Sclerotic bone: a sign of bone reaction in patients with medication related osteonecrosis of the jaw.

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse reaction associated with antiresorptive drugs such as bisphosphonates and denosumab. When dealing with advanced and/or multiple MRONJ lesions undergoing surgical therapy, the extent of surgery is often a topic of discussion. The aim of this study was to identify the differences in bone density in and around the MRONJ lesion before and after surgical treatment to evaluate the needed surgical extend of the modelling osteotomy. In this retrospective study 26 patients with MRONJ lesions that were surgically treated in our department were observed. Length, width and bone density were measured in panoramic radiograph pre and postoperatively with the Imaging processing software Sidexis and ImageJ (Fiji). The necrotic area, the surrounding sclerotic area as well as the healthy contralateral side were observed. Measurements were performed by two independent observers. Pearson correlation was calculated to determine the interobserver variability. Bone density was significantly reduced in the necrotic bone area compared to the healthy unaffected contralateral reference side. The sclerotic bone area surrounding the necrosis showed increased bone density compared to the contralateral unaffected reference side. The density of the sclerotic bone area was increased in the previously affected MRONJ area in the postoperative panoramic radiograph. The pre and postoperative density showed no significant correlation to healing behaviour. The focus of the modelling osteotomy in surgical treatment of mature MRONJ lesions should be predominantly on the parts that appear necrotic and less dense in the panoramic radiograph as sclerotic areas might be an expression of bone reaction.

Equivalence trial of proposed denosumab biosimilar GP2411 and reference denosumab in postmenopausal osteoporosis: the ROSALIA study.

Denosumab is a monoclonal antibody used to reduce risk of fractures in osteoporosis. ROSALIA was a multicenter, double-blind, randomized, integrated phase I/phase III study comparing the efficacy, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and safety of proposed biosimilar denosumab GP2411 with reference denosumab (REF-DMAb) (Prolia®; Amgen). Postmenopausal women with osteoporosis were randomized 1:1 to 2 60-mg doses of GP2411 or REF-DMAb, one at study start and one at week 26. At week 52, the REF-DMAb group was re-randomized 1:1 to a third dose of REF-DMAb or switch to GP2411. The primary efficacy endpoint was percentage change from baseline (%CfB) in LS-BMD at week 52. Secondary efficacy endpoints were %CfB in LS-BMD, FN-BMD, and TH-BMD at weeks 26 and 78 (and week 52 for FN-BMD and TH-BMD). Primary PK and PD endpoints were the area under the serum concentration-time curve extrapolated to infinity and maximum drug serum concentration at week 26, and the area under the effect-time curve of the %CfB in serum CTX at week 26. Secondary PK and PD endpoints included drug serum concentrations and %CfB in serum CTX and P1NP during the study period. Similar efficacy was demonstrated at week 52, with 95% CIs of the difference in %CfB in LS-BMD between treatment groups fully contained within prespecified equivalence margins. Similarity in PK and PD was demonstrated at week 26. Immunogenicity was similar between groups and was not impacted by treatment switch. The rate of new vertebral fractures was comparable. Treatment-emergent adverse events were comparable between groups (63.6% [GP2411/GP2411]; 76.0% [REF-DMAb/REF-DMAb]; 76.6% [REF-DMAb/GP2411]). In conclusion, ROSALIA showed similar efficacy, PK and PD, and comparable safety and immunogenicity of GP2411 to REF-DMAb in postmenopausal osteoporosis.

Denosumab is a biologic treatment that stops bone breakdown. This clinical trial evaluated how similar GP2411 (a denosumab biosimilar in development) is compared with European-approved reference denosumab in women with post-menopausal osteoporosis. Biosimilars are highly similar to the original treatment ('reference denosumab') and may have a lower price. 263 patients were randomly assigned to receive GP2411 and 264 to reference denosumab. Treatment was given at the study beginning, at Week 26 and at Week 52. 124 patients were re-assigned at Week 52 to test the effect of changing from reference denosumab to GP2411. The study showed similarity in how the body interacts with the treatments, what effects the treatment has (both measured over 26 weeks), and bone mineral density (measured over 78 weeks). Antibody responses to GP2411 were detected in similar proportions of patients on each treatment. Reported adverse events were similar between treatments before Week 52, and from Week 52 to 78, and <5% of patients experienced serious adverse events. A change of treatment from reference denosumab to GP2411 did not affect outcomes. These results showed similarity between GP2411 and reference denosumab in this population. In future, GP2411 may enable more patients to benefit from denosumab.

