Who is the person primarily responsible for the proper conduct of the trial at the site?

• A. Sponsor
• B. Investigator
• C. IRB/IEC
• D. Regulatory authority

Answer: (B)

The investigator is the person responsible for the proper conduct of the trial at the site. In GCP, the investigator is accountable for all aspects of the study at their site, including protecting the rights, safety, and welfare of participants, ensuring that the protocol is followed, that consent is properly obtained, and that data are accurately recorded and reported. They may delegate specific tasks to qualified staff, but the investigator retains overall responsibility for adherence to the protocol, regulatory requirements, and ethical standards.

The sponsor designs the study, provides the protocol and resources, and conducts monitoring and oversight at the sponsor level, but does not run the trial at the site. The IRB/IEC reviews and approves the study and ongoing safety, and the regulatory authority enforces compliance, but neither directly conducts the trial at the site.