What is the ultimate responsibility of the investigator in a clinical trial?

• A. The sponsor holds the ultimate responsibility.
• B. The IRB holds the ultimate responsibility.
• C. The investigator retains the ultimate responsibility and should maintain oversight of delegated activities to ensure rights, safety, and well-being, and data reliability.
• D. Delegated personnel hold their own responsibility.

Answer: (B)

The fundamental idea is that the ethics oversight body is the ultimate guardian of participants’ rights and welfare. The IRB (institutional review board) is tasked with protecting subjects by reviewing the study design, assessing risk-to-benefit balance, and approving informed consent processes. It has the authority to approve, request changes, suspend, or terminate a trial based on safety and ethical considerations, and it continues to monitor the trial as it proceeds.

While the investigator is responsible for conducting the trial at the site in compliance with the protocol and GCP, obtaining informed consent, ensuring participant safety, and supervising any delegated tasks, the IRB holds the final responsibility for those ethical safeguards. The sponsor and delegated personnel play important roles in the operation and execution of the study, but ultimate ethical accountability for participant protection rests with the IRB.