The bisphosphonate Bonivaca (ibandronate sodium), taken orally in an investigational, once-monthly regimen, was at least equivalent to the previously approved once-daily oral Boniva in increasing spine and hip bone mineral density (BMD) and reducing bone resorption (bone breakdown) and was generally well tolerated, according to study findings reported at the 26th Annual Meeting of the American Society for Bone Mineral Research (ASBMR).

The US FDA approved a once-daily oral formulation of Boniva in May 2003. Roche and GlaxoSmithKline, which are co-developing the drug, are not marketing the daily dose but have been exploring less frequent dosing regimens before launching the product. A supplemental new drug application (sNDA) for a once-monthly dosing formulation of Boniva was submitted to the FDA in May 2004 for the treatment and prevention of postmenopausal osteoporosis.

The findings were based on data from MOBILE (Monthly Oral iBandronate In LadiEs), a two-year, randomized, double-blind trial comparing the efficacy and safety of monthly oral doses of Boniva (100 mg or 150 mg) versus the FDA-approved oral daily regimen (2.5 mg) in 1,609 women with postmenopausal osteoporosis.

These findings are important because they show that Boniva had potential for once-monthly oral dosing, which may provide a more convenient treatment option for many women with postmenopausal osteoporosis, said lead investigator Robert Recker, chief of Endocrinology and director of the Osteoporosis Research Centre at the Creighton University School of Medicine in Omaha, Neb.

Less frequent dosing may be less disruptive to patients at morning routines and help them stay on therapy, which is critical since osteoporosis is a chronic disease that requires patients to take medication as prescribed over the long-term to derive the most benefit, he said.

During the presentations researchers provided one-year results from MOBILE showing-Monthly and daily Boniva reduced bone resorption (as measured by serum CTX) to normal premenopausal levels within three months of initiation, and maintained this suppression with continued therapy; women taking monthly Boniva had at least an equal reduction in bone resorption, compared to women who received daily Boniva; a greater proportion of women in the 150 mg/month group achieved pre-defined reductions (greater than 30 per cent, 50 per cent and 70 per cent below baseline levels) in bone resorption (as measured by serum CTX) compared to those in the daily dose group; women taking monthly Boniva had at least an equal increase in BMD of the lumbar spine and hip compared to women who received daily Boniva; those taking the 150 mg/month dose had the greatest increase in BMD; Further, a greater proportion of women in the 100 mg and 150 mg per month groups achieved increases above baseline in lumbar spine and total hip BMD after one year compared to those in the daily dose group.

Boniva (2.5 mg once-daily) is indicated for the treatment and prevention of osteoporosis in postmenopausal women. In postmenopausal women with osteoporosis, Boniva increases bone mineral density and reduces the incidence of vertebral fractures. Boniva also may be considered for postmenopausal women who are at risk for developing osteoporosis and for whom the desired clinical outcome is to maintain bone mass and reduce the risk of vertebral fracture.

In December 2001, Roche and GSK announced that they would co-develop and plan to co-promote Boniva for the treatment and prevention of postmenopausal osteoporosis in all countries, except Japan. The Roche/GSK collaboration provides expertise and commitment to bring new osteoporosis therapies to market as quickly as possible.