpiled to protect entire nations against a possible reintroduction of smallpox. Planning for an appropriate use of these stockpiled vaccines in response to a smallpox outbreak requires a rational assessment of the risks of vaccination-related adverse events, compared to the risk of contracting an infection. Although considerable effort has been made to understand the dynamics of smallpox transmission in modern societies, little attention has been paid to estimating the frequency of adverse events due to smallpox vaccination. Studies exploring the consequences of smallpox vaccination strategies have commonly used a frequency of approximately one death per million vaccinations, which is based on a study of vaccination with the New York City Board of Health (NYCBH) strain of vaccinia virus. However, a multitude of historical studies of smallpox vaccination with other vaccinia strains suggest that there are strain-related differences in the frequency of adverse events after vaccination. Because many countries have stockpiled vaccine based on the Lister strain of vaccinia virus, a quantitative evaluation of the adverse effects of such vaccines is essential for emergency response planning. We conducted a systematic review and statistical analysis of historical data concerning vaccination against smallpox with different strains of vaccinia virus. Methods and Findings We analyzed historical vaccination data extracted from the literature. We extracted data on the frequency of postvaccinal encephalitis and death with respect to vaccinia strain and age of vaccinees. Using a hierarchical Bayesian approach for meta-analysis, we estimated the expected frequencies of postvaccinal encephalitis and death with respect to age at vaccination for smallpox vaccines based on the NYCBH and Lister vaccinia strains. We found large heterogeneity between findings from different studies and a time-period effect that showed decreasing incidences of adverse events over several decades. To estimate death rates, we then restricted our analysis to more-recent studies. We estimated that vaccination with the NYCBH strain leads to an average of 1.4 deaths per million vaccinations (95% credible interval, 0–6) and that vaccination with Lister vaccine leads to an average of 8.4 deaths per million vaccinations (95% credible interval, 0–31). We combined age-dependent estimates of the frequency of death after vaccination and revaccination with demographic data to obtain estimates of the expected number of deaths in present societies due to vaccination with the NYCBH and Lister vaccinia strains. Conclusions Previous analyses of smallpox vaccination policies, which rely on the commonly assumed value of one death per million vaccinations, may give serious underestimates of the number of deaths resulting from vaccination. Moreover, because there are large, strain-dependent differences in the frequency of adverse events due to smallpox vaccination, it is difficult to extrapolate from predictions for the NYCBH-derived vaccines (stockpiled in countries such as the US) to predictions for the Lister-derived vaccines (stockpiled in countries such as Germany). In planning for an effective response to a possible smallpox outbreak, public-health decision makers should reconsider their strategies of when to opt for ring vaccination and when to opt for mass vaccination., Analysis of historical data for adverse events suggests that the commonly assumed number of one death per million vaccinations is inaccurate. Large differences between different vaccinia strains used should be taken into account when mass vaccinations are considered., Editors' Summary Background. For thousands of years, smallpox was one of the world's most-feared diseases. This contagious disease, caused by the variola virus, historically killed about 30 percent of the people it infected. Over the centuries, it probably killed more people than all other infectious diseases combined, but it was also the first disease to be prevented by vaccination. In 1796, the English physician Edward Jenner rubbed pus from the spots of a milkmaid with cowpox into scratches on a young boy's arm; according to folklore, people who caught cowpox, a related but mild disease of cows, were protected against smallpox. Six weeks later, after a mild bout of cowpox, when the boy was challenged with pus from a smallpox patient, he did not develop smallpox. This vaccination procedure was later refined so that people were inoculated with pure preparations of live vaccinia virus, which is closely related to the smallpox and cowpox viruses, and by 1979 a global vaccination campaign had totally eradicated the disease. Why Was This Study Done? Smallpox vaccination has some adverse effects. In particular, vaccinia virus occasionally infects the brain. This so-called post-vaccination encephalitis can cause permanent brain damage and, it has been estimated, kills one vaccinee in every million. Consequently, as smallpox became rarer, the dangers of vaccination began to outweigh its benefits. Routine smallpox vaccination stopped in the US in 1972, and in 1980 the World Health Organization recommended that all countries