San Francisco, CA USA (UroToday.com) Stolten and colleagues presented abstract 244 describing responses to abiraterone among African American men to augment the minimal clinical trial data for this population. The investigators performed a retrospective cohort study of men seen at a single institution. Covariates included in their analysis included age at diagnosis, prior enzalutamide and/or docetaxel, as well as baseline alkaline phosphatase, hemoglobin, and lactate dehydrogenase. The primary outcome of interest was duration of treatment with abiraterone, and velocity of PSA decline (defined by PSA half-life and time to nadir) and PSA response and progression by PCWG2 criteria were secondary outcomes.
In total 103 men with metastatic castration-resistant prostate cancer (mCRPC) were treated with abiraterone during the period of the study, including 24 African American men and 79 Caucasian men. Men had similar baseline age (61.8 years for African American men and 62.4 years for Caucasian men). In terms of prior therapy with abiraterone, 4.2% of African American men and 6.3% of Caucasian men received treatment. Prior treatment with docetaxel was more common, with 33.3% of African Americans and 29.1% of Caucasian men receiving treatment prior to inclusion in the study. The median duration of treatment with abiraterone was not significantly different between African American and Caucasian men at 207 and 253 days, respectively. There were no significant differences between African American men and Caucasian men in baseline laboratory values. PSA decline was also similar between groups, with decline of >30% in 50% of African American men and 52% of Caucasian men, a decline of >50% in 46% of African American men and 39% of Caucasian men, and a decline of >90% in 21% of African American men and 14% of Caucasian men. Finally, neither time to progression nor median time to PSA nadir were significantly different between groups (time to progression = 157 days vs 131 days for African American and Caucasian men, respectively, and median time to PSA nadir was 119 days vs 137 days for African American vs Caucasian men, respectively).
Small sample sizes limited the power of this analysis to find more subtle differences in these outcomes, but the authors’ conclusion regarding future investigations of minority men with prostate cancer should be heeded. African American men are disproportionately affected by this disease. It is imperative that we seek to improve upon low rates of clinical trial participation as we seek to advance therapeutic development for all men suffering with this disease.
Presented By:
Dr. Michael D. Stolten, MD
Reported By:
Alicia K. Morgans, MD, at the 2016 Genitourinary Cancers Symposium - January 7 - 9, 2016 – San Francisco, CA
Assistant Professor of Medicine Medical Oncologist
Vanderbilt - Ingram Cancer Center