Clinical trials in drug development are commonly divided into 3 categories or phases. The first phase aims to find the range of doses of potential clinical use, usually by identifying the maximum tolerated dose. The second phase aims to find doses that demonstrate promising efficacy with acceptable safety. The third phase aims to confirm the benefit previously found in the second phase using clinically meaningful end points and to demonstrate safety more definitively.
Dose-finding trials—studies conducted to identify the most promising doses or doses to use in later studies—are a key part of the second phase and are intended to answer the dual questions of whether future development is warranted and what dose or doses should be used. If too high a dose is chosen, adverse effects in later confirmatory phase 3 trials may threaten the development program. If too low a dose is chosen, the treatment effect may be too small to yield a positive confirmatory trial and gain approval from a regulatory agency. A well-designed dose-finding trial is able to establish the optimal dose of a medication and facilitate the decision to proceed with a phase 3 trial.
Viele K, Connor JT. Dose-Finding TrialsOptimizing Phase 2 Data in the Drug Development Process. JAMA. 2015;314(21):2294-2295. doi:10.1001/jama.2015.16702