A systematic review of racial disparities in enrollment into clinical trials and clinical outcomes in men with metastatic prostate cancer.

Abstract

e17028 Background: Men of African ancestry have a disproportionately higher incidence of prostate cancer than Caucasians. Yet, men of African ancestry have historically been underrepresented in clinical trials for metastatic prostate cancer (MPC). Further, differences in the magnitude of clinical benefit from treatment by race have been reported. The objective of this study was to assess the racial disparities in clinical trial enrollment of men with MPC and the magnitude of difference in clinical benefit between men of African ancestry and Caucasians with MPC. Methods: A systematic review of MEDLINE was conducted to identify studies published between January 2001 to May 2021. We included: (a) studies that enrolled adults with metastatic castration-resistant prostate cancer (mCRPC) or metastatic hormone sensitive prostate cancer; (b) clinical trials with complete race-stratified frequencies for enrolled subjects; or (c) clinical trials or observational studies that reported race-stratified subgroup analyses or adjusted effect estimates for efficacy/effectiveness outcomes. Outcome measures included overall survival (OS) and progression-free survival (PFS). Results: Of 2,140 retrieved articles, 39 studies involving 39,181 subjects met eligibility criteria. The majority of the studies (n = 35) enrolled mCRPC subjects. Of the 39 studies, 24 were clinical trials and 15 were observational studies. Twenty-one studies enrolled only patients in the US while 18 were multinational studies. Of the 15,761 subjects enrolled in clinical trials, 1750 (11.1%) were men of African ancestry and 12,321 (78.1%) Caucasian. The median (interquartile range) enrollment rate of men of African ancestry in clinical trials was 5.7% (2.3%, 10.1%). Of the 39 eligible studies, 15 reported race-stratified clinical outcomes. Three studies compared men of African ancestry vs Caucasians, 2 men of African ancestry vs non-African ancestry, 3 Caucasian vs others or vice-versa. The remaining 7 studies reported separate estimates on survival by race. All 5 studies comparing men of African ancestry versus other racial groups were conducted in mCRPC subjects. No difference in survival risks by race was observed in the 3 studies that compared men of African ancestry vs Caucasian (HR: 1.09 [0.77, 1.53], 0.68 [0.36, 1.29] and 1.05 [0.97, 1.14]). HRs of 0.90 [0.52, 1.57] and 0.76 [0.61, 0.95] were reported in the 2 studies comparing OS in men of African ancestry vs non-African ancestry. No studies reported a significant increased risk of death by race. Conclusions: Overall, men of African ancestry were largely underrepresented in MPC clinical trials. Concerted efforts are needed to increase the enrollment of this at-risk population in future clinical trial programs. Additional studies are needed to confirm the absence of differences in survival by race in real-life settings.