Clinical experience with denosumab discontinuation.

In patients receiving long-term treatment with denosumab, denosumab discontinuation via sequential treatment with zoledronate, resulted in a minor decrease in bone mass density (BMD) of 0-2.5% within the first year and stabile BMD in the second year, thus showing that repeated treatments with zoledronate limit the loss of BMD, when discontinuing denosumab.

Purpose: Discontinuing denosumab (DMAb) rapidly decreases bone mineral density (BMD) and increases the risk of multiple vertebral fractures. We wanted to examine if the recommendation stated in the ECTS position paper on DMAb discontinuation can prevent the bone loss in a clinical setting.

Methods: We conducted a retrospective cohort study based on medical records of patients referred for DMAb discontinuation. We administered zoledronate (ZOL) 6 months after the last DMAb injection and 3, 6, 12, and 24 months thereafter if p-C-terminal collagen crosslinks (CTX) increased above 0.5 μg/l or BMD decreased (≥ 5% at the hip, ≥ 3% at the spine) at months 12 and 24.

Results: We included 66 women and men discontinuing DMAb after a mean treatment duration of 6.7 ± 2.7 (mean ± SD) years. BMD decreased 12 months after the initial ZOL treatment by 2.5 ± 4.2% and 1.9 ± 2.5% at the LS and TH, respectively (n = 44) (p ≤ 0.001 for all). There was no significant change in FNBMD (0.0 ± 5.1) (p > 0.05). No significant change in BMD was seen from month 12 to month 24 at any site (p > 0.05 for all). Thirty percent and twenty-two percent of patients experienced flu-like symptoms after the first and second ZOL infusion. No fractures occurred during the study period.

Conclusion: Adhering to the recommendation in the ECTS position statement, a mean of 3 infusions of ZOL limited the bone loss 12 and 24 months after DMAb discontinuation, thereby preserving most of the BMD gained during DMAb treatment. The frequent occurrence of flu-like symptoms after ZOL proves to be a challenge, showing that routine prophylaxis against acute phase responses should be considered in patients treated with ZOL after discontinuing DMAb.