RANKL treatment of vascular endothelial cells leading to paracrine pro-calcific signaling involves ROS production.

Numerous studies have highlighted the causal link between over-production of reactive oxygen species (ROS) and cardiovascular complications such as vascular calcification (VC). Receptor-activator of nuclear factor-κB ligand (RANKL) has previously been shown to act on endothelial cells, eliciting the production/release of paracrine pro-calcific signals that act, in-turn, upon underlying vascular smooth muscle cells (VSMCs) to induce osteoblastic differentiation and VC. A role for endothelial ROS signaling in this process has not been established however. In the current paper, we investigate the possibility that RANKL leads to ROS signaling within the endothelial layer as part of the RANKL-driven VC signaling cascade. Human aortic endothelial cells (HAECs) were treated with RANKL (25 ng/ml, 72 h) and monitored for ROS production, in parallel with various pro-calcific signaling indices. Antioxidant co-treatments included TRAIL (5 ng/ml), apocynin (10 mM) and N-acetylcysteine (5 mM). Treatment of HAECs with RANKL-induced robust ROS production. This surge could be partially attenuated by TRAIL and strongly attenuated by apocynin and N-acetylcysteine. RANKL also elicited a range of signaling events in HAECs that we have previously demonstrated are coupled to osteoblastic differentiation in underlying VSMCs. These include non-canonical NF-κB/p52 activation, elevated BMP-2 release and increased alkaline phosphatase (ALP) enzyme activity (cellular and extracellular). Importantly, these RANKL-induced signaling events could be completely prevented by co-treatment of HAECs with antioxidants. In summary, RANKL elicits ROS generation in HAECs with direct consequences for generation of paracrine pro-calcific signals known to effect calcification in underlying VSMCs.

Regulation of osteoclast homeostasis and inflammatory bone loss by MFG-E8.

The glycoprotein milk fat globule-epidermal growth factor factor 8 (MFG-E8) is expressed in several tissues and mediates diverse homeostatic functions. However, whether it plays a role in bone homeostasis has not been established. In this study, we show for the first time, to our knowledge, that osteoclasts express and are regulated by MFG-E8. Bone marrow-derived osteoclast precursors from MFG-E8-deficient (Mfge8(-/-)) mice underwent increased receptor activator of NF-κB ligand-induced osteoclastogenesis, leading to enhanced resorption pit formation compared with wild-type controls. Consistently, exogenously added MFG-E8 inhibited receptor activator of NF-κB ligand-induced osteoclastogenesis from mouse or human osteoclast precursors. Upon induction of experimental periodontitis, an oral inflammatory disease characterized by loss of bone support of the dentition, Mfge8(-/-) mice exhibited higher numbers of osteoclasts and more bone loss than did wild-type controls. Accordingly, local microinjection of anti-MFG-E8 mAb exacerbated periodontal bone loss in wild-type mice. Conversely, microinjection of MFG-E8 inhibited bone loss in experimental mouse periodontitis. In comparison with wild-type controls, Mfge8(-/-) mice also experienced >60% more naturally occurring chronic periodontal bone loss. In conclusion, MFG-E8 is a novel homeostatic regulator of osteoclasts that could be exploited therapeutically to treat periodontitis and perhaps other immunological disorders associated with inflammatory bone loss.

Denosumab and bone-metastasis-free survival in men with castration-resistant prostate cancer: results of a phase 3, randomised, placebo-controlled trial.

