The FDA approved Denali Therapeutics’ Avlayah (tividenofusp alfa) for Hunter syndrome (mucopolysaccharidosis II) under the accelerated approval pathway, a notable win amid scrutiny that has followed recent rare-disease rejections. Avlayah’s approval follows the FDA’s earlier rejection of Regenxbio’s Hunter gene therapy, highlighting the agency’s demand for stronger evidence in the setting of clinical benefit claims for rare diseases. The decision comes after political pressure around rare-disease review consistency, and sets up Avlayah for continued clinical and potential label expansion as Denali aligns development expectations with the FDA’s framework.