Skeletal response to treatment with teriparatide (TPD) after bisphosphonate in post-menopausal women with osteoporosis and a high prevalence of secondary risk factors in real-life setting of a metabolic bone clinic; effect of age and vitamin D status

Skeletal response to teriparatide in real-life setting: effects of age, baseline bone density and prior denosumab use

OBJECTIVES

Teriparatide (TPD) is an osteoanabolic agent used in patients with high osteoporotic fracture risk. Predictors of therapeutic response to TPD in real-life setting are not well characterised. This study investigated the influence of previous antiresorptive therapy, age and other patient characteristics on the skeletal response to TPD.

METHODS

Retrospective study at the metabolic bone clinic, University Hospitals Leuven, Belgium. Patients with osteoporosis and a high fracture burden received TPD for 9-18 months. Bone mineral density (BMD) was measured at baseline, 9 and 18 months at lumbar spine (LS), femoral neck (FN) and total hip (TH).

RESULTS

BMD at LS increased at 9 months (change mean (standard error) 6.8 % (0.7) p < 0.001) and at 18 months (8.0 % (0.9) p < 0.001), while BMD at FN and TH did not change significantly. Non-response in BMD change at the LS was seen with prior denosumab use (odds ratio 0.21, 95% confidence interval (CI) 0.049-0.912, p = 0.037). Changes in BMD at TH were significantly greater in younger patients and in patients with a lower baseline BMD.

CONCLUSION

TPD-induced changes in BMD at TH might depend on age and baseline BMD and at LS on prior denosumab use. The results suggest that these factors may be relevant for clinical decision making when initiating TPD treatment, although larger studies are needed to confirm these findings.

Serum 25-hydroxy-vitamin D and the risk of fractures in the teriparatide versus risedronate VERO clinical trial

PURPOSE

Using data from the 2-year, randomized, double-dummy VERO trial, we examined the changes in 25-hydroxy-vitamin D (25[OH]D) concentrations over time, and whether the fracture risk reduction of teriparatide versus risedronate varies by baseline 25(OH)D sufficiency category.

METHODS

Postmenopausal women with established osteoporosis received subcutaneous daily teriparatide 20 μg or oral weekly risedronate 35 mg, with concomitant 500-1000 mg of elemental calcium and 400-800 IU/day of vitamin D supplements. Fracture endpoints were analyzed by predefined subgroups of 25(OH)D insufficient and sufficient patients. Heterogeneity of the treatment effect on fractures was investigated by logistic and Cox proportional hazards regression models.

RESULTS

At baseline, mean serum 25(OH)D was 31.9 ng/mL in the teriparatide group and 31.5 ng/mL in the risedronate group, and 16.8% and 17.9% of patients, respectively, were 25(OH)D insufficient. At month 6, the mean serum 25(OH)D concentration decreased in teriparatide-treated patients to 24.5 ng/mL (by approximately 23%) but remained relatively constant in risedronate-treated patients (32.2 ng/mL) (p < 0.001). Proportions of 25(OH)D insufficient patients at month 6 were 26.7% and 5.6%, respectively (p < 0.001). The risk reduction with teriparatide versus risedronate for any of the fracture endpoints did not significantly differ between subgroups by 25(OH)D sufficiency status at baseline, with nonsignificant (p > 0.1) treatment-by-25(OH)D interactions in all fracture analyses.

CONCLUSIONS

Serum 25(OH)D concentration decreases during teriparatide treatment. Fracture risk reduction with teriparatide versus risedronate did not significantly differ between the two groups of patients defined by baseline 25(OH)D.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01709110 EudraCT Number: 2012-000123-41.