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Abiraterone therapy tied to longer survival in Black vs. white men with metastatic castration-resistant prostate cancer

JAMA Network Open
Reuters Health - 13/01/2022 - African American men with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone survive longer than their non-Hispanic white counterparts, a new study suggests.

"Our study demonstrated that abiraterone for first-line mCRPC therapy was associated with better outcomes for African American men compared to non-Hispanic White men in a real-world predominantly community-based practice setting," said lead author Dr. Mallika Marar of Stanford University in California.

"This difference in outcomes may be driven by decreased benefit of abiraterone, relative to other therapies like enzalutamide, among non-Hispanic White men," she told Reuters Health by email.

As reported in JAMA Network Open, Dr. Marar and her colleagues used a nationwide database of 3,808 men receiving first-line therapy for mCRPC over a seven-year period at roughly 280 cancer clinics in the U.S. The patients were newly diagnosed with mCRPC and were receiving first-line systemic therapy during the study period.

The researchers investigated the patients' overall survival from the start of treatment, and they analyzed overall survival within each race, using first-line enzalutamide as the comparator.

The cohort included 2,615 non-Hispanic white men (69%; mean age at diagnosis, 74 years) and 404 Black men (11%; mean age at diagnosis, 69 years). Of these, 45% received first-line abiraterone.

Among men receiving abiraterone, Black men had significantly longer median overall survival than white men (23 months vs. 17 months). There was significant race-by-treatment interaction for abiraterone, but not enzalutamide.

The authors found no overall survival difference between first-line abiraterone and first-line enzalutamide among Black patients (24 months for both groups). But abiraterone was linked with lower median overall survival compared with enzalutamide among white patients (17 months vs. 20 months).

"Our findings should prompt important conversations between oncologists and their patients about race-based differences in the effectiveness of first-line therapy in prostate cancer," said senior author Dr. Ravi B. Parikh of the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia.

"Specifically, Black men should be reassured that abiraterone is equally effective as other first-line therapies," he told Reuters Health by email.

For Dr. Leanne Burnham, an assistant professor in the Division of Health Equities at City of Hope Comprehensive Cancer Center in Duarte, California, "This study represents the possibility of achieving health equity in clinical care by actively advancing inclusive research."

"While we have known for decades that African American men suffer worse outcomes when diagnosed with prostate cancer, we have not had a proactive approach to including an adequate proportion of this population in key studies evaluating treatment response," she told Reuters Health by email.

"Bolstered by the knowledge that African American men treated with first-line abiraterone have significantly longer survival, clinicians can make better-informed decisions for their highest-risk patients," noted Dr. Burnham, who was not involved in the study.

"This is the largest real-world study to date investigating differential outcomes with abiraterone by race," she added. "While the findings are encouraging, it remains sobering that similar studies in the field are limited. It is crucial to close the gap in prostate-cancer mortality for high-risk African American men using a precision medicine approach."

The research team is planning further related studies. "We are actively pursuing similar projects to validate prior findings regarding race-based differences in prostate and other cancer therapeutic effectiveness, and to link abiraterone effectiveness to genetic and molecular characteristics," Dr. Parikh said.

SOURCE: https://bit.ly/3qi1NDW JAMA Network Open, online January 5, 2022.

By Lorraine L. Janeczko

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