A drug used to treat men with late-stage prostate cancer proved effective in stemming progression of the disease in research participants who had not yet received chemotherapy and extended their survival, according to results from a multi-national phase III clinical trial
An analysis of the study’s results, published in the New England Journal of Medicine and presented at the American Society of Clinical Oncology annual meeting in Chicago, found that participants treated with enzalutamide saw an 81 percent reduction in the risk the cancer would progress and a 29 percent reduction in the risk of death.
The oral medication, which is marketed under the brand name Xtandi, also helped prevent bone metastases, delayed the need for chemotherapy, and reduced evidence of prostate cancer in the bloodstream.
“Based on the study results, this drug could fill an important gap in prostate cancer treatment today,” said Tomasz Beer, the lead author on the study and deputy director of the Knight Cancer Institute at Oregon Health & Science University. “The strong response to this new use of enzalutamide shows that it can provide a viable, less toxic alternative to chemotherapy in staving off the disease in men who aren’t responding to standard first line hormonal treatments.”
Beer also holds the Grover C. Bagby Endowed Chair for Prostate Cancer Research, and in 2012 was selected as one of six scientists to take part in a Stand Up To Cancer Dream Team to study advanced prostate cancer.
The double-blind phase III study included 1,717 research participants enrolled at 207 sites globally between September 2010 and September 2012; 872 received enzalutamide while the others received a placebo. All patients enrolled had metastatic prostate cancer that was progressing despite treatment with traditional hormone therapy. None had yet received chemotherapy.
The trial, named PREVAIL, was concluded early following a planned interim analysis, due to treatment response. At this point, 72 percent of enzalutamide patients and 63 percent of placebo patients were alive at the trial cutoff date showing a 29 percent overall improvement in survival. Fatigue and hypertension were among the most common clinically relevant side effects.
Enzalutamide is approved by FDA for men whose disease has not been stopped by other treatments including surgery, radiation, androgen deprivation therapy and chemotherapy.
The drug’s sponsors, Astellas Pharma Global Development and Medivation Inc., are collaborating on a comprehensive global development program that includes studies of enzalutamide across the full spectrum of advanced prostate cancer as well as advanced breast cancer. The companies jointly commercialize Xtandi capsules in the U.S. and Astellas is responsible for all global manufacturing and regulatory filings. During the study, Beer received grants from Astellas Pharma Global and Medivation.