The RANKL inhibitor denosumab in combination with dual checkpoint inhibition is associated with increased CXCL-13 serum concentrations.

BACKGROUND: Recent evidence suggests additional immunomodulatory properties of RANKL inhibition possibly boosting the clinical efficacy of immune checkpoint inhibitors (ICI). METHODS: We conducted a prospective, multicentre clinical trial in unresectable stage IV melanoma patients with bone metastases who received denosumab in parallel with dual ICI (BONEMET) and performed comprehensive immune monitoring at baseline and 4, 12, and 24 weeks after initiation of therapy. Secondary endpoints included tolerability and efficacy. For comparison, biospecimens from melanoma patients treated with dual ICI without denosumab were analyzed accordingly and served as retrospective reference cohort. RESULTS: In both the BONEMET (n = 16) and the reference cohort (n = 18) serum levels of 17 cytokines, including IFNγ were significantly increased after 4 weeks of treatment. Patients who received ICI and denosumab showed a significantly higher increase in serum CXCL-13 and a significant decrease in VEGFc compared with the reference cohort. While no changes in T cell composition were observed at 4 weeks, patients in the BONEMET cohort showed a significant decrease in the peripheral naïve T-cell population and an increase in CD8+ effector cells after 12 weeks. Treatment-related adverse events occurred with comparable frequency (93.8% in the BONEMET cohort versus 83.3% in the reference cohort). 7/16 patients in the BONEMET cohort and 8/18 patients in the reference cohort achieved disease control. CONCLUSION: Denosumab in combination with dual ICI modulates cytokine expression and T-cell composition in peripheral blood. The upregulation of CXCL-13, a key factor for initiating tertiary lymphoid structures, strengthens the hypothesis that denosumab indeed boost immunological effects.

Recurrent severe hypocalcemia following chemotherapy regimen changes in advanced breast cancer: two case reports.

BACKGROUND: As an oncologic emergency related to abnormalities in calcium metabolism, hypercalcemia associated with paraneoplastic syndrome and bone metastases is well known. Meanwhile, the incidence of hypocalcemia is low, except in cases associated with bone-modifying agents used for bone metastases. Hypocalcemia induced by bone-modifying agents typically occurs early after the initial administration, and its incidence can be significantly reduced by preventive administration of calcium and vitamin D3 supplements. CASE REPORT: We report two cases of recurrent severe hypocalcemia occurring during chemotherapy for metastatic breast cancer with multiple bone metastases. Case 1: A 35-year-old Japanese woman developed metastases in the bone, liver, and ovaries during postoperative endocrine therapy for invasive lobular carcinoma of the breast. She underwent chemotherapy and treatment with denosumab. She experienced recurrent episodes of severe hypocalcemia subsequent to a change in the chemotherapy regimen. Case 2: A 65-year-old Japanese woman encountered multiple bone metastases after postoperative anti-human epidermal growth factor receptor 2 therapy and during endocrine therapy for invasive ductal carcinoma of the breast. She underwent anti-human epidermal growth factor receptor 2 therapy and treatment with denosumab. She experienced recurrent severe hypocalcemia subsequent to a change in the chemotherapy regimen to letrozole + lapatinib, trastuzumab emtansine, and lapatinib + capecitabine. CONCLUSIONS: We observed two cases of recurrent severe hypocalcemia in patients with advanced breast cancer and bone metastases after modifications to their therapy regimens. These cases differed from the typical hypocalcemia induced by bone-modifying agents. It is possible that antitumor drugs affect calcium and bone metabolism associated with bone metastases. While these cases are rare, it is crucial for oncologists to be aware of hypocalcemia not only at the initiation of bone-modifying agents but also throughout the entire antitumor therapy, as hypocalcemia can lead to fatal outcomes.

