  Purpose: The early identification of maximum tolerated dose (MTD) in phase I
trial leads to faster progression to a phase II trial or an expansion cohort to
confirm efficacy. Methods: We propose a novel adaptive design for identifying
MTD early to accelerate dose-finding trials. The early identification of MTD is
determined adaptively by dose-retainment probability using a trial data via
Bayesian analysis. We applied the early identification design to an actual
trial. A simulation study evaluates the performance of the early identification
design. Results: In the actual study, we confirmed the MTD could be early
identified and the study period was shortened. In the simulation study, the
percentage of the correct MTD selection in the early identification Keyboard
and early identification Bayesian optimal interval (BOIN) designs was almost
same from the non-early identification version. The early identification
Keyboard and BOIN designs reduced the study duration by about 50% from the
model-assisted designs. In addition, the early identification Keyboard and BOIN
designs reduced the study duration by about 20% from time-to-event
model-assisted designs. Conclusion: We proposed the early identification of MTD
maintaining the accuracy to be able to short the study period.

Methodology