FDA perspective on companion diagnostics: an evolving paradigm.

Therapeutic products are now being developed that target particular molecular lesions found in various types of cancers. The ability to correctly identify patients whose cancers have targetable lesions generally depends on a well-validated diagnostic test. Development and use of diagnostic tests together with therapies in clinical trials yields the information necessary to make a regulatory determination that both products are safe and effective, likely have clinical utility when used together, and reach the market for patient benefit. This model, called co-development, has been developed relatively recently, and is being put to use in numerous cancer therapeutic development programs. The U.S. Food and Drug Administration (FDA) has articulated a policy that requires the coapproval of a diagnostic with a therapeutic product when the diagnostic is essential to the safe and effective use of the therapeutic product. At the same time, FDA has implemented a number of processes to manage the model without slowing the approval of the co-developed products. New diagnostic technologies, together with a rapid uptick in interest in targeted drugs, will challenge the still-evolving regulatory paradigm, but will likely result in some simplified approaches presenting new challenges in determining safety and effectiveness, but all with the promise of greater benefit to patients with cancer. See all articles in this CCR Focus section, "The Precision Medicine Conundrum: Approaches to Companion Diagnostic Co-development."