Second rebound-associated vertebral fractures after denosumab discontinuation

Denosumab for osteoporosis treatment: when, how, for whom, and for how long. A pragmatical approach

Denosumab produces a continuous increase in bone mineral density over ten years, associated with a low risk of vertebral and non-vertebral fractures. Denosumab is well tolerated and easy to manage in daily clinical practice. For all these reasons, this treatment has a huge success. On the other hand, discontinuation of treatment is associated with a severe rebound effect including a sharp increase in bone turnover markers, loss of the bone density gained and a risk of nearly 20% of multiple vertebral fractures in postmenopausal women. High doses of potent bisphosphonates are needed to maintain bone turnover markers in the low range of premenopausal women, to mitigate this rebound effect. Prolonged treatment with denosumab is associated with a greater rebound effect and increases the risk of an early rebound effect. The occurrence of rare side effects such as osteonecrosis of the jaw or atypical femoral fracture, as well as the onset of severe renal failure, leave clinicians at a therapeutic impasse. Continuing denosumab or switching to bisphosphonates remains suboptimal and, currently, no evidence clarifies the optimal treatment approach for these patients. The aim of this review is to give a very practical clinical approach to the use of denosumab (duration of treatment), and to the management of rebound effect and possible adverse effects.

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 RANK/RANKL/OPG system and tumor bone metastasis: Potential mechanisms and therapeutic strategies

With the markedly increased diagnosis and incidence of cancer in the population, tumor bone metastasis has become a frequent event in tumor patients. Healthy bone integrity is maintained by a delicate balance between bone formation and bone resorption. Unfortunately, many tumors, such as prostate and breast, often metastasize to the bone, and the alterations to the bone homeostasis can particularly favor tumor homing and consequent osteolytic or osteoblastic lesions. Receptor activator of NF-κB ligand (RANKL), its receptor RANK, and osteoprotegerin (OPG) are involved in the regulation of the activation, differentiation, and survival of osteoclasts, which play critical roles in bone metastasis formation. High rates of osteoclastic bone resorption significantly increase fracture risk, cause severe bone pain, and contribute to homing tumor cells in bone and bone marrow. Consequently, suppression of the RANK/RANKL/OPG system and osteoclastic activity can not only ameliorate bone resorption but may also prevent tumor bone metastases. This review summarizes the important role of the RANK/RANKL/OPG system and osteoclasts in bone homeostasis and its effect on tumor bone metastasis and discusses therapeutic strategies based on RANKL inhibition.

Is Adynamic Bone Always a Disease? Lessons from Patients with Chronic Kidney Disease

Renal osteodystrophy (ROD) is a common complication of end-stage kidney disease that often starts early with loss of kidney function, and it is considered an integral part in management of patients with chronic kidney disease (CKD). Adynamic bone (ADB) is characterized by suppressed bone formation, low cellularity, and thin osteoid seams. There is accumulating evidence supporting increasing prevalence of ADB, particularly in early CKD. Contemporarily, it is not very clear whether it represents a true disease, an adaptive mechanism to prevent bone resorption, or just a transitional stage. Several co-players are incriminated in its pathogenesis, such as age, diabetes mellitus, malnutrition, uremic milieu, and iatrogenic factors. In the present review, we will discuss the up-to-date knowledge of the ADB and focus on its impact on bone health, fracture risk, vascular calcification, and long-term survival. Moreover, we will emphasize the proper preventive and management strategies of ADB that are pivotal issues in managing patients with CKD. It is still unclear whether ADB is always a pathologic condition or whether it can represent an adaptive process to suppress bone resorption and further bone loss. In this article, we tried to discuss this hard topic based on the available limited information in patients with CKD. More studies are needed to be able to clearly address this frequent ROD finding.

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.

Multiple vertebral fractures after suspension of denosumab. A series of 56 cases

BACKGROUND

Denosumab is a monoclonal antibody approved for the treatment of postmenopausal osteoporosis. The withdrawal of denosumab produces an abrupt loss of bone mineral density and may cause multiple vertebral fractures (MVF).

