Randomized phase II trials: time for a new era in clinical trial design.

The classic single-arm oncology phase II trial designs for evaluating an experimental regimen/agent are limited by multiple sources of bias arising from the inability to separate trial effects (such as patient selection, trial eligibility, imaging techniques and assessment schedule, and treatment locations) from treatment effect on clinical outcomes. Changes in patient population based on biologic subsetting, newer imaging technologies, the use of alternative end points, constrained resources, and the multitude of promising therapies for a given disease make randomized phase II designs, with a concurrent control arm where necessary, attractive. In this brief report, we discuss the salient features of the randomized designs for phase II trials, which when properly applied under the constraints of their underlying inference framework can assure optimal use of limited phase III financial and patient resources.