Evaluating publication bias for clinical trials supporting new dermatologic drug approvals from 2003 to 2018

The degree of publication bias and impact of the Food and Drug Administration Amendments Act (FDAAA) of 2007, which aimed to improve clinical trial transparency, has yet to be examined for recent dermatologic drugs. The objective of our study was to estimate the degree of publication bias for clinical trials supporting FDA approval of new dermatologic drugs. This retrospective cohort study examined all phase II and III efficacy trials supporting approval of new dermatologic drugs from 2003 to 2018. FDA drug approval documents were reviewed for supportive clinical trial information, and publications were matched using PubMed and Google Scholar searches. Ratios of relative risks (RRR) comparing positive versus non-positive trials before and after FDAAA enactment served to estimate publication bias. We found that the likelihood of publishing positive versus non-positive drug trials in dermatology was unchanged before and after FDAAA enactment (RRR 0.87, 95% CI 0.37-2.08), as was the likelihood of publishing without misleading interpretation (RRR 1.51, 95% CI 0.22-10.50). There was no measurable publication bias for efficacy trials supporting new drug approvals in dermatology over the past 15 years. Fewer pre-FDAAA trials (n = 21) compared to post-FDAAA trials (n = 106) met inclusion criteria. Though not analyzed in this study, safety and secondary efficacy results are other potential sources for publication bias.