BACKGROUND: Bone metastases are a major cause of morbidity and mortality in men with prostate cancer. Preclinical studies suggest that osteoclast inhibition might prevent bone metastases. We assessed denosumab, a fully human anti-RANKL monoclonal antibody, for prevention of bone metastasis or death in non-metastatic castration-resistant prostate cancer. METHODS: In this phase 3, double-blind, randomised, placebo-controlled study, men with non-metastatic castration-resistant prostate cancer at high risk of bone metastasis (prostate-specific antigen [PSA] ≥8·0 µg/L or PSA doubling time ≤10·0 months, or both) were enrolled at 319 centres from 30 countries. Patients were randomly assigned (1:1) via an interactive voice response system to receive subcutaneous denosumab 120 mg or subcutaneous placebo every 4 weeks. Randomisation was stratified by PSA eligibility criteria and previous or ongoing chemotherapy for prostate cancer. Patients, investigators, and all people involved in study conduct were masked to treatment allocation. The primary endpoint was bone-metastasis-free survival, a composite endpoint determined by time to first occurrence of bone metastasis (symptomatic or asymptomatic) or death from any cause. Efficacy analysis was by intention to treat. The masked treatment phase of the trial has been completed. This trial was registered at ClinicalTrials.gov, number NCT00286091. FINDINGS: 1432 patients were randomly assigned to treatment groups (716 denosumab, 716 placebo). Denosumab significantly increased bone-metastasis-free survival by a median of 4·2 months compared with placebo (median 29·5 [95% CI 25·4-33·3] vs 25·2 [22·2-29·5] months; hazard ratio [HR] 0·85, 95% CI 0·73-0·98, p=0·028). Denosumab also significantly delayed time to first bone metastasis (33·2 [95% CI 29·5-38·0] vs 29·5 [22·4-33·1] months; HR 0·84, 95% CI 0·71-0·98, p=0·032). Overall survival did not differ between groups (denosumab, 43·9 [95% CI 40·1-not estimable] months vs placebo, 44·8 [40·1-not estimable] months; HR 1·01, 95% CI 0·85-1·20, p=0·91). Rates of adverse events and serious adverse events were similar in both groups, except for osteonecrosis of the jaw and hypocalcaemia. 33 (5%) patients on denosumab developed osteonecrosis of the jaw versus none on placebo. Hypocalcaemia occurred in 12 (2%) patients on denosumab and two (<1%) on placebo. INTERPRETATION: This large randomised study shows that targeting of the bone microenvironment can delay bone metastasis in men with prostate cancer. FUNDING: Amgen Inc.

Denosumab versus zoledronic acid for treatment of bone metastases in men with castration-resistant prostate cancer: a randomised, double-blind study.

BACKGROUND: Bone metastases are a major burden in men with advanced prostate cancer. We compared denosumab, a human monoclonal antibody against RANKL, with zoledronic acid for prevention of skeletal-related events in men with bone metastases from castration-resistant prostate cancer. METHODS: In this phase 3 study, men with castration-resistant prostate cancer and no previous exposure to intravenous bisphosphonate were enrolled from 342 centres in 39 countries. An interactive voice response system was used to assign patients (1:1 ratio), according to a computer-generated randomisation sequence, to receive 120 mg subcutaneous denosumab plus intravenous placebo, or 4 mg intravenous zoledronic acid plus subcutaneous placebo, every 4 weeks until the primary analysis cutoff date. Randomisation was stratified by previous skeletal-related event, prostate-specific antigen concentration, and chemotherapy for prostate cancer within 6 weeks before randomisation. Supplemental calcium and vitamin D were strongly recommended. Patients, study staff, and investigators were masked to treatment assignment. The primary endpoint was time to first on-study skeletal-related event (pathological fracture, radiation therapy, surgery to bone, or spinal cord compression), and was assessed for non-inferiority. The same outcome was further assessed for superiority as a secondary endpoint. Efficacy analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00321620, and has been completed. FINDINGS: 1904 patients were randomised, of whom 950 assigned to denosumab and 951 assigned to receive zoledronic acid were eligible for the efficacy analysis. Median duration on study at primary analysis cutoff date was 12·2 months (IQR 5·9-18·5) for patients on denosumab and 11·2 months (IQR 5·6-17·4) for those on zoledronic acid. Median time to first on-study skeletal-related event was 20·7 months (95% CI 18·8-24·9) with denosumab compared with 17·1 months (15·0-19·4) with zoledronic acid (hazard ratio 0·82, 95% CI 0·71-0·95; p = 0·0002 for non-inferiority; p = 0·008 for superiority). Adverse events were recorded in 916 patients (97%) on denosumab and 918 patients (97%) on zoledronic acid, and serious adverse events were recorded in 594 patients (63%) on denosumab and 568 patients (60%) on zoledronic acid. More events of hypocalcaemia occurred in the denosumab group (121 [13%]) than in the zoledronic acid group (55 [6%]; p<0·0001). Osteonecrosis of the jaw occurred infrequently (22 [2%] vs 12 [1%]; p = 0·09). INTERPRETATION: Denosumab was better than zoledronic acid for prevention of skeletal-related events, and potentially represents a novel treatment option in men with bone metastases from castration-resistant prostate cancer. FUNDING: Amgen.

