Table 6

Adaptive trial designs

Key features

  • Interventions and/or randomization structure altered based on early data according to ‘pre-determined’ rules

Advantages

  • Smaller sample size (n)

  • Shorter duration

  • Can identify benefits/harm to smaller subgroups

  • Allows for very long-term ‘constantly’ adapting trials

Disadvantages

  • Short-term ‘definitive’ positive results may mask long-term negatives

  • Too many ‘adaptive’ steps can affect validity of results

  • Power analysis complex

  • Trial design complex requiring detailed expert planning

Example

  • Stroke Prevention in Atrial Fibrillation (START) trial