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Rationale: Optimizing pyrazinamide dosing is critical to improve treatment efficacy while minimizing toxicity during tuberculosis treatment. Study 31/AIDS Clinical Trials Group A5349 represents the largest phase 3 randomized controlled therapeutic trial to date for such an investigation. Objectives: We sought to report pyrazinamide pharmacokinetic parameters, risk factors for lower pyrazinamide exposure, and relationships between pyrazinamide exposure and efficacy and safety outcomes. We aimed to determine pyrazinamide dosing strategies that optimize risks and benefits. Methods: We analyzed pyrazinamide steady-state pharmacokinetic data using population nonlinear mixed-effects models. We evaluated the contribution of pyrazinamide exposure to long-term efficacy using parametric time-to-event models and safety outcomes using logistic regression. We evaluated optimal dosing with therapeutic windows targeting ≥95% durable cure and safety within the observed proportion of the primary safety outcome. Measurements and Main Results: Among 2,255 participants with 6,978 plasma samples, pyrazinamide displayed sevenfold exposure variability (151-1,053 mg·h/L). Body weight was not a clinically relevant predictor of drug clearance and thus did not justify the need for weight-banded dosing. Both clinical and safety outcomes were associated with pyrazinamide exposure, resulting in therapeutic windows of 231-355 mg · h/L for the control and 226-349 mg·h/L for the rifapentine-moxifloxacin regimen. Flat dosing of pyrazinamide at 1,000 mg would have permitted an additional 13.1% (n = 96) of participants allocated to the control and 9.2% (n = 70) to the rifapentine-moxifloxacin regimen dosed within the therapeutic window, compared with the current weight-banded dosing. Conclusions: Flat dosing of pyrazinamide at 1,000 mg/d would be readily implementable and could optimize treatment outcomes in drug-susceptible tuberculosis. Clinical trial registered with www.clinicaltrials.gov (NCT02410772).

Despite known treatments, tuberculosis (TB) remains the worlds top infectious killer, highlighting the pressing need for new drug regimens. To prioritize the most efficacious drugs for clinical testing, we previously developed a PK-PD translational platform with bacterial dynamics that reliably predicted short-term monotherapy outcomes in Phase IIa trials from preclinical mouse studies. In this study, we extended our platform to include PK-PD models that account for drug-drug interactions in combination regimens and bacterial regrowth in our bacterial dynamics model to predict cure at the end of treatment and relapse 6 months post-treatment. The Phase III STAND trial testing a new regimen comprised of pretomanid (Pa), moxifloxacin (M), and pyrazinamide (Z) (PaMZ) was suspended after a separate ongoing trial (NC-005) suggested that adding bedaquiline (B) to the PaMZ regimen would improve efficacy. To forecast if the addition of B would, indeed, benefit the PaMZ regimen, we applied an extended translational platform to both regimens. We predicted currently available short- and long-term clinical data well for drug combinations related to BPaMZ. We predicted the addition of B to PaMZ to shorten treatment duration by 2 months and to have similar bacteriological success to standard HRZE treatment (considering only treatment success but not withdrawal from side effects and other adverse events), both at the end of treatment for treatment efficacy and 6 months after treatment has ended in relapse prevention. Using BPaMZ as a case study, we have demonstrated our translational platform can predict Phase II and III outcomes prior to actual trials, allowing us to better prioritize the regimens most likely to succeed.

Tuberculous meningitis (TBM) disables more than a third of its sufferers. Recent research has focused on optimizing the antitubercular regimen, mainly by increasing the dosage of rifampicin. However, pyrazinamide, with higher penetration into the central nervous system, is generally overlooked. We discuss the potential clinical impact of using pyrazinamide throughout antitubercular therapy in TBM, in contrast to only the intensive phase. This approach may improve the treatment outcomes and reduce disability in TBM. We summarize the available data regarding this approach from in vitro studies, clinical cohorts, toxicity data, and baseline resistance rates. Additionally, we discuss the two ongoing clinical trials evaluating this approach. Plain Language Summary: Tuberculosis (TB) is a disease caused by the organism Mycobacterium tuberculosis. TB meningitis (TBM) is a medical condition in which the layers covering the brain are infected with TB bacteria. TBM is one of the worst forms of TB as it kills a lot of people who suffer with the disease and leaves many permanently disabled. Currently, the World Health Organization recommends 12 months of treatment for TBM. The drugs used in the treatment are rifampicin, isoniazid, ethambutol, and pyrazinamide. Usually, pyrazinamide is given only for the first 2 months of TB treatment. Many studies have shown that pyrazinamide penetrates the brain better than other drugs and kills TB bacteria more effectively. In addition, ethambutol does not get into the brain well compared to other drugs. In this narrative review, we present evidence to reconsider the duration of pyrazinamide usage beyond 2 months for improving the results of TBM treatment. We also report the challenges of this approach, such as side effects and pyrazinamide resistance. [ABSTRACT FROM AUTHOR]

