Effects of anti-RANKL antibodies administered to pregnant mice on bone and tooth development in neonates.

OBJECTIVES: This study examined how the anti-bone resorptive agent denosumab, which comprises anti-receptor activator of nuclear factor kappa B ligand (anti-RANKL) monoclonal antibodies, administered during pregnancy affected neonatal development. Anti-RANKL antibodies, which are known to bind to mouse RANKL and inhibit osteoclast formation, were administered to pregnant mice. Following this, the survival, growth, bone mineralization, and tooth development of their neonates were analyzed. METHODS: Anti-RANKL antibodies (5 mg/kg) were injected into pregnant mice on day 17 of gestation. After parturition, their neonatal offspring underwent microcomputed tomography at 24 h and at 2, 4, and 6 weeks after birth. Three-dimensional bone and teeth images were subjected to histological analysis. RESULTS: Approximately 70% of the neonatal mice born to mice who received anti-RANKL antibodies died within 6 weeks after birth. These mice had a significantly lower body weight and significantly higher bone mass compared with the control group. Furthermore, delayed tooth eruption and abnormal tooth morphology (eruption length, enamel surface, and cusps) were observed. Conversely, while the tooth germ shape and mothers against decapentaplegic homolog 1/5/8 expression remained unchanged at 24 h after birth in the neonatal mice born to mice that received anti-RANKL antibodies, osteoclasts were not formed. CONCLUSIONS: These results suggest that anti-RANKL antibodies administered to mice in the late stage of pregnancy results in adverse events in their neonatal offspring. Thus, it is speculated that administering denosumab to pregnant humans will affect fetal development and growth after birth.

Osteonecrosis mandibular: hallazgos clínicos e imagenológicos en un paciente tratado con denosumab / Mandibular osteonecrosis: clinical and imaging findings in a patient treated with denosumab

Introducción: La administración de bifosfonatos y medicamentos antiangiogénicos en pacientes con cáncer es un esquema terapéutico usual en oncología. Existen reportes de osteonecrosis de los maxilares en pacientes sometidos a este esquema de tratamiento, luego de realizar un procedimiento dental invasivo. Objetivo: A partir de las características clínicas e imagenológicas de la patología, ilustrar al odontólogo sobre los medicamentos para el tratamiento del cáncer, susceptibles de generar osteonecrosis de los maxilares. Presentación de caso: Paciente masculino de 89 años, con cáncer de próstata tratado con denosumab, que desarrolló osteonecrosis del maxilar inferior posterior a una extracción dental. Es de vital importancia que el odontólogo identifique los medicamentos, factores de riesgo y las medidas para minimizar el riesgo de osteonecrosis de los maxilares en pacientes susceptibles(AU)

Introduction: The administration of bisphosphonates and antiangiogenic drugs in cancer patients is a usual therapeutic scheme in oncology. There are reports of osteonecrosis of the jaws in patients undergoing this treatment scheme, after performing an invasive dental procedure. Objective: Show the dentist from the clinical and imaging characteristics of the pathology on the drugs for the treatment of cancer sensitivity to generate osteonecrosis of the jaws. Case presentation: An 89-year-old male patient with prostate cancer treated with denosumab developed osteonecrosis of the lower jaw after tooth extraction. It is vitally important that the dentist identifies medications, risk factors and measures to minimize the risk of osteonecrosis of the jaws in sensitivy patients(AU)

[Pharmaceutical Intervention According to Strict Management System Can Normalize Decreased Serum Calcium Level by Denosumab and Prevent Its Aggravation].

Denosumab is a fully monoclonal antibody against the receptor activator of nuclear factor kappa-B ligand (RANKL), and prevents skeletal-related events by bone metastasis. Hypocalcemia is the most typical adverse effect of denosumab use. We have developed a management system for the more efficient and safer management of denosumab administration, and evaluated pharmaceutical interventions for the better control of hypocalcemia. All pharmaceutical interventions in the system from April 2016 to March 2020 were retrospectively evaluated. We have also assessed the incidence of hypocalcemia in 158 patients who were administered denosumab for six months or more in the period. A total of 282 pharmaceutical interventions (7.0% of the total administration) were conducted. The most conducted intervention was regarding hypocalcemia, which involved the suspension of the injection and/or the increase of calcium and vitamin D supplement with 65% adoption and 17% temporary treatment suspensions. Other interventions were about hypercalcemia, request of laboratory examination and ordering supplements, dental consultation, and poor renal function. A total of 199 interventions (70.6%) were adopted, with 33 administrations suspended. The frequency of hypocalcemia was 27.8% with just one patient having grade 2 hypocalcemia, suggesting that there were no severe cases. Moreover, hypocalcemia was significantly normalized following pharmaceutical intervention and/or handling by physicians (p=0.02) according to the system. Conversely, the normalization rate in hypercalcemia did not differ according to the countermeasures. In conclusion, pharmaceutical interventions according to our management system benefit safe denosumab treatment, especially in severe hypocalcemia prevention.

