Adnan Dahdul, MD – FDA Warning Letter, Jun 20, 2024

The FDA issued a Warning Letter to Adnan Dahdul, MD, on March 12, 2026, following a clinical site inspection conducted from May 6 to June 20, 2024. The inspection identified significant violations of federal regulations under 21 CFR Parts 312 and 50 regarding the conduct of a biologics clinical study. The primary issues included a failure to obtain legally effective informed consent, as several subjects underwent study procedures before signing consent forms. Additionally, Dr. Dahdul failed to follow the investigational plan by enrolling participants with exclusionary medical conditions, such as unstable psychiatric disorders and substance abuse, which jeopardized their safety. The site also mishandled the investigational product by administering incorrect or expired doses and failed to maintain accurate records. Investigators noted missing documentation, non-attributable data entries, and a failure to accurately report a subject"s cause of death in the study database. While Dr. Dahdul previously implemented some corrective actions, the FDA found them inadequate because the violations persisted after staff training. Dr. Dahdul is required to submit a written response within 15 business days detailing how he will improve investigator oversight and ensure the integrity of study data moving forward.