REGENXBIO Clears Path for NAVSUNLI Approval in Hunter Syndrome

Following a successful appeal of a February 2026 Complete Response Letter, the FDA acknowledged that existing long-term data from the CAMPSIITE study provides sufficient evidence to support an accelerated approval process. The regulator dropped its previous demand for an untreated control arm, clearing a significant hurdle that had previously stalled the therapy’s progress. REGENXBIO plans to initiate a Type A meeting in July to finalize the review of biomarker and clinical data, which will serve as the basis for the formal Biologics License Application resubmission.

Curran Simpson, CEO of REGENXBIO, noted that the company is encouraged by the FDA’s willingness to prioritize rare disease treatments with clear unmet medical needs. Should the application succeed, the therapy—designed to deliver the iduronate-2-sulfatase gene directly to the central nervous system—will be commercialized in the United States by NS Pharma, a subsidiary of Nippon Shinyaku. The company anticipates that this regulatory shift will provide a vital, one-time treatment option for the approximately 2,000 patients worldwide currently diagnosed with the progressive, neurodegenerative disorder.