Bone Abstracts

Introduction: Teriparatide is a potent anabolic drug that has demonstrated efficacy on fracture risk reduction in women with severe postmenopausal osteoporosis. Denosumab, designed to inhibit RANKL (RANK ligand), is a fully human MAB for the treatment of osteoporosis. BMD changes, measured by DXA, is an established tool for monitoring the effects of anti-osteoporotic therapy. Our purpose is to compare teriparatide vs denosumab efficacy on hip BMD variations, in postmenopausal women with primary osteoporosis.

Methods: 68 female patients (mean age 75.5±7.0 years), with severe postmenopausal osteoporosis, characterized by multiple vertebral fractures, were treated either with Denosumab (n: 34, group D) or with Teriparatide (n: 34, group T), for 12 months.

Results: Since the treatments were not randomly administered, baseline unbalancing between two groups should be taken into account, even more than in case of randomized trial. We found that the denosumab group was slightly lower in terms of BMD (0.59 vs 0.63, P=0.138), clearly lower in terms of T-score (−3.3 vs −2.4, P<0.001) and older (78.4 vs 72.6, P<0.001). Therefore, baseline measures were entered as covariate to statistically control their effect on treatment effects. ANCOVA indicated that the increase of BMD was larger (P=0.028) after teriparatide (+0.06, 95% CI: +0.04, +0.08) than after denosumab (+0.02, 95% CI: +0.01, +0.04). The increase of T-score was significant in the whole sample (P<0.01), but without difference between the two treatments (P=0.132). In particular, after teriparatide t-score increased of 0.44 (95% CI: +0.28, +0.61), while after denosumab of 0.25 (95% CI: +0.08, +0.41).

Conclusions: Our preliminary observation suggests a possible greater efficacy of teriparatide, when compared to denosumab. This finding could be related to the faster anabolic effect of Teriparatide, in comparison to denosumab, which displays a slower and more gradual efficacy. However, prolongation of follow-up is needed to confirm our data.