for Hunter syndrome (MPS II)
FDA approved Avlayah (tividenofusp alfa-eknm) on March 25, 2026 for the treatment of Hunter syndrome (MPS II) — ~2 weeks ahead of the extended Apr 7 PDUFA. First validation of Denali's enzyme transport vehicle (ETV) brain-shuttle technology in a commercial approval; opens read-through to the broader CNS-ERT pipeline (MPS IIIA, MPS IIIB, Parkinson's LRRK2).
Hunter syndrome is a rare inherited disease where large sugar molecules build up in body tissues, causing progressive damage. Avlayah is a lab-made replacement for the missing iduronate-2-sulfatase enzyme, engineered to cross into the brain. By delivering the needed enzyme directly to the central nervous system, this treatment may address the neurological damage that other therapies cannot reach.
This is a Phase 2/3, multiregional, two-arm, double-blind, randomized, active (standard-of-care)-controlled study of the efficacy and safety of tividenofusp alfa (DNL310), an investigational central nervous system (CNS)-penetrant enzyme-replacement therapy (ERT) for mucopolysaccharidosis type II (MPS II). Participants may also qualify to enter an open-label treatment phase with DNL310 or idursulfase based on pre-specified criteria.
Source: ClinicalTrials.gov