Tumor microenvironment in giant cell tumor of bone: evaluation of PD-L1 expression and SIRPα infiltration after denosumab treatment.

Giant cell tumor of bone (GCTB) is an intermediate malignant bone tumor that is locally aggressive and rarely metastasizes. Denosumab, which is a receptor activator of nuclear factor kappa B ligand (RANKL) inhibitor, can be used to treat GCTB. We focused on potential immunotherapy for GCTB and investigated the tumor microenvironment of GCTB. Programmed death-ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO1) expression and signal-regulatory protein alpha (SIRPα), forkhead box P3 (FOXP3), and cluster of differentiation 8 (CD8) infiltration were assessed by immunohistochemical studies of 137 tumor tissues from 96 patients. Of the naive primary specimens, 28% exhibited PD-L1 expression and 39% exhibited IDO1 expression. There was significantly more SIRPα+, FOXP3+, and CD8+ cell infiltration in PD-L1- and IDO1-positive tumors than in PD-L1- and IDO1-negative tumors. The frequency of PD-L1 expression and SIRPα+ cell infiltration in recurrent lesions treated with denosumab was significantly higher than in primary lesions and recurrent lesions not treated with denosumab. PD-L1 expression and higher SIRPα+ cell infiltration were significantly correlated with shorter recurrence-free survival. PD-L1 and SIRPα immune checkpoint inhibitors may provide clinical benefit in GCTB patients with recurrent lesions after denosumab therapy.

Rhizomelia and Impaired Linear Growth in a Girl with Juvenile Paget Disease: The Natural History of the Condition.

In ultra-rare bone diseases, information on growth during childhood is sparse. Juvenile Paget disease (JPD) is an ultra-rare disease, characterized by loss of function of osteoprotegerin (OPG). OPG inhibits osteoclast activation via the receptor activator of nuclear factor-κB (RANK) pathway. In JPD, overactive osteoclasts result in inflammatory-like bone disease due to grossly elevated bone resorption. Knowledge on the natural history of JPD, including final height and growth, is limited. Most affected children receive long-term antiresorptive treatment, mostly with bisphosphonates, to contain bone resorption, which may affect growth. In this study, we report the follow-up of height, growth velocity, and skeletal maturation in a 16-year-old female patient with JPD. The patient was treated with cyclic doses of pamidronate starting at 2.5 years of age and with 2 doses of denosumab at the age of 8 years, when pamidronate was paused. In the following years, a sustainable decline in a height z-score and a stunted pubertal growth spurt; despite appropriate maturation of the epiphyseal plates of the left hand, the proximal right humerus and both femora were observed. Whether this reflects the growth pattern in JPD or might be associated to the antiresorptive treatments is unclear, since there is very limited information available on the effect of bisphosphonates and denosumab on growth and the growth plate in pediatric patients. Studies are needed to understand the natural history of an ultra-rare bone disease and to assess the effects of antiresorptive treatment on the growing skeleton.

Increased fracture risk after discontinuation of anti-osteoporosis medications among hip fracture patients: A population-based cohort study.

