Enzalutamide, an experimental androgen receptor antagonist drug, significantly prolongs survival in men with metastatic hormone-refractory prostate cancer after chemotherapy, according to the results of a study published in the New England Journal of Medicine.

The prostate is a male sex gland responsible for producing fluid that forms semen. It is located below the bladder, in front of the rectum, and surrounds the urethra. Prostate cancer occurs when the cells in the prostate gland grow out of control.

Prostate cancer is a hormonally sensitive disease that can often be controlled for long periods with androgen deprivation therapy (ADT). When prostate cancer stops responding to this treatment, it is referred to as hormone-refractory prostate cancer. Metastatic hormone-refractory prostate cancer is a challenging form of the disease to treat because the cancer has spread to distant sites in the body and does not respond to treatment with hormonal therapy.

Enzalutamide targets multiple steps in the androgen-receptor–signaling pathway, interfering with molecular pathways that help the cancer grow. What’s more, the drug does not cause side effects commonly associated with chemotherapy, such as nausea and hair loss.

To evaluate whether enzalutamide prolongs survival, researchers conducted a phase 3, double-blind, placebo-controlled trial that included nearly 1,200 men with metastatic hormone-refractory prostate cancer that had stopped responding to previous treatments—including hormonal therapy and chemotherapy. The men were randomly assigned to receive oral enzalutamide or placebo.

The results indicated that men taking enzalutamide lived 37 percent longer. The median overall survival for men taking enzalutamide was 18.4 months compared to 13.6 months for those taking placebo.

The researchers concluded that enzalutamide significantly prolongs survival in men with metastatic hormone-refractory prostate cancer. Research is ongoing to evaluate the drug in combination with other drugs and also to evaluate its effect when used earlier in the disease.


Scher HI, Fizazi K, Saad F, et al. Increased survival with enzalutamide in prostate cancer after chemotherapy. New England Journal of Medicine. Published early online August 15, 2012. Doi: 10.1056/NEJMoa1207506

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