Clinical trial designs for targeted agents.

With an increasing number of targeted agents available for testing, clinical trials must be rationally designed based on sound knowledge of the molecular mechanisms linking target and disease, fortified by strong preclinical data demonstrating how this relationship is modified by the targeted agent. Patients and resources are precious and should be expended judiciously on clinical trials that are well planned. Although traditional trial designs and endpoints may not be adequate for developing contemporary targeted drugs, transiting directly from phase I to phase III testing should be avoided except in distinct circumstances. Increased research efforts should be spent on the prospective evaluation and validation of novel biologic endpoints and innovative clinical designs, such that promising targeted agents can be effectively developed to benefit the care of cancer patients.