The U.S. Food and Drug Administration (FDA) has issued a formal warning letter to Purushothaman Damodara Kumaran, M.D., a clinical investigator at Senthil Specialty Hospital in Pondicherry, India, citing significant violations of federal regulations during a clinical bioequivalence study, according to agency records. The warning letter, dated Dec. 22, 2025, stems from an FDA inspection conducted at the facility between Jan. 20 and Jan. 24, 2025.
The inspection was part of the agency’s Bioresearch Monitoring Program, which assesses compliance with federal standards designed to protect the rights, safety, and welfare of human subjects in clinical trials. According to the FDA, Dr. Kumaran failed to conduct the in vivo bioavailability-bioequivalence study in accordance with the approved investigational plan and applicable provisions of the Federal Food, Drug, and Cosmetic Act and Title 21 of the Code of Federal Regulations. Specifically, the agency noted that required safety monitoring including weekly hematology and pulmonary function tests was not performed at mandated intervals for subjects enrolled in the study.
The warning letter states that half of the protocol-required safety assessments were not completed during critical periods of the trial, undermining the integrity of the study and raising concerns about the protection of study participants.
In his written response to an FDA Form 483 inspectional observation report, Dr. Kumaran cited “pragmatic reasons” for deviating from the schedule, including patient travel commitments and treatment plans. He also asserted that follow-ups, including telephone consultations, were used to monitor for adverse events. However, the FDA found no evidence to support that the study sponsor approved these deviations in advance or that the follow-ups occurred as claimed.
The FDA emphasized that it could not evaluate the adequacy of corrective actions because detailed plans to ensure future compliance were not provided in the investigator’s response. The agency instructed Dr. Kumaran to submit written documentation within 15 business days detailing steps taken to prevent recurrence of similar violations.
The warning letter highlights the agency’s ongoing scrutiny of international clinical research practices and underscores the importance of strict adherence to investigational plans to protect human subjects and ensure the reliability of data submitted for regulatory review.
