Study: New Drug Enzalutamide Extends Life in Advanced Prostate CancerAug 20, 2012
Editor’s Note: The US Food and Drug Administration (FDA) on August 31, 2012 approved enzalutamide for men with advanced prostate cancer that has continued to grow even though they received chemotherapy and treatment to suppress hormones. The drug will have the brand-name Xtandi. It was approved under the FDA’s accelerated approval program for drugs that show promise against a serious disease.
Xtandi will be co-marketed by Astellas Pharma U.S., Inc. of Northbrook, Ill and Medivation, Inc. of San Francisco.
A clinical trial of the experimental drug enzalutamide (formerly called MDV3100) has shown it extends life by an average of about 5 months in the most advanced stages of prostate cancer, even after other treatments.
Lead researcher Howard Scher, MD, Memorial Sloan-Kettering Cancer Center, and colleagues followed 1199 men whose advanced prostate cancer was no longer responding to hormone therapy and chemotherapy. About two-thirds of the men took enzalutamide daily as capsules, while the other third received inactive placebo capsules. Average survival time for men who received the drug was 18.4 months, compared to 13.6 months for patients who received the placebo.
The trial, known by the acronym AFFIRM, was stopped early so that men who were receiving the placebo could be offered the drug. The results were published early online August 15, 2012 in the New England Journal of Medicine.
Enzalutamide is a kind of drug called an anti-androgen, which is a type of hormone therapy. These drugs work by blocking the body’s ability to use hormones called androgens, which include testosterone. Prostate cancer cells have androgen receptors on their surface. When androgens come into contact with these receptors, it sends a signal to help the cells grow. Anti-androgens help block this signal, but eventually almost all prostate cancers treated with currently available anti-androgens or other forms of hormone therapy become resistant to them.
Enzalutamide seems to bind more strongly to cancer cells’ androgen receptors than standard anti-androgen drugs, and keeps them from being able to grab onto androgen molecules. This may make it more effective, even after other types of hormone therapy have been tried. Enzalutamide also keeps cells from pulling androgen receptors inside the cell nucleus, which prevents the cells from getting the signal to grow.
The drug is not yet available outside of clinical trials, but it has been submitted to the US Food and Drug Administration (FDA) for approval.
The most commonly reported side effects included fatigue, diarrhea, and hot flashes.
Increased Survival with Enzalutamide in Prostate Cancer after Chemotherapy. Published early online August 15, 2012 in the New England Journal of Medicine. First author: Howard I. Scher, MD, Memorial Sloan-Kettering Cancer Center, New York.