E-Poster Presentation ESA-SRB-ANZBMS 2021

Vertebral Fractures following Interruption of Denosumab Therapy (#771)

Sin Dee Yap 1 , Linh Ngo 2 , Christopher Gilfillan 1
  1. Department of Endocrinology, Eastern Health, Box Hill, Victoria, Australia
  2. Department of Medicine, Eastern Health, Box Hill, Victoria, Australia

Objective:

To assess the incidence of new vertebral fractures in patients with interruption of denosumab therapy between January 2019 and April 2021 at Eastern Health.

Background:

FREEDOM extension trial demonstrated lower rates of vertebral and non-vertebral fractures in patients treated with denosumab therapy for up to 10 years1. Multiple case reports and a recent systematic review suggested increased risk of multiple vertebral fractures in patients when denosumab therapy was discontinued2,3.

Method:

This was designed as a retrospective audit. All patients with a diagnosis of fracture who were taking denosumab between January 2019 and April 2021 were identified within the hospital database. For the purpose of this study, only patients with vertebral fractures were included. Medical record of each patient was reviewed to determine if vertebral fractures occurred in the setting of denosumab interruption. This was defined as interruption of delay of > 1 month. Data collected were entered into Microsoft Excel and data analysed using SPSS IBM 25.0. Student t-test was used to compare the differences of sample mean in both groups.

Results:

48 patients were included in this study. Of those 48 patients, 17 patients had interruption of denosumab therapy. Both groups had similar clinical characteristics at baseline. Incidence of new vertebral fractures was similar in those with and without denosumab interruption. Results are summarised in table 1.

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Conclusion:

In this single-centre retrospective audit, we observed a large proportion (35.4%) of vertebral fractures occurring in patients on denosumab occurred in those who had interrupted denosumab therapy. Steroid use may be an important co-factor in denosumab discontinuation and subsequent fracture. In order to determine whether denosumab interruption contributes to the risk of fracture, we would need to know the rate of interruption in the denosumab treated population. However, larger studies are required to confirm the findings.

  1. Bone, H, Wagman, R, Brandi, M, Brown, J, Chapurlat, R, Cummings, R, et al. ‘10 years of denosumab treatment in postmenopausal women with osteoporosis: results from the phase 3 randomise FREEDOM trial and open-label extension’, 2017, the Lancet Diabetes & Endocrinology, vol.5, no.7, pp.513-523.
  2. Tsourdi, E, Zilikens, M, Meier, C, Body, JJ, Rodriguez, EG, Anastasilakis, AD et al, ‘ Fracture risk and management of discontinuation of denosumab therapy: A systematic review and position statement by ECTS’, 2021, Journal of Clinical Endocrinology and metabolism, vol.106, no.1, pp.264-281.
  3. Tsourdi, E, Langdahl, B, Cohen-Solal, M, Aubry-Rozier, B, Eriksen, EF, Guanabens, N et al. ‘ Discontinuation of Denosumab therapy for osteoporosis: A systematic review and position statement by ECTS’, 2017, Bone, vol. 105, pp.11-17.