PSA decline and objective response rates in White (W), Black (B), and Asian men with metastatic castration-resistant prostate cancer (mCRPC).

Abstract

5021 Background: We have shown previously in multivariable analysis that AA men had 19% lower risk of death than C men with metastatic castration resistant prostate cancer (mCRPC) treated with a docetaxel (D) and prednisone (P) based regimen. The primary goal of this analysis was to compare ≥50%PSA decline and objective response rate (ORR) in C men, AA men, and Asian men with mCRPC treated with a DP based regimen. Methods: Individual patient data from 8,151 mCRPC men randomized on eight phase III trials to a D containing regimen were combined. Race used in the analysis was based on self-report. The endpoints were ≥50% PSA decline from baseline defined by the PSA working group 2 and ORR (defined as complete or partial response). The logistic regression model was employed to assess the prognostic importance of race in predicting ≥50% PSA decline and ORR adjusting for treatment arm, performance status, and site of metastases. Results: Of 8,151, 7,687 (94%) patients had evaluable PSA data. Of 7,687 men, 6,535 (85%) were W, 445 (6%) were B, 395 (5%) were Asian and 312 (4%) had race unspecified. Men with race unspecified were excluded from the analysis, leaving 7,375 men. Percentage of patients who experienced PSA decline from baseline were: 64%, 58% and 62% in W, B and Asian men, respectively. In multivariable analysis adjusting for risk factors, the pooled odds ratios for PSA decline for AA vs. W were 0.9 (95% CI = 0.7-1.1, p = 0.16) and 1.0 (95% CI = 0.8-1.2, p = 0.92) for Asian vs. W. In 2,760 patients with measurable disease, the percentage of patients who had ORR were: 39%, 31% and 34% in W, B and Asian men, respectively. In multivariable analysis, the pooled odds ratios for ORR were 1.0 (95% CI = 0.7-1.4) for B vs. W and 0.9 (95% CI = 0.6-1.4) for Asian vs. W. Conclusions: There were no differences in PSA decline and ORR outcomes in W, B, or Asian men with mCRPC enrolled on these phase III clinical trials with DP. Clinical trial information: NCT00110214.