Denali Therapeutics Falls After FDA Extends Drug Review
Shares drop over 2% after the agency pushes its decision on the company's Hunter Syndrome treatment, Tividenofusp Alfa, by three months.
Shares of Denali Therapeutics (NASDAQ: DNLI) fell more than 2% in after-hours trading after the company for its key drug candidate, Tividenofusp Alfa. The new Prescription Drug User Fee Act (PDUFA) date, the deadline for the agency to make a decision on the Biologics License Application (BLA), is now set for April 5, 2026.
The delay was triggered by Denali's submission of updated clinical pharmacology information, which the FDA classified as a Major Amendment to the application, thus requiring additional time for review. The company clarified that the extension was a standard procedure and was not prompted by any concerns over the drug's efficacy, safety, or biomarker data.
Tividenofusp Alfa is an investigational enzyme replacement therapy for Mucopolysaccharidosis Type II (MPS II), also known as Hunter Syndrome. Hunter Syndrome is that primarily affects young boys and leads to progressive and severe neurological and physical decline. What makes Denali's candidate notable is its proprietary Enzyme Transport Vehicle (ETV) technology, designed to cross the blood-brain barrier to address both the systemic and neurological symptoms of the disease—a significant limitation of current treatments.
The treatment has previously been by the FDA, highlighting its potential to provide a substantial improvement over existing therapies. Despite the near-term setback and resulting stock drop, the long-term outlook for the drug among analysts remains positive. Prior to the announcement, on DNLI stock, pointing to the transformative potential of Tividenofusp Alfa based on promising Phase 1/2 study results.
The three-month delay introduces a degree of uncertainty and pushes back the potential commercial launch of a critical therapy for patients and a significant revenue driver for Denali. Investors will now be closely watching for the new PDUFA date in April 2026, which will be a pivotal moment for the company and the Hunter Syndrome community.