Mycobacterium tuberculosis (Mtb) has evolved to be exquisitely adapted to survive within host macrophages. The capacity to damage the phagosomal membrane has emerged as central to Mtb virulence. While Mtb factors driving membrane damage have been described, host factors that maintain phagosomal integrity or repair Mtb-induced damage to contain the pathogen remain largely unknown. We used a genome-wide CRISPR screen to identify host factors required to repair Mtb-damaged phagosomal membranes. Vacuolar protein sorting-associated protein 18 (VPS18), a member of the HOPS and CORVET trafficking complexes, was among the top hits. VPS18 colocalized with Mtb in macrophages beginning shortly after infection, and VPS18-knockout macrophages demonstrated increased damage of Mtb-containing phagosomes without impaired autophagy. Mtb grew more robustly in VPS18-knockout cells, and the first-line antituberculosis antibiotic pyrazinamide was less effective. Our results identify VPS18 as required for phagosomal membrane integrity in Mtb-infected cells and suggest that modulating phagosome integrity may hold promise for improving the efficacy of antibiotic treatment for TB. [ABSTRACT FROM AUTHOR]

Pyrazinamide (PZA) is a key first-line antituberculosis drug that plays an important role in eradicating persister Mycobacterium tuberculosis (TB) bacilli and shortening the duration of tuberculosis treatment. However, PZA-resistance is on the rise, particularly among persons with multidrug-resistant (MDR) tuberculosis. This nationwide study was conducted to explore the prevalence of mutations conferring PZA resistance, catalogue mutation diversity, investigate the associations of PZA resistance with specific lineages, examine co-resistance to 13 first- and second-line drugs, and evaluate the diagnostic accuracy of sequencing pnc A and pan D genes for predicting PZA resistance. Whole genome sequencing was performed on 2,207 M. tuberculosis isolates from 25 States and 4 Union Territories of India. The majority of phenotypically PZA-resistant isolates (77%) harbored 171 distinct mutations in pnc A; however, a small number of mutations in pan D, rps A and clp C1 were also observed. A set of novel mutations associated PZA resistance was uncovered, along with an additional 143 PZA resistance-conferring mutations in pnc A based on application of WHO-endorsed grading rules. PZA resistance was predominately observed in Lineage 2 and eight lineage-specific resistance markers were identified. Mutations distributed across pnc A correlate to 94% of PZA resistance and were the predominant drivers of phenotypic resistance; evidence generated herein substantiates sequencing the entire gene and promoter for comprehensive genotypic-based prediction of PZA resistance. This work provides key insights into the scope of PZA-resistance in India, a high drug-resistant TB burden country, and can support the effectiveness of TB prevention and control efforts. [ABSTRACT FROM AUTHOR]

Introduction Pyrazinamide, one of the first-line antituberculosis drugs, displays variability in drug exposure that is associated with treatment response. A simple, low-cost assay may be helpful to optimize treatment. This study aimed to develop and validate a point-of-care assay to quantify the concentration of pyrazinamide in saliva. Methods All measurements were conducted using the nano-volume drop function on the mobile ultraviolet (UV) spectrophotometer (NP80, Implen, Germany). Assay development involved applying second derivative spectroscopy in combination with the Savitzky–Golay filter between wavelengths of 200–300 nm to increase spectral resolution. Assay validation included assessing selectivity, linearity, accuracy, precision, carry-over and matrix effects. Specificity was also analysed by evaluating the impact of co-administered medications on pyrazinamide results. Sample stability was measured at various temperatures up to 40°C. Results The calibration curve (7.5–200 mg/L) was linear (R2 = 0.9991). The overall accuracy (bias%) and precision (CV%) ranged from −0.66% to 5.15%, and 0.56% to 4.95%, respectively. Carry-over and matrix effects were both acceptable with a bias% of <±4% and CV% of <7.5%. Commonly co-administered medications displayed negligible interferences. Levofloxacin displayed analytical interference (bias% = −10.21%) at pyrazinamide concentrations < 25 mg/L, but this will have little clinical implications. Pyrazinamide was considered stable in saliva after 7 days in all storage conditions with a CV% of <6.5% and bias% of <±10.5% for both low- and high-quality control concentrations. Conclusions A saliva-based assay for pyrazinamide has been successfully developed and validated using the mobile UV spectrophotometer. [ABSTRACT FROM AUTHOR]

