What action must a sponsor take if a trial is halted due to safety concerns?

When a trial is halted due to safety concerns, the sponsor has an obligation to prioritize participant safety and ensure that the appropriate oversight mechanisms are engaged. Notifying regulatory authorities and the Institutional Review Board (IRB) is crucial because these entities are responsible for the oversight of clinical trials, ensuring that they comply with ethical standards and regulations designed to protect human subjects.

This action allows for a prompt review of the safety concerns raised, leading to necessary actions that may include an investigation into the issues, a reassessment of the trial protocols, or a complete cessation of the study. Notification to these bodies ensures transparency and facilitates the necessary oversight to determine how to move forward responsibly.

The other options do not align with the standard operational protocols that prioritize participant safety and regulatory compliance. Implementing new treatment protocols without proper evaluation, continuing under modified conditions without proper guidance and permission, or recruiting additional participants could further compromise patient safety and violate ethical standards. Therefore, notifying regulatory authorities and the IRB is the correct course of action in response to safety concerns in a clinical trial.