BACKGROUND: To compare the risks of major osteoporotic, vertebral, and non-vertebral fractures between patients who discontinued anti-osteoporosis medications. METHODS: We conducted a comparative effectiveness study with a nationwide population-based cohort study design. Patients aged ≥50 years admitted between 2012 and 2015 for incident hip fractures and receiving denosumab or bisphosphonates with sufficient compliance for at least 1 year were included. Patients were categorized into persistent or non-persistent denosumab or bisphosphonates users based on their subsequent use pattern. The main outcomes were subsequent hospitalizations for a major osteoporotic, vertebral or non-vertebral fracture. Multivariate, time-varying Cox proportional hazards model was used to evaluate the risk of major outcomes. RESULTS: Compared with persistent denosumab users, non-persistent denosumab users had a significantly higher risk of major osteoporotic fractures (hazard ratio [HR] = 1.60; 95% confidence interval [CI], 1.20-2.14), vertebral fractures (HR = 2.18; 95% CI, 1.46-3.24) and death (HR = 3.57; 95%CI, 2.63-4.84). However, the increased risk of fracture was not found in both persistent and non-persistent bisphosphonates users. Noteworthy, the increased risk of vertebral fractures in non-persistent denosumab users was more pronounced within 1 year post-discontinuation (HR = 2.90; 95% CI, 1.77-4.74) and among patients who discontinued from 2-year denosumab therapy (HR = 3.58; 95% CI, 1.74-7.40). DISCUSSION: Discontinuation of denosumab resulted in an increased risk of major osteoporotic fractures, especially vertebral fractures. The increased risk tends to reveal within 1 year post-discontinuation and be greater after a longer treatment duration. Notably, only fracture with hospitalization was identified as our research outcome, the real risk of osteoporotic fracture post discontinuation is believed to be higher, especially for vertebral fracture.

Denosumab versus romosozumab for postmenopausal osteoporosis treatment.

Denosumab and romosozumab, a recently approved new drug, are effective and widely known molecular-targeted drugs for postmenopausal osteoporosis treatment. However, no studies have directly compared their therapeutic effects or safety in postmenopausal osteoporosis. This retrospective observational registry study compared the efficacy of 12-month denosumab or romosozumab treatment in postmenopausal osteoporosis patients. The primary outcome was the change in bone mineral density (BMD) at the lumbar spine. Secondary outcomes included BMD changes at the total hip and femoral neck, changes in bone turnover markers, and adverse events. Propensity score matching was employed to assemble patient groups with similar baseline characteristics. Sixty-nine patients each received either denosumab or romosozumab for 12 months. The mean 12-month percentage change from baseline in lumbar spine BMD was 7.2% in the denosumab group and 12.5% in the romosozumab group, indicating a significant difference between the groups. The percentage changes in BMD at both the total hip and femoral neck were also significantly higher at 12 months in the romosozumab group than in the denosumab group. In denosumab patients, bone formation and bone resorption markers were significantly decreased at 6 and 12 months from baseline. In the romosozumab group, the bone formation marker was significantly increased at 6 months and then returned to baseline, while the bone resorption marker was significantly decreased at both time points. Adverse events were few and predominantly minor in both groups, with no remarkable difference in the incidence of new vertebral fractures. Romosozumab showed a higher potential for improving BMD than denosumab in this clinical study of postmenopausal osteoporosis patient treatment.

Nutritional Status in Patients with Medication-Related Osteonecrosis of the Jaw (MRONJ).

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe side effect of mostly antiresorptive drugs. The aim of this prospective clinical study was to evaluate the nutritional status in MRONJ patients scheduled for surgical treatment (intraoral soft tissue closure). The following parameters were evaluated: body weight, body height, BMI, nutritional risk index (NRI), bioelectric impedance analysis (BIA), vitamins A, B12, D3, E, K1, folic acid, iron, total protein, transferrin, ferritin, prealbumin, albumin, and zinc. All subjects were admitted to hospital four to five days before surgery and sip-fed with Nutritia Fortimel Compact Protein in addition to regular oral food intake. During surgery, a nasogastric tube was inserted and only removed on hospital discharge five days postoperatively. A total of 58 patients could be included. Half of the MRONJ patients were identified to be at risk for malnutrition. Deficiencies regarding protein levels were revealed, whereas hardly any relevant deficits of micronutrients were noted. The intraoral wound healing four weeks post-surgery was highly satisfactory with a low dehiscence rate of intraoral mucosal sites. Of all parameters analyzed, the dehiscence rate at the last follow-up four weeks post-surgery was significantly influenced by vitamin K, transferrin, and ferritin levels (p = 0.030, p = 0.004, and p = 0.023, respectively). In conclusion, perioperative dietary counselling and appropriate nutritional therapy are important supportive measures in MRONJ patients scheduled for intraoral soft tissue closure.

Denosumab biosimilar in postmenopausal osteoporotic women: A randomized, assessor-blind, active-controlled clinical trial.