OBJECTIVE

The objective of this study is to study the clinical, biochemical, and densitometric characteristics in a large series of postmenopausal women who suffered MVF after denosumab withdrawal. Likewise, we try to identify those factors related to the presence of a greater number of vertebral fractures (VF).

PATIENTS AND METHODS

Fifty-six patients (54 women) who suffered MVF after receiving denosumab at least for three consecutive years and abruptly suspended it. A clinical examination was carried out. Biochemical bone remodelling markers (BBRM) and bone densitometry at the lumbar spine and proximal femur were measured. VF were diagnosed by magnetic resonance imaging MRI, X-ray, or both at dorsal and lumbar spine.

RESULTS

Fifty-six patients presented a total of 192 VF. 41 patients (73.2%) had not previously suffered VF. After discontinuation of the drug, a statistically significant increase in the BBRM was observed. In the multivariate analysis, only the time that denosumab was previously received was associated with the presence of a greater number of VF (P = .04).

CONCLUSIONS

We present the series with the largest number of patients collected to date. 56 patients accumulated 192 new VF. After the suspension of denosumab and the production of MVF, there was an increase in the serum values of the BBRM. The time of denosumab use was the only parameter associated with a greater number of fractures.

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.

Medical treatment of osteoporosis

Osteoporosis is a common chronic condition that markedly increases the risk of fractures. Osteoporotic-related fractures increase morbidity and mortality and impair quality of life. Therefore, a correct approach for fracture prevention seems mandatory. Lifestyle changes should be recommended to all patients, including weight reduction if patients are obese/overweight, increasing physical activity and avoiding alcohol consumption and smoking. Additionally, calcium and vitamin D3 should be prescribed until the vitamin D deficit is resolved. Osteoporosis treatment options mainly include antiresorptives (i.e. estrogens, selective estrogen receptor modulators, bisphosphonates, denosumab) and anabolic agents (i.e. teriparatide, abaloparatide, romosozumab). Although presenting differences in efficacy and side effects, they have all been shown to increase bone mineral density (BMD) and to reduce osteoporotic-related fractures. Monotherapy with antiresorptive agents, particularly oral bisphosphonates, should be considered routinely as the first option for treatment of postmenopausal women. However, in the case of side effects, therapeutic failure or the need for long-term use, anabolic agents may be considered. In high-risk patients, anabolic agents may be considered as an initial therapeutic option. The combination of antiresorptive and anabolic agents may be useful to increase BMD compared with monotherapy, but more information is warranted to determine the effects on fracture risk.

Denosumab Discontinuation in Patients Treated for Low Bone Density and Osteoporosis

Denosumab (DMAB) is a potent antiresorptive treatment used for treatment of osteoporosis and low bone mineral density (BMD) in those at high risk for fracture. In postmenopausal women with osteoporosis, DMAB treatment for 10 years has been studied, with results showing continued gains in BMD, sustained fracture risk reduction, and low risk of adverse events. However, upon discontinuation of DMAB, there is a rapid reversal of effect, with increase in bone turnover, loss of BMD, and in a subset of patients, a greater risk for multiple vertebral fractures.

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

Rebound-associated vertebral fractures (RAVFs) could occur in a minority of the patients who discontinue denosumab. In such patients, denosumab is often reinstituted to rapidly suppress bone turnover and avert the risk of additional fractures. Herein we report the cases of 2 patients who sustained RAVFs, and in whom resuming denosumab treatment did not avert the occurrence of new RAVFs a few months later, despite the suppression of bone turnover markers. It seems that denosumab reinstitution cannot completely eliminate the risk of new RAVFs and that the rebound of bone turnover may not be the sole mechanism to explain this phenomenon.