Effect of denosumab on inflammation and bone health in active Charcot foot: A phase II randomised controlled trial.

AIMS: We aimed to investigate the effect of denosumab on pedal bone health and clinical resolution in active Charcot foot (CN). METHODS: This multicentre open-label phase 2 randomised controlled trial recruited adults with diabetes mellitus and active CN within 3 months of onset. Participants were randomised to standard care alone, or with denosumab 60 mg subcutaneously. Denosumab was administered at baseline and again at 6 months, unless foot temperature had normalised (i.e. <2 °C compared to contralateral foot). Co-primary outcomes were change in calcaneal Stiffness Index and foot temperature normalisation over 18 months. RESULTS: Twelve participants per group were analysed; mean age 58 ± 11 years, 83 % male and 92 % had type 2 diabetes. Active CN duration was median 8 (IQR 7-12) weeks. Ninety-two percent were Eichenholtz stage 1 and 96 % involved the midfoot. After 1-month, median decline in Stiffness Index was less in the denosumab verses standard care group (0.5 [IQR -1.0 to 3.9] vs -2.8 [-8.5 to -1.0], p = 0.008). At 18-months, 92 % of the denosumab group attained foot temperature normalisation versus 67 % of the standard care group (p = 0.13). CONCLUSIONS: Denosumab ameliorated the early decline in calcaneal Stiffness Index associated with active CN. However, no difference in normalisation of foot temperature was observed.

Medication-related osteonecrosis of the jaw in a paediatric patient taking denosumab: a case report.

Medication-related osteonecrosis of the jaw (MRONJ) is a known complication of antiresorptive and anti-angiogenic therapies in adults. Increasingly, these drugs are being prescribed for children with a variety of conditions, such as osteogenesis imperfecta and cancers of the bone. Review of the literature, however, reveals no reported paediatric MRONJ cases to date. We present such a case in a nine-year-old female patient with a vertebral aneurysmal bone cyst, who received dental extractions subsequent to denosumab therapy.

Zinc improves Denosumab and eldecalcitol efficacy for bone mineral density in patients with hypozincemia.

INTRODUCTION: We aimed to investigate the effects of zinc deficiency and zinc medication in osteoporosis patients undergoing denosumab (DMAb). MATERIALS AND METHODS: This retrospective study was conducted at a single hospital. The participants were female osteoporosis patients visiting between April 2019 and April 2020. All patients were treated with DMAb and eldecalcitol and recommended zinc-rich food. Based on zinc medication and serum zinc levels at the 12th month of dietary guidance, patients were categorized into the following four groups: hypozincemia with zinc medication, latent zinc deficiency with zinc medication, without zinc medication, and control without zinc medication. Longitudinal serum zinc concentrations, bone mineral density (BMD), and occurrence of fractures were measured. We investigated the factors influencing no response to DMAb and eldecalcitol treatment. RESULTS: Among the 145 patients followed up for 24 months, dietary guidance did not change the serum zinc concentration; however, zinc medication significantly increased these levels. The hypozincemia group did not show a significant BMD increase in the lumbar spine and femoral neck after DMAb and eldecalcitol treatment during dietary guidance; however, zinc medication increased these to the same levels as the other groups. In multivariate analyses, hypozincemia and thyroid disease were identified as the factors affecting no response. While 28.2% of patients with latent zinc deficiency without zinc medication suffered fractures, no fractures occurred in hypozincemia patients with zinc medication. CONCLUSION: Hypozincemia may reduce the efficacy of DMAb and eldecalcitol in increasing BMD and fracture prevention.

Cancer risk in patients treated with denosumab compared with alendronate: A population-based cohort study.

