Bioequivalence and Bioavailability Clinical Trials: A Status Report from the National Institutes of Health ClinicalTrials.gov Registry.

Drug development is an expensive process that is marked by a high-failure rate. For this reason early stage bioequivalence and pharmacokinetic studies are essential in determining the fate of new drug products. In this study, we sought to systematically assess the current trends of ongoing and recently completed bioequivalence and bioavailability trials that have been registered within a national clinical trials registry. All bioequivalence and bioavailability studies registered in the United States ClinicalTrials.gov registry from late-2007 through 2011 were identified. Over this period, more than 2300 interventional bioequivalence and bioavailability trials were registered. As of 2013, the vast majority of studies (86%) have been completed, 10% are actively recruiting participants, and the remainder are engaged in data analysis (4%). When compared to completed trials, ongoing trials are in later phases of clinical development, recruiting larger numbers of participants, and more likely to recruit women and children (<0.001 for all). These data suggest that the quality of bioequivalence and bioavailability studies has improved rapidly, even over the last five years. However, further work is needed to sustain - and accelerate - these improvements in the design of bioequivalence and bioavailability studies to ensure that safe and efficacious medicines swiftly reach healthcare providers and their patients.