Denosumab for prevention of fractures in postmenopausal women with osteoporosis.

BACKGROUND: Denosumab is a fully human monoclonal antibody to the receptor activator of nuclear factor-kappaB ligand (RANKL) that blocks its binding to RANK, inhibiting the development and activity of osteoclasts, decreasing bone resorption, and increasing bone density. Given its unique actions, denosumab may be useful in the treatment of osteoporosis. METHODS: We enrolled 7868 women between the ages of 60 and 90 years who had a bone mineral density T score of less than -2.5 but not less than -4.0 at the lumbar spine or total hip. Subjects were randomly assigned to receive either 60 mg of denosumab or placebo subcutaneously every 6 months for 36 months. The primary end point was new vertebral fracture. Secondary end points included nonvertebral and hip fractures. RESULTS: As compared with placebo, denosumab reduced the risk of new radiographic vertebral fracture, with a cumulative incidence of 2.3% in the denosumab group, versus 7.2% in the placebo group (risk ratio, 0.32; 95% confidence interval [CI], 0.26 to 0.41; P<0.001)--a relative decrease of 68%. Denosumab reduced the risk of hip fracture, with a cumulative incidence of 0.7% in the denosumab group, versus 1.2% in the placebo group (hazard ratio, 0.60; 95% CI, 0.37 to 0.97; P=0.04)--a relative decrease of 40%. Denosumab also reduced the risk of nonvertebral fracture, with a cumulative incidence of 6.5% in the denosumab group, versus 8.0% in the placebo group (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01)--a relative decrease of 20%. There was no increase in the risk of cancer, infection, cardiovascular disease, delayed fracture healing, or hypocalcemia, and there were no cases of osteonecrosis of the jaw and no adverse reactions to the injection of denosumab. CONCLUSIONS: Denosumab given subcutaneously twice yearly for 36 months was associated with a reduction in the risk of vertebral, nonvertebral, and hip fractures in women with osteoporosis. (ClinicalTrials.gov number, NCT00089791.)

Denosumab in men receiving androgen-deprivation therapy for prostate cancer.

BACKGROUND: Androgen-deprivation therapy is well-established for treating prostate cancer but is associated with bone loss and an increased risk of fracture. We investigated the effects of denosumab, a fully human monoclonal antibody against receptor activator of nuclear factor-kappaB ligand, on bone mineral density and fractures in men receiving androgen-deprivation therapy for nonmetastatic prostate cancer. METHODS: In this double-blind, multicenter study, we randomly assigned patients to receive denosumab at a dose of 60 mg subcutaneously every 6 months or placebo (734 patients in each group). The primary end point was percent change in bone mineral density at the lumbar spine at 24 months. Key secondary end points included percent change in bone mineral densities at the femoral neck and total hip at 24 months and at all three sites at 36 months, as well as incidence of new vertebral fractures. RESULTS: At 24 months, bone mineral density of the lumbar spine had increased by 5.6% in the denosumab group as compared with a loss of 1.0% in the placebo group (P<0.001); significant differences between the two groups were seen at as early as 1 month and sustained through 36 months. Denosumab therapy was also associated with significant increases in bone mineral density at the total hip, femoral neck, and distal third of the radius at all time points. Patients who received denosumab had a decreased incidence of new vertebral fractures at 36 months (1.5%, vs. 3.9% with placebo) (relative risk, 0.38; 95% confidence interval, 0.19 to 0.78; P=0.006). Rates of adverse events were similar between the two groups. CONCLUSIONS: Denosumab was associated with increased bone mineral density at all sites and a reduction in the incidence of new vertebral fractures among men receiving androgen-deprivation therapy for nonmetastatic prostate cancer. (ClinicalTrials.gov number, NCT00089674.)