BACKGROUND: Antiresorptive treatment is currently used in millions of patients with osteoporosis and cancer worldwide. Early studies of denosumab suggested a small signal in ovarian cancer incidence and emerging data suggest that denosumab stimulates germ cell proliferation in the gonads. This study aims to determine the association between the use of denosumab and the risk of reproductive cancers compared with the use of alendronate. RESEARCH DESIGN AND METHODS: Using a cohort study design, we used the Danish nationwide registries to identify a population of subjects ≥50 years of age during 2010-2017 who started denosumab after being on alendronate treatment for at least six months. The cohort was matched 1:2 with patients who had been treated with alendronate alone for at least six months. The risk of reproductive cancers and the risk difference between groups were estimated using the Longitudinal Targeted Maximum Likelihood Estimation (L-TMLE) method. RESULTS: We identified 6054 Danish individuals who underwent treatment with denosumab. These individuals were matched with 12,108 receiving alendronate. The absolute risk of reproductive cancer was 1.05 % (95 % CI 0.75-1.34) after three years for denosumab users and was not different 0.03 % (-0.34-0.39) than for alendronate users. In supplemental analyses, there was no increased risk of non-reproductive cancers associated with the use of denosumab (risk difference of 0.54 % (-0.41-1.19). Analysis comparing denosumab users with the general population gave similar results. CONCLUSION: There was no difference in the risk of cancer following treatment with denosumab compared to treatment with alendronate assessed after a short follow-up of 3 years.

Denosumab-induced hypocalcemia in patients with solid tumors and renal dysfunction: a multicenter, retrospective, observational study.

BACKGROUND: Bone metastases are frequently observed in advanced cancer, and bone modifying agents are used to prevent or treat skeletal-related events. Zoledronic acid is contraindicated in patients with severe renal impairment (Ccr < 30 mL/min), but it is not completely known whether denosumab can be used in them. We aimed to determine the association between renal function and hypocalcemia development during denosumab treatment. METHODS: We included patients with solid cancer and bone metastases who started denosumab treatment between April 2017 and March 2019. They were classified into four groups based on creatinine clearance (Ccr; mL/min): normal (Ccr ≥ 80), mild (50 ≤ Ccr ˂80), moderate (30 ≤ Ccr ˂50), and severe (Ccr ˂30). Hypocalcemia was evaluated using the Common Terminology Criteria for Adverse Events (v5.0) based on the albumin-adjusted serum calcium levels; its incidence (stratified by renal function) and risk factors were investigated using a Chi-square test and logistic regression analysis. RESULTS: Of 524 patients (age: 69 ± 11 years; 303 men), 153 had a normal renal function and 222, 117, and 32 had mild, moderate, and severe renal dysfunction. The albumin-adjusted serum calcium level was higher than the measured (total) calcium level in most patients. The incidence of grade ≥ 1 hypocalcemia was 32.0% in the normal group and 37.4%, 29.9%, and 62.5% in the mild, moderate, and severe renal dysfunction groups, respectively. It was, therefore, higher in the severe renal dysfunction groups than in the normal group (P = 0.002). The incidence of grade ≥ 3 hypocalcemia did not differ significantly among the groups. Pre-treatment low serum calcium levels and severe renal dysfunction were risk factors for hypocalcemia. CONCLUSIONS: Evaluating denosumab-induced hypocalcemia required albumin adjustment, and its incidence was high among patients with severe renal dysfunction. Reduced serum calcium levels and severely impaired renal function were associated with an elevated hypocalcemia risk.

Sustained hypophosphatemia after denosumab in a patient on hemodialysis.

