If the trial is blinded, what must the investigator do in the event of any premature unblinding?

• A. If the trial is blinded, the investigator should promptly document and explain to the sponsor any premature unblinding of the investigational product(s).
• B. Unblinding must be avoided at all costs and not documented.
• C. The subject should be informed but not sponsor.
• D. Unblinding does not need to be documented.

Answer: (A)

When a blinded trial experiences premature unblinding, it can affect both participant safety assessments and the integrity of the study data. The investigator must promptly document the unblinding event in the trial records and inform the sponsor with a clear explanation of why the unblinding occurred, exactly what was revealed, and who was involved. The sponsor uses this information to assess safety implications, determine any necessary disclosures to oversight bodies, and decide if any measures are needed to protect the remaining blind data. Documentation and timely reporting ensure traceability and accountability and support appropriate safety and data integrity considerations. Unblinding should not be hidden or ignored, and the subject’s treatment assignment is not typically disclosed to the participant unless required for safety; the key requirement is to document and report to the sponsor.