Prolia Side Effects Increase Risk of Low-Trauma Fractures: Public Citizen

A prominent consumer watchdog group is warning that the Amgen bone drug Prolia could increase the risk of sudden bone fractures, which may occur with little or no trauma at all.  

In the latest edition of Public Citizen’s Worst Pills, Best Pills Newsletter (subscription required), the group indicates that there have been concerns over the potential side effects of Prolia since 2009, a year before it became the first drug ever approved by the FDA for the treatment of postmenopausal osteoporosis.

While warnings about the risk of femur fractures from Prolia have been issued in Canada, similar warnings have not been issued by the FDA in the United States.

As a result of the risk, Public Citizen is urging consumers and health care providers to avoid Prolia, placing the osteoporosis drug on it’s “Do Not Use” list.

According to Public Citizen, Prolia (denosumab) interferes with bone metabolism and the body’s immune system, resulting toinatypical bone fractures and breaks that happen spontaneously without the usual trauma, like a fall, needed to break a bone.

According to Amgen, Prolia fractures have been confirmed among patients who are part of an ongoing study to extend the use of of the drug for postmenopausal osteoporosis. The fractures appear to occur in one out of every 10,000 patients that use the drug. In most cases the fractures produce a dull, unusual aching pain in the thigh, hip, or pelvis area.

Public Citizen looked at data from the clinical trials and found that in one study those taking Prolia for three years saw their risk of hip fracture triple, while those taking a placebo saw their hip fracture risk actually drop. The newsletter notes that the absolute difference in fracture risk between those taking Prolia and those taking a placebo were relatively small; a difference of about 4.8%.

There were other concerns with the drug as well that were known before the FDA granted approval, Public Citizen maintains. The group claims there were concerns over infections, dermatologic adverse events, as well as problems linked to the suppression of bone turnover; including atypical fractures, osteonecrosis of the jaw and delayed fracture healing.

Atypical Fracture Problems Affect Other Bone Drugs

Many of the same problems have been linked to bisphosphonate medications, a family of bone drugs that includes Fosamax and Zometa.

Merck & Co. currently faces hundreds of Fosamax femur fracture lawsuits that have been filed by individuals who claim the drug maker failed to adequately warn about the potential risk of problems.  Complaints allege that side effects of Fosamax may weaken the ability of the femur bone to repair itself from microdamage, increasing the risk of a sudden femur fracture.

In October 2010, the FDA required the Merck and the manufacturers of other bisphosphonate medications approved for treatment of osteoporosis to add warnings about the risk of sudden femur fractures. Since then, information has been provided in a Medication Guide distributed with each prescription for the drugs, warning consumers to contact their doctor if they experience new thigh or groin pain, which can occur weeks or months before a complete femur fracture occurs on the osteoporosis drugs.