An 81-year-old Caucasian man who had commenced thrice weekly hemodialysis (HD) three months earlier, presented with a hip fracture, two vertebral fractures and a bone mineral density T-score of -3.6. He had received weekly iron sucrose infusions for 6 weeks and alphacalcidol on dialysis days. Although he suffered from coeliac disease and cirrhosis, he was fully ambulatory and well-nourished. He was normocalcaemic with a marginally low plasma phosphate and the PTH was 11.8 pmol/L (<2-times the upper range of the assay). In view of his severe osteoporosis, it was decided to treat him with denosumab (dmab). Laboratory assessment 2 weeks post dmab showed severe hypophosphatemia and hypocalcemia; phosphate 0.11 mmol/L and ionized calcium 0.83 mmol/L, and he was admitted for intravenous phosphate infusion. Three months later he remained on a phosphate supplement. The case illustrates that, in addition to the risks of hypocalcemia in patients with kidney failure and high bone turnover, kidney failure patients without evidence of high bone turnover, can also be at risk of hypocalcemia and severe hypophosphatemia requiring acute hospitalization and phosphate infusion. The potential role of compromised phosphate absorption versus increased deposition will be discussed. We recommend a cautious approach to dmab therapy in patients on dialysis, with evaluation of bone turnover and serum phosphate levels prior to initiation of treatment.

RANKL blockade for erosive hand osteoarthritis: a randomized placebo-controlled phase 2a trial.

Erosive hand osteoarthritis (OA) is a prevalent and disabling disease with limited treatment options. Here we present the results of a monocentric, placebo-controlled, double-blind, randomized phase 2a clinical trial with denosumab, a receptor activator of nuclear factor-κB ligand inhibitor, evaluating the effects on structure modification in erosive hand OA. Patients were randomized to 48 weeks treatment with denosumab 60 mg every 3 months (n = 51, 41 females) or placebo (n = 49, 37 females). The primary (radiographic) endpoint was the change in the total Ghent University Scoring System (GUSS) at week 24, where positive changes correspond to remodeling and negative changes to erosive progression. Secondary endpoints were the change in the GUSS at week 48 and the number of new erosive joints at week 48 by the anatomical phase scoring system. Baseline mean GUSS (standard deviation) of target joints was 155.9 (69.3) in the denosumab group and 158.7 (46.8) in the placebo group. The primary endpoint was met with an estimated difference between groups of 8.9 (95% confidence interval (CI) 1.0 to 16.9; P = 0.024) at week 24. This effect was confirmed at week 48 (baseline adjusted GUSS (standard error of the mean) denosumab and placebo were 163.5 (2.9) and 149.2 (3.9), respectively; with an estimated difference between groups of 14.3 (95% CI 4.6 to 24.0; P = 0.003)). At patient level, more new erosive joints were developed in the placebo group compared with denosumab at week 48 (odds ratio 0.24 (95% CI 0.08 to 0.72); P = 0.009). More adverse events occurred in the placebo group (125 events in 44 patients (90%)) compared with the denosumab group (97 events in 41 patients (80%)). These results demonstrate that denosumab has structure modifying effects in erosive hand OA by inducing remodeling and preventing new erosive joints. EU Clinical Trials Register identifier 2015-003223-53 .

Etiopathogenesis of medication-related osteonecrosis of the jaws: a review.

This study compiles the main hypotheses involved in the etiopathogenesis of medication-related osteonecrosis of the jaw (MRONJ). A narrative review of the literature was performed. The etiopathogenesis of MRONJ is multifactorial and not fully understood. The main hypothesis considers the disturbance of bone turnover caused by anti-resorptive drugs. Bisphosphonates and denosumab inhibit osteoclast activity through different action mechanisms, accumulating bone microfracture. Other hypotheses also consider oral infection and inflammation, the antiangiogenic effect and soft tissue toxicity of bisphosphonates, and the inhibition of lymphangiogenesis. Knowledge of the current theories for MRONJ is necessary to define future studies and protocols to minimize the incidence of this severe condition.

A Rare Reason for Severe Hypocalcemia Following Kidney Transplant: Denosumab Treatment.

