Search

Hypercalcemia due to excess parathyroid hormone (PTH) production is a common condition among patients with end-stage renal disease (ESRD), often referred to as tertiary hyperparathyroidism. There are limited effective medical treatment options currently available for such patients. Denosumab is a monoclonal antibody that inhibits osteoclast activation, thereby reducing calcium release from bones. Denosumab has been used to treat medically-refractory hypercalcemia in non-ESRD patients with hyperparathyroidism. Denosumab has also been used to treat non-PTH-mediated hypercalcemia in patients with advanced chronic kidney disease and ESRD. In this case report, we describe the use of denosumab to successfully treat a case of medically refractory hypercalcemia due to immobilization in a patient on peritoneal dialysis with severe underlying tertiary hyperparathyroidism. In spite of persistently elevated PTH, hypercalcemia quickly resolved after a single dose of denosumab. The patient subsequently developed temporary hypocalcemia requiring medical intervention. Our case report, which is the first described use of denosumab for treatment of hypercalcemia in the setting of tertiary hyperparathyroidism in a peritoneal dialysis patient, adds to the body of literature suggesting denosumab is a useful therapeutic agent in patients with ESRD. Issues with post-treatment electrolyte management and other therapeutic considerations are also discussed.

BackgroundTwo recombinant enzymes (agalsidase alfa 0.2 mg/kg/every other week and agalsidase beta 1.0 mg/kg/every other week) have been registered for the treatment of Fabry disease (FD), at equal high costs. An independent international initiative compared clinical and biochemical outcomes of the two enzymes.MethodsIn this multicentre retrospective cohort study, clinical event rate, left ventricular mass index (LVMI), estimated glomerular filtration rate (eGFR), antibody formation and globotriaosylsphingosine (lysoGb3) levels were compared between patients with FD treated with agalsidase alfa and beta at their registered dose after correction for phenotype and sex.Results387 patients (192 women) were included, 248 patients received agalsidase alfa. Mean age at start of enzyme replacement therapy was 46 (±15) years. Propensity score matched analysis revealed a similar event rate for both enzymes (HR 0.96, P=0.87). The decrease in plasma lysoGb3 was more robust following treatment with agalsidase beta, specifically in men with classical FD (β: −18 nmol/L, P<0.001), persisting in the presence of antibodies. The risk to develop antibodies was higher for patients treated with agalsidase beta (OR 2.8, P=0.04). LVMI decreased in a higher proportion following the first year of agalsidase beta treatment (OR 2.27, P=0.03), while eGFR slopes were similar.ConclusionsTreatment with agalsidase beta at higher dose compared with agalsidase alfa does not result in a difference in clinical events, which occurred especially in those with more advanced disease. A greater biochemical response, also in the presence of antibodies, and better reduction in left ventricular mass was observed with agalsidase beta.

Patients with Fabry disease (FD) are at a high risk for developing chronic kidney disease and cardiovascular disease. The availability of specific but costly therapy has elevated the profile of this rare condition. This KDIGO conference addressed controversial areas in the diagnosis, screening, and management of FD, and included enzyme replacement therapy and nonspecific standard-of-care therapy for the various manifestations of FD. Despite marked advances in patient care and improved overall outlook, there is a need to better understand the pathogenesis of this glycosphingolipidosis and to determine the appropriate age to initiate therapy in all types of patients. The need to develop more effective specific therapies was also emphasized.

Enzyme replacement therapy with a-galactosidase A has been used to treat Fabry disease since 2001. This article reviews the published evidence for clinical efficacy of the two available enzyme preparations. We focused on heart, kidney, and nervous system manifestations, which impact both quality of life and overall prognosis. A literature search was undertaken to identify prospective open or randomized controlled trials of enzyme replacement therapy in patients with Fabry disease published since 2001. To date, no definitive conclusion can be drawn from studies that have directly compared therapeutic responses between the two commercially available enzyme preparations. Significant clinical benefits of enzyme replacement therapy have been demonstrated, mainly in patients at an early phase of the disease, with beneficial effects on heart, kidneys, pain, and quality of life in treated patients. Incidence of antibodies against agalsidase alfa and agalsidase beta observed during major clinical studies suggests a greater antigenic response to agalsidase beta. Further studies are required to confirm the long-term clinical benefits of enzyme replacement therapy. More studies with female patients are needed as are investigations of early initiation of enzyme replacement therapy to determine the optimal time to start treatment to prevent irreversible organ damage. The value of adjunctive and supportive therapies should also be rigorously analyzed.

Purpose: Fabry disease is a progressive multiorgan, multisystem disorder that is caused by a deficiency in the lysosomal enzyme a-galactosidase A. Serious renal, cardiac, and cerebrovascular involvement are responsible for much of the morbidity and premature mortality associated with Fabry disease, and neuropathic pain, gastrointestinal problems, and hypohidrosis negatively affect quality of life of patients with Fabry disease. Fabry disease is X-linked, but women are often symptomatic and may be as severely affected as men.Methods: We propose a series of therapeutic and symptomatic goals for use in setting the expectations of enzyme replacement therapy and for assessing the response to enzyme replacement therapy in the treatment of Fabry disease.Results: Enzyme replacement therapy has been available since 2001 and has been associated with benefit in clinical trials, including stabilization of kidney function, improvement of cardiac structure and function, reduction in severity of neuropathic pain, and improvement in gastrointestinal involvement.Conclusions: The presentation of these therapeutic goals will aid in the evaluation of response to enzyme replacement therapy and be useful in establishing an overall management plan for individual patients.

