Demographic diversity of US-based participants in GSK-sponsored interventional clinical trials.

BACKGROUND: Demographic diversity among clinical trials is required for representing the real-world populations intended for treatment and disease prevention. Moreover, genetic and environmental differences between ethnic and racial groups necessitate appropriately powered trials for relevant subgroups. We investigate the racial and ethnic demographic diversity of US-based participants in GSK-sponsored interventional trials. We also assess the evaluation of demographic diversity against US Census and epidemiologic data. METHODS: GSK-sponsored interventional phase I-IV clinical trials conducted from 2002 to 2019 across three areas were analyzed: pharmaceutical (includes therapeutic medicines except for vaccines and human immunodeficiency virus (HIV)), vaccine (includes prophylactic and therapeutic vaccines), and ViiV (includes HIV therapies). A total of 1005 global trials encompassing 460,707 global participants were identified, of which 495 had US-based sites with a total of 108,261 (23.5% of global) US participants (pharmaceutical, n = 357 trials; vaccine, n = 45 trials; and ViiV, n = 93 trials). We evaluated how GSK US-based trial recruitment compares with US Census (in line with previously published studies from other groups) and with epidemiologic data. RESULTS: GSK participant data for race and ethnicity combined across areas were generally similar to US Census levels (e.g. GSK versus census: White, 76.5% versus 76.3%; Black or African American, 15.1% versus 13.4%; Asian, 1.8% versus 5.9%; Hispanic or Latino, 14.0% versus 18.5%; Non-Hispanic White, 63.5% versus 60.1%). However, this was not the case for the individual pharmaceutical, vaccine, and ViiV data sets; least represented groups were Asian individuals for pharmaceutical and ViiV trials and American Indian or Alaskan Native individuals for vaccine trials (6.2%, 11.8%, and 11.1% of trials met/exceeded census level representation, respectively). The percentage of trials reaching/exceeding census levels also varied per trial phase for race and ethnicity. Furthermore, disparities in the percentage of trials reaching/exceeding census levels versus epidemiology-based prevalence levels have revealed opportunities to improve industry success metrics; in HIV trials, the proportion of Black or African American individuals (35.1%) exceeded census (13.4%) but not epidemiologic levels (55.3%). CONCLUSION: Further work is required to achieve demographic diversity across clinical trials. We conclude that US Census data are an inappropriate universal benchmark. A shift to epidemiology benchmarking will enable the consideration of global participants into US analyses for highly intrinsic (i.e. influenced by ancestry) diseases and more firm requirements for US-based participants into US analyses for extrinsic (i.e. influenced by location or culture) diseases. Benchmarking in line with epidemiologic data will allow us to set better trial enrollment goals, with the aim of conducting more demographically balanced, diverse, and representative clinical trials and enabling a better understanding of drug safety and efficacy per demographic group.

Characterization of cardiovascular clinical events and impact of event adjudication on the treatment effect of darapladib versus placebo in patients with stable coronary heart disease: Insights from the STABILITY trial.

BACKGROUND: Clinical Endpoint Classification (CEC) in clinical trials allows FOR standardized, systematic, blinded, and unbiased adjudication of investigator-reported events. We quantified the agreement rates in the STABILITY trial on 15,828 patients with stable coronary heart disease. METHODS: Investigators were instructed to report all potential events. Each reported event was reviewed independently by 2 reviewers according to prespecified processes and prespecified end point definitions. Concordance between reported and adjudicated cardiovascular (CV) events was evaluated, as well as event classification influence on final study results. RESULTS: In total, CEC reviewed 7,096 events: 1,064 deaths (696 CV deaths), 958 myocardial infarctions (MI), 433 strokes, 182 transient ischemic attacks, 2,052 coronary revascularizations, 1,407 hospitalizations for unstable angina, and 967 hospitalizations for heart failure. In total, 71.8% events were confirmed by CEC. Concordance was high (>80%) for cause of death and nonfatal MI and lower for hospitalization for unstable angina (25%) and heart failure (50%). For the primary outcome (composite of CV death, MI, and stroke), investigators reported 2,086 events with 82.5% confirmed by CEC. The STABILITY trial treatment effect of darapladib versus placebo on the primary outcome was consistent using investigator-reported events (hazard ratio 0.96 [95% CI 0.87-1.06]) or adjudicated events (hazard ratio 0.94 [95% CI 0.85-1.03]). CONCLUSIONS: The primary outcome results of the STABILITY trial were consistent whether using investigator-reported or CEC-adjudicated events. The proportion of investigator-reported events confirmed by CEC varied by type of event. These results should help improve event identification in clinical trials to optimize ascertainment and adjudication.