REGENXBIO Wins an FDA Reset on NAVSUNLI Gene Therapy for Hunter Syndrome
REGENXBIO reached alignment with the FDA on an accelerated approval path for its MPS II gene therapy NAVSUNLI, reversing a February complete response letter and enabling a third-quarter resubmission.
Shares of REGENXBIO jumped after the company said it had reached alignment with the U.S. Food and Drug Administration on a path forward for accelerated approval of NAVSUNLI, its one-time gene therapy for MPS II, the rare pediatric disorder also known as Hunter syndrome.
REGENXBIO is a clinical-stage gene therapy developer whose adeno-associated virus platform underpins programs across rare metabolic, neuromuscular and retinal diseases. NAVSUNLI (clemidsogene lanparvovec) would, if cleared, become the first gene therapy approved for MPS II, a condition that progressively damages the brain and body of affected boys.
The update marks a striking reversal. The FDA issued a complete response letter for the program in February 2026, but has now told the company that no additional studies are required and that longer-term data from the CAMPSIITE study will be reviewed on an expedited basis under the accelerated approval pathway. Management expects to resubmit the biologics license application in the third quarter of 2026, putting a potential approval decision back within reach.
Regulatory alignment is not approval, and the FDA could still decline the resubmitted application.
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