Fabry disease is a progressive multiorgan, multisystem disorder that is caused by a deficiency in the lysosomal enzyme α-galactosidase A. Serious renal, cardiac, and cerebrovascular involvement are responsible for much of the morbidity and premature mortality associated with Fabry disease, and neuropathic pain, gastrointestinal problems, and hypohidrosis negatively affect quality of life of patients with Fabry disease. Fabry disease is X-linked, but women are often symptomatic and may be as severely affected as men.

Enzyme replacement therapy with α-galactosidase A has been used to treat Fabry disease since 2001. This article reviews the published evidence for clinical efficacy of the two available enzyme preparations. We focused on heart, kidney, and nervous system manifestations, which impact both quality of life and overall prognosis. A literature search was undertaken to identify prospective open or randomized controlled trials of enzyme replacement therapy in patients with Fabry disease published since 2001. To date, no definitive conclusion can be drawn from studies that have directly compared therapeutic responses between the two commercially available enzyme preparations. Significant clinical benefits of enzyme replacement therapy have been demonstrated, mainly in patients at an early phase of the disease, with beneficial effects on heart, kidneys, pain, and quality of life in treated patients. Incidence of antibodies against agalsidase alfa and agalsidase beta observed during major clinical studies suggests a greater antigenic response to agalsidase beta. Further studies are required to confirm the long-term clinical benefits of enzyme replacement therapy. More studies with female patients are needed as are investigations of early initiation of enzyme replacement therapy to determine the optimal time to start treatment to prevent irreversible organ damage. The value of adjunctive and supportive therapies should also be rigorously analyzed.

Purpose: This 10-week study was conducted to determine the pharmacokinetics of varying doses of agalsidase alfa and evaluate the effect of dose and dosing frequency on plasma Gb3levels.Methods: Eighteen adult male Fabry patients, naive to enzyme replacement therapy, were randomized to one of five regimens: 0.1, 0.2, or 0.4 mg/kg weekly; 0.2 mg/kg every other week (the approved dose); or 0.4 mg/kg every other week. Intravenous infusion rate was 0.1 mg/kg per 20 minutes. Plasma Gb3levels were assessed at baseline and periodically during the study.Results: The mean half-life was 56–76 minutes, and the mean volume of distribution at steady state was 17%–18% of body weight, with no significant association between dose and half-life, clearance, or volume of distribution at steady state. The area under the curve was linearly proportional to the dose from 0.1 to 0.4 mg/kg. Baseline average plasma Gb3was 9.12 ± 2.61 nmol/mL and after 10 weeks of treatment was significantly reduced by about 50% in each group with no statistically significant differences between groups.Conclusions: Reduction of plasma Gb3levels was independent of dose or dose frequency in the range tested. These observations, coupled with the clinical trial experience of both agalsidase alfa and agalsidase beta, indicate that the standard dose of agalsidase alfa is sufficient to maximally reduce plasma Gb3. However, because plasma Gb3is not a validated surrogate of disease severity in Fabry disease, further clinical study will be required to determine the optimal dosing regimen for providing maximal clinical benefit.

Interest in the diagnosis and treatment of Fabry disease has been greatly stimulated by the availability of Food and Drug Administration–pproved, effective enzyme replacement therapy. This review will update the progress in this area since enzyme replacement therapy has become available. Fabry disease is often associated with proteinuric chronic kidney disease (CKD), and it appears that the treatment paradigms that have proven to be so effective in diabetes mellitus and other forms of proteinuric kidney disease are also effective in conjunction with enzyme replacement therapy for treating the kidney manifestations of Fabry disease. As such, Fabry disease represents an interesting example of progressive proteinuric kidney disease in which the usual blood pressure is lower than in other forms of CKD. This makes the use of effective antiproteinuric therapy challenging, especially considering the autonomic dysfunction that appears to be part of the disease. Comprehensive therapy for Fabry disease includes enzyme replacement therapy and all of the adjunctive therapies that are currently used to treat all forms of proteinuric CKD. It is anticipated that this approach will preserve kidney function and also benefit the cardiac and cerebrovascular systems in patients with Fabry disease.

The application of the N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker for the solid-phase synthesis of oligosaccharides is described. The oligosaccharide products can be cleaved from the resin by hydrazine, ammonia or primary amines, but the linker is stable under the conditions of oligosaccharide synthesis. The first sugar can be attached to the resin linker via a vinylogous amide bond, or by ether linkage using a p-aminobenzyl alcohol converter.

Clarithromycin is a macrolide antibiotic similar in structure to erythromycin, but suggested to have fewer drug interactions. Although a pharmacokinetic interaction between clarithromycin and cyclosporine was recently reported, its magnitude and mechanism have not been explored. A 43‐year‐old renal transplant recipient receiving cyclosporine was treated with clarithromycin because of pneumonia. A cyclosporine pharmacokinetic study was performed 8 days after the initiation of the clarithromycin and 14 days after stopping the drug. Clarithromycin coadministration caused an approximately 2‐fold increase in the area under the whole blood concentration versus time curve of cyclosporine. The oral clearance of cyclosporine was halved by clarithromycin, but the terminal elimination rate constant decreased only 15% and mean residence time 20%. These observations suggest that clarithromycin inhibits not only the hepatic metabolism but also the intestinal metabolism of cyclosporine. Caution is advised when administering the two drugs concurrently, and additional studies are necessary to elucidate the mechanism of this interaction.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

For Abstract see ChemInform Abstract in Full Text.