FDA Extends Review of DNLI's Hunter Syndrome Drug by Three Months

Core Insights - Denali Therapeutics Inc. (DNLI) announced that the FDA has extended the review timeline for its Biologics License Application (BLA) for tividenofusp alfa, a treatment for mucopolysaccharidosis type II (MPS II) [1][3][7] - The new target date for the BLA review is now April 5, 2026, pushed back from January 5, 2026, due to the submission of updated clinical pharmacology information [3][7] - The extension is classified as a major amendment and is not related to the drug's efficacy, safety, or biomarkers [3][4][7] Company Performance - Denali's stock experienced a decline of 26.5% year to date, contrasting with the industry average gain of 9.2% [2] Drug Development Details - Tividenofusp alfa is designed to deliver the iduronate 2-sulfatase (IDS) enzyme to address symptoms of Hunter syndrome [4][5] - The FDA has previously granted Fast Track and Breakthrough Therapy designations to tividenofusp alfa, and the European Medicines Agency has given it Priority Medicines designation [8] Other Pipeline Candidates - Denali is also developing DNL126 for Sanfilippo syndrome type A (MPS IIIA), with the FDA considering cerebrospinal fluid heparan sulfate as a potential surrogate endpoint for accelerated approval [9] - Another candidate, TAK-594/DNL593, is in collaboration with Takeda for treating frontotemporal dementia (FTD) [10] - Denali and Biogen are jointly evaluating BIIB122/DNL151 for Parkinson's disease, with a global phase IIb study currently ongoing [11][12] Market Position - Denali currently holds a Zacks Rank 3 (Hold), while competitors Amicus Therapeutics and CorMedix have higher rankings of 1 (Strong Buy) and 2 (Buy) respectively [13]