Tolerability of Once-weekly Alendronate in Patients with Osteoporosis: a Randomized, Double-blind, Placebo-controlled Study

Objective: To compare the upper gastrointestinal (GI) tract tolerability of once-weekly oral alendronate, 70 mg, and placebo.

Patients And Methods: This was a 12-week multicenter, randomized, double-blind, placebo-controlled study. The first patient initiated treatment on June 5, 2000, and the last patient completed treatment on March 1, 2001. The study enrolled 450 postmenopausal women and men with osteoporosis (224 took alendronate, 226 took placebo) who were ambulatory and community dwelling at 48 outpatient study centers in the United States. By design, approximately half of the patients were naive to bisphosphonates. The primary end point was upper GI tract tolerability based on the incidence of any upper GI tract adverse events. Secondary end points included the number of discontinuations due to drug-related upper GI tract adverse events and the change from baseline in bone resorption, assessed by the urinary N-telopeptide-creatinine ratio at 12 weeks. A subgroup analysis of the primary and secondary end points was performed on the patients stratified by prior bisphosphonate use. The safety and tolerability of the weekly alendronate and placebo regimens were captured as clinical and laboratory adverse events.

Results: A total of 11% of the alendronate patients and 13% of the placebo patients reported an upper GI tract adverse event. Discontinuations due to drug-related upper GI tract adverse events occurred in 3% of alendronate patients and 1% of placebo patients. The differences between the treatment groups for the primary and secondary end points were not significant. For the primary end point, the upper limit of the 95% confidence interval of the difference was well within the prespecified 14% comparability bound (-2.2%; 95% confidence interval, -8.3% to 3.9%). The overall incidence of upper GI tract adverse events was lower in the subgroup of patients with prior bisphosphonate exposure (8%) than in those who were bisphosphonate naive (16%). However, regardless of prior bisphosphonate exposure, the incidence of upper GI tract adverse events was similar between the alendronate and placebo patients. The urinary N-telopeptide-creatinine ratio showed a significant decrease in the alendronate patients (72% of baseline, P<.001) compared with a slight increase in the placebo patients (106% of baseline) at week 12.

Conclusion: In this 3-month study, the incidence of upper GI tract adverse events in patients treated with once-weekly alendronate, 70 mg, was comparable to that with placebo.