Key clinical point: Enzalutamide plus androgen-deprivation therapy (ADT) results in a significantly longer overall survival (OS) in men with nonmetastatic castration-resistant prostate cancer (CRPC) and a rapidly rising prostate-specific antigen (PSA) vs. placebo plus ADT.

Major finding: The median OS was 67.0 months in the enzalutamide group vs. 56.3 months in the placebo group. Enzalutamide plus ADT was associated with a significantly lower risk of death vs. placebo plus ADT (hazard ratio, 0.73; P = .001).

Study details: In this final OS analysis of the phase 3 PROSPER trial, 1401 men with nonmetastatic CRPC with increasing PSA were randomly assigned 2:1 to receive ADT with either enzalutamide or placebo.

Disclosures: This study was supported by Pfizer and Astellas Pharma. The presenting author is an employee of Astellas Pharma and reported receiving consulting fees from Merck Sharp and Dohme (MSD), Pfizer, Roche/Genentech, Incyte, AstraZeneca, Sanofi-Genzyme, Medscape, Urotoday, Astellas Pharma, and Clovis.

Commentary

“Over the last several years, strategies for the treatment advanced prostate cancer have included the introduction of therapies earlier in the disease course based on features that are associated with higher risk. To this end, three androgen receptor blockers have been approved by the FDA based on positive early outcomes for those with rapid PSA doubling time. Sternberg et al. report a final overall survival analysis from the PROSPER trial, where patients with a PSA doubling time of 10 months or less were randomized to enzalutamide versus placebo. Median overall survival was 67 months in the treatment group versus 56.3 months in the control group. This is yet another piece of evidence that supports this strategy. As newer, more sensitive, imaging techniques become more widely utilized, it remains to be seen whether the patients that benefit have detectable metastatic disease or a biochemical-only recurrence at the time of treatment initiation.”

Mark Klein, MD