Second rebound-associated vertebral fractures after denosumab discontinuation

Here, we report the case of a 69-year-old female who discontinued denosumab to undergo dental treatment. She subsequently suffered rebound-associated vertebral fractures (RVFs) twice. Denosumab is approved in several countries for osteoporosis treatment. Its discontinuation can result in bone turnover rebound increase and rapid bone mineral density loss. Rebound-associated vertebral fractures (RVFs) after discontinuing denosumab have been widely reported. We previously reported the case of a patient who suffered RVFs after discontinuing denosumab to undergo dental treatment. A 69-year-old female suffered five acute VFs 10 months after the last denosumab injection. The current report identifies the risks associated with denosumab discontinuation to undergo dental treatment. The patient described in this report also underwent an additional clinical course after the first RVFs. Next month after the first RVFs, she developed severe back pain when she changed her posture. Magnetic resonance imaging showed new RVFs at T9 and T12 levels. This case indicates that RVFs may occur more than once. In addition, it suggests that additional denosumab injections do not completely eliminate the risk of RVFs.

Rebound-associated vertebral fractures after discontinuation of denosumab for the treatment of maxillitis

We reported a 69-year-old female who discontinued denosumab due to dental treatment and subsequently suffered rebound-associated vertebral fractures 10 months after the last injection. This case raised an alarm regarding the discontinuation of denosumab for dental treatment. Denosumab, a human monoclonal antibody administered by subcutaneous injection, to the best of our knowledge, is the only fully investigated inhibitor of receptor activator of nuclear factor kappa B ligand. Discontinuation of denosumab leads to bone turnover rebound and rapid bone mineral density loss. Several studies have reported rebound-associated vertebral fractures after discontinuation of denosumab. We report on a new case of rebound-associated vertebral fractures after discontinuation of denosumab. A 69-year-old female, who withdrew from denosumab treatment after 3 years due to maxillitis, presented to our hospital with severe low back pain without any history of trauma. Ten months had passed since the last injection. Magnetic resonance imaging showed five acute vertebral fractures, which appeared to be rebound-associated vertebral fractures caused by discontinuation of denosumab due to dental treatment. This case clearly demonstrates the risk of discontinuation of denosumab for dental treatment.

Rebound-associated vertebral fractures after discontinuation of denosumab-from clinic and biomechanics

Rebound-associated vertebral fractures may follow treatment discontinuation of highly potent reversible bone antiresorptives, resulting from the synergy of rapid bone resorption and accelerated microdamage accumulation in trabecular bone.

INTRODUCTION

The purposes of this study are to characterize rebound-associated vertebral fractures following the discontinuation of a highly potent reversible antiresorptive therapy based on clinical observation and propose a pathophysiological rationale.

METHODS

This study is a case report of multiple vertebral fractures early after discontinuation of denosumab therapy in a patient with hormone receptor-positive non-metastatic breast cancer treated with an aromatase inhibitor.

RESULTS

Discontinuation of highly potent reversible bone antiresorptives such as denosumab may expose patients to an increased fracture risk due to the joined effects of absent microdamage repair during therapy followed by synchronous excess activation of multiple bone remodelling units at the time of loss-of-effect. We suggest the term rebound-associated vertebral fractures (RVF) for this phenomenon characterized by the presence of multiple new clinical vertebral fractures, associated with either no or low trauma, in a context consistent with the presence of high bone turnover and rapid loss of lumbar spine bone mineral density (BMD) occurring within 3 to 12 months after discontinuation (loss-of-effect) of a reversible antiresorptive therapy in the absence of secondary causes of bone loss or fractures. Unlike atypical femoral fractures that emerge from failure of microdamage repair in cortical bone with long-term antiresorptive treatment, RVF originate from the synergy of rapid bone resorption and accelerated microdamage accumulation in trabecular bone triggered by the discontinuation of highly potent reversible antiresorptives.

CONCLUSIONS

Studies are urgently needed to i) prove the underlying pathophysiological processes suggested above, ii) establish the predictive criteria exposing patients to an increased risk of RVF, and iii) determine appropriate treatment regimens to be applied in such patients.