Cases of active tuberculosis (TB) in the U.S. Military have fallen over the last century in large part due to improved screening and treatment options. The subset of multidrug-resistant TB (MDR-TB) is almost nonexistent within the U.S. Military. We present a case of MDR-TB in an active duty U.S. Military health care worker and discuss several considerations for treatment that may present challenges for U.S. Military medical practitioners. A 30-year-old active duty Soldier was referred to Army public health services after a bronchoscopy sample was positive for Mycobacterium tuberculosis complex. Sputum smears were negative for acid-fast bacilli, suggesting lower risk for community spread. One month after initiation of the standard 4-drug regimen for active TB, genetic susceptibility testing found the patient's M. tuberculosis isolate to be resistant to rifampin, isoniazid, and pyrazinamide. Contact investigation efforts among co-workers and family members fortunately found no new interferon-gamma release assay conversions. Coordination of public health assets to ensure a successful treatment regimen occurred across varied local, state, and federal agencies. Atypical medications required coordination with the FDA for procurement. An extensive surveillance plan for medication adverse effects was required. Finally, questions of public health authority versus patient autonomy arose requiring multidisciplinary input and ethical discussions. [ABSTRACT FROM AUTHOR]

The objective: to assess effectiveness, safety and pharmacoeconomic feasibility of using a dispersible fixed-dose combination (isoniazid 150 mg, rifampicin 150 mg, pyrazinamide 375 mg) in patients with respiratory tuberculosis and preserved susceptibility of Mycobacterium tuberculosis (MTB) to anti-tuberculosis drugs.Subjects and Methods. A post-registration observational study was conducted to assess treatment effectiveness of pulmonary tuberculosis in 60 adult patients with drug susceptible tuberculosis. In Main Group, patients received the fixed-dose combination (isoniazid 150 mg, rifampicin 150 mg, pyrazinamide 375 mg), while in Control Group, patients were treated with the regimen consisting of single anti-tuberculosis drugs.Results. Sputum conversion rate made 76.7% by the end of the intensive phase (60 doses) when replacing isoniazid, rifampicin and pyrazinamide with the dispersible fixed-dose combination, while with the standard choice of drugs, it was 66.7%. The incidence of adverse reactions was 7-fold lower when using the investigational drug which contributed to a high level of adherence and high effectiveness of therapy. Pharmacoeconomic analysis convincingly demonstrated advantages and economic benefits of the dispersible fixed-dose combination (isoniazid 150 mg, rifampicin 150 mg, pyrazinamide 375 mg), which was more costly than the combination of single drugs.

Purpose: To observe the variability in the plasma concentrations and pharmacokinetic-pharmacodynamic (PK-PD) profiles of first-line antitubercular drugs in pulmonary tuberculosis (TB) patients with and without diabetes mellitus (DM). Methods: Newly diagnosed pulmonary TB patients aged 18–60 years with or without DM were included in the study. Group I (n = 20) included patients with TB, whereas group II (n = 20) included patients with both TB and DM. After 2 weeks of therapy, plasma concentrations and other PK-PD parameters were determined. Improvements in clinical features, X-ray findings, sputum conversion, and adverse drug reactions (ADRs) were assessed after 2 months of therapy. Results: Isoniazid displayed non-significantly higher plasma concentrations in diabetic patients, along with a significantly (P < 0.05) longer elimination half-life (t1/2). Rifampicin plasma concentrations at 4, 8, and 12 h were significantly (P < 0.05) lower, and it displayed significantly (P < 0.05) lower area under the curve (AUC0-12 and AUC0-∞), shorter t1/2, higher clearance (Cl), and a lower AUC0-∞/MIC ratio in diabetic patients. Pyrazinamide and ethambutol showed non-significantly higher plasma concentrations, AUC0-12, AUC0-∞, and t1/2 in diabetic patients. The improvements in clinical features, X-ray findings, sputum conversion, and ADRs were comparable in both groups. Conclusions: The presence of DM in TB patients affects the PK-PD parameters of isoniazid, rifampicin, pyrazinamide, and ethambutol variably in the Indian population. Studies with a larger number of patients are required to further elucidate the role of DM on the PK-PD profile of first-line antitubercular drugs and treatment outcomes in TB patients with concomitant DM. Trial registration: CTRI/2021/08/035578 dated 11/08/2021. [ABSTRACT FROM AUTHOR]

