ABSTRACT Cancer is the leading cause of death in Americans younger than 85 years of age and kills one American every 56 seconds. Advances in understanding of cancer biology have given us the potential to develop new, effective targeted therapies. However, progress is slowed by suboptimal/outdated clinical trial design paradigms and by regulatory complexity and rigidity. For instance, simulations suggest that restricting randomized trials to patients expressing drug target, instead of using unselected patient populations, could substantially reduce patient numbers required to demonstrate efficacy. High response rates that are achievable…