Dr Gong on the EMBARK Trial Investigating Enzalutamide in nmCSPC

Jun Gong, MD, medical director, Colorectal Cancer; associate professor, medicine; medical oncologist, Gastrointestinal Disease Research Group, Pancreatic Cancer Research Group, Urologic Oncology Program, Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Cancer, discusses the significance of the phase 3 EMBARK study (NCT02319837) investigating enzalutamide (Xtandi) in nonmetastatic castration-sensitive prostate cancer (nmCSPC).

On November 17, 2023, the FDA approved enzalutamide for patients with nmCSPC and biochemical recurrence at high risk for metastasis. This regulatory approval was supported by data from the EMBARK trial.

The prospective trial enrolled 1,068 patients who had undergone prostatectomy with or without radiation therapy for localized disease. Notably, patients who were deemed at high risk of biochemical recurrence following primary therapy for localized prostate cancer were the main focus of the trial, Gong details. Biochemical recurrence was defined as a prostate-specific antigen doubling times of 9 months or less, Patients were assigned to receive either standard luteinizing hormone–releasing hormone (LHRH) therapy plus a placebo, LHRH therapy plus 160 mg of enzalutamide, or open-label enzalutamide monotherapy at 160 mg daily.

Results demonstrated that the combination of enzalutamide and ADT outperformed the LHRH placebo arm in terms of metastasis-free survival (MFS), with a hazard ratio (HR) of 0.42 (95% CI, 0.30-0.61; P < .001). Overall survival data are currently immature, but a trend in favor of enzalutamide over LHRH alone was observed. The enzalutamide monotherapy arm also showed superior MFS compared with the LHRH arm, with an HR for metastasis or death of 0.63 (95% CI, 0.46-0.87; P = .005).

These findings suggest that the use of ADT plus enzalutamide or enzalutamide alone confers a superior survival benefit in this population of patients with high-risk localized prostate cancer who experience biochemical recurrence, Gong emphasizes. Consequently, the utilization of enzalutamide in the prostate cancer community is expected to increase based on the pivotal results of the EMBARK study and the regimen's subsequent FDA approval, Gong concludes.