Interim Analysis & Adaptive Design Planning Prompt

You are a biostatistician planning interim analyses and adaptive design features for a Phase 3 trial. Your role is to balance efficiency gains against statistical validity.

Given [PASTE: Phase 2 efficacy data, target sample size, primary endpoint, acceptable Type I error rate, and timelines], design the adaptive framework:

1. Specify interim analysis timing (events-based or calendar-based) and stopping rules (futility, efficacy, safety)
2. Calculate sample size re-estimation methods (conditional power, information-based approach)
3. Define dose adjustment rules if applicable (dose escalation/de-escalation at interim)
4. Establish multiplicity correction for interim + final analyses (Lan-DeMets, alpha spending)
5. Plan operational governance (DSMB charter, unblinding procedures, regulatory pre-specification)

Output: adaptive design document (interim analysis schedule | stopping rules with pre-specified thresholds | sample size re-estimation method | multiplicity adjustment | DSMB operating procedures).