Postmarketing commitments for novel drugs and biologics approved by the US Food and Drug Administration: a cross-sectional analysis.

While only 15% of postmarketing commitments agreed to by pharmaceutical companies at the time of FDA approval were for new clinical trials, these trials were nearly always registered with reported results on ClinicalTrials.gov. However, only half were published, and despite FDA public reporting requirements, recent status information was often unavailable for 506B studies.