Deviations of calcium, phosphate, parathyroid hormone, and vitamin D levels are the basis for the diagnosis of calcium-phosphate metabolism disorders. The plasma concentration of the biologically active form known as free calcium is regulated in a harmonious manner by its exchange in the bones and reabsorption by the kidneys. These steps take place under the control of parathyroid hormone and calcitriol. In the process of chronic kidney disease, the kidney cannot synthesize adequate calcitriol, and the resulting hypocalcemia and hyperphosphatemia cause the development of secondary hyperparathyroidism. Osteoporosis is a metabolic bone disease and is essentially the consequence of osteoclastogenesis-induced bone resorption that exceeds bone formation. Osteoporosis is common after kidney transplant. However, hypocalcemia following kidney transplant is rare. The hungry bone syndrome after parathyroidectomy is often responsible for this condition in the pretransplant period. Denosumab is a human monoclonal antibody developed against the receptor activator of nuclear factor kappa-B ligand (known as RANKL). Denosumab exerts an antiresorptive effect on bones by reducing differentiation into osteoclasts. It is an effective treatment option for osteoporosis in the general population. There is insufficient scientific data regarding the use of denosumab in kidney transplant patients. Here, we present the case of a kidney transplant recipient who developed severe hypocalcemia (serum calcium 4.7 mg/dL) after denosumab treatment for osteoporosis.

Pharmacokinetics and pharmacodynamics of the proposed biosimilar denosumab GP2411 and reference denosumab in healthy males.

BACKGROUND: This Phase I study compared the pharmacokinetic (PK) and pharmacodynamic (PD) similarity of GP2411 proposed denosumab biosimilar to reference denosumab (a monoclonal antibody for specific pro-resorptive conditions). RESEARCH DESIGN AND METHODS: Healthy males (28-65 years, 50-90 kg) were randomized to a single sub-therapeutic subcutaneous injection of 35 mg GP2411, EU-Xgeva® or US-Xgeva®, and followed for 39 weeks. The primary endpoints were AUCinf, AUClast, and Cmax. RESULTS: Four hundred ninety-two participants completed treatment. The 90% confidence intervals (CIs) (AUCinf, AUClast, and Cmax) and 95% CI of the geometric mean ratios of AUEC of % change from baseline in serum CTX were fully contained within the prespecified equivalence margins (0.80, 1.25), demonstrating similarity. The occurrence of treatment-emergent adverse events (TEAEs) with GP2411, EU-Xgeva® and US-Xgeva® was similar (72.9%, 76.0%, and 71.0% of participants, respectively). Most were Grade 1 or 2, <30% were treatment-related, and there was only one TEAE-related study discontinuation. Rates of positive anti-drug antibodies (ADAs) were similar (57.8%, 64.9%, and 69.1% of participants respectively), but immunogenicity was only borderline detectable and of very low magnitude. Ninety-nine percent of positive ADAs were transient. CONCLUSION: GP2411 demonstrated similarity with EU-Xgeva® and US-Xgeva® in PK, PD, safety, and immunogenicity in this population. CLINICAL TRIAL REGISTRATION: EudraCT 2019-001651-39.

Denosumab is a biological treatment that inhibits bone degradation. It is very effective in conditions characterized by elevated bone degradation, such as osteoporosis in women who have gone through the menopause, and in the treatment of specific bone cancers. However, the cost of the original patented denosumab ('reference denosumab') treatment may result in fewer eligible patients receiving denosumab treatment. A biosimilar is highly similar to the original treatment but at a lower price, enabling more patients to benefit.GP2411 is being developed as a proposed biosimilar to denosumab. This Phase I clinical trial was the first clinical trial to compare GP2411 to the EU and US versions of the reference denosumab (EU-Xgeva® and US-Xgeva®). All three products were given at a dose of 35 mg to 502 healthy males. The dose was lower than the dose that would be used in clinical practice to provide a more sensitive evaluation of similarity. Healthy males were chosen because they have fewer hormonal fluctuations than females, and are considered the most appropriate population for detecting differences in pharmacological effects of denosumab.The results demonstrate that GP2411 proposed denosumab biosimilar is highly similar to the reference products in absorption, distribution, and elimination, and other outcomes, including bone turnover. The incidence of adverse events was also comparable, most adverse events were very mild, and GP2411 was not associated with a higher rate of immune reactions.These results support its continued development and GP2411 may, in future, enable more patients to benefit from denosumab treatment.

