Bone drugs get new fracture-risk warning

The FDA's review of bone-drug safety turned up enough evidence for a new warning about the risk of a rare-but-serious fracture of the thigh bone. There's been talk about a link between fractures and the popular class of osteoporosis drugs, known as bisphosphonates, for some time. But this is the first time FDA has required a new warning for the drugs' labels.

The warning will be added to those bone drugs approved for osteoporosis, whether oral--such as Merck's Fosamax, Roche and GlaxoSmithKline's Boniva, and Warner Chilcott's Actonel and new drug Atelvia (a next-generation version of Actonel)--or injectable, such as Novartis' Reclast. It won't apply to bisphosphonates marketed for cancer patients or Paget's disease, such as Novartis' Zometa.

FDA is asking doctors to keep a close eye on patients who've used bisphosphonates for longer than five years, because the fracture risk appears to be related to long-term use. The agency is continuing its safety review of long-term use of the drugs; so far, a causal link between the drugs and fractures hasn't been proven. Meanwhile, European regulators recently launched their own probe of the drugs and their possible link to stress fractures.

Reuters notes that the FDA warning could inspire patients to switch to Amgen's new bone drug, Prolia, which isn't a bisphosphonate. One analyst notes that Prolia sales could get a bump as early as next quarter. "Today's label change is likely to raise the level of concern among patients about the safety of bisphosphonates significantly," Bernstein & Co.'s Geoffrey Porges says in a research note.