New Chemotherapies Benefit African-American Men With mCRPC

African-American men with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC) may derive greater overall survival benefit from treatment with newer chemotherapies abiraterone acetate and enzalutamide than Caucasian men, according to the results of a retrospective study presented ahead of the 2019 Genitourinary Cancers Symposium being held February 14–16 in San Francisco.

In the study, African-American men had almost a 20% improvement in overall survival compared with Caucasian men.

“When controlling for access to care through a single payer system in chemotherapy-naive mCRPC patients, African-American men may have better overall survival than Caucasian men when treated with abiraterone acetate or enzalutamide,” Megan McNamara, MD, assistant professor of medicine at the Duke University School of Medicine in Durham, North Carolina, said at a press conference ahead of the 2019 ASCO Genitourinary Cancers Symposium.

According to McNamara, despite studies suggesting that African-American men with mCRPC may have better outcomes in response to certain prostate cancer treatments, there is a lack of real-world data looking at survival in these populations when treated with abiraterone acetate or enzalutamide.

This study included 2,123 Caucasian and 787 African American men from the Veterans Health Administration database. The mean age of patients was 74 and 71, respectively. All men had surgical or medical castration and no chemotherapy for the prior 12 months.

African-American men in the study were significantly more likely to have comorbid hypertension (P < .0001), type 2 diabetes (P < .0001), and liver damage or abnormality (P = .0003).

The median overall survival for African-American men was 30 months compared with 26 months for Caucasian men. Univariate analysis showed that African-American men had better overall survival than Caucasian men when treated with abiraterone acetate or enzalutamide. Multivariate analysis confirmed this with approximately 18% improvement in overall survival seen in African-American men (hazard ratio [HR], 0.826; 95% CI, 0.732–0.933; P = .002).

“Our study is retrospective, but it emphasizes the need for prospective trials in order to validate these findings and in order to try to understand the mechanism that underlies these differences in survival outcomes between African American and Caucasians with mCRPC when treated with these novel hormone therapies,” McNamara said.

Commenting on the results of the study, ASCO Expert Robert Dreicer, MD, MS, MACP, FASCO, said, “When it comes to cancer treatments, it’s important to understand how different groups respond to different therapies. Mining historic records in large databases can often help researchers home in on the patients who are more likely to benefit from certain medications. These findings provide important evidence that African-American men with metastatic prostate cancer, who have long had among the highest incidence and poorest outcomes of this disease, may now have better survival when treated with newer prostate cancer medications as compared with other men.”