Dr Freedland on the Efficacy Results From the EMBARK Trial of Enzalutamide in Prostate Cancer

“What we are seeing is significantly improved OS with a 40% reduction in the risk of death [with enzalutamide plus ADT vs ADT alone], a profound reduction.”

Stephen Freedland, MD, a professor, a urologic surgeon, and the Warschaw, Robertson, Law Families Chair in Prostate Cancer at Cedars-Sinai; as well as associate director of Education & Training and director of the Center for Integrated Research in Cancer and Lifestyle at Cedars-Sinai Cancer Institute, discussed the phase 3 EMBARK trial (NCT02319837) evaluating overall survival (OS) with enzalutamide (Xtandi) in patients with biochemically recurrent prostate cancer.

Protocol-defined on-trial treatment lasted for 37 weeks. Notably, the trial enrolled a patient population that had no metastases on bone scans, CT scans, or MRIs per central read.

Freedland dove into the OS results from the EMBARK trial and how each arm of the trial performed. Freedland pointed out that patients who received the combination of enzalutamide and androgen deprivation therapy (ADT; n = 355) had the most significant improvement in OS that translated to an approximately 40% reduction in the risk of death vs ADT alone (n = 358; HR, 0.597; 95% CI, 0.444-0.804; P = .0006). Freedland then went on to discuss how the enzalutamide monotherapy arm decreased the risk of death by 17% but that this reduction ultimately failed to reach statistical significance (HR, 0.830; 95% CI, 0.630-1.095; P = .1867).

Freedland mentioned updates on efficacy data from the trial, bringing up secondary end points like skeletal events and time to prostate-specific antigen progression. Freedland noted that even know the enzalutamide monotherapy arm (n = 355) did not reach statistical significance for the primary end point of OS, it did accomplish such for many secondary end points. Freedland also stated that there have been no new updates or signals regarding safety with longer follow-up.

Disclosures: Freedland reported having consultant roles with Astellas Pharma Inc., AstraZeneca, Bayer, Eli Lilly, Johnson & Johnson Innovative Medicine (formerly Janssen), Merck, Novartis, Pfizer Inc., Sanofi, Sumitomo Pharma America, Inc. (formerly Myovant Sciences, Inc.), and Tolmar.