Encouraging Sign For Long-term Safety Of Bisphosphonates

Bisphosphonates are the most common class of drugs used for the treatment of osteoporosis because of their demonstrated effect on fracture reduction but the incidence of microcracks - small cracks in the skeleton - has been shown to increase with bisphosphonate treatment. This has led to some concerns regarding the potential long-term adverse effects of these agents. This study shows that the continued use of alendronate (a bisphosphonate) is not associated with continued accumulation of microdamage.

Matt R. Allen, Ph.D., assistant research professor, and David B. Burr, Ph.D., chairman, both from the Indiana University School of Medicine Department of Anatomy and Cell Biology, Indianapolis, IN, evaluated the effects of alendronate in one-year-old female beagles. The beagles were given oral doses of alendronate at levels comparable to that employed in humans (.2 mg/kg/day) or at five times the clinical dose (1 mg/kg/day) for either 1 year or 3 years.

Researchers found there was no increase in vertebral microcracks after 3 years of alendronate treatment in comparison to the beagles treated for 1 year. These results suggest that microcrack accumulation is greatest during the early course of alendronate treatment. This is an encouraging sign for long-term safety of these drugs.

ASBMR President-Elect Steve Goldring, M.D., notes: "These findings have important clinical implications with respect to the long-term safety of bisphosphonates in patients with osteoporosis."

Disclosures: Dr. Allen and Dr. Burr have received financial support from Eli Lilly, Procter & Gamble (The Alliance for Better Bone Health), Merck, and Amgen. Dr. Burr has been a consultant for Eli Lilly, Procter & Gamble (The Alliance for Better Bone Health), and Amgen, has participated in a speakers bureau for Eli Lilly and Procter & Gamble (The Alliance for Better Bone Health), and holds stock in Pfizer and Amgen.