Translational clinical trials: an entropy-based approach to sample size.

Translational clinical trials are small studies of therapies emerging from the laboratory. These trials are essential for generating early evidence regarding the effects of treatment on specific targets in the disease pathway and for guiding the next studies to be done. The statistical properties of such studies have been neglected, in part, because they do not fit the well-known clinical trials developmental paradigm. This paper discusses the translational trial setting, and presents an information (entropy) based approach to understanding the properties and use of these trials. The combination of biological knowledge with a designed experiment (albeit a small one) is a powerful device for resolving much of the considerable uncertainty surrounding an emerging therapeutic concept. An approach to motivating the sample size for translational trials is presented.