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. 2022 Jan 4;5(1):e2142093.
doi: 10.1001/jamanetworkopen.2021.42093.

Outcomes Among African American and Non-Hispanic White Men With Metastatic Castration-Resistant Prostate Cancer With First-Line Abiraterone

Mallika Marar  1   2 , Qi Long  3 , Ronac Mamtani  4 , Vivek Narayan  4 , Neha Vapiwala  2 , Ravi B Parikh  4   5   6
Affiliations

Outcomes Among African American and Non-Hispanic White Men With Metastatic Castration-Resistant Prostate Cancer With First-Line Abiraterone

Mallika Marar et al. JAMA Netw Open. .

Abstract

Importance: Prospective evidence suggests abiraterone is associated with superior progression-free survival for African American men compared with non-Hispanic White men with metastatic castration-resistant prostate cancer (mCRPC).

Objective: To investigate differences in outcomes with first-line abiraterone therapy between African American and non-Hispanic White men with mCRPC in a national real-world cohort.

Design, setting, and participants: This retrospective cohort study used a nationwide electronic health record-derived database of 3808 men receiving first-line therapy for mCRPC between January 1, 2012, and December 31, 2018. Data analysis was performed between January 1, 2020, and June 1, 2021. Median follow-up was 13 months (IQR, 7-22 months). Propensity score-based inverse probability of treatment weighting was applied to reduce imbalance in measured confounders between patients receiving first-line abiraterone vs other first-line therapies. Deidentified patient data originated from a geographically diverse set of approximately 280 cancer clinics (approximately 800 sites of care) throughout the United States. Participants had newly diagnosed mCRPC and were receiving first-line systemic therapy during the study period.

Exposures: Receipt of abiraterone for first-line therapy.

Main outcomes and measures: Overall survival from start of first-line treatment. Stratified analyses investigated overall survival within each race group, with first-line enzalutamide as the comparator.

Results: Among 3808 patients with mCRPC, there were 2615 non-Hispanic White men (68.7%; mean [SD] age at diagnosis, 74 [8] years) and 404 African American men (10.6%; mean [SD] age at diagnosis, 69 [9] years), and 1729 patients (45.4%) in the cohort received first-line abiraterone. Among patients receiving first-line abiraterone, African American men had higher median overall survival than non-Hispanic White men (23 months [IQR, 10-37 months] vs 17 months [IQR, 9-32 months], respectively; inverse probability of treatment weighting hazard ratio, 0.76; 95% CI, 0.60-0.98). A race-by-treatment interaction existed for first-line abiraterone vs first-line enzalutamide (hazard ratio for abiraterone vs enzalutamide: non-Hispanic White men, 1.21 [95% CI, 1.06-1.38]; African American men, 1.05 [95% CI, 0.74-1.50]; interaction P = .02). There was no overall survival difference between first-line abiraterone and first-line enzalutamide among African American patients (24 vs 24 months, respectively; inverse probability of treatment weighting hazard ratio, 1.05; 95% CI, 0.74-1.50). First-line abiraterone was associated with decreased median overall survival relative to first-line enzalutamide among non-Hispanic White patients (17 months [IQR, 9-32 months] vs 20 months [IQR, 10-36 months], respectively; inverse probability of treatment weighting hazard ratio, 1.21; 95% CI, 1.06-1.38).

Conclusions and relevance: In this cohort study of patients who received first-line systemic therapy for mCRPC, African American men who received abiraterone had improved overall survival compared with non-Hispanic White men. Future prospective studies should assess drivers of differential abiraterone outcomes in mCRPC between African American and non-Hispanic White men, including differences in genetic factors and socioeconomic status, to inform treatment strategies.

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Long reported receiving grants from the National Institutes of Health (NIH) during the conduct of the study and grants from Pfizer and Bayer outside the submitted work. Dr Mamtani reported receiving fees for travel and speaking from Flatiron Health, personal fees from Seagen/Astellas and BMS, and grants from Merck outside the submitted work. Dr Narayan reported receiving grants from Pfizer, Merck, and Janssen; and personal fees from Pfizer, Merck, Janssen, Myovant Sciences, Exelixis, Regeneron, and Amgen outside the submitted work. Dr Parikh reported receiving grants from NIH, Prostate Cancer Foundation, National Palliative Care Research Center, NCCN Foundation, Conquer Cancer Foundation, Humana, and Veterans Health Administration; personal fees and equity from GNS Healthcare and Onc.AI; personal fees from Cancer Study Group, Thyme Care, Humana, and NanOlogy; fees for travel and speaking from Flatiron Health; and honoraria from Medscape outside the submitted work. He also reported a board membership (unpaid) at the Coalition to Transform Advanced Care and leadership consortium (unpaid) at the National Quality Forum outside the submitted work. No other disclosures were reported.

Figures

Figure 1.
Figure 1.. Overall Survival by Race, African American vs Non-Hispanic White Men
Numbers at risk represented in Kaplan-Meier curves are scaled according to the propensity score analysis inverse probability of treatment weighting. HR indicates hazard ratio; OS, median overall survival; and 1L, first line.
Figure 2.
Figure 2.. Overall Survival by Race and Treatment, First-Line Abiraterone vs First-Line Enzalutamide
Treatment groups correspond to abiraterone-based first-line regimens and first-line single-agent enzalutamide. Numbers at risk represented in Kaplan-Meier curves are scaled according to the propensity score analysis inverse probability of treatment weighting. OS indicates median overall survival; 1L, first line.
See this image and copyright information in PMC

References

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