Bioequivalence and Bioavailability Forum

Dear Amira,

❝ Is it applicable to use the same volunteers in fast and fed studies for the same product separated with adequate wash out period? Is there any reference in guidelines for such?

If you run two separate studies, I'm not aware of any provision in guidelines that would prevent to re-use the same subjects in the second study, if you respect a wash-out period and if the blood loss remains reasonable. In most protocols (and IIRC, in the ANVISA guidelines) there are criteria for a minimum time between two studies (e.g. 2 or 3 months) and this would have to be respected too.

But if you run two separate studies I would not make it a strict requirement that it should only be the same subjects participating in both: there would be a higher risk of drop-out. Helmut would explain you that the loss of power due to a couple of drop-outs is minimal, but if there are many subjects missing you could get in trouble. If you fear a high drop-out rate, you would need to enrol more subjects in the first study in order to still have enough in the second. The longer the time between the two studies, the higher the risk of loosing subjects.

If you insist on having the same subjects in both trials: you should make it clear in the protocol of the second study, so that the Ethics Committee can check the time between studies and the cumulative blood loss.