Greater survival benefit shown in men with early and less aggressive mCRPC treated with Zytiga® plus prednisone

Janssen-Cilag International NV announced that data from a post-hoc analysis of the Phase III COU-AA-302 trial showed that ZYTIGA^® (abiraterone acetate) plus prednisone provided an 11.8 months overall survival (OS) benefit (53.6 months versus 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

Janssen-Cilag International NV announced that data from a post-hoc analysis of the Phase III COU-AA-302 trial showed that ZYTIGA^® (abiraterone acetate) plus prednisone provided an 11.8 months overall survival (OS) benefit (53.6 months versus 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 today at the European Association of Urology (EAU) 2016 Congress in Munich, Germany, demonstrated an increase in the OS benefit previously shown (4.4 months) in the final analysis of the COU-AA-302 trial (34.7 months abiraterone acetate plus prednisone versus 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 80ng/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 80ng/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 abiraterone acetate 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, Charite? 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 abiraterone acetate 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 abiraterone acetate plus prednisone, compared to placebo plus prednisone:

• Time to chemotherapy use was increased by 12.7 months in Group 1 and 8.8 months in Group 2
  • Group 1: 37.0 months versus 24.3 months; HR=0.64 [95% CI, 0.46–0.89]; p=0.0073
  • Group 2: 23.3 months versus 14.5 months; HR=0.71 [95% CI, 0.60-0.85]; p=0.0001
• There was an improvement in median time to opiate use for cancer-related pain in both groups
  • Group 1: not reached versus 41.0 months; HR=0.69 [95% CI, 0.48-0.99]; p=0.0409
  • Group 2: 30.5 months versus 19.3 months; HR=0.70 [95% CI, 0.59-0.84]; p=0.0001
• Median time on treatment increased in both groups
  • Group 1: 20.4 months versus 11.2 months; HR=0.41 [95% CI, 0.31-0.54]; p<0.0001
  • Group 2: 12.3 months versus 7.2 months; HR=0.54 [95% CI, 0.46-0.62]; p<0.0001

Jane Griffiths, Company Group Chairman, Janssen Europe, the Middle East and Africa (EMEA) said: “Janssen is proud that this study continues to deliver valuable insights as to how best to treat different stages of advanced prostate cancer. We hope that this additional analysis will help healthcare professionals to define the most effective treatment pathway for individual patients. We remain committed to continuing our research in this area with the aim of helping to improve outcomes for men affected by this disease now and in the future.”

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 CJ 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. Last accessed September 2014.
3. ZYTIGA^® summary of product characteristics (February 2016). Last accessed February 2016.