RegenXBio sells Hunter Syndrome Gene Therapy's U.S., Asia Commercial Rights for $110M Upfront

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RegenXBio sells Hunter Syndrome Gene Therapy’s U.S., Asia Commercial Rights for $110M Upfront

With an FDA approval submission for RegenXBio’s Hunter syndrome gene therapy already underway, the biopharma has now found a commercialization partner for both the U.S. and Asian markets.

That partner, Japan’s Nippon Shinyaku, is handing over $110 million upfront to lead on the commercialization of two gene therapies—RGX-121 for Hunter syndrome and RGX-111 for Hurler syndrome. RegenXBio will also be in line for up to $40 million in development and regulatory milestones and $660 million in sales milestones as well as double-digit royalties on net sales.

RegenXBio began its rolling submission to the FDA for accelerated approval of RGX-121 in the third quarter of last year with the expectation that the submission be completed in the first quarter of 2025. With a regulatory decision expected before the end of this year, RGX-121 could become the first gene therapy approved for Hunter syndrome.

Also known as mucopolysaccharidosis type II, Hunter syndrome is a rare inherited disorder in which the body is unable to break down sugar molecules. This leads to buildup in the organs and can cause damage over time that affects patients’ physical and mental abilities.

RGX-111, which is being developed for a similar inherited disorder called Hurler syndrome, is further back in development. RegenXBio said the gene therapy has demonstrated “very promising results” in a phase 1/2 study. While RGX-121 is designed to deliver the IDS gene within cells in the central nervous systems of patients, RGX-111 uses a AAV9 vector to deliver the IDUA gene.

“This partnership with Nippon Shinyaku is exciting in that it maximizes our collective strengths and enables access of two potentially transformational medicines to key markets,” RegenXBio CEO Curran Simpson said in the release. “The structure of the agreement allows us to leverage our expertise in gene therapy manufacturing while also capturing milestones and a meaningful share of future product revenues.”

Under the agreement, Nippon Shinyaku will commercialize both gene therapies in the U.S. and Asia, while RegenXBio will retain control of the further clinical development of the candidates. RegenXBio is also keeping hold of the proceeds from the priority review voucher it may receive once RGX-111 gets approved.