The synthesis of pyrazine-2-carboxylic acid hydrazide, a heterocyclic hydrazide compound, with negligible production of the by-product (pyrazine-2-carboxylic acid) in a solvent-free reaction condition was developed using the acyltransferase activity of amidase of Bacillus smithii strain IITR6b2. This study involves a greener approach with no hazardous chemicals and one-step biotransformation of pyrazinamide to its acid hydrazide (through hydrazinolysis). The Central Composite Design of the Response Surface Methodology was used to find the factors affecting the synthesis of the pyrazine-2-carboxylic acid hydrazide and pyrazine-2-carboxylic acid to find its true optimum. The four factors, namely pyrazinamide, hydrazine dihydrochloride, temperature, and cell concentrations, were considered during optimization. The optimized reaction conditions from the Central Composite Design for achieving the 32.26 mM of pyrazine-2-carboxylic acid hydrazide involve 40 mM of pyrazinamide, 1000 mM of hydrazine dihydrochloride with 2.5 mg/mL cell concentration at 20 °C. It resulted in an optimum production of pyrazine-2-carboxylic acid hydrazide utilizing the acyltransferase activity of amidase of Bacillus smithii IITR6b2, and the results obtained through the Design of Experiments were validated. The fed-batch biotransformation was carried out with alginate-entrapped whole-cell enzyme with the following parameters: agitation at 200 rpm, a pyrazinamide concentration of 40 mM, and 1000 mM of hydrazine dihydrochloride. The final pyrazine-2-carboxylic acid hydrazide concentration of 126 mM was obtained, corresponding to a 63% molar conversion. [ABSTRACT FROM AUTHOR]

Context: In this paper, we present a theoretical study on the complexation of Co(II), Ni(II), and Cu(II) with a pyrazinamide ligand (PZA), which plays an important role in the treatment of tuberculosis and has biological and pharmacological benefits. It is a hybrid organic/inorganic material involving coordination between a metal ion and PZA ligand containing different coordination sites. This allows it to have different binding modes with metal ions and, therefore, provides a versatile ability to coordinate with metals. This study aimed to optimize the structures of the [M(PZA)2Cl2] complexes using density functional theory (DFT) at the B3LYP/6-311G + (d,p) level and the M06-2X functional is a high-nonlocality functional of double the amount of nonlocal exchange 2X. Various properties, including geometrical parameters, natural bonding orbital (NBO) to determine atomic charges, HOMO–LUMO energies, electronic properties, reactivity (ELF, LOL), NCI-RDG, and molecular electrostatic potential (MEP) on the surfaces of key metal-PZA complexes were determined and described. The AIM method has also been used to examine the chemical bonds. Furthermore, an in silico analysis aiming to explore the ADMET profiles of the compounds under investigation revealed promising aqueous solubility, oral bioavailability and gastrointestinal absorption, in addition to favorable druglikeness non-toxic and non-carcinogenic characteristics. Methods: The DFT method was carried out using Gaussian 09 software and GaussView 5.0. Avogadro software was used to define the geometry of the complexes. The Multiwfn program was used to produce scatter plots of the reduced density gradient (RDG), non-covalent interactions (NCI), ELF, LOL, and to define the parameters selected for the topological analysis of the BCPs using Bader's AIM. [ABSTRACT FROM AUTHOR]

