Roche’s and GSK’s joint force in osteoporosis is even stronger following news that intravenous Bonviva (ibandronate) injected every three months is at least as – and possibly more – effective than the oral daily oral dose in reducing the risk of fracture in osteoporosis. These results are a further boost to the Roche/GSK osteoporosis portfolio, coming one day after Bonviva became the first and only once-monthly tablet to win the backing of the European regulatory body for osteoporosis [[27/06/05b]].

Data on three-monthly IV Bonviva come from the DIVA study, which includes nearly 1,400 postmenopausal women with osteoporosis. After one year, women receiving IV Bonviva had significantly greater increases in bone mineral density at the spine than women randomised to oral treatment, while IV treatment also increased BMD at the hip. As the gold standard measure of bone strength, BMD is a good predictor of future risk of fracture.

Oral bisphosphonates, such as Bonviva, MSD’s market leader Fosamax (alendronate) and Actonel (risedronate) from Aventis/Procter and Gamble, are first-line treatments for postmenopausal osteoporosis, but less than half of women are able to tolerate them long term because of complex dosing instructions and gastrointestinal side effects.

IV Bonviva, submitted to the regulators in the both US and Europe, will be a very attractive option once approved. Initial target patients are likely to be women with severe osteoporosis, who are currently treated off-licence with Novartis’ IV cancer treatments Aredia (pamidronate) or Zometa (zoledronate). However, GI problems become more common with age and, if the licence allows, many other older women may find a three-monthly injection more attractive than a daily, weekly or even monthly oral bisphosphonate.