Nippon Shinyaku buys rights to Regenxbio rare disease gene therapies

Regenxbio and Nippon Shinyaku have partnered for the development and commercialization of two AAV gene therapies targeting mucopolysaccharidoses, rare genetic disorders that occur when the body can't break down sugar molecules.

The deal gives the Japan-based drugmaker the rights to commercialize two Regenxbio products in the U.S. and Asia — RGX-121 for the treatment of mucopolysaccharidosis II (MPS II), also known as Hunter syndrome, and RGX-111 for mucopolysaccharidosis I (MPS I), also known as Hurler syndrome. Regenxbio will lead the manufacturing of both products for clinical and commercial supply in the U.S. and Asia and will also lead future clinical development.

RGX-121 is poised to be the first gene therapy for MPS II with potential FDA approval anticipated in late 2025, and RGX-111 has demonstrated promising results in a phase 1/2 study.

MPS II is a rare disease caused by a variation in the IDS gene, which contains the instructions for the production of a specific enzyme known as I2S. RGX-121, designed to deliver a functional copy of the I2S gene directly to the central nervous system, is a potential one-time AAV therapeutic for the treatment of boys with MPS II.

MPS I is caused by a mutation in the α-l-iduronidase (IDUA) gene. RGX-111 is designed to use the AAV9 vector to deliver the IDUA gene to the central nervous system, potentially helping prevent the progression of cognitive deficits that otherwise occurs in MPS I patients.

Under the terms of the agreement, Regenxbio will receive $110 million at closing and up to an additional $700 million if certain milestones are achieved, consisting of $40 million in potential development and regulatory milestones and $660 million in potential sales milestones. Regenxbio will also receive royalties on sales in the U.S. and Asia.

Regenxbio is advancing a pipeline of AAV therapeutics for retinal and rare diseases, including RGX-202 in Duchenne muscular dystrophy. Back in November, the company announced it had advanced the gene therapy into pivotal stage trials and dosed its first patient.