Denosumab in osteoporosis and oncology

Supra-Physiological Levels of Magnesium Counteract the Inhibitory Effect of Zoledronate on RANKL-Dependent Osteoclastogenesis

Bisphosphonates (BPs) are drugs used to cure metabolic diseases like osteoporosis and oncological conditions, such as multiple myeloma and bone metastases. The pharmacological activity of these compounds is mediated by their capacity to induce a systemic osteoclast depletion, finally resulting in reduced bone resorption. In spite of their efficacy, the clinical application of BPs is sometimes associated with a frightening side effect known as osteonecrosis of the jaw (ONJ). In principle, a therapeutic approach able to elicit the local re-activation of osteoclast production could counteract the onset of ONJ and promote the healing of its lesions. Using a vitamin D3-dependent model of osteoclast differentiation, it has been previously demonstrated that when used at supra-physiological concentrations, magnesium strongly favors the process under consideration, and its effect is furtherly enhanced by the presence of a BP called zoledronate. Here, we show that similar results can be obtained in a RANKL-dependent model of osteoclast differentiation, suggesting that a topical therapy based on magnesium may be also suitable for ONJ determined by denosumab in light of the ability of this monoclonal antibody to target RANKL.

Surgical and conservative treatment outcomes of medication-related osteonecrosis of the jaw located at tori: a retrospective study

PURPOSE

Tori and exostoses are considered risk factors for the development of medication-related osteonecrosis of the jaw (MRONJ). The aims of this study were to present the prevalence of MRONJ located at tori in the Copenhagen ONJ Cohort, evaluate the surgical treatment of MRONJ located at tori and explore trauma to tori as an additional risk factor in patients on antiresorptive medication.

METHODS

Data from a consecutive series of 506 patients with MRONJ (Copenhagen ONJ Cohort) were reviewed for the presence of tori and MRONJ located at tori. Demographic and medical data were analyzed, and healing outcomes and pain after the prophylactic removal of tori, surgical treatment of MRONJ located at tori, and conservative treatment of MRONJ located at tori were evaluated and compared using Fisher's exact test.

RESULTS

MRONJ located at tori was frequent and could be identified in 53% of the patients with tori, which accounts for a prevalence of 5.1% in the entire cohort. Of the 28 surgically treated patients, 27 (96.4%) healed uneventfully with no exposed bone after their first or second revision surgery. Fourteen (41.2%) patients with tori underwent therapeutic removal, eight (23.5%) underwent prophylactic removal, and six (17.6%) underwent both therapeutic and prophylactic removals. Two (33.3%) of the six conservatively treated patients healed spontaneously. Both treatment types resulted in a significant decrease in pain.

CONCLUSION

Prophylactic and therapeutic surgical removal of tori are reliable treatments and should be considered if a patient's general health allows surgery.

TRIAL REGISTRATION

The study was approved by the Regional Scientific Ethical Committee (H-6-2013-010) on November 20, 2013, and was retrospectively registered.

Balancing the Scales: The Dual Role of Interleukins in Bone Metastatic Microenvironments

Bone metastases, a common and debilitating consequence of advanced cancers, involve a complex interplay between malignant cells and the bone microenvironment. Central to this interaction are interleukins (ILs), a group of cytokines with critical roles in immune modulation and inflammation. This review explores the dualistic nature of pro-inflammatory and anti-inflammatory interleukins in bone metastases, emphasizing their molecular mechanisms, pathological impacts, and therapeutic potential. Pro-inflammatory interleukins, such as IL-1, IL-6, and IL-8, have been identified as key drivers in promoting osteoclastogenesis, tumor proliferation, and angiogenesis. These cytokines create a favorable environment for cancer cell survival and bone degradation, contributing to the progression of metastatic lesions. Conversely, anti-inflammatory interleukins, including IL-4, IL-10, and IL-13, exhibit protective roles by modulating immune responses and inhibiting osteoclast activity. Understanding these opposing effects is crucial for developing targeted therapies aimed at disrupting the pathological processes in bone metastases. Key signaling pathways, including NF-κB, JAK/STAT, and MAPK, mediate the actions of these interleukins, influencing tumor cell survival, immune cell recruitment, and bone remodeling. Targeting these pathways presents promising therapeutic avenues. Current treatment strategies, such as the use of denosumab, tocilizumab, and emerging agents like bimekizumab and ANV419, highlight the potential of interleukin-targeted therapies in mitigating bone metastases. However, challenges such as therapeutic resistance, side effects, and long-term efficacy remain significant hurdles. This review also addresses the potential of interleukins as diagnostic and prognostic biomarkers, offering insights into patient stratification and personalized treatment approaches. Interleukins have multifaceted roles that depend on the context, including the environment, cell types, and cellular interactions. Despite substantial progress, gaps in research persist, particularly regarding the precise mechanisms by which interleukins influence the bone metastatic niche and their broader clinical implications. While not exhaustive, this overview underscores the critical roles of interleukins in bone metastases and highlights the need for continued research to fully elucidate their complex interactions and therapeutic potential. Addressing these gaps will be essential for advancing our understanding and treatment of bone metastases in cancer patients.

Nuclear Factor-Kappa B Regulation of Osteoclastogenesis and Osteoblastogenesis

Maintenance of skeletal integrity requires the coordinated activity of multinucleated bone-resorbing osteoclasts and bone-forming osteoblasts. Osteoclasts form resorption lacunae on bone surfaces in response to cytokines by fusion of precursor cells. Osteoblasts are derived from mesenchymal precursors and lay down new bone in resorption lacunae during bone remodeling. Nuclear factorkappa B (NF-κB) signaling regulates osteoclast and osteoblast formation and is activated in osteoclast precursors in response to the essential osteoclastogenic cytokine, receptor activator of NF-κB ligand (RANKL), which can also control osteoblast formation through RANK-RANKL reverse signaling in osteoblast precursors. RANKL and some pro-inflammatory cytokines, including tumor necrosis factor (TNF), activate NF-κB signaling to positively regulate osteoclast formation and functions. However, these cytokines also limit osteoclast and osteoblast formation through NF-κB signaling molecules, including TNF receptor-associated factors (TRAFs). TRAF6 mediates RANKL-induced osteoclast formation through canonical NF-κB signaling. In contrast, TRAF3 limits RANKL- and TNF-induced osteoclast formation, and it restricts transforming growth factor β (TGFβ)-induced inhibition of osteoblast formation in young and adult mice. During aging, neutrophils expressing TGFβ and C-C chemokine receptor type 5 (CCR5) increase in bone marrow of mice in response to increased NF-κB-induced CC motif chemokine ligand 5 (CCL5) expression by mesenchymal progenitor cells and injection of these neutrophils into young mice decreased bone mass. TGFβ causes degradation of TRAF3, resulting in decreased glycogen synthase kinase-3β/β-catenin-mediated osteoblast formation and age-related osteoporosis in mice. The CCR5 inhibitor, maraviroc, prevented accumulation of TGFβ+/CCR5+ neutrophils in bone marrow and increased bone mass by inhibiting bone resorption and increasing bone formation in aged mice. This paper updates current understanding of how NF-κB signaling is involved in the positive and negative regulation of cytokine-mediated osteoclast and osteoblast formation and activation with a focus on the role of TRAF3 signaling, which can be targeted therapeutically to enhance bone mass.

