Efficacy and safety of oral recombinant calcitonin tablets in postmenopausal women with low bone mass and increased fracture risk: a randomized, placebo-controlled trial

SUMMARY: The effect of an investigational oral calcitonin tablet upon bone mineral density (BMD) of the spine was investigated in postmenopausal women with low bone mass and at increased risk of fracture. Compared to placebo, calcitonin tablets increased lumbar spine BMD. This agent may provide an additional choice for patients. INTRODUCTION: An investigational oral salmon calcitonin preparation was previously shown to increase lumbar spine BMD in postmenopausal women with osteoporosis. Our objective was to evaluate the use of this agent in postmenopausal women with low bone mass and at increased fracture risk but not meeting BMD criteria for osteoporosis. METHODS: Treatment-naïve women were randomized to receive oral recombinant salmon calcitonin tablets or placebo once daily for 1 year. Dual-energy X-ray absorptiometry was performed at baseline and at study weeks 28 and 54. CTx-1, a bone resorption marker, was obtained at the same time points. Subjects returned periodically for tolerability assessment and adverse event (AE) recording. RESULTS: One hundred twenty-nine women in the USA were randomized, 86 to calcitonin and 43 to placebo. Calcitonin recipients experienced a significant increase from baseline in lumbar spine BMD; the difference compared with placebo was significant. Dosing at bedtime or with dinner was equally effective. CTx-1 was suppressed in calcitonin recipients but not in placebo subjects. Gastrointestinal AEs were common, but the overall safety profile was comparable between groups. CONCLUSIONS: Oral calcitonin may provide a useful therapeutic alternative for some women with low bone mass.