Effects of teriparatide versus alendronate for treating glucocorticoid-induced osteoporosis: thirty-six-month results of a randomized, double-blind, controlled trial

Abstract

Objective: To compare the bone anabolic drug teriparatide (20 microg/day) with the antiresorptive drug alendronate (10 mg/day) for treating glucocorticoid-induced osteoporosis (OP).

Methods: This was a 36-month, randomized, double-blind, controlled trial in 428 subjects with OP (ages 22-89 years) who had received > or =5 mg/day of prednisone equivalent for > or =3 months preceding screening. Measures included changes in lumbar spine and hip bone mineral density (BMD), changes in bone biomarkers, fracture incidence, and safety.

Results: Increases in BMD from baseline were significantly greater in the teriparatide group than in the alendronate group, and at 36 months were 11.0% versus 5.3% for lumbar spine, 5.2% versus 2.7% for total hip, and 6.3% versus 3.4% for femoral neck (P < 0.001 for all). In the teriparatide group, median percent increases from baseline in N-terminal type I procollagen propeptide (PINP) and osteocalcin (OC) levels were significant from 1 to 36 months (P < 0.01), and increases in levels of C-terminal telopeptide of type I collagen (CTX) were significant from 1 to 6 months (P < 0.01). In the alendronate group, median percent decreases in PINP, OC, and CTX were significant by 6 months and remained below baseline through 36 months (P < 0.001). Fewer subjects had vertebral fractures in the teriparatide group than in the alendronate group (3 [1.7%] of 173 versus 13 [7.7%] of 169; P = 0.007), with most occurring during the first 18 months. There was no significant difference between groups in the incidence of nonvertebral fractures (16 [7.5%] of 214 subjects taking teriparatide versus 15 [7.0%] of 214 subjects taking alendronate; P = 0.843). More subjects in the teriparatide group (21%) versus the alendronate group (7%) had elevated predose serum calcium concentrations (P < 0.001).

Conclusion: Our findings indicate that subjects with glucocorticoid-induced OP treated with teriparatide for 36 months had greater increases in BMD and fewer new vertebral fractures than subjects treated with alendronate.