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.

Denosumab for Effective Tumor Size Reduction in Patients With Giant Cell Tumors of the Bone: A Systematic Review and Meta-Analysis

BACKGROUND

Denosumab is a human monoclonal antibody that has been used successfully in the treatment of giant cell tumors of bone. These tumors are rare and, in principle, benign, but they are highly aggressive, locally advanced, osteolytic bone tumors that can metastasize to the lungs. Denosumab is an effective treatment when these tumors cannot be surgically removed or when surgical resection is likely to lead to severe morbidity (eg, loss of limbs or joints). The aim of this systematic review and meta-analysis was to investigate patients with giant cell tumors of bone who experienced tumor progression during treatment with denosumab and to compare them with patients who experienced reduction of their giant cell tumors of bone during treatment with denosumab.

METHODS

Embase, Cochrane Library, and MEDLINE/PubMed databases were searched for trials submitted by January 7, 2020, that reported the efficacy and safety of denosumab in patients with giant cell tumors of bone.

RESULTS

Sixty studies were reviewed, involving a total of 1074 patients who had giant cell tumors of bone and were treated with denosumab. Of the 60 studies, 58% of the patients were from case series studies, 39% from open-label phase II studies, and 3% from case reports. The response rate for denosumab as a treatment for giant cell tumors of bone was 97.5%, with statistical significance (P < .0001). Pain in the limbs was statistically the most common adverse event for denosumab treatment in case series studies (P < .0001). No treatment-related deaths occurred in the reviewed studies.

CONCLUSION

Cumulative evidence supports the addition of surgery to optimal medical therapy with denosumab to reduce tumor size, clinical symptoms, and mortality among patients with giant cell tumors of bone.

The Efficacy of Denosumab in the Management of a Tibial Paediatric Aneurysmal Bone Cyst Compromised by Rebound Hypercalcaemia

Surgery is the main treatment option for patients with aneurysmal bone cyst (ABC). We report our experience of using denosumab as an alternative treatment in a child with a multiply recurrent and unresectable tibial ABC. The efficacy and safety of denosumab in the paediatric population, and in the treatment of ABC, are still to be fully evaluated. We describe a 13-year-old boy with an extensive and aggressive ABC involving the proximal tibia, which had recurred following multiple previous surgeries. The patient had ongoing severe pain, was unable to weight-bear, and was at significant risk of pathological fracture. En bloc resection and embolization were not deemed viable, and a decision to use denosumab was made. He received 17 doses of subcutaneous denosumab (70 mg/m²) over a 27-month period, at increasing dose intervals. His symptoms significantly improved, and bony consolidation was observed within six months of treatment. He was able to walk without protection and fully weight-bear without any pain by 18 months. With an increase to a six-month dosing interval, the patient presented with a severe, symptomatic rebound hypercalcaemia requiring bisphosphonate therapy. This reoccurred on two further occasions. This case adds to the evidence that denosumab is effective in the treatment of ABC in paediatric patients, but there is a risk of rebound hypercalcaemia. Therefore, patient awareness and biochemical monitoring for rebound hypercalcaemia are essential.

High Concentrations of Polyelectrolyte Complex Nanoparticles Decrease Activity of Osteoclasts

Fracture treatment in osteoporotic patients is still challenging. Osteoporosis emerges when there is an imbalance between bone formation and resorption in favor of resorption by osteoclasts. Thus, new implant materials for osteoporotic fracture treatment should promote bone formation and reduce bone resorption. Nanoparticles can serve as drug delivery systems for growth factors like Brain-Derived Neurotrophic Factor (BDNF), which stimulated osteoblast differentiation. Therefore, polyelectrolyte complex nanoparticles (PEC-NPs) consisting of poly(l-lysine) (PLL) and cellulose sulfate (CS), with or without addition of BDNF, were used to analyze their effect on osteoclasts in vitro. Live cell images showed that osteoclast numbers decreased after application of high PLL/CS PEC-NPs concentrations independent of whether BDNF was added or not. Real-time RT-PCR revealed that relative mRNA expression of cathepsin K and calcitonin receptor significantly declined after incubation of osteoclasts with high concentrations of PLL/CS PEC-NPs. Furthermore, Enzyme-Linked Immunosorbent Assay indicated that tartrate-resistant acidic phosphatase 5b activity was significantly reduced in the presence of high PLL/CS PEC-NPs concentrations. Consistent with these results, the pit formation analysis showed that less hydroxyapatite was resorbed by osteoclasts after incubation with high concentrations of PLL/CS PEC-NPs. BDNF had no influence on osteoclasts. We conclude that highly concentrated PLL/CS PEC-NPs dosages decreased osteoclastogenesis and osteoclasts activity. Moreover, BDNF might be a promising growth factor for osteoporotic fracture treatment since it did not increase osteoclast activity.

Molecular-Based Treatment Strategies for Osteoporosis: A Literature Review

Osteoporosis is an unavoidable public health problem in an aging or aged society. Anti-resorptive agents (calcitonin, estrogen, and selective estrogen-receptor modulators, bisphosphonates, anti-receptor activator of nuclear factor κB ligand antibody along with calcium and vitamin D supplementations) and anabolic agents (parathyroid hormone and related peptide analogs, sclerostin inhibitors) have major roles in current treatment regimens and are used alone or in combination based on the pathological condition. Recent advancements in the molecular understanding of bone metabolism and in bioengineering will open the door to future treatment paradigms for osteoporosis, including antibody agents, stem cells, and gene therapies. This review provides an overview of the molecular mechanisms, clinical evidence, and potential adverse effects of drugs that are currently used or under development for the treatment of osteoporosis to aid clinicians in deciding how to select the best treatment option.

