Positive Results for Xtandi™ in Phase III PREVAIL Trial
Results published in the New England Journal of Medicine announce the results of the PREVAIL trial; an international, randomised, double-blind, placebo-controlled clinical study of enzalutamide (XTANDI™) in men with metastatic castration-resistant prostate cancer (mCRPC) who are asymptomatic or mildly symptomatic after failure of androgen deprivation therapy and in whom chemotherapy is not yet clinically indicated.
The results from the PREVAIL trial are encouraging as they demonstrate enzalutamide’s efficacy in the pre-chemotherapy setting, and researchers believe this represents a significant step forward in the way we will treat men with chemotherapy-naïve metastatic castration-resistant prostate cancer. Men treated with enzalutamide demonstrated a statistically significant reduction both in the risk of death and a delay in cancer progression as compared to those treated with placebo.1 Enzalutamide reduced the risk of death by 29% (HR=0.71; p < 0.001), compared with placebo.1 In addition, treatment with enzalutamide significantly reduced the risk of radiographic progression or death by 81% compared with placebo treatment (HR=0.19; p < 0.001).1 Men taking enzalutamide experienced a 17-month delay in the time to initiation of chemotherapy compared with men taking placebo (28.0 months versus 10.8 months; HR=0.35; p<0.0001).1
The most common clinically relevant adverse events among the enzalutamide population as compared with placebo-treated patients in the PREVAIL trial included fatigue, hot flush and hypertension.1 Hypertension was observed in 13.4% of patients taking enzalutamide compared with 4.1% of placebo-treated patients.1 Grade 3 or higher cardiac adverse events were reported in 2.8% of enzalutamide versus 2.1% of placebo-treated patients.1 Investigators reported zero seizures in the enzalutamide-treated group and one in the placebo group prior to the data cut-off date.1 One seizure was reported in the enzalutamide group after the data cut-off date.1
Enzalutamide is currently approved for the treatment of adult men with mCRPC whose disease has progressed on or after docetaxel chemotherapy in Europe. Following these results a variation to amend the European Marketing Authorisation Application for enzalutamide for the treatment of adult men with mCRPC who are asymptomatic or mildly symptomatic after failure of androgen deprivation therapy and in whom chemotherapy is not yet clinically indicated was submitted for review by the European Medicines Agency on May 6, 2014.
The paper, "Enzalutamide in Metastatic Prostate Cancer before Chemotherapy" appears in the June 1 online issue of The New England Journal of Medicine. and is available at http://www.nejm.org/doi/full/10.1056/NEJMoa1405095
Reference:
1. Beer T, et al. Enzalutamide Decreases Risk of Death and Delays Progression in Phase 3 Trial of Men with Metastatic Prostate Cancer. Presentation ASCO GU February 2014
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