Detailed Explanation
Interim analyses provide opportunities to evaluate accumulating evidence during a trial, enabling ethical decisions about whether to continue, modify, or terminate the study based on observed data. These analyses serve multiple purposes: detecting overwhelming efficacy that would make continued randomization to placebo unethical, identifying futility when the treatment is unlikely to demonstrate benefit even with complete enrollment, and monitoring safety signals that might require study termination or modification. The timing, number, and methodology of interim analyses must be pre-specified to maintain trial integrity.