Monoclonal Antibodies for the Treatment of Multiple Myeloma: An Update

The past two decades have seen a revolution in multiple myeloma (MM) therapy with the introduction of several small molecules, mostly orally effective, whose mechanisms are based on proteasome inhibition, histone deacetylase (HDAC) blockade, and immunomodulation. Immunotherapeutic approaches to MM treatment using monoclonal antibodies (mAbs), while long in development, began to reap success with the identification of CD38 and SLAMF7 as suitable targets for development, culminating in the 2015 Food and Drug Administration (FDA) approval of daratumumab and elotuzumab, respectively. This review highlights additional mAbs now in the developmental pipeline. Isatuximab, another anti-CD38 mAb, currently is under study in four phase III trials and may offer certain advantages over daratumumab. Several antibody-drug conjugates (ADCs) in the early stages of development are described, including JNJ-63723283, which has attained FDA breakthrough status for MM. Other mAbs described in this review include denosumab, recently approved for myeloma-associated bone loss, and checkpoint inhibitors, although the future status of the latter combined with immunomodulators has been clouded by unacceptably high death rates that caused the FDA to issue clinical holds on several of these trials. Also highlighted are the therapies based on the B Cell Maturation Antigen (BCMA), another very promising target for anti-myeloma development.

Medication-related osteonecrosis of the jaw: definition and best practice for prevention, diagnosis, and treatment

Skeletal complications caused by osteoporosis or bone metastases are associated with considerable pain, increased mortality, and reduced quality of life. Furthermore, such events place a burden on health care resources. Agents that prevent bone resorption, such as bisphosphonates or denosumab, can reduce the risk of skeletal-related events and are widely used in patients with osteoporosis or bone metastases of cancer. Medication-related osteonecrosis of the jaw (MRONJ) is a rare, but potentially serious, adverse event associated with high cumulative doses of bisphosphonates or denosumab. However, MRONJ can be treated, and the likelihood of the development of this condition can be reduced through prophylactic dental care and the maintenance of good oral hygiene. Dentists, as part of a multiprofessional team, have a critical role in preventing MRONJ. This review describes the incidence and pathophysiology of MRONJ and provides guidance for dental practitioners with regard to the screening, prophylactic treatment, diagnosis, and management of patients with this condition.

Denosumab in patients with aneurysmal bone cysts: A case series with preliminary results

Purpose:

Aneurysmal bone cyst (ABC) is a rare skeletal tumor usually treated with surgery/embolization. We hypothesized that owing to similarities with giant cell tumor of bone (GCTB), denosumab was active also in ABC.

Methods:

In this observational study, a retrospective analysis of ABC patients treated with denosumab was performed. Patients underwent radiologic disease assessment every 3 months. Symptoms and adverse events were noted.

Results:

Nine patients were identified (6 male, 3 female), with a median age of 17 years (range 14–42 years). Primary sites were 6 spine–pelvis, 1 ulna, 1 tibia, and 1 humerus. Patients were followed for a median time of 23 months (range 3–55 months). Patients received a median of 8 denosumab administrations (range 3–61). All symptomatic patients had pain relief and 1 had paresthesia improvement. Signs of denosumab activity were observed after 3 to 6 months of administration: bone formation by computed tomography scan was demonstrated in all patients and magnetic resonance imaging gadolinium contrast media decrease was observed in 7/9 patients. Adverse events were negligible. At last follow-up, all patients were progression-free: 5 still on denosumab treatment, 2 off denosumab were disease-free 11 and 17 months after surgery, and the last 2 patients reported no progression 12 and 24 months after denosumab interruption and no surgery.

Conclusions:

Denosumab has substantial activity in ABCs, with favorable toxicity profile. We strongly support the use of surgery and/or embolization for the treatment of ABC, but denosumab could have a role as a therapeutic option in patients with uncontrollable, locally destructive, or recurrent disease.

Medication-related osteonecrosis of the jaw: Prevention, diagnosis and management in patients with cancer and bone metastases

Medication-related osteonecrosis of the jaw (MRONJ) is primarily an adverse side effect of denosumab or bisphosphonates (particularly when used at high doses to prevent skeletal-related events [SREs] in patients with cancer and bone metastases) or possibly anti-angiogenic cancer treatment. While the implementation of preventive measures over recent years has reduced the risk of MRONJ in patients with bone metastases due to cancer, it is imperative to balance the risk of MRONJ against the beneficial effects of treatment with denosumab or bisphosphonates on the skeletal health of patients. Despite growing awareness of MRONJ within the medical community, there is a lack of large-scale, prospective clinical studies in this rapidly evolving field. Discussing preventive measures with patients and implementing them, both before and during treatment with bisphosphonates or denosumab, is the best option to reduce the risk of MRONJ. In particular, avoiding bone trauma and preventing and treating dental infections before and during denosumab or bisphosphonate therapy is crucial to minimize the risk of MRONJ. If MRONJ develops, conservative (non-surgical) treatment can provide symptom relief, but achieving mucosal closure remains challenging. When management of symptoms and mucosal healing are the ultimate goals of therapy, or after failure of conservative treatment, a surgical approach may be beneficial. This critical review, based on a best-evidence review of currently available literature, provides clear practical guidelines to help to prevent, manage and treat MRONJ. Overall, a multidisciplinary, pragmatic approach to MRONJ should be adopted, prioritizing patient's quality of life and management of their skeletal malignant disease.

New Strategies Using Antibody Combinations to Increase Cancer Treatment Effectiveness

Antibodies have proven their high value in antitumor therapy over the last two decades. They are currently being used as the first-choice to treat some of the most frequent metastatic cancers, like HER2⁺ breast cancers or colorectal cancers, currently treated with trastuzumab (Herceptin) and bevacizumab (Avastin), respectively. The impressive therapeutic success of antibodies inhibiting immune checkpoints has extended the use of therapeutic antibodies to previously unanticipated tumor types. These anti-immune checkpoint antibodies allowed the cure of patients devoid of other therapeutic options, through the recovery of the patient’s own immune response against the tumor. In this review, we describe how the antibody-based therapies will evolve, including the use of antibodies in combinations, their main characteristics, advantages, and how they could contribute to significantly increase the chances of success in cancer therapy. Indeed, novel combinations will consist of mixtures of antibodies against either different epitopes of the same molecule or different targets on the same tumor cell; bispecific or multispecific antibodies able of simultaneously binding tumor cells, immune cells or extracellular molecules; immunomodulatory antibodies; antibody-based molecules, including fusion proteins between a ligand or a receptor domain and the IgG Fab or Fc fragments; autologous or heterologous cells; and different formats of vaccines. Through complementary mechanisms of action, these combinations could contribute to elude the current limitations of a single antibody which recognizes only one particular epitope. These combinations may allow the simultaneous attack of the cancer cells by using the help of the own immune cells and exerting wider therapeutic effects, based on a more specific, fast, and robust response, trying to mimic the action of the immune system.