stop vaccination. Now, however, there are fears that smallpox may be used for bioterrorism. If this did happen, exposed individuals and their contacts, possibly even whole populations, would have to be vaccinated as quickly as possible (very few people now have strong immunity to smallpox). Many countries have stockpiles of smallpox vaccines for this eventuality, but these contain different vaccinia virus strains. In this study, the researchers examined historical data to discover whether these strains differ in their potential to cause encephalitis and death. This information should help public-health officials plan their vaccination strategies in response to a bioterrorism attack with smallpox. What Did the Researchers Do and Find? The researchers collected data from published studies on smallpox vaccination and adverse events from several countries from the late 1950s onwards. They then used these data to extrapolate how often the different vaccinia strains might cause encephalitis and death if they were used today in vaccination programs. They estimate that vaccinating with the New York City Board of Health (NYCBH) strain, which is stockpiled in the US, might cause 2.9 cases of post-vaccination encephalitis and 1.4 deaths per million vaccinated individuals. In contrast, the Lister strain, which is stockpiled in many European countries, might cause 26.2 cases of post-vaccination encephalitis and 2.5 deaths per million vaccinees. For both strains, vaccination of children younger than 1 year old would cause the highest death rate, and individuals being re-vaccinated would be less likely to die than those being vaccinated for the first time. Finally, the researchers use their figures to estimate that about ten people would die if mass vaccination with the NYCBH strain were used in the Netherlands (population 16 million), whereas 55 people would die if the Lister strain were used. What Do These Findings Mean? The data used in this study are of variable quality, so the figures calculated by the researchers are only estimates. For instance, given the scatter of the original data, mass vaccination in the Netherlands with the Lister strain might cause anywhere between seven and nearly 200 deaths. However, the study clearly suggests that more serious adverse events would occur after vaccination with the Lister strain than after vaccination with the NYCBH strain. It also indicates that even in the US, where the NYCBH vaccine strain is stockpiled, previous analyses of the effects of vaccination in response to a bioterrorist attack have probably underestimated how many people might die from post-vaccination encephalitis. Public-health decision makers should incorporate these new estimates into their planning for a smallpox outbreak. These increased estimates of adverse events after vaccination might, for example, make mass vaccination with the Lister strain of vaccinia virus less acceptable. Instead, public-health officials might decide to rely on vaccination of only the people directly exposed to released smallpox virus and their close contacts (ring vaccination) to contain a smallpox outbreak. Additional Information. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030272. World Health Organization, information on smallpox and preparedness in the event of a smallpox outbreak MedlinePlus encyclopedia entry on smallpox US National Institute of Allergy and Infectious Diseases, patient fact sheet on smallpox US Centers for Disease Control and Prevention, information for patients and professionals on smallpox Wikipedia page on smallpox (note that Wikipedia is a free online encyclopedia that anyone can edit) Wellcome Library MedHist, links to information on the history of smallpox vaccination

The series of disease mongering articles in the April 2006 issue of PLoS Medicine overall seem to define the term as “widening the boundaries of illness” [ 1] by “taking a normal function and implying that there's something wrong with it and that it should be treated” [ 2]. While there is undoubtedly a strong case to be made for this sort of practice by pharmaceutical companies, perhaps we should also question ourselves on what we mean by “disease boundaries.” All of the conditions touched on by the disease mongering series (e.g., bipolar disease, attention deficit hyperactivity disorder, restless legs syndrome, and sexual dysfunctions) share the fact that they represent spectra of symptoms felt by virtually everyone, but which for some people can reach a point at which they become disturbing. However, since the benefit of treating these symptoms is ultimately dependent on their significance in a patient's life, it seems doubtful that anyone but the patient can adequately define the “boundaries” of illness for these conditions. The existence of these large “grey zones” between disease and normality (as well as the difficulty of doctors in dealing with them) might help to explain the increase in “lifestyle drug use” and self-prescription of psychiatric medication [ 3]. While these behaviors undoubtedly carry risks, they might well be an inevitable development in an age where information on anything (including