Data from A Proposal Regarding Reporting of <i>In Vitro</i> Testing Results

Abstract

<div>Abstract<p>The high rate of negative clinical trials and failed drug development programs calls into question the use of preclinical testing as currently practiced. An important issue for the <i>in vitro</i> testing of agents that have advanced into the clinic is the use of clinically irrelevant concentrations in reports making claims for anticancer activity, as illustrated by publications for sorafenib, vorinostat, and metformin. For sorafenib, high protein binding leads to a dichotomy between concentrations active in the 10% serum conditions commonly used for <i>in vitro</i> testing and concentrations active in plasma. Failure to recognize this distinction leads to inappropriate claims of activity for sorafenib based on the micromolar concentrations commonly used for <i>in vitro</i> testing in low serum conditions. For vorinostat and metformin, results using <i>in vitro</i> concentrations higher than those achievable in patients are reported despite the availability of publications describing human pharmacokinetic data for each agent. We encourage journal editors and reviewers to pay greater attention to clinically relevant concentrations when considering reports that include <i>in vitro</i> testing of agents for which human pharmacokinetic data are available. Steps taken to more carefully scrutinize activity claims based on <i>in vitro</i> results can help direct researchers away from clinically irrelevant lines of research and toward lines of research that are more likely to lead to positive clinical trials and to improved treatments for patients with cancer. <i>Clin Cancer Res; 19(11); 2828–33. ©2013 AACR</i>.</p></div>