Effects of odanacatib on BMD and safety in the treatment of osteoporosis in postmenopausal women previously treated with alendronate: a randomized placebo-controlled trial.

CONTEXT: Odanacatib (ODN) is a selective cathepsin K inhibitor being developed to treat osteoporosis. OBJECTIVE: The effects of ODN were evaluated on bone mineral density (BMD), biochemical markers of bone turnover, and safety in patients previously treated with alendronate. DESIGN: This was a randomized, double-blind, placebo-controlled, 24-month study. SETTING: The study was conducted at private or institutional practices. PARTICIPANTS: Postmenopausal women (n = 243) ≥ 60 years of age with low BMD at the total hip, femoral neck, or trochanter (T-score ≤-2.5 but >-3.5 without prior fracture or ≤-1.5 but >-3.5 with prior fracture) on alendronate for ≥ 3 years. INTERVENTION: The intervention included ODN 50 mg or placebo weekly. MAIN OUTCOME MEASURES: The primary end point was percentage change from baseline of femoral neck BMD at month 24. BMD was assessed by dual-energy x-ray absorptiometry at baseline and 6, 12, and 24 months. Biochemical markers of bone turnover (serum C-telopeptides of type 1 collagen, urinary N-telopeptides of type 1 collagen, serum bone specific alkaline phosphatase, and serum N-terminal propeptide of type 1 collagen) were measured at baseline and 3, 6, 12, 18, and 24 months. RESULTS: In the ODN group, BMD changes from baseline at the femoral neck, trochanter, total hip, and lumbar spine at 24 months (1.7%, 1.8%, 0.8%, and 2.3%, respectively) were significantly different from the placebo group. ODN significantly decreased urinary N-telopeptides of type 1 collagen to creatinine ratio and significantly increased serum N-terminal propeptide of type 1 collagen compared with placebo. Serum C-telopeptides of type 1 collagen was unexpectedly increased with ODN treatment. The safety profile appeared similar between groups. CONCLUSIONS: ODN provided incremental BMD gains in osteoporotic women after alendronate treatment.

Treatment with alendronate plus calcium, alendronate alone, or calcium alone for postmenopausal low bone mineral density.

OBJECTIVE: Bisphosphonates such as alendronate are widely used for postmenopausal osteoporosis. Supplemental calcium is also generally recommended. This trial directly compares alendronate to supplemental calcium and examines the effect of calcium supplementation on alendronate treatment. METHODS: This 2-year, randomized, double-blind, multicenter trial enrolled healthy, postmenopausal women with low bone mineral density (BMD). Patients with a dietary calcium intake > or = 800 mg/day received daily vitamin D 400 IU and alendronate 10 mg/calcium-placebo, alendronate 10 mg/elemental calcium 1000 mg, or alendronate-placebo/calcium 1000 mg (2:2:1). Endpoints included BMD, bone turnover markers (BTMs), and adverse events. RESULTS: Randomized patients (N = 701) were an average of 20.4 years postmenopausal. After 24 months, increases in lumbar spine BMD differed significantly between patients receiving calcium alone (0.8%) and either alendronate alone (5.6%) or alendronate + calcium (6.0%) (p < 0.001). Significant differences were also seen at the trochanter and femoral neck (p < 0.001). BTMs were significantly lower with alendronate-containing treatments than calcium alone (p < 0.001). Addition of calcium supplementation to alendronate did not significantly increase BMD compared to alendronate alone (p = 0.29 to 0.97), but did result in a statistically significant, though small, additional reduction in urinary NTx. Adverse events were similar among treatment groups. Limitations include no assessment of vitamin D levels and a discontinuation rate of approximately 30%, although discontinuation rates were similar among treatment groups. CONCLUSIONS: In postmenopausal women with a daily intake of > or =800 mg calcium and 400 IU vitamin D, 24-month treatment with alendronate 10 mg daily with or without calcium 1000 mg resulted in significantly greater increases in BMD and reduction of bone turnover than supplemental calcium alone. Addition of supplemental calcium to alendronate treatment had no effect on BMD and resulted in a small, though statistically significant, additional reduction in NTx.