Relationship between Medication-Related Osteonecrosis of the Jaw and CDK4/6 Inhibitors in Breast Cancer.

OBJECTIVE: We aimed to evaluate the use of CDK4/6 inhibitors as a risk factor for medication-related osteonecrosis of the jaw (MRONJ) in a cohort of patients with metastatic breast cancer treated with denosumab. METHODS: This was a multicentre, retrospective, observational study. All patients with breast cancer treated with denosumab (January 2011-December 2022) were included. The relationship between CDK4/6 inhibitors and MRONJ was analysed. RESULTS: A total of 243 patients were included, ninety-five (44.2%) of whom used a CDK4/6 inhibitor. There were 21 patients with MRONJ. In patients treated with denosumab without CDK4/6 inhibitors, the incidence of MRONJ and mean time to the occurrence of MRONJ were 6.6% (8/120) and 16.8 months (SD 7.8), respectively; in patients treated with denosumab and CDK4/6 inhibitor, these values were 13.7% (13/95) and 15.4 months (SD 8.7), respectively. The difference in the incidence was not significant (p = 0.085). Among the 19 patients who used abemaciclib, the probability of MRONJ occurrence was significantly higher compared to patients not using CDK4/6 inhibitors (p = 0.0178). CONCLUSIONS: These results suggest that the incidence of MRONJ in patients with metastatic breast cancer treated with denosumab is higher, and the onset of MRONJ occurs earlier in the presence of CDK4/6 inhibitors. The differences were statistically significant in the patients who used abemaciclib. Given that the use of this combination is very common in routine clinical practice, it would be advisable to carry out larger prospective studies to clarify the risk of this association.

Severe Hypocalcemia With Denosumab Among Older Female Dialysis-Dependent Patients.

Importance: Dialysis-dependent patients experience high rates of morbidity from fractures, yet little evidence is available on optimal treatment strategies. Chronic kidney disease-mineral and bone disorder is nearly universal in dialysis-dependent patients, complicating diagnosis and treatment of skeletal fragility. Objective: To examine the incidence and comparative risk of severe hypocalcemia with denosumab compared with oral bisphosphonates among dialysis-dependent patients treated for osteoporosis. Design, Setting, and Participants: Retrospective cohort study of female dialysis-dependent Medicare patients aged 65 years or older who initiated treatment with denosumab or oral bisphosphonates from 2013 to 2020. Clinical performance measures including monthly serum calcium were obtained through linkage to the Consolidated Renal Operations in a Web-Enabled Network database. Exposures: Denosumab, 60 mg, or oral bisphosphonates. Main Outcomes and Measures: Severe hypocalcemia was defined as total albumin-corrected serum calcium below 7.5 mg/dL (1.88 mmol/L) or a primary hospital or emergency department hypocalcemia diagnosis (emergent care). Very severe hypocalcemia (serum calcium below 6.5 mg/dL [1.63 mmol/L] or emergent care) was also assessed. Inverse probability of treatment-weighted cumulative incidence, weighted risk differences, and weighted risk ratios were calculated during the first 12 treatment weeks. Results: In the unweighted cohorts, 607 of 1523 denosumab-treated patients and 23 of 1281 oral bisphosphonate-treated patients developed severe hypocalcemia. The 12-week weighted cumulative incidence of severe hypocalcemia was 41.1% with denosumab vs 2.0% with oral bisphosphonates (weighted risk difference, 39.1% [95% CI, 36.3%-41.9%]; weighted risk ratio, 20.7 [95% CI, 13.2-41.2]). The 12-week weighted cumulative incidence of very severe hypocalcemia was also increased with denosumab (10.9%) vs oral bisphosphonates (0.4%) (weighted risk difference, 10.5% [95% CI, 8.8%-12.0%]; weighted risk ratio, 26.4 [95% CI, 9.7-449.5]). Conclusions and Relevance: Denosumab was associated with a markedly higher incidence of severe and very severe hypocalcemia in female dialysis-dependent patients aged 65 years or older compared with oral bisphosphonates. Given the complexity of diagnosing the underlying bone pathophysiology in dialysis-dependent patients, the high risk posed by denosumab in this population, and the complex strategies required to monitor and treat severe hypocalcemia, denosumab should be administered after careful patient selection and with plans for frequent monitoring.

