Children sought for clinical trial of Sanfilippo syndrome treatment

A clinical trial testing an experimental treatment for Sanfilippo syndrome type B is recruiting participants in the U.S.

The Phase 1/2 study (NCT07640984) testing JR-446 is sponsored by JCR Pharmaceuticals. Researchers expect to recruit about a dozen kids with Sanfilippo B, ages 5 and younger, who meet specific criteria related to disease progression and cognitive/developmental testing. The study is being run at sites in the U.S., the U.K., and Germany; a site in Oakland, California, is currently enrolling participants.

All participants will receive JR-446, administered by infusion into the bloodstream. The study’s main goal is to evaluate the drug’s safety profile over the course of a year of treatment.

JCR is developing JR-446 in collaboration with Medipal Holdings, which holds commercialization rights for the experimental medication outside of Japan. Earlier this month, the companies announced that the Phase 1/2 study had dosed its first participant.

“Dosing the first patient in this Phase I/II clinical trial is an important milestone for the [Sanfilippo B] community, as there is no approved treatment for this devastating and life-limiting lysosomal storage disorder that impacts patients’ neurocognitive development, independence, and quality of life,” Irene Chang, MD, the study’s principal investigator and associate professor at the University of California San Francisco, said in a press release from JCR and Medipal.

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Japan trial also recruiting

JCR is sponsoring a separate Phase 1/2 study (NCT06488924) in Japan, which is testing JR-446 in children and adolescents with Sanfilippo B ages 17 and younger. That trial is actively recruiting at sites in Hiroshima, Tokyo, and Okinawa.

Sanfilippo syndrome, also called mucopolysaccharidosis type III or MPS III, is a lysosomal storage disorder — a genetic condition that causes problems with lysosomes, cellular compartments that normally act like a garbage disposal, removing molecular waste. In all forms of Sanfilippo, lysosomes lack an enzyme needed to break down the sugar molecule heparan sulfate. Consequently, this sugar builds to toxic levels in brain cells, driving Sanfilippo symptoms.

Sanfilippo syndrome type B (MPS IIIB) is caused by mutations in the NAGLU gene, which leads to a deficiency of the lysosomal enzyme alpha-N-acetylglucosaminidase. The first treatment for any type of Sanfilippo was recently approved in the U.S., but that therapy is specifically designed for use in Sanfilippo type A, a different form of the disease caused by a mutation in a different gene. There are no available treatments for Sanfilippo B.

“Patients and families affected by this condition continue to face significant unmet medical needs, and we are encouraged to take this next step in evaluating the potential of this investigational therapy,” Chang said.

JR-446 is an enzyme replacement therapy designed to deliver a working version of the alpha-N-acetylglucosaminidase enzyme to the body’s cells, with the aim of clearing toxic heparan sulfate buildup and slowing disease progression. The therapy has been granted orphan drug status in the U.S. and Europe. This regulatory designation aims to incentivize the development of treatments for rare diseases.

JCR is also developing a similar enzyme replacement therapy for Sanfilippo syndrome type A,  JR-441.