CHICAGO — A 2-year analysis has shown that once-monthly ibandronate provides bone mineral density increases in women with postmenopausal osteoporosis superior to those seen with the proven daily dose.
Previously reported 1-year results from the Monthly Oral Ibandronate in Ladies (MOBILE) study showed that once-monthly ibandronate (Boniva) was superior to daily dosing at the spine and total hip, and comparable in other areas. “At 2 years there was actually superiority in all areas of the hip, plus the spine, and the adverse event profile was very comparable at 1 and 2 years,” Dr. Michael A. Bolognese, who headed the prospective, phase III study for Hoffman-La Roche Inc., said in an interview.
Overall, 1,609 women, aged 55–80 years, with postmenopausal osteoporosis were randomized to oral ibandronate 2.5 mg daily or to one of three different monthly ibandronate doses: 150-mg, 100-mg, or two 50-mg doses on 2 consecutive days. The per-protocol population included 395 women in the 2.5-mg daily group and 396 in the 150-mg monthly ibandronate group.
In a per-protocol analysis, mean lumbar spine bone mineral density scores increased 4% from baseline in the daily group and 5% in the monthly group after 1 year, and 5% and 7%, respectively, after 2 years. Similar increases were seen in the intent-to-treat population, Dr. Bolognese and his associates reported in a poster at the annual meeting of the American Association of Clinical Endocrinologists.
After 2 years, superior mean bone mineral density gains were seen at the hip with 150-mg monthly ibandronate, compared with daily dosing (total hip, 4% vs. 3%; femoral neck, 3% vs. 2%; trochanter, 6% vs. 4%).
There was no difference in the incidence of clinical fractures between the daily- and monthly-dose groups (26 vs. 29). The number of withdrawals due to adverse events was low and comparable for daily and monthly treatment (10% vs. 9%), reported Dr. Bolognese, who is in private practice in Bethesda, Md., and is a Roche speaker and grant recipient.
Patients have to sit upright for 60 minutes after taking monthly ibandronate, compared with 30 minutes for the daily dose. But because it's only once a month, it's still easier to tolerate, particularly for patients on multiple medications or in nursing facilities, he said.
In another poster, 1- and 2-year data from the Dosing Intravenous Administration (DIVA) study suggest that intermittent intravenous ibandronate injections are generally well tolerated and provide a safe alternative for patients unable to take oral bisphosphonates.
The phase III study randomized 1,395 postmenopausal women, aged 55–80 years, with osteoporosis to four treatment groups: 2-mg IV ibandronate injection every 2 months plus daily oral placebo; 2.5-mg daily oral ibandronate plus placebo IV injection every 2 months; 3-mg IV ibandronate every 3 months plus daily oral placebo; and 2.5-mg daily oral ibandronate plus placebo IV injection every 3 months.
Adverse events were balanced across treatment arms, noted Dr. Mone Zaidi, professor of medicine at Mount Sinai School of Medicine, New York, and his associates. The most frequently reported adverse events were nasopharyngitis, back pain, hypertension, and arthralgia.
The number of patients who experienced a fracture at 2 years was low (85/1,382 or 6%), and was similar for all treatment groups, according to the study, which also was supported by Roche.
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