Do RANKL inhibitors (denosumab) affect inflammation and immunity?

Receptor activator of nuclear factor kappa B ligand (RANKL) and its natural antagonist, osteoprotegerin (OPG), are, respectively, an indispensable factor and a potent inhibitor for osteoclast differentiation, activity, and survival. The development of a human monoclonal antibody to RANKL, denosumab, constitutes a novel approach to prevent fragility fractures in osteoporosis, skeletal complications of malignancy, and potentially bone erosions in rheumatoid arthritis (RA). In addition to being expressed by osteoblasts, RANKL is abundantly produced by activated T cells, and synoviocytes in RA, whereas its receptor, RANK, is also expressed by monocytes/macrophages and dendritic cells. However, in preclinical and clinical studies of RA-including patients with some degree of immunosuppression-RANKL inhibitors did not significantly alter inflammatory processes. RANKL, RANK, and OPG deficiency in murine models highlights the important role of this pathway in the development and maturation of the immune system in rodents, including functions of T and/or B cells, whereas OPG overexpression in mice and rats seems innocuous with regard to immunity. In contrast, loss-of-function mutations in humans have more limited effects on immune cells. In clinical studies, the overall rate of infections, cancer, and death was similar with denosumab and placebo. Nevertheless, the risk of severe infections and cancer in some specific tissues remains to be carefully scrutinized.

[Denosumab for treatment of postmenopausal osteoporosis]. / Denosumab for behandling av postmenopausal osteoporose.

BACKGROUND: Treatment with bisphosphonates reduces the risk of new fractures and is the treatment of choice for osteoporosis. Denosumab inhibits bone resorption via a different mechanism than bisphosphonates, and is a new option in the treatment of osteoporosis. In this paper we give an overview of the mode of action and clinical effects. MATERIAL AND METHODS: The paper is based on a non-systematic literature search in Pubmed/Medline. RESULTS: Denosumab is a human monoclonal antibody to receptor-activated nuclear factor kappa B (RANKL), a member of the TNF family that is formed in the osteoblast. Binding to RANKL results in reduced recruitment and activity of osteoclasts. Denosumab 60 mg given subcutaneously every six months is shown to inhibit bone resorption to a greater degree than bisphosphonates. In a three-year study of 7,868 women with postmenopausal osteoporosis, a reduction in the relative risk of vertebral, non-vertebral and hip fractures compared to placebo was found (68. 20 and 40 %, correspondingly). In the clinical trials with denosumab, the safety profile was similar to placebo, except for a slightly higher incidence of cellulitis and exanthema. Denosumab has also shown promising skeletal effects in the treatment of cancer and rheumatoid arthritis. INTERPRETATION: Treatment with denosumab has an effect on postmenopausal osteoporosis and may be an alternative to treatment with bisphosphonates. There are few adverse effects and it is simple to administer.

Denosumab. Limited efficacy in fracture prevention, too many adverse effects.

