Journal of Biometrics & Biostatistics

Alternative Designs for Phase II Clinical Trials when Attained Sample Sizes are Different from Planned Sample Sizes

Abstract

Chang M, Li Y, An Q

Phase II cancer clinical trials are conducted for initial evaluation of the therapeutic efficacy of a new treatment regimen, and two-stage designs often are implemented in such trials. Typically, designs of phase II trials not only satisfy predefined significance and power requirements but also have some desirable features such as minimizing the total sample size, minimizing the average sample size under the null hypothesis, etc. A frequent issue is that the attained sample sizes differ from the planned sample sizes. We propose alternative designs adjusted to the attained sample sizes when they are different than the planned sample sizes. We present extensive examples and compare the proposed designs to that of Green and Dahlberg. We apply the proposed designs to a phase II trial in non-Hodgkin’s lymphoma patients.