NEW ORLEANS, LA USA (UroToday.com) - Dr. Arnauld A. Villers presented his group’s work on the TERRAIN trial in today’s Late Breaking Abstract session. Enzalutamide was designed to block androgen-receptor signaling by inhibiting multiple steps in the signaling pathway, along with its features of anti-proliferative, pro-apoptotic, and direct anti-tumor effects. The purpose of the TERRAIN trial was to evaluate the clinical benefit of enzalutamide vs bicalutamide in patients with metastatic castrate-resistant prostate cancer.
Three hundred seventy-five asymptomatic, chemo-naïve patients with mCRPC were randomized to receive enzalutamide 160mg/day (n=184) vs bicalutamide 50mg/day (n=191). The primary endpoint of the study was PFS, including radiographic PFS, SRE, change to a new anti-neoplastic therapy, or death. Other endpoints included time to PSA decrease, PSA response, and HR-QOL.
The authors found that median PFS in the enzalutamide group was 15.7 months, vs 5.8 months in the bicalutamide group (HR 0.44, P < 0.0001). PFS improvement was seen in the enzalutamide cohort across all subgroups when stratified by age, geographic region, ECOG PS, Gleason score, disease sites, PSA, and LHRH agonist treatment. Median time to PSA response of 90% decrease was 5.4 months in the enzalutamide group. The enzalutamide group also outperformed the bicalutamide group in all domains of the FACT-P HR-QOL analysis. 28% of enzalutamide vs 23% of bicalutamide patients experienced an adverse event that led to treatment discontinuation.
The authors concluded that enzalutamide is associated with significantly longer PFS vs bicalutamide, with a difference of 10 months in median PFS. Enzalutamide is also associated with a higher PSA response rate and greater HR-QOL benefit while demonstrating an acceptable safety profile.
Presented by Arnauld A. Villers, MD at the American Urological Association (AUA) Annual Meeting - May 15 - 19, 2015 - New Orleans, LA USA
University of Lille
Reported by Nikhil Waingankar, medical writer for UroToday.com