ASCO 2019: Does Adding Abiraterone Acetate to Enzalutamide Improve Outcomes in Metastatic Prostate Cancer?
Posted: Wednesday, June 19, 2019
Adding abiraterone acetate to the combination therapy of enzalutamide and prednisone does not seem to improve outcomes in patients with metastatic castration-resistant prostate cancer and so is not recommended, according to the results of the phase III Alliance A031201 trial. In fact, the investigational combination therapy caused more adverse results than enzalutamide alone. This research was presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 5008) by Michael Morris, MD, of Memorial Sloan Kettering Cancer Center, and colleagues.
“Addition of abiraterone acetate to enzalutamide did not prolong survival in men with metastatic castration-resistant prostate cancer,” the authors wrote.
The randomized trial included 1,311 patients with metastatic castration-resistant prostate cancer. Patients who had received previous treatment with enzalutamide, abiraterone acetate plus prednisone, or taxanes were excluded. Patients were randomly assigned to the enzalutamide treatment arm (657 men) or the arm with abiraterone acetate and prednisone (654 men).
The primary endpoint, overall survival, was 33.6 months for those who received enzalutamide and 32.7 months for those who received enzalutamide plus abiraterone and prednisone (hazard ratio = 0.9). The treatment with abiraterone induced more grade 3 to 5 adverse events (69 %) than enzalutamide alone (56%). In the abiraterone-containing arm, adverse events included increases in fatigue, atrial fibrillation, hypokalemia, transaminitis, and total hematologic toxicity, Dr. Morris noted in an interview with The ASCO Post. More patients treated with abiraterone (12%) discontinued treatment because of adverse events than patients treated with enzalutamide alone (5%).
Disclosure: The study authors’s disclosure information can be found at coi.asco.org.
