Denali Therapeutics Inc. (DNLI) announced that the U.S. FDA has granted accelerated approval for AVLAYAH, marking the first new treatment option for Hunter syndrome in nearly 20 years. AVLAYAH is also the first FDA-approved biologic engineered to cross the blood-brain barrier and reach both the body and the brain, according to the company.
Hunter syndrome, or MPS II, is a rare genetic disorder caused by a deficiency of the IDS enzyme, leading to the buildup of complex sugars that damage organs and the brain. Children with the condition often experience progressive cognitive, behavioral, and physical decline.
AVLAYAH (tividenofusp alfa-eknm) is an intravenous enzyme replacement therapy designed to deliver the IDS enzyme throughout the body and into the central nervous system using Denali's TransportVehicle platform. It is approved for treating neurologic manifestations of Hunter syndrome in pediatric patients weighing at least 5 kg, before advanced neurologic impairment. Continued approval may depend on confirmatory results from the ongoing Phase 2/3 COMPASS study.
The FDA's decision was based on Phase 1/2 data showed a 91% reduction in cerebrospinal fluid heparan sulfate (CSF HS) a key disease biomarker, by week 24. Nearly all treated patients reached biomarker levels comparable to individuals without Hunter syndrome. The most common adverse reactions were infusion-related events.
AVLAYAH is administered once weekly and will be available in the U.S. shortly after approval. The FDA also granted Denali a Rare Pediatric Disease Priority Review Voucher in connection with the approval. The company noted that AVLAYAH is not approved by health authorities outside of the U.S.
DNLI has traded between $10.57 and $23.77 over the past year. The stock closed Wednesday's trading at $22.47, up 7.15%.
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