Spontaneous vertebral fractures after denosumab discontinuation: A case collection and review of the literature.

Objective: Denosumab is an antiresorptive drug with demonstrated efficacy in the treatment of osteoporosis. However, discontinuation of this agent is associated with increased bone turnover and rapid bone loss, and more recently, with the development of vertebral fractures (VF) in some patients. Therefore, the aim of the study was to analyze the clinical characteristics, bone metabolism parameters and evolution of a group of patients who developed vertebral fractures after denosumab discontinuation. In addition, we reviewed the literature on this subject.

Methods: During a period of 28 months (September 2015-January 2018) 7 women presenting spontaneous vertebral fractures after denosumab discontinuation were attended in the Rheumatology Department of our centre. We analyzed their clinical characteristics, bone metabolism parameters and evolution and reviewed the literature related to this subject.

Results: The patients had received denosumab during 24-58 months (median 38), and developed a median of 5 VF per patient at 8-20 months (median 10) since the last dose of denosumab. Only 2 patients presented previous VF, and most (5 patients) received previous bisphosphonate treatment. After VF all restarted antiosteoporotic treatment with no further fractures during follow-up (median 19 months).

Conclusions: In this short series, previous bisphosphonate treatment does not seem to be a protective factor for the development of VF. The possible development of VF following discontinuation of denosumab must be taken into account in the clinical practice of physicians and dentists. Nonetheless, further studies are needed to improve the identification of patients at risk and the most adequate sequential treatment options.