Progression of Rebound-Associated Vertebral Fractures Following Denosumab Discontinuation Despite Reinstitution of Treatment: Suppressing Increased Bone Turnover May Not Be Enough

Twenty-four months of follow-up in women with rebound-associated vertebral fractures after discontinuation of denosumab: a single-centre case series

Evidence on the management of rebound-associated vertebral fractures after denosumab discontinuation is scarce. This study describes seven patients retreated with denosumab, teriparatide or zoledronate for 24 months. Their bone mineral density remained stable or improved and no new fractures occurred suggesting that all three options might be adequate for their treatment.

PURPOSE

To describe the densitometric and biochemical changes achieved with osteoactive treatment after 24 months of follow-up in patients who suffered rebound-associated vertebral fractures (RAVFs) after Dmab discontinuation, and to report the occurrence of new vertebral and non-vertebral fractures.

METHODS

Patients with RAVFs who received retreatment (RT) for 24 months were included. Bone mineral density (BMD) was assessed by dual-energy x-ray absorptiometry at the lumbar spine (LS), femoral neck (FN) and total hip (TH), along with C-terminal cross-linked telopeptide of type I collagen, osteocalcin, and bone alkaline phosphatase. Data were collected at the start of the RT and after 24 months.

RESULTS

Seven female patients were included. RT consisted in Dmab (n = 3), teriparatide (TPT) (n = 3) and zoledronate (Zol) (n = 1). At 24 months, the mean BMD change was 2.2% at LS, 6.8% at FN and 3.8% at TH in the Dmab group, 7.5% at LS, 1.4% at FN and 3.7% at TH in the TPT group and, 5.0% at LS, 0.6% at FN and 3.9% at TH in the patient with Zol. After 24 months of follow-up, no patient suffered new fractures.

CONCLUSION

In this series of patients with RAVFs, we did not observe any new fractures and the BMD remained stable after 24 months of RT. Future studies are needed to evaluate the most suitable treatment approach after RAVFs but these preliminary data suggest that all denosumab, zoledronate and teriparatide might be adequate options.

Similarities and Differences in the Management of Patients with Osteoporotic Vertebral Fractures and Those with Rebound-Associated Vertebral Fractures Following Discontinuation of Denosumab

Rebound-associated vertebral fractures (RVFx) following denosumab discontinuation are typically multiple, are commonly associated with acute sharp pain, increase the risk of imminent fractures, and are pathogenetically different from common osteoporotic vertebral fractures (VFx). A clinically relevant question is whether patients with RVFx should be managed differently from patients with osteoporotic VFx. To address this question, we performed a systematic search of the PubMed database, and we reviewed current evidence on the optimal management of patients with RVFx. For pain relief of patients with RVFx, potent analgesics, often opioids, are essential. Information on the effectiveness of braces in these patients is scarce. Vertebroplasty and kyphoplasty are strongly contraindicated as they confer a substantial risk for new VFx. Exercise may be helpful, but again evidence is lacking. In contrast to patients with osteoporotic VFx, in whom initial treatment with bone-forming agents is recommended, patients with RVFx should initiate treatment with potent antiresorptives. To summarize, patients who have sustained RVFx following denosumab discontinuation are at a very high risk for new fractures, especially VFx. The management of such patients requires a multidisciplinary approach that should not be restricted to pain relief and administration of antiosteoporotic medication, but should also include back protection, early mobilization, and appropriate exercise.

The Role of Bisphosphonates Prior to Denosumab Treatment on Rebound Fractures: A Mini Review

Denosumab is a potent anti-resorptive medication used to treat patients at high risk for osteoporosis; however, its beneficial effects on the skeletal system are quickly reversed after discontinuation. In contrast, bisphosphonates (BPs) are anti-resorptive agents with residual effects on the bone matrix; thus, these are capable of preserving bone mass for a long time. Therefore, subsequent anti-resorptive treatment with BPs is mandatory to prevent rebound fractures. Furthermore, BP administration before denosumab treatment appears to be a reasonable strategy for reducing hyperactivation of bone remodeling. In this review, we summarize the effects of BP administration before denosumab treatment in preventing rebound fractures after denosumab discontinuation.

Rebound-associated vertebral fractures after denosumab discontinuation in a lung cancer patient with bone metastases

Denosumab is a commonly used antiresorptive treatment in patients with osteoporosis or solid tumours with bone metastases. Upon denosumab discontinuation, a rebound phenomenon can occur that results in an increased (vertebral) fracture risk. This phenomenon is well-known in the setting of osteoporosis but rarely reported in cancer patients with bone metastases discontinuing denosumab. We present the case of a 43-year old women with lung cancer and bone metastases who suffered multiple vertebral fractures after discontinuation of denosumab.

Efficacy of Antiosteoporotic Medications in Patients With Rebound-Associated Fractures After Denosumab Discontinuation

Denosumab discontinuation results in rapid bone loss and increased risk of multiple rebound-associated vertebral fractures (RAVFs). The optimal treatment for patients who have sustained such fractures is currently unknown. We aimed to investigate the bone mineral density (BMD) changes achieved with various regimens in postmenopausal women who had sustained RAVFs after denosumab discontinuation in everyday clinical practice. In this multicenter, retrospective observational study, 39 Greek postmenopausal women from six regional bone centers throughout Greece with RAVFs after denosumab discontinuation were included. We collected BMD and fracture data before and 1 year after treatment with denosumab (n = 20), teriparatide (n = 8), zoledronate (n = 8) or teriparatide/denosumab combination (n = 3). Both lumbar spine (LS)-- and femoral neck (FN)-BMD were preserved with all regimens used. With the exception of zoledronate, a trend towards increase was observed with all regimens in LS-BMD. Three patients sustained additional fractures despite treatment reinstitution (2 with zoledronate and 1 with teriparatide). Among patients with RAVFs following denosumab discontinuation both antiresorptive (zoledronate and denosumab) and anabolic (teriparatide) treatment as well as the combination of denosumab with teriparatide seem to be effective in terms of BMD response.

Denosumab Discontinuation and the Rebound Phenomenon: A Narrative Review

Denosumab is a potent antiresorptive agent that substantially increases bone mineral density and reduces fracture rates at all skeletal sites for as long as it is administered. However, its favorable skeletal effects reverse quickly upon its discontinuation, because of a vast increase of osteoclast number and activity, which leads to a subsequent profound increase of bone turnover above pre-treatment values, a phenomenon commonly described as “rebound phenomenon”. More importantly, most patients experience rapid, profound bone loss due to this burst of bone resorption that may lead in a minority of these patients to occurrence of fractures, especially multiple vertebral fractures. Therefore, subsequent antiresorptive treatment is mandatory, although the optimal regimen is yet to be clarified. In the present review, we outline what is currently known regarding the negative effects of denosumab discontinuation on different aspects of bone status, the factors that may affect them, and strategies to prevent them.