The investigator is the person responsible for the conduct of a clinical trial at a trial site and bears primary responsibility for ensuring the protection of human subjects. Under ICH E6 Section 4, investigators must be appropriately qualified by education, training, and experience and must document these qualifications.
What Are Investigator Responsibilities?
The investigator’s core responsibilities include conducting the trial in accordance with the approved protocol, complying with GCP and applicable regulatory requirements, and ensuring that all trial staff are adequately trained and supervised. The investigator is also responsible for the medical care of trial subjects during the study and must be available to respond to adverse events and medical concerns. Effective communication with the sponsor and the Institutional Review Board (IRB) is essential throughout the trial.
Regulatory Framework
ICH E6 Section 4 provides comprehensive guidance on investigator qualifications, resources, and duties. In the United States, 21 CFR Part 312 outlines investigator obligations under FDA regulations, while the EU Clinical Trials Regulation (536/2014) sets corresponding requirements in Europe. Investigators must sign a Form FDA 1572 in the US, committing to comply with the protocol and regulations.
Key Requirements
The investigator must obtain informed consent from every subject before trial participation and ensure that the IRB reviews the protocol and consent documents prior to subject enrollment. Accurate source data recording and case report form completion are mandatory, and all protocol deviations must be documented and reported promptly. The investigator must also oversee investigational product accountability, including receipt, dispensing, and return of study medications.
Documentation
Investigators must maintain adequate and accurate source documents and make them available for monitoring, audits, and inspections. Essential documents include the signed protocol, subject logs, signed consent forms, and correspondence with the IRB and sponsor. All trial records must be retained for the period specified by applicable regulations, typically at least two years after the last marketing application approval or discontinuation of the investigational product.
Conclusion
Investigators carry substantial responsibility for the ethical and scientific conduct of clinical trials. Compliance with ICH E6, regulatory requirements, and the approved protocol is non-negotiable. A thorough understanding of these obligations is essential for anyone serving as a clinical trial investigator.
