Enzalutamide has been shown to improve overall survival in men with metastatic, castration-resistant prostate cancer, but can it delay the onset of metastases in men with nonmetastatic, but castration-resistant disease who have a rapidly-rising PSA? New research by Hussain and colleagues (2018) explored this question. They found that enzalutamide can indeed delay the onset of metastatic disease. Their results are from a double-blind, phase 3 trial, for which 1401 patients were randomized to receive either enzalutamide or placebo. There was a clear effect of enzalutamide on the onset of radiographic metastasis. Indeed, the authors reported a 71% lower risk of metastasis or death associated with enzalutamide (versus placebo) in men with high-risk, nonmetastatic, castrate-resistant prostate cancer.
Although enzalutamide treatment can lead to clinically meaningful reduction in the risk of metastasis and death, patients need to be aware that enzalutamide is not free of side effects. Fatigue is common and there is an increased risk of falls and fractures.
Summary of Study:
Hussain, M., Fizazi, K., Saad, F., Rathenborg, P., Shore, N., Ferreira, U., Ivashchenko, P., Demirhan, E., Modelska, K., Phung, Krivoshik, A., & Sternberg, C. N. (2018). Enzalutamide in men with nonmetastatic, castration-resistant prostate cancer. New England Journal of Medicine, 378(26), 2465-2474. doi: 10.1056/NEJMoa1800536