The standard drug for postmenopausal osteoporotic women with a high risk of fracture is alendronic acid, used in conjunction with non-drug measures. There are no drugs with demonstrated efficacy on the risk of fracture in castrated men with prostate cancer. Denosumab, a monoclonal antibody that inhibits a cytokine acting mainly on bone cells and lymphocytes, has been authorised in the European Union for use in both these settings. There are no trials comparing denosumab versus alendronic acid for symptomatic fracture prevention. In two trials involving 1189 and 504 women, the incidence of clinical fractures, recorded as simple adverse effects, did not differ significantly between the groups. In a placebo-controlled trial in about 7900 elderly osteoporotic women, denosumab significantly reduced the incidence of symptomatic vertebral fractures (0.8% versus 2.6% after 3 years) and hip fractures (0.7% versus 1.2%). An indirect comparison, providing weak evidence, suggests that denosumab is less effective than alendronic acid. In a placebo-controlled trial in 1468 castrated men with prostate cancer, denosumab did not reduce the incidence of symptomatic fractures after 3 years. Only the incidence of vertebral fractures, detected on routine radiographs, showed a statistically significant decline (1.5% versus 3.5%). Denosumab has numerous adverse effects. In placebo-controlled trials, this monoclonal antibody was associated with a higher incidence of deep-seated infections such as endocarditis, cancer, and skin rash. More data are needed on the risk of pancreatitis, long-term bone disorders (atypical fractures, delayed fracture healing, osteonecrosis of the jaw), hypocalcaemia and cataracts, all of which were reported in clinical trials. In practice, denosumab is not sufficiently effective to outweigh its established and potential risks in postmenopausal osteoporotic women or in castrated men with prostate cancer.

Osteonecrosis of the jaw.

This review looks at osteonecrosis in the stomatognathic system (mainly the jaws). Osteonecrosis of the jaw (ONJ) is a rare but serious clinical condition. It affects patients treated with bisphosphonates, and also with denosumab, mainly in oncological doses. In osteoporosis, it is a problem of relatively small significance. Article presents a thorough review of this phenomenon, including its definition, pathogenesis, risk factors, prevention and treatment methods, and its incidence rate.

Denosumab in patients with giant-cell tumour of bone: an open-label, phase 2 study.

BACKGROUND: Giant-cell tumour (GCT) of bone is a primary osteolytic bone tumour with low metastatic potential and is associated with substantial skeletal morbidity. GCT is rich in osteoclast-like giant cells and contains mononuclear (stromal) cells that express RANK ligand (RANKL), a key mediator of osteoclast activation. We investigated the potential therapeutic effect of denosumab, a fully human monoclonal antibody against RANKL, on tumour-cell survival and growth in patients with GCT. METHODS: In this open-label, single-group study, 37 patients with recurrent or unresectable GCT were enrolled and received subcutaneous denosumab 120 mg monthly (every 28 days), with loading doses on days 8 and 15 of month 1. The primary endpoint was tumour response, defined as elimination of at least 90% of giant cells or no radiological progression of the target lesion up to week 25. Study recruitment is closed; patient treatment and follow-up are ongoing. The study is registered with Clinical Trials.gov, NCT00396279. FINDINGS: Two patients had insufficient histology or radiology data for efficacy assessment. 30 of 35 (86%; 95% CI 70-95) of evaluable patients had a tumour response: 20 of 20 assessed by histology and 10 of 15 assessed by radiology. Adverse events were reported in 33 of 37 patients; the most common being pain in an extremity (n=7), back pain (n=4), and headache (n=4). Five patients had grade 3-5 adverse events, only one of which (grade 3 increase in human chorionic gonadotropin concentration not related to pregnancy) was deemed to be possibly treatment related. Five serious adverse events were reported although none were deemed treatment related. INTERPRETATION: Further investigation of denosumab as a therapy for GCT is warranted. FUNDING: Amgen, Inc.

Optimizing clinical benefits of bisphosphonates in cancer patients with bone metastases.

