Bisphosphonates Maintain BMD After Sequential Teriparatide and Denosumab in Premenopausal Women with Idiopathic Osteoporosis

Abstract

Context: We previously reported that sequential teriparatide followed by denosumab substantially increases bone mineral density (BMD) in premenopausal idiopathic osteoporosis (PremenIOP).

Objective: To determine whether administration of bisphosphonates after denosumab cessation is associated with stable BMD in PremenIOP.

Design: Open-label extension study.

Participants: Twenty-four PremenIOP Teriparatide-Denosumab Study participants.

Interventions: Oral alendronate (ALN), 70 mg weekly, or intravenous zoledronic acid (ZOL), 5 mg once (patient choice), was administered 7 months (M) after final denosumab dose.

Outcomes: BMD by dual-energy x-ray absorptiometry and serum C-telopeptide (CTX) q6M; Vertebral Fracture Assessment (VFA), and high-resolution peripheral quantitative computed tomography (HR-pQCT) q12 M.

Results: Twenty-four women with PremenIOP (aged 43 ± 8 years), severely affected with low trauma adult fractures (range 0-12; 9 with vertebral fractures) and/or very low BMD, had large BMD increases on sequential teriparatide-denosumab (spine: 25 ± 9%; total hip: 11 ± 6%). During the Bisphosphonate Extension, mean BMD and CTX changes in the entire group were small and not statistically significant at 6 or 12 M.Women choosing ZOL (n = 6) vs ALN (n = 18) did not differ by baseline age, body mass index, fractures, BMD, or CTX. On ZOL, there were small lumbar spine BMD declines and CTX increases, particularly between 6 M and 12 M, while greater stability was observed on ALN.Changes in BMD and CTX did not differ by duration of denosumab (36 M vs <36 M) or between 20 women who remained premenopausal and 4 who transitioned into menopause. Higher pre-teriparatide CTX, likely reflecting baseline remodeling status, predicted more spine and hip bone loss. No new vertebral (clinical or vertebral fraction assessment screening) or nonvertebral fractures occurred.

Conclusion: BMD remained stable in women with PremenIOP who received bisphosphonates after sequential teriparatide-denosumab therapy.

Keywords: HR-pQCT; alendronate; bisphosphonate; bone density; bone turnover markers; denosumab; premenopausal osteoporosis; teriparatide; zoledronic acid.

Figure 1.

Consort diagram.

Figure 2.

Change in BMD and CTX on 12 months of bisphosphonate after denosumab withdrawal in all subjects. (A) Percent change in BMD at the lumbar spine; (B) percent change in BMD at the total hip; (C) percent change in BMD at the femoral neck; (D) change in serum CTX. There were no statistically significant changes in BMD or CTX at any timepoint. Abbreviations: BMD, bone mineral density; CTX, C-telopeptide.

Figure 3.

Change in BMD and CTX on 12 months of bisphosphonate after denosumab withdrawal in the alendronate and zoledronic acid groups. (A) Percent change in BMD at the lumbar spine; (B) percent change in BMD at the total hip; (C) percent change in BMD at the femoral neck; (D) change in serum CTX. Alendronate group: solid line; zoledronic acid group: dashed line. # P < .05 for within group change vs baseline; * P < .05 for comparison of change in alendronate vs zoledronic acid groups. Abbreviations: BMD, bone mineral density; CTX, C-telopeptide.