The impact of the globalization of cancer clinical trials on the enrollment of Black patients.

BACKGROUND

The enrollment of Black patients in cancer clinical trials continues to trend far below the true prevalence of disease in Black patients in the United States, limiting the generalizability of trial results. A potentially overlooked contributor to the underenrollment of Black patients may be the increasing enrollment of cancer trials in countries outside the United States. However, the impact of the globalization of cancer clinical trials on recruitment of racial minority patients has been understudied.

METHODS

In this study, race and accrual location data for all cancer drugs approved by the US Food and Drug Administration (FDA) between 2015 and 2018 were analyzed. A disparity score was calculated for each approval, a metric comparing Black enrollment in clinical trials with the estimated burden of disease in Black patients.

RESULTS

Of 49 global clinical trials supporting 35 FDA drug approvals with race data available, Black patients accounted for 2.5% of enrollment (range, 0%-10%), with a median disparity score of 0.19 (range, 0.01-0.98). In 21 clinical trials supporting 18 FDA drug approvals with both race and accrual location data available, 64% patients were enrolled outside the United States (range, 0%-100%). Black patients accounted for 3.2% of enrollment (range, 0.2%-10%), and the median disparity score was 0.23 (range, 0.01-0.98). There was a significant inverse correlation between the proportion of trial patients enrolled outside the United States and the disparity score (Pearson correlation, -0.61; P = .007).

CONCLUSIONS

The globalization of cancer clinical trials is associated with a widening racial enrollment disparity gap in the United States. The impact of global trials on domestic clinical trial generalizability warrants further consideration from a regulatory and policy standpoint.

LAY SUMMARY

Black patients continue to be underrepresented in cancer clinical trials; this disparity has worsened in recent years perhaps because of the globalization of cancer clinical trials. In an analysis of demographic information from 21 cancer clinical trials leading to US Food and Drug Administration approvals between 2015 and 2018, clinical trials conducted primarily outside the United States were 2-fold less likely to enroll Black participants than US clinical trials. Thus, the globalization of cancer clinical trials may have the unintended consequence of further exacerbating existing racial disparities in cancer clinical trial representation and ultimately the generalizability of trial results.