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 genetic disorder where missing enzymes cause harmful sugar molecules to build up in tissues, leading to progressive damage throughout the body. Avlayah delivers a lab-made version of the missing enzyme (iduronate-2-sulfatase) that’s specially designed to cross into the brain, where standard treatments can’t reach. By replacing the deficient enzyme throughout the body and nervous system, Avlayah may help slow the disease’s progression and improve patients’ quality of life.
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