September 13th, 2012

Xtandi Approved for Metastatic Hormone-Refractory Prostate Cancer


The U.S. Food and Drug Administration (FDA) has approved Xtandi® (enzalutamide) for the treatment of patients with metastatic, hormone-refractory prostate cancer who have previously received docetaxel.

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.

Xtandi 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.

The approval of Xtandi was based on a single randomized, placebo-controlled multi-center clinical trial that included 1,199 patients with metastatic hormone-refractory prostate cancer who had previously received docetaxel. Patients were randomly assigned to receive Xtandi (160 mg orally once daily) or placebo. Patients were required to continue hormonal therapy. The primary endpoint of the study was overall survival. Median overall survival was 18.4 months in the Xtandi group and 13.6 months in the placebo group.

The most common adverse events included fatigue, back pain, diarrhea, hot flashes, peripheral edema, musculoskeletal pain, headache, upper respiratory infection, muscular weakness, dizziness, insomnia, lower respiratory infection, spinal cord compression and cauda equina syndrome, hematuria, paresthesia, anxiety, and hypertension. Grade 3-4 adverse events were reported in 47 percent of Xtandi patients and 53 percent of placebo patients.

Seizures occurred in 0.9 percent of patients taking Xtandi and these patietns were permanently discontinued from the treatment. No patients in the placebo group experienced seizures.

The drug was reviewed under the agency’s priority review program, which allows an expedited six-month review of drugs that may offer major advances in treatment.


FDA approves new treatment for a type of late stage prostate cancer. [FDA News Release]. U.S. Food and Drug Administration website. Available at:


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Tags: Metastatic Stage IV (D) Prostate Cancer, News, Prostate Cancer, Refactory/Recurrent Prostate Cancer, Uncategorized