OBJECTIVE: The study assessed the efficacy, safety, pharmacokinetic (PK), and immunogenicity profiles of denosumab-biosimilar and denosumab-reference in postmenopausal osteoporotic women from India. MATERIALS AND METHODS: In this randomized, assessor-blind, active-control, multicenter trial, 114 patients were randomly allocated to receive denosumab-biosimilar (n = 58) or denosumab-reference (n = 56) at a subcutaneous dose of 60 mg every 6 months, for a year. Vitamin D and oral calcium were given daily. Lumbar spine bone mineral density (BMD) change was the primary end point. RESULTS: Of 114 randomized patients, 111 (denosumab-biosimilar, n = 56; denosumab-reference, n = 55) completed the study. All 114 patients were part of safety and immunogenicity analyses, 110 (denosumab-biosimilar, n = 56; denosumab-reference, n = 54) were part of efficacy analysis, and 20 (denosumab-biosimilar, n = 10; denosumab-reference, n = 10) were part of PK analysis. The bone mineral density (BMD) (lumbar spine) percent change at 1 year with denosumab-biosimilar and denosumab-reference (7.22 vs. 7.62; difference:-0.40; 95% confidence interval: -5.92, 5.12) showed no statistically relevant difference. Likewise, alkaline phosphatase (bone-specific) and PK parameters also did not show statistically relevant differences. Adverse events were reported in 44.83% of patients on denosumab-biosimilar versus 33.93% of patients on denosumab-reference; most events were mild or moderate and not related to the study drugs. No patients showed anti-denosumab antibody positivity. CONCLUSIONS: Denosumab-biosimilar and denosumab-reference showed biosimilarity in osteoporotic postmenopausal women. Availability of denosumab-biosimilar provides a treatment alternative for patients.

The Duration of Denosumab Treatment and the Efficacy of Zoledronate to Preserve Bone Mineral Density After Its Discontinuation.

CONTEXT: Zoledronate is used to prevent bone loss following denosumab discontinuation but its efficacy differs among studies. OBJECTIVE: To test if the duration of denosumab treatment affects the efficacy of subsequent zoledronate infusion. METHODS: This multicenter, prospective cohort study, conducted at 2 Greek and 1 Dutch bone centers, included 47 postmenopausal women (n = 47) who received a single zoledronate infusion 6 months after the last denosumab injection and then were followed for 1 year. Twenty-seven women received ≤ 6 denosumab injections (≤ 6 Group) and 20 received > 6 denosumab injections (> 6 Group). The main outcome measure was changes in lumbar spine (LS) bone mineral density (BMD). RESULTS: At 12 months LS-BMD values were maintained in the ≤ 6 Group (0.98 ±â€…0.10 to 0.99 ±â€…0.9 g/cm2, P = 0.409) but decreased significantly in the > 6 Group (1.0 ±â€…0.11 to 0.93 ±â€…0.12 g/cm2, P < 0.001). The percent change of LS-BMD of the ≤ 6 Group (+1.0%) was significantly different (P < 0.001) from the change of the > 6 Group (-7.0%). In the whole cohort, the duration of denosumab treatment was negatively correlated with the percentage change of LS-BMD (rs = -0.669, P < 0.001) but not with the change of femoral neck (FN)-BMD. Bone turnover markers increased in all patients 6 months following zoledronate administration with no difference between the 2 groups. CONCLUSION: The duration of denosumab treatment significantly affects the efficacy of subsequent zoledronate infusion to maintain BMD gains. Frequent follow-up of patients treated with denosumab longer than 3 years is advisable as additional therapeutic interventions may be needed.

Osteoporosis - risk factors, pharmaceutical and non-pharmaceutical treatment.

Osteoporosis is a metabolic disease of the skeletal system which currently affects over 200 million patients worldwide. The WHO criteria define osteoporosis as low bone mineral density, with a T-score ≤ -2.5 found in the spine, the neck of the femur, or during a full hip examination. Osteoporosis considerably reduces a patient's quality of life. QoL should be carefully evaluated before fractures occur to enable the development of an appropriate treatment plan. The progression of osteoporosis may be significantly inhibited by following a proper diet, leading a healthy lifestyle, taking dietary supplements, and receiving appropriate treatment. Education and the prevention of the disease play a major role. Potentially modifiable risk factors for osteoporosis are vitamin D deficiency, smoking, alcohol consumption, low calcium intake, low or excessive phosphorus intake, protein deficiency or a high-protein diet, excessive consumption of coffee, a sedentary lifestyle or lack of mobility, and insufficient exposure to the sun. Pharmaceutical treatment for osteoporosis involves bisphosphonates, calcium and vitamin D3, denosumab, teriparatide, raloxifene, and strontium ranelate. Data indicates that 30%-50% of patients do not take their medication correctly. Other methods of treatment include exercise, kinesitherapy, treatment at a health resort, physical therapy, and diet.

