The FDA pushed back its target PDUFA date for Denali Therapeutics’ enzyme replacement therapy tividenofusp alfa (tivi) for Hunter syndrome by three months to April 5, 2026 after classifying an updated clinical pharmacology submission as a major amendment. Denali said the amendment corrected nonclinical molecular‑weight metadata used by the agency but did not add new efficacy or safety data. Management described the extension as procedural; investors reacted cautiously given the longer review timeline for a rare‑disease filing.