According to phase 3 clinical trials, enzalutamide, an androgen receptor signaling inhibitor, increases survival duration in patients with advanced prostate cancer. The study was published recently in the New England Journal of Medicine.
Enzalutamide does not increase only survival but also improves quality of life, because adverse effects are less harmful than classic chemotherapy, stressed co-author, Thomas Flaig, MD, medical director of the University of Colorado Cancer Center’s Clinical Investigations Shared Resource and associate professor of medicine at the University of Colorado School of Medicine. Researchers are optimistic about this finding. Flaig added that:”We are in a renaissance period in the medical therapy of prostate cancer.”
Prostate cancer generally occurs in men over 50 years and is the second most commonly diagnosed cancer among men. In the United States is the most common cancer in men. Risk factors include age, family history and obesity. Prostate cancer develops and grows slowly and symptoms that arise are difficulties in urinating, erectile dysfunction, sometimes pain occurs. Regarding the treatment of prostate cancer, there are many options such as: surgical removal, cryosurgery, radiotherapy, chemotherapy, hormonal therapy and immunotherapy.
One of the treatments of prostate cancer is hormone therapy because most of these cancers are hormone dependent. However, androgen receptor antagonists (which reduces circulating testosterone) have limited effect as prostate cancer becomes resistant to this treatment. In fact, it happens what is called castration resistant prostate cancer or hormone refractory prostate cancer. This resistance is partly due to overexpression of androgen receptor. Evaluated in a randomized, double-blind, placebo controlled phase 3 clinical trial, enzalutamide been shown to increase survival by 5 months in patients with advanced prostate cancer. Another advantage of enzalutamide is that it can be administered without concomitant administration of prednisone.
The study included 1199 patients that were randomized to receive either enzalutamide (800 patients) or placebo (399). It was found that in those treated with enzalutamide the overall median survival was 18.4 months, while in those who received placebo was 13.6 months. It was also found that in the group receiving enzalutamide adverse event rate was lower. Also, it was observed that these effects appear later, that is after 12.6 months from randomization, compared with the placebo group to which side effects occurred after 4 months. The most common adverse effects included: fatigue, headache, diarrhea, musculoskeletal pain. An adverse reaction in enzalutamide group was seizure, which was observed in 5 of 800 patients. However, it is possible that these patients had predisposing factors for this neurological response.