Long-Term Follow-Up of Denosumab Discontinuers with Multiple Vertebral Fractures in the Real-World: A Case Series

Denosumab discontinuation is associated with rapid reversal of bone turnover suppression and with a considerable increase in fracture risk, including a risk for multiple vertebral fractures (MVF). Long-term follow-up of patients who sustained MVF after denosumab discontinuation has not been reported. This case-series was aimed to provide a long-term follow-up on the management and outcome of denosumab discontinuers who initially presented with multiple vertebral fractures. Denosumab discontinuers were identified from a computerized database of a large healthcare provider. Baseline and follow-up clinical, laboratory, and imaging data were obtained from the computerized database and electronic medical records. The post-denosumab discontinuers MVF patients consisted of 12 women aged 71±12. Osteoporotic fractures were prevalent before denosumab discontinuation in 6 of the patients. The majority received bisphosphonates before denosumab. MVF occurred 134±76 days after denosumab discontinuation. The patients were followed for a median of 36.5 (IQR 28.2, 42.5) months after MVF. Two patients passed-away. Two patients suffered recurrent vertebral fractures. Following MVF, patients were treated inconsistently with denosumab, teriparatide, oral, and intravenous bisphosphonates, in various sequences. Two patients underwent vertebroplasty/kyphoplasty. This long-term follow-up of real-world patients with MVF following denosumab discontinuation reveals that management is inconsistent, and recurrent fractures are not uncommon. It calls for clear management guidelines for patients with MVF after denosumab discontinuation and for special attention to this high-risk group.

The Effect of Teriparatide for the Treatment of Multiple Spontaneous Clinical Vertebral Fractures after Discontinuation of Denosumab in a Female Patient with Rheumatoid Arthritis: A Case Report

Discontinuation of denosumab is associated with the risk of rebound in bone turnover and rebound-associated spontaneous clinical vertebral fractures. This case report presents an 86-year-old woman with rheumatoid arthritis who experienced rebound-associated spontaneous clinical vertebral fractures at 9 months after denosumab discontinuation. Following 5-year bisphosphonate treatment, the patient had 9 injections of 60-mg denosumab every 6 months. Because of tooth extraction, denosumab treatment was discontinued, and raloxifene was administered. At 9 months after the last denosumab injection, the patient experienced severe low back pain. Magnetic resonance imaging (MRI) and radiograph demonstrated clinical fracture at the fourth lumbar vertebra. MRI performed at 3 months after first fracture showed two additional fractures at the second and third lumbar vertebrae. Teriparatide was administered for management of rebound-associated spontaneous clinical, multiple vertebral fractures. Teriparatide was effective for accelerating the fracture healing and suppressing the occurrence of new fractures. However, 2-year treatment of teriparatide did not have suppressive effect of rebound in bone turnover and general bone loss. This case suggested that teriparatide was effective for suppression of new rebound-associated spontaneous clinical vertebral fractures, but not effective in prevention of general bone loss after denosumab discontinuation.

Fracture risk and management of discontinuation of denosumab therapy: a systematic review and position statement by ECTS

CONTEXT

Denosumab discontinuation is characterized by an increase in bone turnover overriding pre-treatment status, a rapid bone loss in the majority and multiple vertebral fractures (VFx) in some patients.

METHODS

A working group of the European Calcified Tissue Society (ECTS) performed an updated systematic review of existing literature on changes of bone turnover, bone mineral density (BMD), and fracture risk after denosumab discontinuation and provided advice on management based on expert opinion.

RESULTS

Important risk factors for multiple VFx following denosumab cessation are prevalent VFx, longer duration off therapy, greater gain in hip BMD during therapy, and greater loss of hip BMD after therapy according to a retrospective analysis of the FREEDOM Extension Study. Case series indicate that prior bisphosphonate therapy mitigates the biochemical rebound phenomenon after denosumab discontinuation, but it is uncertain whether this attenuation prevents BMD loss and fractures. Current evidence indicates partial efficacy of subsequent antiresorptive treatment with results seemingly dependent on duration of denosumab treatment.