drugs) is so widely available. Moreover, tampering with body chemistry is nothing new (alcohol, coffee, chocolate, and sunlight come to mind as examples), and it is hard to expect people will not do it because of pharmaceutical labels. Therefore, complain as we may, it is unlikely that this trend can be feasibly prevented. Therefore, if we want to prevent disease mongering, perhaps we should start by focusing on our own concept of “disease.” Maybe it is time we start to loosen the grip on our powers to define disease and start working less as diagnosing machines and more as decision facilitators for patients. It seems quite absurd to decide on a “concept” of erectile dysfunction or depression that can define who should be treated. On the contrary, our role should be to inform patients of the benefits and risks of treatment (or nontreatment) for their particular condition. This also means being comfortable with the fact that, no matter which criteria one uses to define disease, there will always be “normal” people who will want treatment as well as “sick” people who will refuse it. And in both cases they are probably entitled to do so, without necessarily receiving a diagnosis of “normal” or “sick.” Moreover, since the trend for self-prescription is not likely to be prevented, and since the pharmaceutical industry will surely try to capitalize on it, perhaps we should also worry about making nonprofit, unbiased scientific information more available to the public. Education on health matters is an important responsibility that traditionally has been overlooked by doctors in most countries. Now, if ever, seems to be the time to change that, because if physicians do not concentrate on it, drug companies will be happy to do it for them. It is obvious that medicine cannot abandon the concept of disease boundaries, since most of our medical knowledge and research is still based on it. Moreover, there are fields in which medical responsibility is sure to remain important in defining these boundaries (e.g., attribution of public funds, research studies, and treatment of children). But after reading so much on disease mongering, it seems to me that if we become a little more flexible in admitting that “disease boundaries” for many conditions are an oxymoron, perhaps the pharmaceutical industry will make less of a fuss in trying to convince people they are ill. My guess is that this would do everybody a favor.

Fake artesunate could compromise the hope that artemisinin-based combination therapy offers for malaria control in Africa and Asia.

Baune and Hay discuss the strengths and limitations of an ecological study that found an inverse correlation between suicide rates and fluoxetine prescriptions.

The term antidepressant refers to a drug that helps to rectify specific biological abnormalities that give rise to the symptoms of depression. This exemplifies what we have called the “disease-centred” model of psychotropic drug action [ 1]. Modelled on paradigmatic situations in general medicine—such as the use of insulin in diabetes, antibiotics in infectious disease, chemotherapy in cancer—the disease-centred model suggests that antidepressants help restore normal functioning by acting on the neuropathology of depression or of depressive symptoms. In contrast, we propose in this Essay that an alternative “drug-centred” model can better explain observed drug effects in psychiatric conditions. This drug-centred model suggests that instead of relieving a hypothetical biochemical abnormality, drugs themselves cause abnormal states, which may coincidentally relieve psychiatric symptoms ( Table 1). Alcohol's disinhibiting effects may relieve symptoms of social phobia, but that does not imply that alcohol corrects a chemical imbalance underlying social phobia. Sedation may lessen high arousal, present in many acute psychiatric situations. Drugs that induce indifference, such as neuroleptics or opiates, may help reduce the distress of acute psychotic symptoms. Low-dose stimulants may help improve attention and concentration in the short term. Table 1 Main Assumptions of Two Models of Psychotropic Drug Action The disease-centred model in psychiatry leads researchers to infer antidepressant effects from patients' scores on symptom rating scales presumed to assess the manifestations of the disease. The drug-centred model, on the other hand, suggests that physiological and subjective effects of drugs should be examined in their own right. These effects include various forms of sedation, stimulation, and a plethora of biopsychological states. Depending on individual inclination and context (including a person's emotional state upon drug ingestion), intoxication with some drugs produces euphoria or mood elevation. Because tolerance develops, however, euphoriant effects do not persist with long-term use. If antidepressants or any other psychotropic drugs could be shown to have mood-elevating effects that were long-term and not diminished by being in a depressed emotional state, this would distinguish them from psychotropic drugs that cause euphoria and might prove uniquely useful in depressed patients (see Sidebar).

