FDA approves enzalutamide for metastatic castration-resistant prostate cancer
The FDA today approved enzalutamide for patients with metastatic castration-resistant prostate cancer that has spread or recurred, despite medical or surgical therapy to reduce testosterone.
Approved for prostate cancer patients previously treated with docetaxel, enzalutamide (Xtandi, Medivation Inc.) was reviewed under the FDA’s priority review program.
“The need for additional treatment options for advanced prostate cancer continues to be important for patients,” Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in FDA’s Center for Drug Evaluation and Research said in an FDA release. “Xtandi is the latest treatment for this disease to demonstrate its ability to extend a patient’s life.”
The FDA based its approval on a study of 1,199 patients with metastatic castration-resistant prostate cancer who had received prior treatment with docetaxel. The study was defined to measure OS in men receiving enzalutamide compared with men receiving placebo. The median OS for patients receiving enzalutamide was 18.4 months vs. 13.6 months for the patients who received placebo.
The most commonly observed adverse effects in study participants assigned enzalutamide were weakness or fatigue; hematuria; spinal cord compression and cauda equina syndrome; tissue swelling; diarrhea; musculoskeletal pain; headache; respiratory infections; dizziness; difficulty sleeping; tingling sensations; anxiety; and elevated blood pressure.
Seizures were reported in approximately 1% of those patients who received enzalutamide, at which point therapy was discontinued.
Exclusion criteria for the study consisted of patients with a history of seizure, temporary decrease in blood to the brain during the previous 12 months, reported underlying brain injury with notable loss of consciousness, stroke, brain metastases and patients taking medications that could lower the seizure threshold. At present, the safety profile for enzalutamide is unknown in patients with these conditions.