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MUNICH—(UroToday)— Data from a post-hoc analysis of the Phase 3 COU-AA-302 trial showed that ZYTIGA® (abiraterone acetate) plus prednisone provided an 11.8 months overall survival (OS) benefit (53.6 months vs 41.8 months; HR = 0.61 [95% CI, 0.43-0.87]; p = 0.0055), compared to an active control of placebo plus prednisone, in men with early and less aggressive chemotherapy-naïve metastatic castration-resistant prostate cancer (mCRPC).1 Data from the post-hoc analysis, presented at the European Association of Urology (EAU) 2016 Congress in Munich, Germany, demonstrated almost triple the OS benefit previously shown (4.4 months) in the final analysis of the COU-AA-302 trial (34.7 months ZYTIGA plus prednisone vs 30.3 months placebo plus prednisone; HR = 0.81 [95% CI, 0.70-0.93]; p = 0.0033). The final analysis was originally presented at the European Society for Medical Oncology (ESMO) 2014 Congress and included a broader range of men with asymptomatic or mildly symptomatic chemotherapy-naïve mCRPC.2 The post-hoc analysis divided patients into two groups to identify which group experienced a greater treatment benefit. The patients in Group 1 were in an earlier, less advanced and less symptomatic stage of the disease (which was defined as having a Brief Pain Inventory [BPI] Short Form score of 0-1, prostate-specific antigen [PSA] below 80 ng/ml and a Gleason score [GS] of below 8). Those in Group 2 were in a later, more advanced and more symptomatic stage of the disease (defined as a having a BPI of 2 or over and/or PSA of 80 ng/ml or above, and/or a GS of 8 or more). The analysis revealed that patients in both groups experienced an OS benefit when treated with ZYTIGA plus prednisone, compared to placebo plus prednisone (Group 1: 11.8 months; HR = 0.61 [95% CI, 0.43-0.87]; p = 0.0055) (Group 2: 2.8 months; HR = 0.84 [95% CI, 0.72-0.99]; p = 0.0321).1 “Post-hoc analyses such as this are very important in helping us to identify the patients who could benefit most from therapies such as novel hormone agents, and at what stage of a patient’s disease they could be most effective.” said Professor Kurt Miller, Department of Urology, Chariteì Berlin, Berlin, Germany. “As men with prostate cancer are living longer, quality of life is an increasingly important factor for them and their families. It is therefore encouraging to see that when used earlier, patients can stay on ZYTIGA for longer and delay the need for additional, more invasive treatments,” he continued. In addition to OS benefit, the post-hoc analysis data also revealed that both groups showed improvement in disease progression, cancer-related pain and treatment duration when treated with ZYTIGA plus prednisone, compared to placebo plus prednisone:
EAU 2016 Greater Survival Benefit Shown in Men with Early and Less Aggressive Metastatic Castration-Resistant Prostate Cancer Treated with ZYTIGA® Plus Prednisone (EAU 2016 Congress poster session #61, 14 March 2016.)1 About the COU-AA-302 study COU-AA-302 is an international, randomized, double-blind, placebo controlled Phase 3 study that included 1,088 men with mCRPC who had not received prior chemotherapy and were randomized to receive ZYTIGA (abiraterone acetate) 1,000 milligrams (mg) administered orally once-daily plus prednisone 5 mg administered twice-daily or placebo plus prednisone 5 mg administered twice-daily. The co-primary endpoints of the study were rPFS and OS. Key secondary endpoints included time to opiate use, time to initiation of chemotherapy, time to Eastern Cooperative Oncology Group (ECOG) performance status deterioration and time to PSA progression. The final analysis was presented at the European Society for Medical Oncology (ESMO) 2014 Congress. The post-hoc analysis used the final dataset for the intent-to-treat population (n = 1088), to stratify patients into Group 1 (BPI 0-1, PSA < 80 ng/ml and GS < 8) and Group 2 (BPI ≥ 2 and/or PSA ≥ 80 ng/ml and/or GS ≥ 8). OS, radiographic progression-free survival (rPFS), time to CT use, time to opiate use, and time on treatment with ZYTIGA plus prednisone vs placebo plus prednisone were analysed by the Kaplan–Meier method and Cox proportional hazards regression.
References 1 Miller, K. et al. The phase 3 COU-AA-302 study of abiraterone acetate (AA) in men with chemotherapy (CT)-naïve metastatic castration-resistant prostate cancer (mCRPC): Stratified analysis based on pain, prostate-specific antigen (PSA) and Gleason score (GS). Poster #61 presented at the European Association of Urology 2016 Congress, March 11-15, Munich, Germany. 2 Ryan C.J et al. Final overall survival (OS) analysis of COU-AA-302, a randomized phase 3 study of abiraterone acetate (AA) in metastatic castration-resistant prostate cancer (mCRPC) patients (pts) without prior chemotherapy. Abstract presented at the European Society for Medical Oncology 2014 Congress, September 26-30, Madrid, Spain. Oral Presentation. ESMO abstract #753O. Available at: https://www.webges.com/cslide/library/esmo/browse/search/eor#9f9k02Lm. |