FDA Grants Priority Review to Denali's Hunter Syndrome Therapy

Denali Therapeutics announced that the FDA has accepted its Biologics License Application (BLA) for tividenofusp alfa, a novel enzyme replacement therapy targeting Hunter syndrome, and granted it Priority Review with a PDUFA target action date of January 5, 2026. Hunter syndrome is a rare genetic disorder caused by an enzyme deficiency that leads to the accumulation of harmful substances in the brain and body, with current treatments unable to cross the blood-brain barrier to address neurological symptoms. Tividenofusp alfa utilizes Denali's proprietary TransportVehicle™ platform to deliver the missing enzyme across the blood-brain barrier, potentially treating both physical and cognitive symptoms, marking the first significant advancement in nearly two decades. The FDA's acceptance is supported by data from a Phase 1/2 study involving 47 participants, and an ongoing Phase 2/3 COMPASS study aims to further validate the treatment's safety and efficacy for global approval. While the Priority Review designation signals a promising opportunity for Denali to address an unmet medical need and potentially boost revenues, the company faces typical drug development risks and competitive challenges in the lysosomal storage disease treatment landscape. Denali is preparing for a potential U.S. commercial launch contingent upon successful regulatory outcomes.