Pharmacokinetics and pharmacodynamics of JR-051, a biosimilar of agalsidase beta, in healthy adults and patients with Fabry disease: Phase I and II/III clinical studies.

Fabry disease is a rare X-linked lysosomal disease, in which mutations in the gene encoding α-galactosidase A result in progressive cellular accumulation of globotriaosylceramide (GL-3) in various organs including the skin, kidney, and heart, often leading to life-threatening conditions. Enzyme replacement therapy is currently the standard therapy for the disease, to which two α-galactosidase A formulations have been approved: agalsidase α (Replagal®, Shire) and agalsidase β (Fabrazyme®, Sanofi). We have recently developed a biosimilar of agalsidase β, JR-051, and investigated its pharmacokinetics and pharmacodynamics to assess its bioequivalence to agalsidase β. In a randomized phase I study, healthy adult male volunteers were treated with JR-051 or agalsidase β and the pharmacokinetics of the drugs were compared. The ratio of geometric means (90% confidence interval [CI]) of the AUC and C for JR-051 over agalsidase β were 0.91 (0.8294, 1.0082) and 0.90 (0.7992, 1.0125), respectively. In a 52-week, single-arm, phase II/III study, patients with Fabry disease switched therapy from agalsidase β to JR-051 to evaluate its pharmacodynamics. The mean (95% CI) plasma GL-3 concentrations at weeks 26 and 52 relative to pre-JR-051 administration were 1.03 (0.91, 1.15) and 0.96 (0.86, 1.06), respectively, which were within the pre-determined bioequivalence acceptance range (0.70, 1.43). The mean (95% CI) plasma globotriaosylsphingosine (lyso-GL-3) concentrations at weeks 26 and 52 relative to pre-JR-051 administration were 1.07 (0.92, 1.23) and 1.13 (1.03, 1.22), respectively. Estimated glomerular filtration rate and left ventricular mass index, as renal and cardiac function indicators, showed no notable changes from baseline throughout the study period, and no new safety concerns were identified. In conclusion, these studies demonstrated bioequivalence of JR-051 to agalsidase β in terms of its pharmacokinetics and pharmacodynamics. JR-051 offers a potential new treatment option for patients with Fabry disease.