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.

[fa icon="thumb-tack"]  Prof. Farhad Ravandi (MD Anderson, Texas A&M) answers questions about the VALOR Trial Promising Zone. Results discussed at 9:30. Interim Analysis discussed at 10:30. 

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Promising Zone Infographic