SAN FRANCISCO, CA USA (UroToday.com) - Complete Title: GU Cancers Symposium 2014 - Session Highlights: Results from a phase 3, randomized, double-blind, multicenter, placebo-controlled trial of orteronel (TAK-700) plus prednisone in patients with mCRPC that has progressed during or following docetaxel-based therapy (ELM-PC 5 trial)
Novel mechanisms of steroid hormone production inhibition present exciting therapies for targeting castration-resistant prostate cancer. Orteronel (TAK-700) is a non-steroidal inhibitor of 17,20-lyase (similar to abiraterone), an enzyme integral to steroid production. Results from the ELM-PC5 trial of TAK-700 and prednisone for the treatment of progressive or docetaxel-refractory, metastatic castration-resistant prostate cancer (mCRPC) were presented. The trial was performed at 260 centers from 42 countries across 5 continents. Disease progression was determined based on radiographic or PSA criteria. Patients were randomized 2:1 to orteronel and prednisone or placebo and prednisone, and primary endpoints examined include overall (OS) and radiographic progression-free survival (PFS).
Among the 1 099 patients randomized prior to trial accrual due to failure to meet its primary endpoint, median OS was 17.0 months (95% CI 15.2, 19.9) versus 15.2 months (95% CI 13.5, 16.9) (HR: 0.886 [95% CI: 0.739, 1.062]; P=0.1898) among patients treated with orteronel and placebo, respectively. Striking regional differences in OS were reported, with patients responding more favorably to orteronel than placebo in North America (OS 20.9 vs. 16.9 months) and the rest of the world (OS 15.3 vs. 10.1 months), but not in Europe (OS 18.3 vs. 17.3 months). One explanation posited to explain the regional differences in OS was the discrepant use of subsequent therapies in North America (26%), Europe (28%), and non-Europe/North America (8%).
Among the overall cohort, orteronel was associated with significantly improved radiographic PFS (median 8.3 months vs. 5.7 months; HR: 0.76 [95% CI: 0.653, 0.885]; P=0.00038). The most common side effects reported were nausea (16%), emesis (8%), fatigue (11%), and diarrhea (9%). Severe (≥ grade 3) toxicities include elevated amylase and lipase (< 1%) and fatigue (3%). The most common adverse event that led to discontinuation of therapy was GI toxicity. Overall, therapy was well tolerated and associated with minimal mineralocorticoid-related excess toxicity.
Highlights of a presentation by Robert Dreicer, MD at the 2014 Genitourinary Cancers Symposium - January 30 - February 1, 2014 - San Francisco Marriott Marquis - San Francisco, California USA
Cleveland Clinic, Cleveland, OH USA
Written by Jeffrey J. Tomaszewski, MD, medical writer for UroToday.com
Click HERE to view the poster from this session