Antiresorptive treatment and talar collapse after displaced fractures of the talar neck: a long-term follow-up of 19 patients.

Background and purpose - Displaced fractures of the talar neck are associated with a high risk of structural collapse. In this observational analysis we hypothesized that pharmacological inhibition of osteoclast function might reduce the risk of structural collapse through a reduction in bone resorption during revascularization of the injured bone.Patients and methods - Between 2002 and 2014 we treated 19 patients with displaced fractures of the talar neck with open reduction and internal fixation. Of these, 16 patients were available for final follow-up between January and November 2017 (median 12 years, IQR 7-13). Among these, 6 patients with Hawkins type 3 fractures and 2 patients with Hawkins type 2b fractures received postoperative antiresorptive treatment (7 alendronate, 1 denosumab) for 6 to 12 months. The remaining 8 patients received no antiresorptive treatment. The self-reported foot and ankle score (SEFAS) was available in all patients and 15 patients had undergone computed tomography (CT) at final follow-up, which allowed evaluation of structural collapse of the talar dome and signs of post-traumatic osteoarthritis.Results - The risk for partial collapse of the talar dome was equal in the 2 groups (3 in each group) and post-traumatic arthritis was observed in all patients. The SEFAS in patients with antiresorptive treatment was lower, at 21 points (95% CI 15-26), compared with those without treatment, 29 points (CI 22-35).Interpretation - Following a displaced fracture of the talar neck, we found no effect of antiresorptive therapy on the rate of talar collapse, post-traumatic osteoarthritis, and patient-reported outcomes.

Minimally Invasive Spinal Stabilization with Denosumab before Total Spondylectomy for a Collapsing Lower Lumbar Spinal Giant Cell Tumor.

A 21-year-old man consulted our hospital for treatment of a spinal giant cell tumor (GCT) of Enneking stage III. Lower lumbar-spine tumors and severe spinal canal stenosis are associated with high risk for surgical mor-bidity. Stability was temporarily secured with a percutaneous pedicle screw fixation in combination with deno-sumab, which shrank the tumor. Total en bloc spondylectomy was then performed 6 months after initiation of denosumab, and the patient was followed for 3 years. There was no local recurrence, and bony fusion was obtained. Minimally invasive surgery and denosumab allowed safer and easier treatment of a collapsing lower lumbar extra-compartmental GCT.

Effect of denosumab switched from bisphosphonates in preventing joint destruction in postmenopausal rheumatoid arthritis patients with anti-cyclic citrullinated peptide antibodies.

INTRODUCTION: This study aimed to determine the effects of denosumab treatment on the joint destruction of Japanese females with rheumatoid arthritis (RA) and anti-cyclic citrullinated peptide (CCP) antibodies. MATERIALS AND METHODS: This retrospective longitudinal study included 56 patients treated with denosumab and 50 patients treated with bisphosphonate. All participants were positive for anti-CCP antibodies. All patients also had a history of osteoporosis treatment with bisphosphonate, which was either continued or switched to 60 mg of subcutaneous denosumab injection every 6 months. To assess the progression of joint destruction, hand and foot radiographs were taken, and changes in modified total Sharp score (mTSS), erosion score (ERO), and joint space narrowing score (JSN) were evaluated at 12 months and 24 months. The changes in BMD of the lumbar spine and hip were also assessed at 12 months. RESULTS: At 12 months, there were significant differences in the change of ERO (p = 0.015) and mTSS (p = 0.01). Similarly, there were significant differences in the change of ERO (p = 0.013) and mTSS (p = 0.003) at 24 months. In contrast, no significant difference was observed in the changes of JSN and clinical parameters. There were significant differences in the changes in BMD in the femoral neck (p = 0.011) and total hip (p = 0.012). CONCLUSION: Denosumab treatment might be effective for the inhibition of bone erosion progression in the patients with RA, and it potentially contributes to the treatment of osteoporosis and prevention of destructive arthritis in patients with switching treatment from bisphosphonate.

