[peapod91]

That’s correct. If a positive effect in the treatment arm of the study is found to be strong enough, it is deemed unethical to continue giving patients the placebo as control. Hence, they terminate the study and proceed to the next phase of approval

[orra]

That it's unethical to continue giving half the participants a placebo makes sense.

I am curious though: do they ever continue with the trial, with the patients on the actual drug? Might that be useful for monitoring rare-ish side effects, even if the drug is highly effective?

[dbbk]

I believe they've only halted recruiting for the trial, not the trial itself. The Pfizer CEO this morning also said they're continuing with plans for two other trials starting soon, which is in people with non-co-morbidities, and to household contacts of confirmed cases.

[orra]

Presumably they're kicking the placebo participants out? As others say, it is not ethical to give them ineffective treatment (placebo), given the effectiveness of the drug has been clearly demonstrated.

[zerkten]

They almost always do this as an approval requirement.

[orra]

Gotcha, thanks.