“It could be that the differences are due to biological reasons or it could be that the African American patients are responding better to docetaxel/prednisone,” said Halabi. “This underscores the importance of enrolling minorities in clinical trials.”
In the Abi Race study, researchers wanted to further investigate clues indicating that the small number of black men who participated in the COU-AA-302 study had better outcomes than the white patients. The study findings prompted the FDA to expand the approval of abiraterone in combination with prednisone for patients with chemotherapy-naïve mCRPC in 2012.
Only 28 of the 1088 patients in the study were black; 53.3% (n = 8) of the 15 black patients who received abiraterone achieved ≥90% PSA decline compared with 30.8% (n = 168) of the 546 white men who took the drug.5
In their pilot study, George and colleagues enrolled 100 men with mCRPC who had not received prior chemotherapy for CRPC and had a Karnofsky performance status ≥70. The population was evenly divided among men who self-identified as black or white. Overall, the median age was 68.5 years and 56% of participants had a Gleason score of 8 to 10. Baseline characteristics between the 2 groups were similar, the researchers said in their abstract.
Although black patients achieved higher rates of PSA decline and a longer interval to worsening of PSA, the median rate of radiographic progression-free survival was 16.7 months for the black patients and 16.5 months for the white patients.
Investigators plan to conduct molecular analyses of blood and tissue from samples collected from study participants. They also are co-leading the IRONMAN study, which seeks to establish an international cohort of at least 5000 men with advanced prostate cancer to collect data on treatment and outcomes (NCT03151629).
<<< 2018 ASCO Annual Meeting
- Halabi S, Dutta S, Tangen CM, et al. Overall survival between African-American (AA) and Caucasian (C) men with metastatic castration-resistant prostate cancer (mCRPC). Presented at: 2018 ASCO Annual Meeting; June 1-5, 2018; Chicago, IL. Abstract LBA5005. meetinglibrary.asco.org/record/161601/abstract.
- George DJ, Heath EI, Sartor, AO, et al Abi Race: a prospective, multicenter study of black (B) and white (W) patients (pts) with metastatic castrate resistant prostate cancer (mCRPC) treated with abiraterone acetate and prednisone (AAP). Presented at: 2018 ASCO Annual Meeting; June 1-5, 2018; Chicago, IL. Abstract LBA5009. meetinglibrary.asco.org/record/161843/abstract
- Prostate cancer rates by race and ethnicity. Centers for Disease Control and Prevention website. www.cdc.gov/cancer/prostate/statistics/race.htm. Updated June 19, 2017. Accessed June 1, 2018.
- SEER cancer stat facts: prostate cancer. National Cancer Institute website. seer.cancer.gov/statfacts/html/prost.html. Updated April 2018. Accessed June 1, 2018.
- Efstathiou E, Deshpande H, George D, et al. An exploratory analysis of efficacy and safety of abiraterone acetate (AA) in black patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) without prior chemotherapy (ctx). Presented at: 2014 AACR Annual Meeting; April 5-9, 2014; San Diego, CA. Abstract CT313. cancerres.aacrjournals.org/content/74/19_Supplement/CT313.