- In patients with metastatic castration-resistant prostate cancer (mCRPC), the treatment sequence of abiraterone+prednisone followed by enzalutamide shows a longer time to PSA progression and higher proportion of patients with PSA response vs the opposite treatment sequence.
Why this matters
- This is the first randomized, head-to-head comparison of abiraterone+prednisone and enzalutamide.
- Second-line enzalutamide can be considered an appropriate treatment option at first progression with abiraterone+prednisone.
- Phase 2 study of 202 patients with mCRPC, randomly assigned 1:1 to abiraterone+prednisone followed by crossover to enzalutamide at PSA progression (abiraterone-enzalutamide group) or vice versa (enzalutamide-abiraterone group).
- Funding: Canadian Cancer Society Research Institute; others.
- The median follow-up, 30.7 months.
- Primary endpoints: in the abiraterone-enzalutamide vs enzalutamide-abiraterone group:
- The median time to second PSA progression was 19.3 vs 15.2 months (HR, 0.66; P=.36).
- 36% vs 4% of patients showed PSA responses (P<.0001 prespecified psa decline threshold for activity was>
- Time to PSA progression was not statistically different after first-line treatment (HR, 0.95; P=.78).
- PSA response was seen in 68% of patients with first-line abiraterone and 82% of patients with first-line enzalutamide.
- Serious adverse events rate was 15% with abiraterone+prednisone and 20% with enzalutamide-abiraterone sequence.
- The most common grade 3-4 adverse events: hypertension and fatigue.
- Open-label study.