PURPOSE To discuss patient eligibility criteria in phase III cancer clinical trials in the larger setting of the complexity of these trials, to review the various reasons for imposing restrictive eligibility requirements, to discuss the problems caused by these requirements, to argue that these requirements should be greatly relaxed in most cancer clinical trials, to provide some guiding principles and practical suggestions to facilitate such a relaxation, and to give an example of how eligibility requirements were reduced in a recent clinical trial in acute lymphocytic leukemia. METHODS Implicit and explicit reasons for including eligibility criteria in clinical trials are reviewed. Safety concerns and sample size issues receive special attention. The types of problems restrictive eligibility criteria cause with respect to scientific interpretation, medical applicability, complexity, costs, and patient accrual are described. RESULTS A list of three items that each eligibility criterion should meet in order to be included is proposed and applied to a recent trial in acute lymphocytic leukemia. CONCLUSION Phase III clinical trials in cancer should have much broader eligibility criteria than the traditionally restrictive criteria commonly used. Adoption of less restrictive eligibility criteria for most studies would allow broader generalizations, better mimic medical practice, reduce complexity and costs, and permit more rapid accrual without compromising patient safety or requiring major increases in sample size.
Sample size estimation for CF clinical trials using rate of lung function decline (RLFD) as an efficacy endpoint
