First Dosing Begins in Phase I/II Trial of JR-446 for MPS IIIB in Japan

In Tokyo and Hyogo, Japan, MEDIPAL HOLDINGS CORPORATION and JCR Pharmaceuticals Co., Ltd. have announced the commencement of a Phase I/II clinical trial for JR-446, with the first patient already dosed. JR-446 is an innovative treatment under development for mucopolysaccharidosis type IIIB (MPS IIIB), also known as Sanfilippo syndrome type B. This rare disorder, affecting between 500 to 1,000 individuals globally, leads to severe central nervous system (CNS) symptoms and currently has no approved treatments.

JR-446 leverages JCR's proprietary J-Brain Cargo® technology, which has shown potential in preclinical trials for addressing MPS IIIB symptoms. The ongoing clinical trial is designed as an open-label, single-arm, and multi-center study that includes patients under the age of 18 who have been diagnosed with MPS IIIB. This trial aims to assess the safety, tolerability, and preliminary efficacy of JR-446. Additionally, the study will determine the optimal dosage through the administration of multiple doses. More details regarding the trial can be found on the Clinical Research Submission and Disclosure System.

Dr. Motomichi Kosuga, the Medical Director of the Division of Medical Genetics at the National Center for Child Health and Development and the leading medical expert of the study, expressed optimism about this development. He highlighted that MPS IIIB is one of the more prevalent forms of MPS III in Japan and primarily affects the CNS, causing severe symptoms. Dr. Kosuga is hopeful that this trial will lead to significant improvements in treatment outcomes and enhance the quality of life for patients and their families.

In a strategic move, MEDIPAL and JCR entered into a licensing agreement in September 2023, granting MEDIPAL the rights to commercialize JR-446 outside of Japan. MEDIPAL will also support JCR in the clinical development of JR-446 within Japan, including the distribution of investigational drugs, raising disease awareness, and advancing the clinical trial. This collaboration underscores the commitment of both companies to develop treatments for ultra-rare diseases, aiming to provide new hope for patients and their families.

Mucopolysaccharidosis type IIIB is a genetic disorder caused by mutations in the NAGLU gene, which encodes for a lysosomal enzyme crucial for degrading heparan sulfate. The accumulation of heparan sulfate in the CNS results in rapid neurological decline, with patients experiencing sleep disorders, loss of speech, and behavioral changes, significantly affecting their quality of life and that of their families.

JCR Pharmaceuticals has pioneered the J-Brain Cargo® platform technology, intended to deliver biotherapeutics into the CNS. The first drug developed using this technology, IZCARGO® (pabinafusp alfa), has been approved in Japan for treating lysosomal storage disorders.

MEDIPAL HOLDINGS CORPORATION is a holding company managing and supporting the activities of its subsidiaries in various sectors, including prescription pharmaceuticals, cosmetics, daily necessities, over-the-counter pharmaceuticals, animal health products, and food processing raw materials. JCR Pharmaceuticals is a global specialty pharmaceutical company focused on developing treatments for rare and genetic diseases, with a nearly 50-year history in Japan and expanding operations in the US, Europe, and Latin America. They are dedicated to addressing conditions such as growth disorder, MPS II, Fabry disease, acute graft-versus-host disease, and renal anemia, among others.

The initiation of this clinical trial represents a significant step forward in the development of effective treatments for MPS IIIB, bringing hope to patients and their families worldwide.