Bisphosphonates are important treatments for bone metastases. Considerations for optimizing the clinical benefits of bisphosphonates include efficacy, compliance, and safety. Several bisphosphonates are approved for clinical use; however, few have demonstrated broad efficacy in the oncology setting and been compared directly in clinical trials. Among patients with bone metastases from breast cancer, the efficacy of approved bisphosphonates was evaluated in a Cochrane review, showing a reduction in the risk of skeletal-related events (SREs) ranging from 8% to 41% compared with placebo. Between-trial comparisons are confounded by inconsistencies in trial design, SRE definition, and endpoint selection. Zoledronic acid has demonstrated clinical benefits beyond those of pamidronate in a head-to-head trial that included patients with breast cancer or multiple myeloma. Compliance and adherence also have effects on treatment efficacy. In a comparison study, the adherence rates with oral bisphosphonates were found to be significantly lower compared with those of intravenous bisphosphonates. The safety profiles of oral and intravenous bisphosphonates differ. Oral bisphosphonates are associated with gastrointestinal side effects, whereas intravenous bisphosphonates have dose- and infusion rate-dependent effects on renal function. Osteonecrosis of the jaw is an uncommon but serious event in patients receiving monthly intravenous bisphosphonates or denosumab. The incidence of this event can be reduced with careful oral hygiene. A positive benefit-risk ratio for bisphosphonates has been established, and ongoing clinical trials will determine whether individualized therapy is possible.

Denosumab for the treatment of osteoporosis.

Being a connective tissue, bone can increase or decrease its mass through the process of remodeling. Using a discovery in the mid-1980s-that tumor necrosis factor (TNF) could dramatically increase formation of osteoclasts (the cells that break down bone)-researchers at Amgen (Thousand Oaks, CA) discovered a TNF-like molecule that regulated bone resorption. Elevations in the expression of this molecule, receptor activator of nuclear factor-κB ligand (RANKL), can cause excessive bone destruction. A blocking antibody to RANKL named denosumab inhibits osteoclast formation and bone degradation. In a large multicenter clinical trial, known as the FREEDOM trial (Fracture Reduction Evaluation of Denosumab in Osteoporosis Every 6 Months), the effects of denosumab were tested in 60- to 90-year-old women over 3 years. Statistically significant reductions in fracture risk at the vertebral column, hip, and nonvertebral sites were associated with increases in bone mineral density (BMD) and reciprocal decreases in markers of bone resorption. However, the FREEDOM trial did not test the most beneficial use of a resorption blocking drug-to target the rapid bone loss that occurs in late perimenopause and early postmenopause. One adverse effect from denosumab is cellulitis, and research in animals suggests that RANKL/RANK interaction is needed for Langerhans cell (LC) survival in the skin. Further mechanistic and clinical studies on the role of RANKL in the skin are needed.

[Austrian guidance for the pharmacologic treatment of osteoporosis in postmenopausal women: Addendum 2010]. / Österreichischer Leitfaden zur medikamentösen Therapie der postmenopausalen Osteoporose: Addendum 2010.

The Austrian Society for Bone and Mineral Research routinely publishes evidence-based guidelines for the treatment of postmenopausal osteoporosis. The fully human monoclonal antibody denosumab (Prolia(®)) has been recently approved by the European Medical Agency (EMEA) and the Food and Drug Administration (FDA) for the treatment of postmenopausal osteoporosis. Denosumab has been shown to reduce vertebral, non-vertebral,and hip-fracture risk effectively. Together with alendronate, risedronate, zoledronate, ibandronate, strontium ranelate, and raloxifene, denosumab constitutes an effective option in the treatment of postmenopausal osteoporosis.

[The role of rank-ligand inhibition in the treatment of postmenopausal osteoporosis]. / Il ruolo dell'inibizione del rank-ligando nel trattamento dell'osteoporosi postmenopausale.

