Determining the optimal use of approved drugs in oncology

Optimising the use of approved drugs requires evidence from post-approval trials that investigate variations of their use. Determining optimal drug use goes beyond the dominant, academic effort to conduct trials to identify effective lower doses of new drugs. Other important therapeutic approaches that use either less, similar, or more drug than the standard dose need testing in clinical trials, to get the most out of these drugs. Trial objectives on survival outcomes vary greatly; some aim for superiority, others for equivalent exposure or non-inferiority. This Personal View aims to inform academic trialists in how to conceive and prioritise questions aimed at determining the optimal use of drugs, taking into account the perspectives of patients, clinicians, and trial funders, to maximise the chances of successful delivery and impact for patients globally.