Oral weekly ibandronate prevents bone loss in postmenopausal women.

OBJECTIVES

To investigate the efficacy, safety, and dose-response of once-weekly oral ibandronate in the prevention of postmenopausal bone loss.

DESIGN

This was a multi-centre, placebo-controlled, double-blind, randomized, 24-month phase II/III dose-finding study.

SETTING

Primary care units in 14 osteoporosis centres.

SUBJECTS

A total of 630 women were stratified into four strata according to time since menopause (TSM, 1-3 vs. >3 years) and baseline bone mineral density (BMD; normal: T-score > or =1 vs. osteopenic: -2.5 < or = T-score < or = 1) of the lumbar spine.

INTERVENTIONS

Within each stratum women were further randomized to receive once-weekly ibandronate (5, 10, or 20 mg week-1) or placebo for 24 months.

MAIN OUTCOME MEASURES

Efficacy parameters were the relative changes from baseline in spine (L1-4) and hip BMD, and biochemical markers of bone turnover (serum and urinary C-telopeptide of collagen type I (CTx), osteocalcin, and alkaline phosphatase) measured by dual energy X-ray absorptiometry and enzyme immunoassays, respectively.

RESULTS

Once-weekly therapy with ibandronate induced dose-dependent increases in spine and hip BMD. At month 24, differences between the relative changes in spine and hip BMD induced by 20 mg ibandronate and placebo was 4.0 and 2.7%, respectively. Similar or more pronounced differences were seen in osteopenic women of TSM 1-3 years (5.3 and 3.5%) and of TSM >3 years (3.5 and 2.9%), respectively. A dose-dependent suppression of all biochemical markers of bone turnover was observed with significant decreases in the 20 mg dose groups of all strata at month 24. The overall safety results indicated that once-weekly oral ibandronate was well-tolerated at all three doses.

CONCLUSION

Once-weekly oral therapy with 20 mg ibandronate provides an effective and safe therapy for the prevention of postmenopausal bone loss.