FDA Clinical Hold on Denali's Brain-Penetrant Pompe Therapy Highlights First-in-Human Safety Scrutiny
SHERIDAN, WYOMING - December 8, 2025 - Denali Therapeutics is facing another regulatory setback after the U.S. Food and Drug Administration (FDA) placed a clinical hold on DNL952, its enzyme replacement candidate for Pompe disease, citing preclinical hypersensitivity signals and demanding protocol changes before the company can start Phase I studies.
FDA Flags Hypersensitivity Risk Before First Human Dosing
The clinical hold, disclosed in an SEC filing, stems from "hypersensitivity reactions" observed in mouse models. While the agency has not required additional non-clinical studies, it is insisting on a more conservative first-in-human plan. Denali has been asked to lower the proposed starting dose for DNL952 and implement "revised inclusion criteria, adjusted stopping rules and unspecified safety monitoring commitments" before the program can proceed.