Background To study the potential association of antidepressant use and suicide at a population level, we analyzed the associations between suicide rates and dispensing of the prototypic SSRI antidepressant fluoxetine in the United States during the period 1960–2002. Methods and Findings Sources of data included Centers of Disease Control and US Census Bureau age-adjusted suicide rates since 1960 and numbers of fluoxetine sales in the US, since its introduction in 1988. We conducted statistical analysis of age-adjusted population data and prescription numbers. Suicide rates fluctuated between 12.2 and 13.7 per 100,000 for the entire population from the early 1960s until 1988. Since then, suicide rates have gradually declined, with the lowest value of 10.4 per 100,000 in 2000. This steady decline is significantly associated with increased numbers of fluoxetine prescriptions dispensed from 2,469,000 in 1988 to 33,320,000 in 2002 (rs = −0.92; p < 0.001). Mathematical modeling of what suicide rates would have been during the 1988–2002 period based on pre-1988 data indicates that since the introduction of fluoxetine in 1988 through 2002 there has been a cumulative decrease in expected suicide mortality of 33,600 individuals (posterior median, 95% Bayesian credible interval 22,400–45,000). Conclusions The introduction of SSRIs in 1988 has been temporally associated with a substantial reduction in the number of suicides. This effect may have been more apparent in the female population, whom we postulate might have particularly benefited from SSRI treatment. While these types of data cannot lead to conclusions on causality, we suggest here that in the context of untreated depression being the major cause of suicide, antidepressant treatment could have had a contributory role in the reduction of suicide rates in the period 1988–2002., An association has been shown between the introduction of the antidepressant fluoxetine in the USA in 1988 and a reduction in the number of suicides., Editors' Summary Background. Depression is very common. For example, in the US, an estimated 10% of men and 20% of women will suffer from major depression at some stage in their lives. One way of treating the condition is with drugs. Several types of antidepressant drugs are available, and in many countries they are among the most commonly prescribed medicines. However, all antidepressants have side effects. One family of antidepressants, called selective serotonin uptake inhibitors (SSRIs), was introduced in the late 1980s. The name of these drugs comes from their effect, which is to prevent the removal (reuptake) from the nerve endings of one type of chemical (serotonin) that is important for transmitting nerve impulses between brain cells. SSRIs are claimed to be more effective and to have fewer side effects than older antidepressants, and many brands of SSRI are now on the market. However, in recent years there have been claims that some people taking SSRIs have committed suicide as a result of the drugs. Whether the SSRIs are the cause of the suicide is hard to know, because people who are depressed do sometimes feel like killing themselves; so if a depressed person taking an SSRI commits suicide, it is hard to tell whether this is a result of the depression or a side effect of the treatment (the SSRI). The drug regulatory authorities in some countries are now carefully studying the issue of suicides and antidepressant use, both in adults and in children. The US Federal Drug Administration has issued what it calls a “black box warning” on the use of these drugs. Why Was This Study Done? The researchers wanted to discover whether the number of suicides in the US had increased or decreased since treatment with the first widely used SSRI (fluoxetine, also known as Prozac) began in 1988. Any difference in the number of suicides found before and after that date would not necessarily be the result of the introduction of this antidepressant, or other SSRIs, but the information would provide helpful information about the effects of these drugs. What Did the Researchers Do and Find? They looked at annual suicide rates between 1960 and 1988 and compared them with annual rates in the period 1988 to 2002. They used several sources of data, including the Centers of Disease Control and the US Census Bureau. The researchers found that from the early 1960s until 1988, in the entire US population, between 12.2 and 13.7 people in every 100,000 committed suicide each year. After that time, the numbers of suicides gradually declined, with the lowest figure (10.4 people per 100,000) reached in 2000. The researchers did mathematical tests, which demonstrated that the steady decline was statistically associated with the increased number of fluoxetine prescriptions—that is, the more prescriptions there were, the fewer suicides there were. (There were around two-and-a-half million prescriptions of the drug in 1988, increasing to over 33 million in 2002.) What Do These Findings Mean? In all scientific research, it is an important principle that finding an association between two events does not prove that one caused the other to occur. However, the authors of this paper suggest that the use of this drug could have contributed to the reduction of suicide rates in the US in the period 1988 to 2002. Several other SSRIs are also now in common use, but they were not considered in this study, nor were other antidepressants, or other treatments for depression. Additional Information. As depression is such a common condition—and because there are so many ways of treating it, including counseling and psychotherapy—there are many Web sites devoted to the subject. We have given a small selection below. Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0030190. • From the American Academy of Family Physicians (AAFP), general advice on depression • Also from the AAFP, advice specifically about antidepressant drugs • MedlinePlus brings together authoritative information about depression from the US National Library of Medicine, National Institutes of Health, and other government agencies and health-related organizations • Health pages of the BBC on depression • Information about depression from other UK health advice sites: Patient UK and NetDoctor.co.uk