Availability of unblinded treatment allocation

[20349546]

What should be done with the record of treatment allocation (e.g. opened randomisation envelope) following [emergency] unblinding of a trial participant?

My impression is that once the participant has been unblinded, "the cat's out of the bag" so to speak, and there's generally no point maintaining secrecy amongst all site staff if the investigator +/- coordinator now know the treatment assignment. The treatment allocation should therefore be filed in the source documents.

Obviously this would be subject to any trial-specific stipulations, and I can think of reasons to keep the allocation secret from some parties, like the below examples. But I'm mostly looking for a general rule here.

• The sponsor wouldn't necessarily need to know (other than the fact that unblinding has taken place)
• Any independent rater at site would need to remain blinded

Look forward to hearing your thoughts!

[Margit Zehrer]

Hi 20349546, just some thoughts
# consult the study protocol or other study manuals for instructions specific for the study.
# consult your site SOP, if there is any.
# the information should be made accessable only for those who need it to take e.g. the decision on medical interventions in the case of emergencies (in most cased the investigator only).
# inform the monitor/sponsor about the fact of unblinding
# the interventions in response to the emergency of course need to be in the source.
# in the trials I remember with randomization/code envelopes we advised the investigators to close the envelopes again (tape; staples...)
# keep the envelope for inspection by the monitor
# the envelope will be return with the whole set of envelopes after last patient out or will be destructed (depending of the trial).