FDA clears once-monthly osteoporosis therapy.(News)

A once-monthly formulation of the bisphosphonate ibandronate was recently approved by the Food and Drug Administration for treating postmenopausal osteoporosis, 2 years after a daily formulation of the drug was approved but never marketed.

Ibandronate, which is being marketed as Boniva by Roche, is the third oral bisphosphonate and the first monthly formulation marketed in the United States for osteoporosis. It was approved in late March.

A 2.5-mg daily formulation was approved in 2003, based on a 3-year study that showed a reduction in vertebral fracture risk, but it was never marketed because of the availability of the more convenient, weekly bisphosphonate formulations, alendronate (Fosamax) and risedronate (Actonel).

Approval of the once-monthly 150-mg formulation of ibandronate was based on a 1-year noninferiority study of 1,602 postmenopausal women.

The noninferiority study showed that bone mineral density (BMD) increases in the lumbar spine in patients on monthly ibandronate were significantly higher than in those on 2.5 mg of ibandronate daily (4.85% vs. 3.86%).

BMD increases at other skeletal sites also were "consistently higher" among those on the monthly dose, according to the drug's label.

Approval of the daily formulation was based on a 3-year study of almost 3,000 women with postmenopausal osteoporosis, during which the risk of having a vertebral fracture was 4.7% among those on ibandronate, vs. 9.6% among those on placebo, which is a highly significant difference.