Macrophages and skeletal health

Bone is in a constant state of remodeling, a process which was once attributed solely to osteoblasts and osteoclasts. Decades of research has identified many other populations of cells in the bone that participate and mediate skeletal homeostasis. Recently, osteal macrophages emerged as vital participants in skeletal remodeling and osseous repair. The exact mechanistic roles of these tissue-resident macrophages are currently under investigation. Macrophages are highly plastic in response to their micro-environment and are typically classified as being pro- or anti-inflammatory (pro-resolving) in nature. Given that inflammatory states result in decreased bone mass, proinflammatory macrophages may be negative regulators of bone turnover. Pro-resolving macrophages have been shown to release anabolic factors and may present a target for therapeutic intervention in inflammation-induced bone loss and fracture healing. The process of apoptotic cell clearance, termed efferocytosis, is mediated by pro-resolving macrophages and may contribute to steady-state bone turnover as well as fracture healing and anabolic effects of osteoporosis therapies. Parathyroid hormone is an anabolic agent in bone that is more effective in the presence of mature phagocytic macrophages, further supporting the hypothesis that efferocytic macrophages are positive contributors to bone turnover. Therapies which alter macrophage plasticity in tissues other than bone should be explored for their potential to treat bone loss either alone or in conjunction with current bone therapeutics. A better understanding of the exact mechanisms by which macrophages mediate bone homeostasis will lead to an expansion of pharmacologic targets for the treatment of osteoporosis and inflammation-induced bone loss.

Medication-related osteonecrosis of the jaws caused lethal sepsis in an edentulous patient with multiple systemic factors

Medication‐related osteonecrosis of the jaw (MRONJ) is developed even in the patients who are edentulous and treated with short‐term bisphosphonate therapy and oral administration. It sometimes causes lethal sepsis in patients who have multiple health problems such as diabetes, cirrhosis, steroid use for interstitial pneumonia, sepsis, and spinal disk herniation.

Therapeutic monoclonal antibodies and derivatives: Historical perspectives and future directions

Biologics, both monoclonal antibodies (mAbs) and fusion proteins, have revolutionized the practice of medicine. This year marks the 30th anniversary of the Food and Drug Administration approval of the first mAb for human use. In this review, we examine the biotechnological breakthroughs that spurred the explosive development of the biopharmaceutical mAb industry, as well as how critical lessons learned about human immunology informed the development of improved biologics. We also discuss the most common mechanisms of action of currently approved biologics and the indications for which they have been approved to date.

Interest of Denosumab for the Treatment of Giant-cells Tumors and Aneurysmal Bone Cysts of the Spine. About Nine Cases

STUDY DESIGN

A prospective cohort study.

OBJECTIVE

The aim of this study was to evaluate the interest of denosumab in the treatment of spinal giant-cells tumors (GCTs) and aneurysmal bone cysts (ABCs).

SUMMARY OF BACKGROUND DATA

To treat GCTs and ABCs, surgical resection remains the best treatment to limit local recurrence (LR) but constitutes an aggressive treatment with potential morbidity. Denosumab, a human antibody anti-RankL, inhibiting the differentiation of osteoclasts, could be an alternative treatment to avoid aggressive surgery.

METHODS

Patients suffering from GCTs and ABCs of the spine were included. Patients received a monthly subcutaneous injection of denosumab (120 mg) during a minimum of 6 months either as a neoadjuvant or as an adjuvant therapy. In association with denosumab, an osteosynthesis was added in case of vertebral fracture and a laminectomy in case of spinal cord compression. Clinical and computed tomography (CT)-scan outcomes were analyzed.

RESULTS

Eight GCTs and one ABC were included. The mean age was 35 years (range: 22-55 yr). Five patients had neurologic deficit. All patients were operated: six osteosynthesis, one "en bloc" resection, four curettages, and two of them associated with an osteosynthesis. Average duration of denosumab therapy was 12.9 months (range: 3.2-24 months). Among them, four patients began denosumab 6 months at least before the surgery. With a mean follow-up of 19.3 months (range: 3.2-52.4 months), back pain and neurologic deficit improved for all patients. Systematic CT-scan at 6 months showed decrease of tumor size and bone consolidation. Regarding patients treated by neoadjuvant denosumab treatment, intraoperative histologic analysis showed an absence of giant cells and a maximum of 10% of alive tumor cells.

CONCLUSION

Denosumab allows bone formation and tumor regression with a maximum efficacy after 6 months of treatment without widely substituting surgery. Long-term results are mandatory to confirm the interest of denosumab and to evaluate LR when stopping denosumab.

LEVEL OF EVIDENCE

3.

Transcriptional regulation of the human TNFSF11 gene in T cells via a cell type-selective set of distal enhancers

In addition to osteoblast lineage cells, the TNF-like factor receptor activator of NF-κB ligand (RANKL) is expressed in both B and T cells and may play a role in bone resorption. Rankl gene (Tnfsf11) expression in mouse T cells is mediated through multiple distal elements marked by increased transcription factor occupancy, histone tail acetylation, and RNA polymerase II recruitment. Little is known, however, of the regulation of human TNFSF11 in T cells. Accordingly, we examined the consequence of T cell activation on the expression of this factor both in Jurkat cells and in primary human T cells. We then explored the mechanism of this regulation by scanning over 400 kb of DNA surrounding the TNFSF11 locus for regulatory enhancers using ChIP-chip analysis. Histone H3/H4 acetylation enrichment identified putative regulatory regions located between -170 and -220 kb upstream of the human TNFSF11 TSS that we designated the human T cell control region (hTCCR). This region showed high sequence conservation with the mouse TCCR. Inhibition of MEK1/2 by U0126 resulted in decreased RANKL expression suggesting that stimulation through MEK1/2 was a prerequisite. ChIP-chip analysis also revealed that c-FOS was recruited to the hTCCR as well. Importantly, both the human TNFSF11 D5a/b (RLD5a/b) enhancer and segments of the hTCCR mediated robust inducible reporter activity following TCR activation. Finally, SNPs implicated in diseases characterized by dysregulated BMD co-localized to the hTCCR region. We conclude that the hTCCR region contains a cell-selective set of enhancers that plays an integral role in the transcriptional regulation of the TNFSF11 gene in human T cells.

