MEDIPAL HOLDINGS CORPORATION  and JCR Pharmaceuticals Co., Ltd.  announced that the Ministry of Health, Labour and Welfare of Japan has granted orphan drug designation to JR-446, an investigational drug for the treatment of mucopolysaccharidosis type IIIB (MPS IIIB or Sanfilippo syndrome type B).

JR-446 was granted orphan drug designation for the treatment of MPS IIIB by the U.S. Food and Drug Administration (FDA) in April 2025, and by the European Commission (EC) in June 2025.

MPS IIIB affects an estimated 500 to 1,000 individuals worldwide, causing severe central nervous system (CNS) symptoms. Despite the dire need, there are currently no approved treatments available for this condition. JR-446, developed using JCR’s proprietary J-Brain Cargo^® technology, has shown promising non-clinical results in addressing the CNS symptoms of this challenging disorder, and it is currently being studied in a Phase I/II trial that is being conducted in Japan (JR-446-101) under a collaboration agreement between the two companies.

In September 2023, MEDIPAL and JCR entered into a licensing agreement in which MEDIPAL will commercialize JR-446 for MPS IIIB outside of Japan. In addition, MEDIPAL will support JCR in the clinical development of JR-446 in Japan, including the distribution of investigational drugs, disease awareness, and clinical trial advancement.

Both companies remain committed to developing a therapy for patients with MPS IIIB as swiftly as possible.