Osteoporosis is a skeletal disease affecting millions of people worldwide in which a decreased bone mass and a microarchitectural deterioration compromise bone strength leading to bone fragility and increased susceptibility to fracture. Bone turnover increases at menopause, with osteoclast-mediated bone resorption exceeding bone formation. Recent discoveries in bone biology have demonstrated that RANKL, a cytokine member of the tumor necrosis factor superfamily, is an essential mediator of osteoclast formation, function and survival. Denosumab is a fully human monoclonal antibody with a high affinity and specificity for human RANKL. By binding to its target, denosumab prevents the interaction of RANKL with its receptor RANK on osteoclasts and their precursors and inhibits osteoclast-mediated bone resorption. Administered as a subcutaneous injection every six months, denosumab has been shown to decrease bone turnover and to increase bone mineral density in postmenopausal women with low bone mass and osteoporosis. In these patients denosumab significantly reduced the risk of vertebral fractures, hip fractures and nonvertebral fractures. In all clinical trials published to date, denosumab was well tolerated with an incidence of adverse events, including infections and malignancy, generally similar to subjects receiving placebo or alendronate. The denosumab therapeutic regimen consisting in a subcutaneous injection every 6 months may increase patient compliance and persistence with a further benefit from treatment. By providing a new molecular target for osteoporosis treatment, denosumab is a promising drug for the treatment of postmenopausal osteoporosis and the prevention of fragility fractures.

Blockade of RANKL/RANK signaling pathway by epigallocatechin gallate alleviates mast cell-mediated inflammatory reactions.

Receptor activator of NF-κB ligand (RANKL) as an osteoclast differentiation factor induces inflammatory reactions via production of thymic stromal lymphopoietin (TSLP). Epigallocatechin gallate (EGCG) is the major and the most active compound in green tea and has anti-inflammatory, anti-cancer, anti-oxidant, and neuroprotective effects. However, the effect and molecular mechanisms of EGCG are still unknown in RANKL-induced inflammatory reactions. Here we investigated the immuno-regulatory effects and its molecular mechanisms of epigallocatechin gallate (EGCG) in RANKL-stimulated human mast cell line, HMC-1 cells. In this study, EGCG prevented expression of PI3 Kinase and phosphorylation of mitogen-activated protein (MAP) Kinases in RANKL-stimulated HMC-1 cells. EGCG prevented caspase-1 activity and decreased transcriptional activity of nuclear factor (NF)-κB by suppressing inhibitory protein κBα phosphorylation in RANKL-stimulated HMC-1 cells. EGCG has been shown to prevent production and mRNA expression of TSLP, interleukin (IL)-1ß, IL-6, and IL-8 by RANKL without cytotoxicity. Furthermore, EGCG prevented degranulation of mast cell in RANKL-stimulated HMC-1 cells. Overall, these results suggest that EGCG acts as a natural agent for preventing and treating RANKL-mediated inflammatory diseases by targeting PI3 Kinase, MAP Kinase, caspase-1, and NF-κB signaling cascade in mast cells.

Efficacy and safety of denosumab in postmenopausal women with osteopenia or osteoporosis: a systematic review and a meta-analysis.

Receptor activator of nuclear factor-kappaB ligand (RANKL) is a cytokine essential for osteoclast differentiation, activation, and survival. Denosumab, a human monoclonal antibody against RANKL, constitutes a promising antiresorptive agent for osteoporosis. We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), and other trial registries through January 2009. We selected randomized controlled trials (RCTs) of denosumab in women with low bone mass that described the changes on bone markers and bone mineral density (BMD) as well as the adverse events including fracture risk. We analyzed data from nine RCTs involving 10 329 participants. Although denosumab universally decreased bone markers and increased lumbar and hip BMD, the efficacy evaluation based on percentage (%) mean change from the baseline was not possible due to missing data. Denosumab was not associated with a significant reduction in fracture risk [OR (95% CI) 0.74 (0.33 to 1.64), p=0.45]. Increased risk of serious adverse events [OR (95% CI) 1.83 (1.10 to 3.04), p=0.02] and serious infections [OR (95% CI) 4.45 (1.15 to 17.14), p=0.03] were evident. In conclusion, although effective as an antiresorptive agent, denosumab has not yet proved its efficacy on fracture risk reduction while increased infection risk questions its safety.