Pyrazinamide is a first line drug used for the treatment of tuberculosis, a pathology that caused the death of more than 1.3 million people in the world during 2022, according to WHO, being a drug of current interest due to its relevance in pharmaceutical and medical sciences. In this context, solubility is one of the most important physicochemical parameters in the development and/or optimization of new pharmaceutical forms, so the present work aims to present a thermodynamic study of the solubility of pyrazinamide in nine organic solvents of pharmaceutical interest. Using the shake-flask method and UV/Vis spectrophotometry, the solubility of this drug was determined at 9 temperatures; the maximum solubility was obtained in dimethyl sulfoxide at 318.15 K ( x 2 = 0.0816 ± 0.004 ) and the minimum in cyclohexane at 283.15 K ( 1.73 ± 0.05 × 10 − 5 ). From the apparent solubility data, the thermodynamic functions of solution and mixing were calculated, indicating an endothermic process. In addition, the solubility parameter of pyrazinamide was calculated using the Hoftyzer-van Krevelen (32.90 MPa1/2) and Bustamante (28.14 MPa1/2) methods. The maximum solubility was reached in dimethyl sulfoxide and the minimum in cyclohexane. As for the thermodynamic functions, the entropy drives the solution process in all cases. In relation to the solubility parameter, it can be analyzed that the mathematical models offer approximations; however, the experimental data are still primordial at the time of inferring any process. [ABSTRACT FROM AUTHOR]

Background Drug-resistant tuberculosis (DR-TB) is one of the challenging forms of TB to treat, not only in adults but also in children and adolescents. Further, there is a void in the treatment strategy exclusively for children due to various reasons, including paucity of pharmacokinetic (PK) data on anti-TB drugs across the globe. In this context, the present study aimed at assessing the PK of some of the anti-TB drugs used in DR-TB treatment regimens. Method A multicentre observational study was conducted among DR-TB children and adolescents (n  = 200) aged 1–18 years (median: 12 years; IQR: 9–14) treated under programmatic settings in India. Steady-state PK (intensive: n  = 89; and sparse: n  = 111) evaluation of moxifloxacin, levofloxacin, cycloserine, ethionamide, rifampicin, isoniazid and pyrazinamide was carried out by measuring plasma levels using HPLC methods. Results In the study population, the frequency of achieving peak plasma concentrations ranged between 13% (for rifampicin) to 82% (for pyrazinamide), whereas the frequency of suboptimal peak concentration for pyrazinamide, cycloserine, moxifloxacin, levofloxacin and rifampicin was 15%, 19%, 29%, 41% and 74%, respectively. Further, the frequency of supratherapeutic levels among patients varied between 3% for pyrazinamide and 60% for isoniazid. In the below-12 years age category, the median plasma maximum concentration and 12 h exposure of moxifloxacin were significantly lower than that of the above-12 years category despite similar weight-adjusted dosing. Conclusions Age significantly impacted the plasma concentration and exposure of moxifloxacin. The observed frequencies of suboptimal and supratherapeutic concentrations underscore the necessity for dose optimization and therapeutic drug monitoring in children and adolescents undergoing DR-TB treatment. [ABSTRACT FROM AUTHOR]

Background: Developing the most suitable treatment against tuberculosis based on resistance profiles is imperative to effectively cure tuberculosis patients. Whole‐genome sequencing is a molecular method that allows for the rapid and cost‐effective detection of mutations in multiple genes associated with anti‐tuberculosis drug resistance. This sequencing approach addresses the limitations of culture‐based methods, which may not apply to certain anti‐TB drugs, such as pyrazinamide, because of their specific culture medium requirements, potentially leading to biased resistance culture results. Methods: Thirty‐four M. tuberculosis isolates were subcultured on a Lowenstein–Jensen medium. The genome of these bacteria was subsequently isolated using cetyltrimethylammonium bromide. Genome sequencing was performed with Novaseq Illumina 6000 (Illumina), and the data were analysed using the GenTB and Mykrobe applications. We also conducted a de novo analysis to compare the two methods and performed mutation analysis of other genes encoding pyrazinamide resistance, namely rpsA and panD. Results: The results revealed mutations in the pncA gene, which were identified based on the databases accessed through GenTB and Mykrobe. Two discrepancies between the drug susceptibility testing and sequencing results may suggest potential instability in the drug susceptibility testing culture, specifically concerning PZA. Meanwhile, the results of the de novo analysis showed the same result of pncA mutation to the GenTB or Mykrobe; meanwhile, there were silent mutations in rpsA in several isolates and a point mutation; no mutations were found in the panD gene. However, the mutations in the genes encoding pyrazinamide require further and in‐depth study to understand their relationship to the phenotypic profile. Conclusions: Compared to the conventional culture method, the whole‐genome sequencing method has advantages in determining anti‐tuberculosis resistance profiles, especially in reduced time and bias. [ABSTRACT FROM AUTHOR]

