Moving Quickly, FDA Approves Second Prostate Cancer Therapy in Nine Months

US regulators have announced the earlier-than-expected approval of Bayer's Xofigo (radium Ra 223 dichloride), a therapy intended to treat advanced prostate cancer in patients who have castration-resistant cancer that has metastasized to a patient's bones after receiving medical or surgical therapy.

In a statement, the US Food and Drug Administration (FDA) said the therapy was approved three months earlier than expected under FDA's priority review program. Xofigo had an expected approval date of 14 August 2013 under the terms of the Prescription Drug User Fee Act, which sets the schedule for FDA to review a drug and render a decision, commonly known as the drugs' "PDUFA date."

In a statement, Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research, explained that Xofigo works by binding with minerals in the bone to deliver radiation directly to the metastasized tumors, "limiting the damage to the surrounding normal tissues."

The early approval was supported by an 809-patient clinical trial that showed a three-month improvement in median overall survival compared to a placebo.

FDA said common side-effects of Xofigo's use include nausea, diarrhea, vomiting, swelling of the appendages, anemia, and low levels of white blood cells, red blood cells, platelets and lymphocytes.

The treatment is the second in nine months to receive approval from FDA. In late August 2012, FDA approved Astellas Pharmaceuticals' Xtandi (enzalutamide) for the treatment of advanced prostate cancer. As with Xofigo, Xtandi was approved months ahead of schedule and benefited from FDA's priority review program.

Xofigo's early approval has at least one drawback: It's sponsor, Bayer, has not yet published a statement regarding its approval. Focus will update this space if once they do.

Edit: Bayer's statement on the approval is now online here.

Read FDA's announcement here.