An open-label, phase 2 trial of denosumab in the treatment of relapsed or plateau-phase multiple myeloma.

RANKL is a key mediator of osteoclast differentiation, activation, and survival. Preclinical data suggest that aberrant production and activation of osteoclasts may influence proliferation of multiple myeloma (MM) cells in the bone marrow. Reports have also shown that inhibiting RANKL may have a direct effect on RANK-expressing myeloma cells and a therapeutic role in treating the disease. In mouse myeloma models, inhibition of RANKL led to reduced serum paraprotein levels and tumor burden. Based on this hypothesis, this proof-of-concept, single-arm study investigated whether RANKL inhibition with denosumab could reduce serum M-protein levels in relapsed or plateau-phase myeloma subjects. All subjects received denosumab monthly, with loading doses on days 8 and 15 of month one, until disease progression or subject discontinuation. Results of this ongoing study demonstrated that no subjects in either cohort met the protocol-defined objective response criteria of complete response (CR) or partial response (PR), but that denosumab effectively inhibited the RANKL pathway regardless of previous exposure to bisphosphonates, as evidenced by suppressed levels of the bone turnover marker, serum C-terminal telopeptide of type 1 collagen (sCTx). Eleven (21%) subjects who relapsed within 3 months before study entry maintained stable disease for up to 16.5 months. Nineteen (46%) subjects with plateau-phase myeloma maintained stable disease for up to 18.3 months. The adverse event (AE) profile for denosumab and its dosing schedule in these populations was consistent with that for advanced cancer patients receiving systemic therapy. Additional controlled clinical studies of denosumab in subjects with both relapsed and plateau-phase MM are warranted.

Denosumab in osteoporosis and oncology.

OBJECTIVE: To review the pharmacology, pharmacokinetics, pharmacodynamics, safety, efficacy, and use of denosumab in osteoporosis, breast cancer, prostate cancer, and multiple myeloma. DATA SOURCES: Studies and abstracts were identified through MEDLINE and International Pharmaceutical Abstracts (1966-July 2009). Key search terms include denosumab, AMG-162, and receptor activator of nuclear factor-kappaB ligand system. Information available in abstract form was retrieved from major oncology and bone metabolism meetings. Additional data were obtained from the manufacturer. STUDY SELECTION AND DATA EXTRACTION: All available studies in humans were included except for studies in rheumatoid arthritis and giant cell tumor of the bone. DATA SYNTHESIS: In patients with osteoporosis, denosumab significantly reduces bone resorption and fractures. Studies of denosumab in the prevention and treatment of osteoporosis have demonstrated significantly increased bone mineral density and reduced bone turnover markers. Studies of denosumab versus placebo in the treatment of osteoporosis have demonstrated reductions in vertebral, hip, and nonvertebral fractures. In oncology, positive results from clinical trials in patients receiving endocrine therapy for breast and prostate cancer demonstrated decreases in bone loss and skeletal-related events. Denosumab seems to be at least as effective in reducing bone turnover markers as intravenous bisphosphonates in the oncology setting. The most common adverse effects in patients with osteoporosis were arthralgia, nasopharyngitis, back pain, and headache. The most common adverse effects in patients with cancer were infection, pain in the extremities, arthralgia, bone pain, fatigue, and pain. Serious adverse effects include infections requiring hospitalization. CONCLUSIONS: Denosumab has documented efficacy and safety in patients with osteoporosis, breast cancer, and prostate cancer. Additional clinical trial data are needed to more completely establish the effectiveness of denosumab in the treatment of osteoporosis and neoplastic disease as well as its cost-effectiveness and long-term safety.