CONCLUSIONS

A careful assessment of indications to start denosumab treatment is advised, especially for younger patients. A case for long-term treatment with denosumab can be made for patients at high fracture risk already on denosumab treatment given the favorable efficacy and safety profile. In case of denosumab discontinuation, alternative antiresorptive treatment should be initiated 6 months after the final denosumab injection. Assessment of bone turnover markers may help define the optimal regimen, pending results of ongoing RCTs. Patients having sustained VFx should be offered prompt treatment to reduce high bone turnover.

A Review on the Role of Denosumab in Fracture Prevention

Denosumab is a receptor activator of nuclear factor kappa-Β ligand inhibitor, which suppresses the bone resorption process to preserve bone mass. It is usually recommended to postmenopausal women and men with high fracture risk. With the recent publication of the results from FREEDOM study and its extension, the long-term effect of denosumab in preventing fragility fractures has been put forward. This review aims at summarising the evidence of denosumab in reducing fracture risk and its safety derived from clinical studies. Most of the evidence are derived from FREEDOM trials up to 10 years of exposure. Denosumab is reported to prevent vertebral and non-vertebral fractures. It is also proven effective in Japanese women, patients with chronic kidney diseases and breast cancer patients receiving antineoplastic therapy. Denosumab discontinuation leads to high remodeling, loss of bone mineral density and increased fracture risk. These negative effects might be preventable by bisphosphonate treatment. The safety profile of denosumab is consistent with increased years of exposure. In conclusion, denosumab is a safe and effective option for reducing fracture risk among patients with osteoporosis.

Romosozumab was not effective in preventing multiple spontaneous clinical vertebral fractures after denosumab discontinuation: A case report

Discontinuation of denosumab is associated with the increase of bone turnover markers to above-baseline levels (so-called rebound in bone turnover) and rapid bone loss. Several studies have reported vertebral fractures (VFs), particularly multiple spontaneous clinical VFs (MSCVFs), occurring after discontinuation of denosumab. There is currently no recommendation for the management of VFs including MSCVFs. Presently, romosozumab is the strongest anti-osteoporotic agent that inhibits sclerostin and rapidly increases bone mass, but it is uncertain that romosozumab is an effective treatment choice to treat VFs occurring after discontinuation of denosumab. Herein we reported a novel case of a 60-year-old woman who was treated with romosozumab after discontinuation of denosumab and subsequently suffered MSCVFs under romosozumab treatment. She had a history of two osteoporotic VFs (T6 and T8) and received five doses of 60 mg denosumab every 6 months following the osteoporosis diagnosis. As per the patient's convenience, the sixth denosumab injection was postponed. To improve the persistent low bone mass in the lumbar spine (T-score −3.8), 210 mg romosozumab was administered monthly after 9 months following the last denosumab injection. At the first romosozumab injection, she had no clinical symptoms such as low back pain, but her bone formation and resorption marker levels elevated compared with those treated with denosumab. After three doses of romosozumab, spontaneous severe low back pain occurred, and time-course radiographs revealed five new VFs (T12, L2, L3, L4, and L5). Romosozumab administration had no suppressive effect on bone resorption during the rebound in bone turnover after discontinuation of denosumab. This case suggests that romosozumab is not effective in preventing VFs or MSCVFs after denosumab discontinuation.

Rebound-associated vertebral fractures may occur in sequential time points following denosumab discontinuation: need for prompt treatment re-initiation

Denosumab discontinuation has been associated with increased risk of rebound-associated multiple vertebral fractures. We report the cases of three patients, two females and one male, who had manifested rebound-associated vertebral fractures after denosumab discontinuation and sustained new vertebral fractures a few months later. Two of the patients had been previously treated with bisphosphonates. Patients discontinued denosumab after 2 to 8 years of treatment. One of the female patients was receiving prednisolone 7.5 mg daily for an unspecified connective tissue disorder and the male patient methylprednisolone 8 mg daily for dermatomyositis. We hypothesize that rebound-associated multiple vertebral fractures after denosumab discontinuation may occur, at least in some cases, sequentially instead of simultaneously. Our cases further underpin the need for prompt initiation of potent antiresorptives in patients who sustained rebound-associated vertebral fractures, in order to prevent not only bone loss but also a second round of fractures.