RQA GPvP Committee
This is not a simple question to answer as the process for rechallenge (re-introducing the suspected medicine after a dechallenge) and dechallenge (stopping of the drug, usually after an adverse event (AE) or at the end of a planned treatment) is not an exact science. The wider context of the treatment should also be taken into account e.g. the disease in question, the clinical setting, the timing of the disappearance / reappearance of the adverse event, concomitant medications, etc. which may make the dechallenge / rechallenge hard to interpret and therefore clinical judgment is also an essential component within the process.
Rechallenge is considered to be justifiable only when the benefit of reintroducing the suspected medicine to the patient outweighs the risk of recurrence of the reaction, in some cases the reaction may be more severe on repeated exposure, and therefore rechallenge requires ethical considerations as well.
The relevant Protocol (as well as data entry guidelines) should provide sufficient detail of what are considered as dechallenge / rechallenge criteria – this then enables consistency to be maintained and documented.
Further information can be located on websites e.g. CIOMS Working Group, FDA