Impact of enzalutamide on patient-related outcomes in metastatic castration-resistant prostate cancer: current perspectives

Prostate cancer claims the lives of more than 25,000 men in the United States yearly, most from metastatic disease. In the past decade, several new medications have been approved for the treatment of metastatic prostate cancer including the antiandrogen enzalutamide. In addition, there has been mounting interest in evaluating health-related quality of life (QoL) in patients with cancer including new more detailed recommendations released by the Prostate Cancer Working Group 3 on how to evaluate patient-related outcomes in clinical trials. A total of four randomized double-blind placebo-controlled trials have evaluated patients with metastatic castration-resistant prostate cancer (mCRPC) randomized to receive enzalutamide vs control or bicalutamide. Each study used validated health-related QoL and pain surveys to evaluate patient-related outcomes. The studies suggest that patients with mCRPC, including those aged 75 years and older, have favorable overall QoL scores taking enzalutamide compared to standard of care. There was short-term improved pain control in patients taking enzalutamide compared to those in the placebo group. Some commonly reported adverse effects included fatigue, back pain, and hot flashes. These studies were limited in their patient attrition in filling out surveys as well as difficulty in comparing them to each other. Future studies examining patients with mCRPC taking enzalutamide will have to rigorously standardize ways patient-reported outcomes are collected and evaluate patients in a more diversified real-world population.