Background In 2019, the World Health Organization called for operational research on all-oral shortened regimens for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We report safety and effectiveness of three 9-month all-oral regimens containing bedaquiline (Bdq), linezolid (Lzd), and levofloxacin (Lfx) and reinforced with cycloserine (Cs) and clofazimine (Cfz), delamanid (Dlm) and pyrazinamide (Z), or Dlm and Cfz. Methods We conducted a prospective cohort study of patients initiating treatment for pulmonary MDR/RR-TB under operational research conditions at public health facilities in Kazakhstan. Participants were screened monthly for adverse events. Participants with baseline resistance were excluded from the study and treated with a longer regimen. We analyzed clinically relevant adverse events of special interest in all participants and sputum culture conversion and end-of-treatment outcomes among individuals who were not excluded. Results Of 510 participants, 41% were women, the median age was 37 years (25th–75th percentile: 28–49), 18% had a body mass index <18.5 kg/m2, and 51% had cavitary disease. A total of 399 (78%) initiated Bdq-Lzd-Lfx-Cs-Cfz, 83 (16%) started Bdq-Lzd-Lfx-Dlm-Z, and 28 (5%) initiated Bdq-Lzd-Lfx-Dlm-Cfz. Fifty-eight individuals (11%) were excluded from the study, most commonly due to identification of baseline drug resistance (n = 52; 90%). Among the remaining 452 participants, treatment success frequencies were 92% (95% CI: 89–95%), 89% (95% CI: 80–94%), and 100% (95% CI: 86–100%) for regimens with Cs/Cfz, Dlm/Z, and Dlm/Cfz, respectively. Clinically relevant adverse events of special interest were uncommon. Conclusions All regimens demonstrated excellent safety and effectiveness, expanding the potential treatment options for patients, providers, and programs. [ABSTRACT FROM AUTHOR]

Background New and shorter regimens against multi-drug resistant tuberculosis (TB) remain urgently needed. To inform treatment duration in clinical trials, this study aimed to identify human pharmacokinetic equivalent doses, antimycobacterial and sterilizing activity of a novel regimen, containing bedaquiline, delamanid, moxifloxacin and sutezolid (BDMU), in the standard mouse model (BALB/c) of Mycobacterium tuberculosis (Mtb) infection. Methods Treatment of mice with B25D0.6M200U200, B25D0.6M200, B25D0.6M200(U2003) or H10R10Z150E100 (isoniazid, rifampicin, pyrazinamide, ethambutol, HRZE), started 3 weeks after Mtb infection. Bactericidal activity was assessed after 1, 2, 3 and 4 months of treatment and relapse rates were assessed 3 months after completing treatment durations of 2, 3 and 4 months. Results B25D0.6M200U200 generated human equivalent exposures in uninfected BALB/c mice. After 1 month of treatment, a higher bactericidal activity was observed for the B25D0.6M200U200 and the B25D0.6M200 regimen compared to the standard H10R10Z150E100 regimen. Furthermore, 3 months of therapy with both BDM-based regimens resulted in negative lung cultures, whereas all H10R10Z150E100 treated mice were still culture positive. After 3 months of therapy 7% and 13% of mice relapsed receiving B25D0.6M200U200 and B25D0.6M200, respectively, compared to 40% for H10R10Z150E100 treatment showing an increased sterilizing activity of both BDM-based regimens. Conclusions BDM-based regimens, with and without sutezolid, have a higher efficacy than the HRZE regimen in the BALB/c model of TB, with some improvement by adding sutezolid. By translating these results to TB patients, this novel BDMU regimen should be able to reduce treatment duration by 25% compared to HRZE therapy. [ABSTRACT FROM AUTHOR]

