Evidence-based Phase 3 Decision Making Provided By
Adpative Sample Size Re-estimation Design's Promising Zone
California-based Sunesis Pharmaceuticals knows developing cancer treatments is a high-stakes endeavor – especially for emerging biotechs and specialty pharmas with limited portfolios.
The worrisome realities for Sunesis Pharmaceuticals and investors: (1) Conventional Phase 3 trials are “all or nothing” propositions, (2) Well over 50% of pivotal oncology studies fail. They ask: "Could an adaptive approach effectively “de-risk” the final clinical stage? And be accepted by FDA reviewers?
Response – an adaptive sample size re-estimation design provides interim analysis-based flexibility and mitigates risk
Unlike conventional studies, adaptive approaches allow beneficial design changes following interim analysis (IA). An FDA-reviewed Sample Size Re-estimation design allows selection of the strategy most likely to succeed.
A “Promising Zone” decision boundary enables choice of most beneficial option:
(1) continuing without adaptations if interim results fall outside the Promising Zone’s conditional power parameters
(2) if within Promising Zone parameters, increasing sample size to achieve pre-determined conditional power
The Sunesis-sponsored VALOR Phase 3 trial continues following the fall 2013 recommendation by the trial's DSMB to go forward with the sample size re-estimation increase as the interim analysis results were indeed within the prescribed Promising Zone.