Who bears the ultimate responsibility for the conduct of a clinical trial at a site?

• A. The Sponsor
• B. The Investigator
• C. The Regulatory Authority
• D. The Monitor

Answer: (B)

Ultimate responsibility for the conduct of a clinical trial at a site rests with the investigator. The investigator is accountable for protecting the rights, safety, and welfare of participants and for carrying out the study in accordance with the protocol, Good Clinical Practice, and applicable laws at that site. This includes obtaining proper informed consent, following procedures as written, managing protocol deviations, and maintaining accurate and complete study documentation. Even when tasks are delegated to sub-investigators or study staff, the investigator remains answerable to the sponsor and to regulatory authorities for how those duties are performed. The sponsor oversees the overall trial design, ethics approvals, and resources, but the day-to-day conduct at the site is the investigator’s responsibility. Regulatory authorities provide oversight and inspections, but they do not conduct the study at the site. Monitors support adherence and quality, but ultimate accountability for site conduct lies with the investigator.