Costs to Medicare of Nonrecommended Bone-Modifying Agent Use for Castration-Sensitive Prostate Cancer.

PURPOSE: Bone-modifying agents (BMAs) do not prevent skeletal-related events among patients with castration-sensitive prostate cancer (CSPC), but many patients receive BMAs unnecessarily. The costs to Medicare from overuse have not been assessed. METHODS: We used linked SEER-Medicare data 2011-2015 to measure the frequency and number of doses of zoledronic acid (ZA) and denosumab received during CSPC (between diagnosis and initiation of metastatic, castration resistant prostate cancer therapy). We estimated excess BMA among patients who received BMA therapy for CSPC and did not have an indication for osteoporosis fracture prevention. We used the Medicare fee schedule for drug prices and peer-reviewed sources to estimate adverse event frequencies and costs. RESULTS: Median CSPC duration was 387 days (IQR, 253-573), during which time 42% of patients received ≥one dose of denosumab (mean doses, 7) and 18% received ≥one dose of ZA (mean doses, 7). Thirty-eight percent of those receiving denosumab and 47% of those receiving ZA had a history of osteoporosis, osteopenia, spine or hip fracture, or hypercalcemia. The estimated, annual excess BMA cost to Medicare was $44,105,041 in US dollars (USD), composed of $43,303,078 USD and $45,512 USD in drug costs for denosumab and ZA, respectively, and $682,865 USD and $75,585 USD in adverse event costs, respectively. In one-way sensitivity analysis, the estimate was most sensitive to denosumab dosing frequency (estimate range, $28,469,237 USD-$98,830,351 USD) and duration of CSPC (estimate range, $36,823,311 USD-$99,015,908 USD). CONCLUSION: BMA overuse in CSPC incurs substantial cost to Medicare, largely because of denosumab drug costs. Excess costs may be reduced by greater adherence to guideline-concordant BMA use.

Effect of denosumab in treatment of unresectable spine and sacrum giant cell tumor of bone.

Giant cell tumor of bone (GCTB) is a rare tumor of the bone that is locally invasive. Surgery is the primary treatment that is usually done by intralesional curettage. In pelvis and spine surgery may be associated with high rate of complications, recently, Denosumab has been proposed for the treatment of these tumors in latter anatomical regions. Denosumab may be administered alone or as an adjuvant to surgery. This study aimed to assess the treatment effects of Denosumab in patients with unresectable GCTB. This study was a case series. Patients with unresectable GCTB of vertebra and sacrum were enrolled in this study. Patients received 120 mg of monthly Denosumab and additional doses on days 8th and 15th of treatment. Images of patients before and after treatment were evaluated. Nine patients with a median age of 30 years with spine and sacrum GCTB were included in this study. The median time of treatment with denosumab was 28 months (range: 3-67). Tumor control was seen in all patients. According to Inverse Choi density/size (ICDS), criteria objective response (complete response and partial response) was seen in 8 patients, and one had stable disease. Based on CT scan images, in 4 patients (44.44%), less than 50% of the transverse diameter of the tumor became ossified, and in the other five patients (55.55%), more than 50% of the tumor's transverse diameter became ossified. The median tumor volume before treatment was 829 cm3, and after treatment was 504 cm3 which was significantly reduced (P = 0.005). No complication related to therapy was seen. Tumor response was seen in all patients, and tumor control according to ICDS criteria was evident in all cases. This finding was in line with previous studies. Clinical improvement of signs and symptoms was also seen in all patients. Generally, our study demonstrates a sustained clinical benefit and tumor response with Denosumab, as tumor response ≥ 24 weeks was evident in all cases. No side effects were seen in patients despite long-term treatment with Denosumab.