Upper gastrointestinal and overall tolerability of alendronate once weekly in patients with osteoporosis: results of a randomized, double-blind, placebo-controlled study

Objective: To compare the upper gastrointestinal (GI) and overall tolerability profiles of alendronate 70 mg once weekly with placebo. Research design and methods: This 12-week international, multi-center, randomized, double-blind, placebo-controlled trial included 449 postmenopausal women and men with osteoporosis at 44 sites in 19 countries in Europe, the Americas, Africa, and Asia-Pacific. Subjects were randomized to alendronate 70 mg once weekly or matching placebo in a 1:1 ratio. Main outcome measures: The safety and tolerability of weekly alendronate and placebo were captured as clinical and laboratory adverse events. The primary endpoint was upper GI tolerability based on the incidence of upper GI tract adverse events. Secondary endpoints included the percentage of subjects who discontinued therapy due to a drug-related upper GI adverse event. Change from baseline in bone turnover as measured by the urinary N-telopeptide-collagen crosslinks corrected for creatinine (NTx/Cr) was assessed at 12 weeks as an indicator of efficacy. Results: The percentages of subjects reporting an upper GI tract adverse event in the alendronate 70 mg once weekly group (9.8%) and the placebo group (9.4%) were similar. The risk difference between the two treatment groups (alendronate minus placebo) was 0.4% [95% confidence interval (CI), -5.1%, 5.9%]. Percentages of subjects who discontinued due to a drug-related upper GI adverse event were also similar (alendronate 2.7%; placebo 2.2%; risk difference 0.4%, 95% CI, -2.4, 3.3). The overall tolerability profile of alendronate 70 mg once weekly, as measured by the percentage of subjects reporting any adverse event, was similar to that of placebo (risk difference 2.1%, 95% CI -6.9, 11.0). There was a significant 43.3% (95% CI, -47.9%, -38.3%) decrease from baseline in urinary NTx/Cr in the alendronate group compared with an 8.0% (95% CI, 1.4%,15.0%) increase in the placebo group at Week 12. Conclusion: Alendronate 70 mg administered once weekly to women and men with osteoporosis has an upper GI and overall tolerability profile similar to that of placebo.