Purpose: We aim to describe reporting and representation of minority patient populations in immune checkpoint inhibitor (ICI) clinical trials and assess predictors of enrollment disparity.
Methods: Trial-level data were acquired from eligible phase II and III trials. Population-based estimates were acquired from the SEER 18 and Global Burden of Disease incidence databases. Trials reporting race, age, and sex were summarized using descriptive statistics. Enrollment-incidence ratio (EIR) was used to assess representation of subgroups. Average annual percentage change (AAPC) in EIR was calculated using Joinpoint Regression Analysis. Trial-level characteristics associated with EIR were assessed using multivariable linear regression.
Results: A total of 107 trials with 48,095 patients were identified. Participation of Black, White, Asian, Native American, Pacific Islander, and Hispanic participants was reported in 65 (61%), 77 (72%), 68 (64%), 40 (37%,) and 24 trials (22%), respectively. Subgroup analyses of clinical outcomes by race, age, and sex were reported in 17 (22%), 62 (78%), and 57 (57%) trials, respectively. Women (trial proportion [TP]: 32%; EIR: 0.90 [95% confidence interval [CI]: 0.84-0.96]), patients aged ≥65 years (TP: 42%; EIR: 0.78 [95% CI: 0.72-0.84]), Black participants (TP: 1.9%; EIR: 0.17 [95% CI: 0.13-0.22]) and Hispanics (TP: 5.9%; EIR: 0.67 [95% CI: 0.53-0.82]) were underrepresented. Representation of Black patients decreased significantly from 2009 to 2020 (AAPC: -23.13). Black participants were significantly underrepresented in phase III trials (P < .001).
Conclusion: The reporting of participation by racial or ethnic subgroup categories is inadequate. Women, older adults, as well as Black and Hispanic participants are significantly underrepresented in ICI clinical trials.
Keywords: Clinical trial enrolment; Disparities; Immune checkpoint inhibitors; Older adults; Race; Women.
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