Evolution of clinical trials: An overview on adaptive designs

Adaptive clinical trials are innovative study designs having flexibility and the ability to adapt its trial features and course for efficiency depending on the accumulating data from the trial itself. Trials with adaptive design elements can be more efficient, informative, and ethical. They have potential applications across all phases of the drug development process, from the exploratory phase to the confirmatory phase. Adaptive elements include randomization, sample size, and combining two clinical trial phases, and have important applications in settings like orphan diseases. Adaptive clinical trials, though efficient, have their own inherent flaws and disadvantages associated with their flexibility, statistical complexity, and difficulties in their implementation and interpretation of the results. Thus, adaptive design elements must be carefully chosen, keeping in view the practical difficulties and uncertainties associated with them after detailed discussion with the different stakeholders. Adaptive designs are unfamiliar and novel, and there is an attitude of conservatism among investigators, sponsors, and funding agencies, which are subject to scrutiny in a strict fashion with extensive review by regulatory agencies.