title: Pilot trial for the assessment of relative bioavailability in generic drug product development: statistical power.
abstract: In developing generic drug products, pilot trials are used for identifying successful test formulations to enter pivotal trials. In this study, we derive the power function based on the log-normal distribution and evaluate the effects of potential influential factors-the true test-reference ratio, intrasubject variability, and sample sizes-on the statistical power of a pilot trial to identify successful test formulations, defined as the probability that the test-reference ratio estimate from a pilot trial falls within a predetermined acceptance range when the true ratio is acceptable. Of these influential factors, the test-reference ratio exhibits the largest impact on the statistical power of a pilot trial, followed by intrasubject variability, sample sizes of pivotal trials, and sample sizes of pilot trials. The sample sizes that are used in pilot trials (8-12 subjects) may be sufficient for test products with low intrasubject variability and true ratio close to 1 and may fall short otherwise.
authors: Department of Statistics and Programming, G.D. Searle and Company, Skokie, Illinois 60077, USA.
authors: Y
authors: Y
authors: Wang
authors: S
authors: S
authors: Zhou
mesh_terms: D001682:Biological Availability; D016568:Drugs, Generic / Q000493:pharmacokinetics* / Q000592:standards; D006801:Humans; D015233:Models, Statistical; D010865:Pilot Projects; D012016:Reference Values; D013810:Therapeutic Equivalency
chemical_list: D016568:Drugs, Generic