Local administration and enhanced release of bone metabolic antibodies from hydroxyapatite/chondroitin sulfate nanocomposite microparticles using zinc cations.

As a local delivery carrier of bone metabolic proteins, we have previously reported hydroxyapatite/chondroitin sulfate composite microparticles (HAp/ChS) and their formulation method using zinc cations (Zn), and the in vitro release properties of proteins from the microparticles. Herein, we report the release properties of model antibodies such as immunoglobulin (IgG), human IgG (hIgG), and denosumab (Dmab) from HAp/ChS using this formulation method. Adding Zn in the formulation of IgG loaded with HAp/ChS microparticles enhanced the release of antibodies from HAp/ChS in phosphate buffer saline. In addition, the biological activity of Dmab released from HAp/ChS formulated with Zn was significantly higher than that without Zn. These results suggest a possible beneficial effect on the treatment for local bone diseases. The sclerostin monoclonal antibody (Sclmab) promotes fracture healing. We prepared HAp/ChS microparticles loaded with Sclmab and locally administered the microparticles into a drilled hole in the distal femoral bone of young rats. After three weeks, the area of the newly formed osteoid around the drilled hole where HAp/ChS loaded with Sclmab and Zn was locally administered was significantly higher than that observed in the control group (normal saline). Thus, HAp/ChS microparticles and the formulation method of monoclonal antibodies using Zn could be useful in the treatment of local bone diseases.

Effects of follow-on therapy after denosumab discontinuation in patients with postmenopausal osteoporosis.

OBJECTIVES: To clarify the effects of follow-on therapy after denosumab (DMAb) discontinuation. METHODS: In this retrospective, multicenter study, postmenopausal patients with osteoporosis who were previously treated by oral bisphosphonates (BP) (n = 26) or teriparatide (TPTD) (n = 27) were switched to DMAb (administered 2.6 times), and then discontinued. Patients (73.1 years, T-scores of the lumbar spine [LS] - 2.7 and femoral neck [FN] - 2.2) were switched to either (1) raloxifene (RAL) (n = 13) or BP [(2) weekly or monthly BP (wmBP) (n = 29) or (3) zoledronate (ZOL) (n = 11)], based on each physician's decision (mean interval after final DMAb administration was 7.2 months). Bone mineral density (BMD) at final DMAb administration were set as baseline. RESULTS: Changes in LS BMD at 1.5 years after final DMAb administration were -2.7% in the RAL, 0.7% in the wmBP, and 1.9% in the ZOL (p = .31 between groups), and in FN BMD were -3.8%, -0.8%, and 1.8%, respectively (p = .02 between the RAL and ZOL; p = .048 between the RAL and BP). Clinical vertebral fracture incidence during 1.5 years after final DMAb administration was 23.1% in the RAL, 3.4% in the wmBP, and 0.0% in the ZOL (p = .048 between the RAL and ZOL; p = .015 between the RAL and BP). No significant differences were observed in these parameters between the wmBP and ZOL. CONCLUSION: These results may contribute to the selection of adequate follow-on therapy after DMAb discontinuation, although further investigations are required.

The safety profile of denosumab in oncology beyond the safety of denosumab as an anti-osteoporotic agent: still more to learn.

INTRODUCTION: Initially endorsed as an antiosteoporotic agent, denosumab ‒ human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL)‒ has currently shown an anticancer potential, rationalizing its exploitation in oncology. A prerequisite for leveraging denosumab in oncology is a favorable safety profile. AREAS COVERED: The present review provides an overview of the adverse events of denosumab in oncology, with a focus on hypocalcemia, medication-related osteonecrosis of the jaw, atypical femoral fracture(s), post-denosumab vertebral fractures, increased risk of infections, and excess of second primary cancer. Representative studies addressing the safety and efficacy of denosumab compared to bisphosphonates in oncology are summarized. Critical gaps in the literature concerning the safety of denosumab in oncology are highlighted as opposed to plenty of available safety data on denosumab as an antiosteoporotic agent. EXPERT OPINION: Despite the generally acceptable safety profile of denosumab in oncology, many issues remain unresolved. Further research is mandatory to counteract current challenges, namely: (i) validation of risk factors for adverse events; (ii) elucidation of the pathophysiology of the adverse events in search of actionable molecular pathways; (iii) illumination of the association of denosumab with increased risk of infections and/or second primary cancer; (iv) establishment of optimal diagnostic, and therapeutic protocols.