According to a new article, to be published on line today in The Lancet, abiraterone acetate + prednisone provides a median overall survival benefit of 4.6 months compared to a placebo in men with metastatic, castration-resistant prostate cancer (mCRPC) who have received prior treatment with docetaxel-based chemotherapy.
As yet, the actual article is not available on The Lancet‘s web site, but a summary of the report has been published on the MedPage Today web site.
According to the summary report, this is the “final” analysis of the original trial initiated by Cougar Pharmaceuticals. It shows that over a median follow-up period of 20.2 months, median overall survival was
- 15.8 months for men randomized to treatment with abiraterone acetate + prednisone
- 11.2 months for men randomized to a placebo + prednisone
Additional data provided show that:
- The final analysis was carried out before any patients were crossed over from placebo to abiraterone and after 775/797 prespecified death events.
- The finding of an overall survival benefit was consistent across all the protocol-specific patient subgroups.
- Median time to biochemical progression (based on a rising PSA value) was
- :8.5 months in men randomized to abiraterone acetate
- 6.6 months in men randomized to the placebo arm
- Median time to radiologic progression was
- 5.6 months in men randomized to abiraterone acetate
- 3.6 months in men randomized to the placebo arm
- The most common grade 3-4 adverse events were fatigue, anemia, back pain, and bone pain (and these were all observed at similar frequencies in both arms of the study)
- Mineralocorticoid-related adverse events occurred more often in men in the abiraterone arm of the trial; so did fluid retention, edema, hypokalemia, and hypertension.
These new data do show that abiraterone acetate offers a somewhat longer overall survival benefit than the data presented when the trial was originally stopped in 2010. The data report suggest that the “final” overall survival benefit of abiraterone acetate is closer to — but still shorter than — the overall survival benefit offered by data from the first analysis of the enzalutamide trial in a comparable group of patients with mCRPC. The only way we will know if one of these products is actually “better” than the other is if someone decides to conduct a head to head trial … and we aren’t expecting to see such a trial in men with mCRPC any time soon, if ever.