The emerging role of denosumab in the long-term management of parathyroid carcinoma-related refractory hypercalcemia

OBJECTIVE

The main cause of death in patients with parathyroid carcinoma is parathyroid hormone (PTH)-induced hypercalcemia. To date, the management of hypercalcemia has been based on the use of bisphosphonates and calcimimetic agents. In recent reports, the use of denosumab has shown encouraging results in cases of refractory hypercalcemia of malignancy. Our objective is to present a case of successful management of resistant hypercalcemia due to parathyroid carcinoma with denosumab, to review similar cases from the literature, and to propose denosumab's use in the clinical management of PTH-induced refractory hypercalcemia.

METHODS

Presentation of a case report and review of the literature for cases of parathyroid carcinoma-mediated hypercalcemia successfully treated with denosumab.

RESULTS

A 71-year-old man with metastatic parathyroid carcinoma was referred to our department for uncontrolled hypercalcemia, resistant to treatment with bisphosphonates and cinacalcet. Treatment with denosumab (120 mg per month) in addition to cinacalcet (180 mg per day) resulted in normalization of calcium levels and maintenance within the normal range for an observation period of 11 months. Review of the literature revealed 4 case reports and a letter to the editor, all of which reported the successful treatment of resistant hypercalcemia associated with parathyroid carcinoma.

CONCLUSION

Based on the above findings of the effectiveness of denosumab in controlling refractory hypercalcemia, its safety in renal failure and the fact that denosumab may reduce PTH-induced bone loss, we endorse its use in the management of hypercalcemia in patients with parathyroid carcinoma and perhaps other conditions with PTH-induced hypercalcemia.

RANK pathway in giant cell tumor of bone: pathogenesis and therapeutic aspects

Giant cell tumor is a relatively uncommon but painful tumor of bone, which can metastasize to the lungs. The RANK pathway is often reported to be involved in the pathogenesis of giant cell tumor of bone (GCTB). This pathway is a key signaling pathway of bone remodeling that plays a critical role in differentiation of precursors into multinucleated osteoclasts, and activation of osteoclasts leading to bone resorption. Dysregulation of RANK ligand (RANKL)-RANK-osteoprotegerin (OPG) signaling cascade induces the imbalance between bone formation and bone resorption, which leads to the changes in bone mass, increases osteoclast-mediated bone destruction, bone metastasis, and the progression of existing skeletal tumors. Recent evidences have shown that targeting the components of RANKL-RANK-OPG signaling pathway is a promising approach in the treatment of GCTB. This review study has focused on the association of RANKL-RANK-OPG pathway in the pathogenesis and progression of GCTB as well as discussed the possible therapeutic strategies by targeting this pathway.

Bilateral atypical femoral fractures in a patient prescribed denosumab - a case report

Atypical fractures of the diaphyseal femoral shaft have been reported in the literature at an increasing rate over the past few years. They have been observed mostly in patients who have been on prolonged courses of bisphosphonates, with no reported cases of atypical femoral fractures in those treated with other anti-resorptive medications. A 59 year old woman sustained an atypical fracture of her right femur in March 2013. She had a past medical history of rheumatoid arthritis and osteoporosis. She had been on alendronate but it was discontinued after five years in 1999. She received denosumab by subcutaneous injection in December 2012. At follow up, she complained of pain in her left femur and a radiograph revealed atypical appearances. She was admitted in June 2013 for prophylactic nailing of the left femur. To our knowledge, this is the first reported case of bilateral atypical femoral changes in a patient prescribed denosumab. Given that denosumab has been on the market for a short time period, we expect that the number of these cases will increase with time. We emphasise previous guidance that patients who present with new onset hip or thigh pain should be screened for atypical femoral fractures.

Proline/arginine-rich end leucine-rich repeat protein N-terminus is a novel osteoclast antagonist that counteracts bone loss

(hbd) PRELP is a peptide corresponding to the N-terminal heparin binding domain of the matrix protein proline/arginine-rich end leucine-rich repeat protein (PRELP). (hbd) PRELP inhibits osteoclastogenesis entering pre-fusion osteoclasts through a chondroitin sulfate- and annexin 2-dependent mechanism and reducing the nuclear factor-κB transcription factor activity. In this work, we hypothesized that (hbd) PRELP could have a pharmacological relevance, counteracting bone loss in a variety of in vivo models of bone diseases induced by exacerbated osteoclast activity. In healthy mice, we demonstrated that the peptide targeted the bone and increased trabecular bone mass over basal level. In mice treated with retinoic acid to induce an acute increase of osteoclast formation, the peptide consistently antagonized osteoclastogenesis and prevented the increase of the serum levels of the osteoclast-specific marker tartrate-resistant acid phosphatase. In ovariectomized mice, in which osteoclast activity was chronically enhanced by estrogen deficiency, (hbd) PRELP counteracted exacerbated osteoclast activity and bone loss. In mice carrying osteolytic bone metastases, in which osteoclastogenesis and bone resorption were enhanced by tumor cell-derived factors, (hbd) PRELP reduced the incidence of osteolytic lesions, both preventively and curatively, with mechanisms involving impaired tumor cell homing to bone and tumor growth in the bone microenvironment. Interestingly, in tumor-bearing mice, (hbd) PRELP also inhibited breast tumor growth in orthotopic sites and development of metastatic disease in visceral organs, reducing cachexia and improving survival especially when administered preventively. (hbd) PRELP was retained in the tumor tissue and appeared to affect tumor growth by interacting with the microenvironment rather than by directly affecting the tumor cells. Because safety studies and high-dose treatments revealed no adverse effects, (hbd) PRELP could be employed as a novel biological agent to combat experimentally induced bone loss and breast cancer metastases, with a potential translational impact.

The role of palliative external beam radiation therapy in boney metastases pain management

Bone is the third most common organ affected by neoplastic metastases, and about 70% of patients with breast cancer or prostate cancer that develop metastases will have osseous involvement. As part of a multi-pronged approach to pain management in these patients, external beam radio therapy (EBRT) continues to be a mainstay of treatment for metastatic bone pain. This article reviews the role of radiation therapy in palliative management strategies for patients with bone metastases, including the clinical and cost-effectiveness of single fraction (SFRT) versus multiple fraction (MFRT) EBRT in pain relief. Studies indicate that SFRT is more cost-effective than MFRT, yet both are clinically effective in pain management. Therefore, EBRT use retains an important place among analgesia, bone modifying agents, chemotherapy, and hormone therapy in improving quality of life (QoL) and reducing morbidity from metastatic bone pain.

