JCR Pharmaceuticals Co., Ltd. announced key results from the 52-week interim data of its global phase I/II study with JR-171 (INN: lepunafusp alfa) in individuals with mucopolysaccharidosis type I (MPS I, also known as Hurler, Hurler-Scheie and Scheie syndrome). JCR Pharmaceuticals plans to host a webinar on October 4, 2023, to present further details of the 52-week results of the clinical study. The phase I/II clinical study is being conducted at several centers in Brazil, Japan and the United States and is composed of two parts: Part one of the open-label study is a 4-week dose-escalation study in adult individuals with MPS I, while part 2 compares two doses of JR-171 in pediatric and adult individuals with MPS I. The main objectives of the phase I/II clinical study are to establish the safety of chronic dosing of JR-171 in individuals with MPS I, the pharmacokinetics of JR-171, to investigate somatic disease control based on biomarkers and somatic endpoints, and to explore early signs of efficacy on central nervous signs and symptoms of MPS I. At a world Sympoisum TM2023 in February 2023, JCR already presented that the reduction of cerebrospinal fluid biomarker was observed in all patients, and biomarkers in serum and urine decreased (in treatment-naive subjects) or were stable (in enzyme replacement therapy ("ERT") - experienced subjects) upon treatment with JR-171 for 12 weeks.

There were no drug-related serious adverse events (SAEs) reported during the study. There were no gross differences in the safety profile of JR-171 at either dose level tested.