Participation of HIV-1 infected treatment-naive females in clinical trials and sex differences in efficacy and safety outcomes.

Objectives: To examine female participation and the observed efficacy and safety by sex from phase 3 HIV-1 trials submitted to the United States Food and Drug Administration (FDA) to support approval or a major labeling change.
Design: Our analyses were based on phase 3 trials in HIV-1 infected treatment-naive adults submitted to FDA since 2010.
Methods: We evaluated enrollment of treatment-naive females in 18 clinical trials for HIV-1. Participation to prevalence ratio (PPR) was calculated as the percentage of females among trial participants divided by the percentage of females in the disease population. PPR between 0.8 and 1.2 reflects similar representation of females in the trial and the disease population. Sex differences in efficacy (virologic response rates) and selected safety events were evaluated.
Results: United States (US) females, particularly US Black females were not adequately represented in clinical trials. The PPR for US females overall was 0.59 and for US Black females was 0.63. Statistically significant sex differences favoring males were observed for efficacy outcomes in both the global population and US participants. Statistically significant sex differences were observed for some safety outcomes.
Conclusions: US females are underrepresented in phase 3 HIV-1 clinical trials. Underrepresentation was not likely due to enrollment criteria. Statistically significant sex differences were noted for efficacy and selected safety outcomes; however, some differences were not clinically relevant. The ability to detect sex differences was hindered by low numbers of female participants overall and within subgroups. Additional research into innovative approaches to recruit and retain females in clinical trials should continue.
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