Denali Therapeutics (Nasdaq: DNLI) announced that the U.S. Food and Drug Administration (FDA) has extended the review period for its Biologics License Application (BLA) for tividenofusp alfa, an investigational therapy for mucopolysaccharidosis type II (MPS II), or Hunter syndrome. The Prescription Drug User Fee Act (PDUFA) target date has been moved from January 5, 2026, to April 5, 2026.
As reported on “drugs.com,” the extension follows Denali’s submission of updated clinical pharmacology data in response to an FDA information request. The FDA classified this as a Major Amendment, which adds three months to the review timeline. Importantly, the extension is not related to efficacy, safety, or biomarker concerns, and no additional data were requested.
“We feel the urgency to deliver for the MPS community and remain committed to working with regulators, physicians, and advocates,” said Ryan Watts, Ph.D., CEO of Denali Therapeutics.
About Tividenofusp Alfa
Tividenofusp alfa (DNL310) combines the iduronate 2-sulfatase (IDS) enzyme with Denali’s proprietary TransportVehicle™ platform, designed to cross the blood-brain barrier and address both neurological and physical symptoms of Hunter syndrome. The therapy has received Fast Track and Breakthrough Therapy designations from the FDA and Priority Medicines status from the European Medicines Agency.
The ongoing Phase 2/3 COMPASS trial is enrolling patients globally to support regulatory submissions. Tividenofusp alfa remains investigational and is not yet approved by any health authority.
About Hunter Syndrome (MPS II)
Hunter syndrome is a rare genetic disorder caused by IDS enzyme deficiency, leading to accumulation of glycosaminoglycans (GAGs) and progressive multi-organ damage, including the brain. Current enzyme replacement therapies do not cross the blood-brain barrier, leaving neurological symptoms untreated. There is a significant unmet need for therapies addressing both central nervous system (CNS) and systemic manifestations.