Background and Objective: Pyrazinamide (PZA) is the standard first‐line treatment for tuberculosis (TB); however, its safety in elderly patients has not been thoroughly investigated. Methods: This retrospective study used data from the Japanese Diagnosis Procedure Combination inpatient database. We identified patients who were admitted for TB between July 2010 and March 2022. Patients were categorized into HRE (isoniazid, rifampicin and ethambutol) and HREZ (isoniazid, rifampicin, ethambutol and PZA) groups. Primary outcomes included in‐hospital mortality and overall adverse events (characterized by a composite of hepatotoxicity, gout attack, allergic reactions and gastrointestinal intolerance). Secondary outcomes included the length of hospital stay, 90‐day readmission and use of drugs related to the primary outcome adverse events. Data were analysed using propensity score matching; we also conducted a subgroup analysis for those aged ≥75 years. Results: Among 19,930 eligible patients, 8924 received HRE and 11,006 received HREZ. Propensity score matching created 3578 matched pairs with a mean age of approximately 80 years. Compared with the HRE group, the HREZ group demonstrated a higher proportion of overall adverse events (3.1% vs. 4.7%; p < 0.001), allergic reactions (1.4% vs. 2.5%; p < 0.001) and antihistamine use (21.9% vs. 27.6%; p < 0.001). No significant differences were observed regarding in‐hospital mortality, hepatotoxicity or length of hospital stay between the groups. Subgroup analysis for those aged ≥75 years showed consistent results. Conclusion: Medical practitioners may consider adding PZA to an initial treatment regimen even in elderly patients with TB. Adding pyrazinamide to the initial tuberculosis treatment regimen (isoniazid, rifampicin and ethambutol) was not associated with in‐hospital mortality in older patients with tuberculosis. Older age alone may not be a reason to avoid pyrazinamide containing regimens. See relatededitorial [ABSTRACT FROM AUTHOR]

The current treatment protocol for drug-sensitive tuberculosis involves all four first-line anti-tuberculosis drugs: rifampicin, isoniazid, pyrazinamide and ethambutol hydrochloride in a single tablet, known as fixed-dose combination tablets. However, the analytical methods are scanty to test all these drugs simultaneously in a single run without any pre-sample process or using a simple method suitable for resource-limited settings. In this method, 50 mM potassium phosphate buffer containing 0.2% triethylamine (without pH adjustment) added with acetonitrile (98:2, v/v) was served as mobile phase A, while mobile phase B was 100% acetonitrile. All four drugs were separated within 10.3 min using a gradient mobile phase program in a C18 column (150 mm × 4.6 mm; 5 μm) and detected at two ultraviolet wavelengths (238 nm for rifampicin, isoniazid and pyrazinamide, and 210 nm for ethambutol hydrochloride). The method was selective, sensitive and linear with a correlation coefficient >0.999 with the acceptable precision and accuracy (<2% relative standard deviation) for all four drugs. In conclusion, the method is simple and it does not require any pH adjustment of the buffer/mobile phase, and within 11 min, the separation of all four drugs can be achieved. Overall, the method is suitable for quality testing of fixed-dose combination tablets in limited-resource settings. [ABSTRACT FROM AUTHOR]

Diagnostic development must occur in parallel with drug development to ensure the longevity of new treatment compounds. Despite an increasing number of novel and repurposed anti-tuberculosis compounds and regimens, there remains a large number of drugs for which no rapid and accurate molecular diagnostic option exists. The lack of rapid drug susceptibility testing for linezolid, bedaquiline, clofazimine, the nitroimidazoles (i.e pretomanid and delamanid) and pyrazinamide at any level of the healthcare system compromises the effectiveness of current tuberculosis and drug-resistant tuberculosis treatment regimens. In the context of current WHO tuberculosis treatment guidelines as well as promising new regimens, we identify the key diagnostic gaps for initial and follow-on tests to diagnose emerging drug resistance and aid in regimen selection. Additionally, we comment on potential gene targets for inclusion in rapid molecular drug susceptibility assays and sequencing assays for novel and repurposed drug compounds currently prioritized in current regimens, and evaluate the feasibility of mutation detection given the design of existing technologies. Based on current knowledge, we also propose design priorities for next generation molecular assays to support triage of tuberculosis patients to appropriate and effective treatment regimens. We encourage assay developers to prioritize development of these key molecular assays and support the continued evolution, uptake, and utility of sequencing to build knowledge of tuberculosis resistance mechanisms and further inform rapid treatment decisions in order to curb resistance to critical drugs in current regimens and achieve End TB targets.Trial registration: ClinicalTrials.gov identifier: NCT05117788..

