and Drugs@FDA: A Comparison of Results Reporting for New Drug Approval Trials

Ann Intern Med. 2016 Sep 20;165(6):421-30. doi: 10.7326/M15-2658. Epub 2016 Jun 14.


Background: Pharmaceutical companies and other trial sponsors must submit certain trial results to The validity of these results is unclear.

Purpose: To validate results posted on against publicly available U.S. Food and Drug Administration (FDA) reviews on Drugs@FDA.

Data sources: (registry and results database) and Drugs@FDA (medical and statistical reviews).

Study selection: 100 parallel-group, randomized trials for new drug approvals (January 2013 to July 2014) with results posted on (15 March 2015).

Data extraction: 2 assessors extracted, and another verified, the trial design, primary and secondary outcomes, adverse events, and deaths.

Results: Most trials were phase 3 (90%), double-blind (92%), and placebo-controlled (73%) and involved 32 drugs from 24 companies. Of 137 primary outcomes identified from, 134 (98%) had corresponding data at Drugs@FDA, 130 (95%) had concordant definitions, and 107 (78%) had concordant results. Most differences were nominal (that is, relative difference <10%). Primary outcome results in 14 trials could not be validated. Of 1927 secondary outcomes from, Drugs@FDA mentioned 1061 (55%) and included results data for 367 (19%). Of 96 trials with 1 or more serious adverse events in either source, 14 could be compared and 7 had discordant numbers of persons experiencing the adverse events. Of 62 trials with 1 or more deaths in either source, 25 could be compared and 17 were discordant.

Limitation: Unknown generalizability to uncontrolled or crossover trial results.

Conclusion: Primary outcome definitions and results were largely concordant between and Drugs@FDA. Half the secondary outcomes, as well as serious events and deaths, could not be validated because Drugs@FDA includes only "key outcomes" for regulatory decision making and frequently includes only adverse event results aggregated across multiple trials.

Primary funding source: National Library of Medicine.

Publication types

  • Comparative Study
  • Validation Study

MeSH terms

  • Clinical Trials as Topic / standards*
  • Databases, Factual / standards*
  • Drug Approval*
  • Drug-Related Side Effects and Adverse Reactions
  • Humans
  • National Library of Medicine (U.S.)*
  • United States
  • United States Food and Drug Administration*