Treatment of High-Risk Biochemically Recurrent Prostate Cancer With Enzalutamide in Combination With Leuprolide:...

The primary analysis of EMBARK reported improved metastasis-free survival for enzalutamide plus leuprolide (enzalutamide combination) vs leuprolide plus placebo (leuprolide alone) in patients with high-risk biochemical recurrence while maintaining quality of life. Here, we present secondary efficacy end points for enzalutamide combination vs leuprolide alone.

EMBARK is a global, multicenter, randomized, controlled, phase 3 trial. Patients were randomized (1:1:1) to enzalutamide combination, leuprolide alone, or enzalutamide monotherapy. Non-key secondary end points reported herein include time to distant metastasis, resumption of any hormonal therapy, castration resistance, symptomatic progression, and first symptomatic skeletal event. Hormonal treatment-related symptoms were assessed using the Quality-of-Life Questionnaire-Prostate 25. Time-to-event end points were summarized using the Kaplan-Meier method, with nominal P values.

Enzalutamide combination vs leuprolide alone was associated with increased 5-year probabilities (95% CI) for remaining free of distant metastasis (91.0% [87.1-93.7] vs 81.5% [76.3-85.7]), resumption of any hormonal therapy after treatment suspension (14.9% [10.8-19.6] vs 7.8% [4.4-12.3]), castration resistance (96.6% [93.9-98.1] vs 67.8% [62.4-72.6]), symptomatic progression (70.9% [65.5-75.6] vs 53.3% [47.6-58.6]), and first symptomatic skeletal event (97.8% [95.4-98.9] vs 91.5% [87.8-94.1]). Time to confirmed clinically meaningful deterioration of hormonal treatment-related symptoms favored leuprolide alone vs enzalutamide combination, although the median difference was small (0.03 months).

Combined with the primary findings from EMBARK, data from non-key secondary efficacy end points strengthen support for enzalutamide combination as a new standard of care for patients with high-risk biochemical recurrence.

NCT02319837.