In preclinical studies, a new antituberculosis drug regimen markedly reduced the time required to achieve relapse-free cure. This study aimed to preliminarily evaluate the efficacy and safety of this four-month regimen, consisting of clofazimine, prothionamide, pyrazinamide and ethambutol, with a standard six-month regimen in patients with drug-susceptible tuberculosis. An open-label pilot randomized clinical trial was conducted among the patients with newly diagnosed bacteriologically-confirmed pulmonary tuberculosis. The primary efficacy end-point was sputum culture negative conversion. Totally, 93 patients were included in the modified intention-to-treat population. The rates of sputum culture conversion were 65.2% (30/46) and 87.2% (41/47) for short-course and standard regimen group, respectively. There was no difference on two-month culture conversion rates, time to culture conversion, nor early bactericidal activity (P > 0.05). However, patients on short-course regimen were observed with lower rates of radiological improvement or recovery and sustained treatment success, which was mainly attributed to higher percent of patients permanently changed assigned regimen (32.1% vs. 12.3%, P = 0.012). The main cause for it was drug-induced hepatitis (16/17). Although lowering the dose of prothionamide was approved, the alternative option of changing assigned regimen was chosen in this study. While in per-protocol population, sputum culture conversion rates were 87.0% (20/23) and 94.4% (34/36) for the respective groups. Overall, the short-course regimen appeared to have inferior efficacy and higher incidence of hepatitis but desired efficacy in per-protocol population. It provides the first proof-of-concept in humans of the capacity of the short-course approach to identify drug regimens that can shorten the treatment time for tuberculosis.

Physiological changes during pregnancy may alter the pharmacokinetics (PK) of antituberculosis drugs. The International Maternal Pediatric Adolescent AIDS Clinical Trials Network P1026s was a multicenter, phase IV, observational, prospective PK and safety study of antiretroviral and antituberculosis drugs administered as part of clinical care in pregnant persons living with and without HIV. We assessed the effects of pregnancy on rifampin, isoniazid, ethambutol, and pyrazinamide PK in pregnant and postpartum (PP) persons without HIV treated for drug-susceptible tuberculosis disease. Daily antituberculosis treatment was prescribed following World Health Organization-recommended weight-band dosing guidelines. Steady-state 12-hour PK profiles of rifampin, isoniazid, ethambutol, and pyrazinamide were performed during second trimester (2T), third trimester (3T), and 2-8 of weeks PP. PK parameters were characterized using noncompartmental analysis, and comparisons were made using geometric mean ratios (GMRs) with 90% confidence intervals (CI). Twenty-seven participants were included: 11 African, 9 Asian, 3 Hispanic, and 4 mixed descent. PK data were available for 17, 21, and 14 participants in 2T, 3T, and PP, respectively. Rifampin and pyrazinamide AUC0-24 and C max in pregnancy were comparable to PP with the GMR between 0.80 and 1.25. Compared to PP, isoniazid AUC0-24 was 25% lower and C max was 23% lower in 3T. Ethambutol AUC0-24 was 39% lower in 3T but limited by a low PP sample size. In summary, isoniazid and ethambutol concentrations were lower during pregnancy compared to PP concentrations, while rifampin and pyrazinamide concentrations were similar. However, the median AUC0-24 for rifampin, isoniazid, and pyrazinamide met the therapeutic targets. The clinical impact of lower isoniazid and ethambutol exposure during pregnancy needs to be determined.

Pyrazinamide (PZA) is a key first-line antituberculosis drug that plays an important role in eradicating persister Mycobacterium tuberculosis (TB) bacilli and shortening the duration of tuberculosis treatment. However, PZA-resistance is on the rise, particularly among persons with multidrug-resistant (MDR) tuberculosis. This nationwide study was conducted to explore the prevalence of mutations conferring PZA resistance, catalogue mutation diversity, investigate the associations of PZA resistance with specific lineages, examine co-resistance to 13 first- and second-line drugs, and evaluate the diagnostic accuracy of sequencing pncA and panD genes for predicting PZA resistance. Whole genome sequencing was performed on 2,207 M. tuberculosis isolates from 25 States and 4 Union Territories of India. The majority of phenotypically PZA-resistant isolates (77%) harbored 171 distinct mutations in pncA; however, a small number of mutations in panD, rpsA and clpC1 were also observed. A set of novel mutations associated PZA resistance was uncovered, along with an additional 143 PZA resistance-conferring mutations in pncA based on application of WHO-endorsed grading rules. PZA resistance was predominately observed in Lineage 2 and eight lineage-specific resistance markers were identified. Mutations distributed across pncA correlate to 94% of PZA resistance and were the predominant drivers of phenotypic resistance; evidence generated herein substantiates sequencing the entire gene and promoter for comprehensive genotypic-based prediction of PZA resistance. This work provides key insights into the scope of PZA-resistance in India, a high drug-resistant TB burden country, and can support the effectiveness of TB prevention and control efforts.