Men with prostate cancer that has spread despite undergoing medical or surgical therapy can heave a sigh of relief. The U.S. Food and Drug Administration (FDA) today approved Xofigo (radium Ra 223 dichloride) for patients suffering from symptomatic late-stage castration-resistant prostate cancer that has spread only to bones.
The prostate is a gland in the male reproductive system found below the bladder and in front of the rectum. The male sex hormone testosterone stimulates the prostate cancers to grow. An estimated 238,590 men will be diagnosed with prostate cancer and 29,720 will die from the disease in 2013, according to the National Cancer Institute statistics. Castration-resistant prostate cancer patients are unable to respond to castration treatment, involving reduction of available testosterone in its various forms or by chemical or surgical means.
Under the agency's priority review program, the FDA approved Xofigo more than three months ahead of the product's prescription drug user fee goal date of Aug. 14, 2013, the date the agency was scheduled to complete review of the drug application. The expedited review is intended for drugs that appear to provide safe and effective therapy in the absence of a satisfactory alternative. But it also happens if the drug offers significant improvement compared to currently available products in the market.
"Xofigo binds with minerals in the bone to deliver radiation directly to bone tumors, limiting the damage to the surrounding normal tissues," said Richard Pazdur, M.D., director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research in a press release. "Xofigo is the second prostate cancer drug approved by the FDA in the past year that demonstrates an ability to extend the survival of men with late-stage prostate cancer."
The safety and effectiveness of Xofigo were tested in single clinical trial of 809 men with symptoms due to castration-resistant prostate cancer that has spread to bones but not to other organs. The investigators randomly assigned patients to receive Xofigo or a dummy pill. An interim analysis of the results suggested that men receiving Xofigo lived up to 14 months compared to 11.2 months for men receiving the dummy. Further analysis of the trial results confirmed Xofigo's ability to extend overall survival.
Patients on Xofigo, marketed by Wayne, N.J.-based Bayer Pharmaceuticals, may still run into a few side effects such as nausea, diarrhea, vomiting and swelling of the leg, ankle or foot. The FDA also mentions some of the most common abnormalities with this drug for prostate cancer: low levels of red blood cells, lymphocytes, white blood cells, platelets and infection-fighting white blood cells.