The investigator must report adverse events to the:

The investigator is required to report adverse events primarily to the sponsor. The sponsor is responsible for the overall conduct of the clinical trial, including safety monitoring. As such, by reporting adverse events, the investigator provides crucial information that enables the sponsor to assess the safety profile of the investigational product.

In clinical trials, the sponsor must have an accurate understanding of any adverse events that occur to ensure participant safety and to comply with regulatory requirements. This information is integral for the ongoing risk-benefit analysis and for making informed decisions about the continuation of the study, potential modifications to the protocol, or the need to provide new information to regulatory authorities.

While the investigator also has obligations to report to the FDA, the Institutional Review Board (IRB), and inform subjects when necessary, the primary and immediate responsibility for adverse event reporting lies with the sponsor due to their oversight role in the trial.