Study Raises Questions about Fosamax and Bone Fractures

A new study, funded by the makers of Fosamax and other osteoporosis drugs, has concluded that oral bisphosphonate drugs are safe, and that the risk of low-trauma femur fractures with the medications are rare. 

The femur fracture study was reported in the latest issue of the New England Medical Journal. The drug company researchers found that bone fractures with Fosamax, Boniva and Reclast were extremely rare and were outweighed by the number of bone breaks prevented by the osteoporosis drugs. The study was funded, in part, by Merck & Co., which makes Fosamax, and Novartis, which makes Reclast.

Fosamax has come under scrutiny recently due to an increasing number of reports of low-trauma bone breaks among Fosamax users, usually in the femur, which is one of the strongest bones in the human body.

A number of Fosamax femur fracture lawsuits have been filed against Merck alleging that the drug maker failed to adequately research their medication or warn users about the risk of the bone breaks. The drug maker also already faces hundreds of lawsuits over Fosamax jaw side effects, involving a rare condition known as osteonecrosis of the jaw (ONJ), which cause portions of the jaw to decay or die.

Fosamax (alendronate sodium), Boniva (ibandronate) and Reclast (zoledronic acid), are all members of a class of drugs known as bisphosphonates, which are prescribed for treatment of osteoporosis. Fosamax, which is the most widely used of the three medications, was approved by the FDA in October 1995, and has been used by more than 20 million people. The drug generated over $3 billion in annual sales for Merck before it became available as a generic last year.

In the latest study, researchers analyzed results from previous trials that looked at the number of bone breaks in more than 14,000 women taking Fosamax or other bisphosphonates. The researchers found that, out of 284 hip or femur fractures, only 12 fit the profile of the low-trauma femur fractures. The researchers acknowledged that sudden bone breaks associated with Fosamax and the other drugs were likely real, but rare.

“The occurrence of fracture of the subtrochanteric or diaphyseal femur was very rare, even among women who had been treated with bisphosphonates for as long as 10 years,” researchers concluded, but cautioned that their study was limited. “There was no significant increase in risk associated with bisphosphonate use, but the study was underpowered for definitive conclusions.”

The study follows a recent FDA announcement that the agency is continuing to review the potential Fosamax bone fracture side effects, but has yet to find a clear link between the breaks and Fosamax. Other studies, however, have had results that suggest there may be a connection.

A study published in the May/June 2008 issue of the Journal of Orthopedic Trauma found a pattern of femur fractures among Fosamax users that was 98% specific to the osteoporosis drug, involving low-energy fractures that were typically caused by falls from a standing height or less. The study also found that the average duration of Fosamax use was longer among those who had signs of these specific femur fractures than those who did not.

In addition, a Fosamax fracture case study published in September 2009, in the Journal of Bone and Mineral Research examined a patient suffering from rheumatoid arthritis with multiple risks for bone fractures who took Fosamax for eight years and developed femur fractures. The report found that the patient had an imbalance between bone resorption and bone formation at the site of a rare femur fracture known as a spontaneous bilateral subtrochanteric/diaphyseal fracture, which suggested a possible connection to the osteoporosis drug.

Merck & Co. faces about 1,000 Fosamax lawsuits over ONJ. The federal Fosamax cases have been consolidated into a multidistrict litigation (NDL) for pretrial proceedings in the U.S. District Court for the Southern District of New York. In December, District Judge John Keenan, overseeing the cases, ruled that at least one Fosamax femur fracture lawsuit should be handled separately, due to the differences between those cases and the Fosamax ONJ suits.