FDA Reverses Course on Regenxbio’s Hunter Syndrome Gene Therapy
Rare Disease & Gene Therapy — June 22, 2026
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Just four months after rejecting it, the FDA told Regenxbio its existing data may support an accelerated approval filing for Navsunli in Hunter syndrome — the latest rare-disease about-face under new agency leadership, landing alongside a completed Rett-syndrome pivotal enrollment and two RNAi regulatory wins.
Today’s top developments:
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What to Watch
- Taysha TSHA-102 catalysts — REVEAL 6-month interim data and FDA BLA pathway feedback, both expected 1H 2027, will be the primary catalysts to track for TSHA-102 and will clarify whether intrathecal AAV evidence standards have evolved since prior CNS program reviews.
- Regeneron cemdisiran in gMG — The PDUFA date and EMA opinion timing will determine whether an siRNA can displace or complement IV complement inhibitors in gMG, with payer willingness to reimburse quarterly subcutaneous dosing at a premium a key open question.
- Solid Biosciences SGT-003 in Duchenne — SGT-003 recruitment pace and early expression data will be watched against ELEVIDYS real-world outcomes to assess whether next-generation capsid engineering translates to clinically meaningful differentiation in Duchenne.
- Alnylam-Pfizer PMCPA episode — The finding raises questions about how promotional conduct standards will apply as multiple RNAi and small-molecule therapies compete for the same rare disease physician audiences in ATTR and adjacent indications.
This brief highlights the edition’s top stories. Read the full June 22, 2026 edition → for all stories and analysis — or browse the Rare Disease & Gene Therapy archive.