Concordance of preclinical and clinical pharmacology and toxicology of monoclonal antibodies and fusion proteins: soluble targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards soluble targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 14 currently approved mAbs and fusion proteins targeted to soluble targets. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions' and United States Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the following approved biopharmaceuticals were included: adalimumab, anakinra, bevacizumab, canakinumab, certolizumab pegol, denosumab, eculizumab, etanercept, golimumab, infliximab, omalizumab, ranibizumab, rilonacept and ustekinumab. Some related biopharmaceuticals in late-stage development were also included for comparison. Good concordance with human pharmacodynamics was found for both non-human primates (NHPs) receiving the human biopharmaceutical and mice receiving rodent homologues (surrogates). In contrast, there was limited concordance for human adverse effects in genetically deficient mice, mice receiving surrogates or NHPs receiving the human pharmaceutical. In summary, the results of this survey show that although both mice and NHPs have good predictive value for human pharmacodynamics, neither species have good predictive value for human adverse effects. No evidence that NHPs have superior predictive value was found.

Denosumab for the treatment of osteoporosis: a systematic literature review

PURPOSE

To determine the efficacy and safety of denosumab in osteoporosis.

METHODS

A systematic search was performed in MEDLINE, EMBASE, and The Cochrane Central Register of Controlled Trials (1950 to July 2010), meeting abstracts (2009-2010), trial registries, and reference lists. The selection criteria were as follows: (population) osteoporosis patients of any age; (intervention) treatment with denosumab; (outcome) efficacy and safety; (study design) randomized clinical trials (RCTs); no language restrictions. Two reviewers independently screened titles and abstracts and subsequently extracted data from the selected studies including quality items, and on outcomes of interest. A meta-analysis was performed for safety issues.

RESULTS

A total of 25 studies were included. Denosumab reduces the risk of new radiographic vertebral fracture in a 68% compared with placebo (p<0.001) and increases bone mineral density (BMD) at lumbar spine, total hip, and one-third radius more than alendronate and placebo. A single subcutaneous dose of denosumab resulted in a dose-dependent, rapid, profound, and sustained decrease bone turnover markers (BTMs). Denosumab was in general well tolerated. A meta-analysis has shown an increase in the incidence of urinary infections (p=0.012) and eczema (p<0.001) in the patients treated with denosumab. Meta-analysis of efficacy was complicated due to the study features.

CONCLUSIONS

Denosumab given subcutaneously twice yearly is associated with a reduction in the risk of vertebral, nonvertebral, and hip fractures in women with osteoporosis. Denosumab is associated with greater and sustained increases in BMD and reductions in BTMs compared with placebo and/or alendronate and with a risk of urinary infections and eczema.

Denosumab, a RANK ligand inhibitor, for postmenopausal women with osteoporosis

OBJECTIVE

To review the evidence for use of denosumab for the treatment of postmenopausal osteoporosis.

DATA SOURCES

A search of MEDLINE and EMBASE databases was conducted during January 2012, using the terms denosumab and osteoporosis, with index dates of 2000 to 2011. Additional information was gathered from Amgen and references cited in articles retrieved.

STUDY SELECTION AND DATA EXTRACTION

English-language articles including clinical trials involving denosumab for treatment of osteoporosis and review articles were reviewed. Articles using denosumab in males or as treatment for conditions other than osteoporosis or osteopenia were excluded.

DATA SYNTHESIS

Many clinical trials have supported the safety and efficacy of denosumab in postmenopausal women with bone loss. It has been shown to improve bone mineral density, decrease markers of bone turnover, and prevent new vertebral fractures. It shows improvement over placebo in studies and has at least similar efficacy to alendronate in measurements of bone mineral density, with less risk for osteonecrosis of the jaw and atypical fracture, but with an increased risk of infections and neoplasms. European cost-effectiveness studies have also demonstrated that denosumab is a cost-effective choice compared to risedronate and no treatment for fracture prevention for postmenopausal women with osteoporosis.

CONCLUSIONS

Denosumab has demonstrated efficacy and safety as a first-line treatment for postmenopausal osteoporosis in multiple clinical trials over at least 6 years. It may be most cost-effective for women who are unable or refuse to take bisphosphonate drugs.

Comparison of clinical efficacy and safety between denosumab and alendronate in postmenopausal women with osteoporosis: a meta-analysis

The aim of this study was to perform a head-to-head comparison of efficacy and safety profile between 60 mg denosumab (Den) subcutaneously (SC) per 6 months (Q6M) and 70 mg alendronate (Aln) orally per week (QW) for postmenopausal women with low bone mineral density. We searched electronic databases comparing efficacy and safety of Den SC Q6M and Aln QW in postmenopausal women. The primary outcomes of efficacy evaluation in included trials were incidence of clinical fracture in both groups and bone mineral density (BMD) at different skeletal sites. And adverse events (AEs), including incidence of neoplasms and infections, were considered as secondary outcomes. Following the instructions of 'Cochrane Handbook for systematic Reviews of Interventions 5.0.2', we identified eligible studies, evaluated the methodological quality and abstracted relevant data. Four heterogeneous randomised controlled trials (RCTs) involving 1942 women were identified. The results of review showed low evidence quality that supported the hypothesis the denosumab vs. alendronate could reduce risk of fracture [OR (95% CI) 1.42 (0.84 to 2.40), 11 more women per 1000 (from 4 fewer to 36 more), p = 0.19] but the moderate to high quality evidence suggesting treatment with 60 mg Den SC Q6M was more effective for postmenopausal women in increasing BMD [at distal radius (DR), total hip (TH), lumbar spine (LS), and femoral neck (FN)]. Hazards of neoplasms [OR (95% CI) 1.10 (0.65 to 1.86), 3 more per 1000 (from 10 fewer to 24 more), p = 0.62] or infections [OR (95% CI) 0.95 (0.79 to 1.15), 12 fewer per 1000 (from 53 fewer to 33 more,), p = 0.62] were appeared to be similar.Our review suggested within 1 year 60 mg Den SC Q6M treatment was more effective in increasing bone mass but could not reduce the fracture risk to a greater extent than 70 mg Aln QW therapy. Also the Den SC Q6M therapy did not increase the risks of neoplasms and infections compared with Aln QW.

Osteoporosis related to disease or therapy in patients with cancer

Osteoporosis is a major public health issue in the general population, particularly in postmenopausal women. Patients with cancer may not only be at risk for primary osteoporosis, but for secondary osteoporosis related to cancer therapies-particularly therapies that impair gonadal function, lead to loss of serum estrogen, and negatively affect bone turnover. Normal bone remodeling is influenced by the receptor activator for nuclear kappa-B ligand pathway, calcium, vitamin D, and other nutrition factors, as well as modifiable and nonmodifiable factors. Identifying which patients with cancer are at risk for bone mineral density loss is important and may include patients with breast or prostate cancer, some survivors of pediatric malignancies, and adults with other tumors. Nurses play a major role in identifying those patients and their risk for low-impact fractures, which can have a significant effect on patient morbidity and mortality. Counseling and teaching are central nursing functions, as well as safely administering therapies, particularly bisphosphonates and denosumab.

