Xgeva Declined for Prostate Cancer Prevention

Prostate cancer bone metastasis and Xgeva risks

(RxWiki News) The Food & Drug Administration (FDA) plays a difficult role in drug approval, and no matter what the agency decides, someone is upset. The recent decision on expanding Xgeva's treatment in prostate cancer illustrates that once again.

While already approved to treat prostate cancer that has metastasized to the bone, when the company that manufactures Xgeva (danosumab) sought approval for using the drug to prevent metastasis, the committee of experts at the FDA voted no.

"Ask your oncologist to explain the side effects from your therapy."

The thirteen member Oncologic Drugs Advisory Committee, reviewed a study funded by the manufacturer, Amgen on 1,435 patients with castration-resistant prostate cancer. They found that the drug did prevent metastasis for four months over placebo (29 months vs 25 months).

However, most importantly, Xgeva did not increase expected lifespan, and the side effects were severe and judged to be too common. A measurement of the drug's effectiveness known as bone metastasis free survival (BMFS) was increased, but this was offset by the increase in serious reportable events (SRE) the worst classification of side effects.

"Ultimately, an application with BMFS as a primary end point would be strengthened by findings that also demonstrate an improvement in the time to SREs or a substantial improvement in quality of life (especially related to clinically relevant pain scores)," the FDA stated.

The committee is formed of health professionals involved in cancer research and treatment.

Not all people feel the same way. Patients especially felt that any option was an improvement over nothing, and the patient representative on the FDA panel voted for the drug's approval.

"There isn't a treatment that a man with prostate cancer gets that doesn't have devastating effects on his masculinity and his quality of life," said James Kiefert, of Olympia, Washington. "In my opinion, the men who would be candidates for this treatment would be standing up and cheering another option for them."

Side effects were notable for including a form of bone destruction called osteonecrosis of the jaw in 33 (4.6 percent) of the patients treated with Xgeva. Other side effects included very low levels of calcium in the blood, rashes and several types of infections.

Xgeva's projected monthly cost is listed at $1,600.

Xgeva is also marketed to women with osteoporosis under the trade name Prolia. More clinical trials on Xgeva are currently under way.

Review Date: 
February 10, 2012