ABSTRACT
Cancer clinical trials investigate the efficacy and toxicity of experimental cancer therapies. If an appropriate dose level of an experimental drug is determined from a phase I trial, the drug’s anticancer activity is assessed through phase II clinical trials. Phase II clinical trials screen out inefficacious experimental therapies before they proceed to further investigation through large scale phase III trials. In order to expedite this process, phase II trials traditionally use a single-arm design to treat patients with experimental therapies only. The efficacy of an experimental therapy is compared with that of a standard therapy using historical controls. The most popular primary endpoint of phase II cancer clinical trials is tumor response which is measured by the change in tumor size before and during treatment. If the size of a target tumor, defined as the largest diameter of the tumor, decreases by at least 30% compared to that at the baseline, a partial response is declared. A complete response is defined as complete disappearance of the tumor. Overall response is defined as partial or complete response.
