Translational research: walking the bridge between idea and cure--seventeenth Bruce F. Cain Memorial Award lecture.

Advances in the understanding of normal and malignant cell biology are allowing the development of biologically targeted drugs directed at specific differences between host and tumor. The array of potential new targets is vast, but drugs currently in development are targeted at cell-cycle regulators, growth factors and their receptors, signal transduction intermediates, angiogenesis, and the mechanisms that mediate apoptosis and DNA repair. Recent results raise the possibility that novel biologically targeted agents, perhaps in combination with traditional cytotoxic agents, may finally cure cancer. However, the development of a biologically targeted drug raises unique challenges in the design of clinical trials to demonstrate its efficacy, and despite the promising preclinical data that exist for most of the agents in development, the clinical trial remains the critical, final step across the bridge from basic research to clinical application. In this review, we discuss some of the challenges in the clinical development of biologically targeted agents and the implications for clinical trial design.