Denosumab and the current status of bone-modifying drugs in breast cancer

BACKGROUND

Bone-modifying therapy is a primary research interest in breast cancer. Several features contribute to the importance of the bone environment in the management of breast cancer. Firstly, bone metastases represent the most common site of breast cancer metastases and secondly, the emergence of cancer treatment-induced bone loss (CTIBL) among breast cancer survivors and patients is of increasing concern. Furthermore, concordant with the "seed and soil" theory, agents that alter the bone microenvironment may even prevent tumor cell seeding in bone and limit cancer growth.

MATERIAL AND METHODS

Medical databases and conference proceedings were searched to identify articles, abstracts and clinical trials that have or are investigating denosumab and bisphosphonates in cancer therapy. Our search included a predefined focus on bone-modifying therapies in early and advanced breast cancer.

RESULTS AND DISCUSSION

Bisphosphonates (BPs) have an established role both in the prevention and treatment of CTIBL and have been studied in the adjuvant setting for early breast cancer (EBC). Denosumab is a monoclonal antibody directed against RANK ligand and thereby inhibits osteoclastogenesis and bone resportion. It is the newest agent approved for the treatment of postmenopausal osteoporosis and the prevention of skeletal-related events (SRE) in cancer patients with solid tumors and bone metastases. Denosumab has a favorable toxicity profile in comparison to BPs and has the potential to improve cancer outcomes.

CONCLUSION

This review examines the existing role of denosumab in the treatment of bone complications of breast cancer and its potential role as adjuvant therapy.

Denosumab for the management of bone disease in patients with solid tumors

Many patients with advanced cancer develop bone metastases, which reduces their quality of life. Bone metastases are associated with an increased risk of skeletal-related events, which can lead to increased morbidity and mortality. In patients with bone metastases, tumor cells disrupt the normal process of bone remodeling, leading to increased bone destruction. Denosumab is a fully human monoclonal antibody against receptor activator of NF-κB ligand (RANKL), a key regulatory factor in bone remodeling. By binding to RANKL, denosumab disrupts the cycle of bone destruction. In clinical studies in patients with prostate or breast cancer and bone metastases, denosumab was superior to the current standard of care, zoledronic acid, for delaying skeletal-related events, while in patients with other solid tumors or multiple myeloma, denosumab was noninferior to zoledronic acid. This article examines the pharmacokinetics, efficacy, and safety and tolerability of denosumab for the management of bone events in patients with cancer.

Clinical efficacy and safety of denosumab in postmenopausal women with low bone mineral density and osteoporosis: a meta-analysis

OBJECTIVE

Clinical trials indicate that denosumab could be a potential treatment for postmenopausal osteoporosis. The objective of this meta-analysis was to assess the clinical efficacy and safety of offering denosumab to postmenopausal women with low bone mass.

METHODS

Data sources included MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) from inception to February 3, 2010 and bibliographies of reviews. Randomized controlled trials comparing the efficacy and safety of denosumab to placebo for treatment of low bone mass (low bone mineral density or osteoporosis) in postmenopausal women were selected. Two reviewers independently abstracted data on study general characteristics and outcomes. Review Manager 5.0 software was used for data syntheses and meta-analysis.

RESULTS

The database search revealed 4 studies (comprising 8864 patients randomized) that met the inclusion criteria and contributed to some or all of the meta-analysis outcomes. Relative risk (95% CI) of fractures for the denosumab compared with placebo group was 0.58 (0.52 to 0.66); relative risk (95% CI) of serious adverse events was 1.33 (0.83 to 2.14); relative risk (95% CI) of serious adverse events related to infection was 2.10 (0.64 to 6.90); relative risk (95% CI) of neoplasm was 1.11 (0.91 to 1.36); relative risk (95% CI) of study discontinuation due to adverse events was 1.10 (0.83 to 1.47); and relative risk (95% CI) of death was 0.78 (0.57 to 1.06). Findings remained robust to sensitivity analyses.

CONCLUSION

Our analysis found a significant reduction in relative fracture risk in the denosumab compared with the placebo group.

Osteoimmunopathology in HIV/AIDS: A Translational Evidence-Based Perspective

Infection with the human immunodeficiency virus-1 (HIV) and the resulting acquired immune deficiency syndrome (AIDS) alter not only cellular immune regulation but also the bone metabolism. Since cellular immunity and bone metabolism are intimately intertwined in the osteoimmune network, it is to be expected that bone metabolism is also affected in patients with HIV/AIDS. The concerted evidence points convincingly toward impaired activity of osteoblasts and increased activity of osteoclasts in patients with HIV/AIDS, leading to a significant increase in the prevalence of osteoporosis. Research attributes these outcomes in part at least to the ART, PI, and HAART therapies endured by these patients. We review and discuss these lines of evidence from the perspective of translational clinically relevant complex systematic reviews for comparative effectiveness analysis and evidence-based intervention on a global scale.

Aortic valve disease and treatment: the need for naturally engineered solutions

The aortic valve regulates unidirectional flow of oxygenated blood to the myocardium and arterial system. The natural anatomical geometry and microstructural complexity ensures biomechanically and hemodynamically efficient function. The compliant cusps are populated with unique cell phenotypes that continually remodel tissue for long-term durability within an extremely demanding mechanical environment. Alteration from normal valve homeostasis arises from genetic and microenvironmental (mechanical) sources, which lead to congenital and/or premature structural degeneration. Aortic valve stenosis pathobiology shares some features of atherosclerosis, but its final calcification endpoint is distinct. Despite its broad and significant clinical significance, very little is known about the mechanisms of normal valve mechanobiology and mechanisms of disease. This is reflected in the paucity of predictive diagnostic tools, early stage interventional strategies, and stagnation in regenerative medicine innovation. Tissue engineering has unique potential for aortic valve disease therapy, but overcoming current design pitfalls will require even more multidisciplinary effort. This review summarizes the latest advancements in aortic valve research and highlights important future directions.

Mouse Rankl expression is regulated in T cells by c-Fos through a cluster of distal regulatory enhancers designated the T cell control region

Receptor activator of NF-κB ligand (Rankl) is a TNF-like factor that induces the formation of osteoclasts responsible for bone resorption. Although T cell activation up-regulates this gene, the molecular mechanism of its transcriptional control remains unknown. We used ChIP-chip analysis in mouse primary T cells and a T cell hybridoma to define the regulatory enhancers responsible for this up-regulation and to characterize their properties. Elevated H3/H4 acetylation and increased RNA polymerase II density were evident at mRL-D5, a known enhancer located 76 kb upstream of the TSS, as well as at a cluster of regulatory sites located even further upstream between -123 to -156 kb, termed the T cell control region (TCCR). Based upon the ability of calcium signaling and MAPK inhibitors to block Rankl expression, we conducted further ChIP-chip analysis of the transcriptional mediators c-Fos, NF-κB, and Nfat. T cell activation induced c-Fos binding at the mRL-D5 enhancer and within the TCCR. The interaction of NF-κB was observed at the transcriptional start site and at mRL-D5. Both mRL-D5 and segments of the TCCR exhibited robust transcriptional activity in reporter assays, and site-specific mutagenesis of c-Fos and Nfat elements abrogated reporter activity, suggesting a role for both factors in the control of enhancer-mediated Rankl transcription. Finally, chromosome conformation capture analysis confirmed that mRL-D5 and segments of the TCCR were located in proximity to the Rankl gene promoter and thus potentially able to influence directly Rankl gene promoter activity. We conclude that both mRL-D5 and the TCCR represent control segments that play an integral role in Rankl expression in T cells.

Antibody-based therapies in multiple myeloma

The unmet need for improved multiple myeloma (MM) therapy has stimulated clinical development of monoclonal antibodies (mAbs) targeting either MM cells or cells of the bone marrow (BM) microenvironment. In contrast to small-molecule inhibitors, therapeutic mAbs present the potential to specifically target tumor cells and directly induce an immune response to lyse tumor cells. Unique immune-effector mechanisms are only triggered by therapeutic mAbs but not by small molecule targeting agents. Although therapeutic murine mAbs or chimeric mAbs can cause immunogenicity, the advancement of genetic recombination for humanizing rodent mAbs has allowed large-scale production and designation of mAbs with better affinities, efficient selection, decreasing immunogenicity, and improved effector functions. These advancements of antibody engineering technologies have largely overcome the critical obstacle of antibody immunogenicity and enabled the development and subsequent Food and Drug Administration (FDA) approval of therapeutic Abs for cancer and other diseases.

Denosumab: A New Injectable Treatment for Postmenopausal Osteoporosis

Background/Introduction:

Osteoporosis results in a significant increase in fractures, leading to morbidity and mortality. Adherence is a concern with commonly used antiresorptive agents, the bisphosphonates. Denosumab, which inhibits bone resorption by a different mechanism and is administered subcutaneously every 6 months, may provide an advantage in decreasing fracture risk in those with osteoporosis.

Objective:

To review the available data with respect to the mechanism of action, efficacy and safety of denosumab for the management of postmenopausal osteoporosis.

Methods:

Several databases were searched to identify phase III randomized controlled trials (RCT) that examined the effect of denosumab on bone mineral density (BMD) and/or fracture rate and the safety of denosumab in the management of postmenopausal osteoporosis.

Results:

In 2 of the 4 trials identified, denosumab was significantly better than placebo at increasing BMD, and in 1 trial reduced the risk of vertebral, nonvertebral and hip fractures. No head-to-head trials comparing fracture risk reduction of denosumab to bisphosphonates were found, however, 2 trials did report increased BMD with denosumab compared to alendronate. In the 4 studies reviewed, adverse effects reported more frequently with denosumab included rash and eczema, as well as bronchitis and influenza-like illness. There is potential for an increased risk of other infections and malignancies.

Conclusions:

The results of RCT trials suggest that denosumab is effective at maintaining or increasing BMD compared to placebo or alendronate in women with either osteopenia or osteoporosis and in 1 trial demonstrated a significant reduction in fracture rate compared to placebo. Overall, denosumab appeared to be well tolerated in the studies reviewed. Continued monitoring is needed to determine long-term safety and efficacy.

Receptor Activator for Nuclear Factor kappa B Ligand (RANKL) as an osteoimmune key regulator in bone physiology and pathology

The strength and integrity of the human skeleton depends on a delicate equilibrium between bone resorption and bone formation. Bone resorption is an elementary cellular activity in the modelling of the skeleton during growth and development. Later in life a most important physiological process in the skeleton is bone remodelling, which is locally initiated by resorption. During remodelling bone resorption is coupled to new bone formation that ensures renewal of bone with only minor local and temporary bone loss. Cells responsible for bone resorption and subsequent bone formation are the osteoclasts and osteoblasts, respectively. The osteoclast is derived from the pluripotent hematopoietic stem cell, which gives rise to a myeloid stem cell that can further differentiate into megakaryocytes, granulocytes, monocytes/macrophages and osteoclasts. The respective bone resorbing and forming actions of osteoclasts and osteoblasts are finely coupled, so that bone mass remains remarkably stable in a healthy adult. Imbalance between osteoclast and osteoblast activities can arise from a wide variety of hormonal changes or perturbations of inflammatory and growth factors resulting in postmenopausal osteoporosis, Paget's disease, lytic bone metastases, or rheumatoid arthritis, leading to increased bone resorption and crippling bone damage. In view of the critical role of osteoclasts in diverse pathology, there has been immense effort aimed at understanding the biology of this unique cell. The present review is focused on the current knowledge of the mechanisms that regulate the functional links between bone turnover and the immune system helping us to understand the main factors that lead to bone loss observed in osteoporosis, cancer and in rheumatoid arthritis. The aim of this review paper is to consider the key molecular interactions involved in the formation of osteoclast cells in normal and pathological conditions.

Emerging drugs for the management of cancer treatment induced bone loss

AREAS COVERED IN THIS REVIEW

We focus our attention on data on the efficacy of currently available and emerging drugs for the management of cancer treatment induced bone loss (CTIBL) found in a PubMed research from 1997 till today.

IMPORTANCE OF THE FIELD

One of the most common and severe safety issues of the antihormonal therapy in both sexes is the CTIBL and the related fragility fractures. In postmenopausal women with estrogenic receptor positive breast cancer, the third-generation aromatase inhibitors (AIs) are the standard therapy. Observational retrospective studies have found that AIs treated patients had a high rate of bone loss and fracture risk (RR 1.3). Also in men with prostate cancer receiving androgen deprivation therapy, the increase in bone turnover and the consequent bone loss are very rapid and sustained significantly increasing the fracture risk.

WHAT THE READER WILL GAIN

The aim of our review is to provide the current evidences for the management of bone loss and fracture risk in this subpopulation.

TAKE HOME MESSAGE

The very high rate of bone loss and the high incidence of fractures indicate that cancer patients at risk of CTIBL need to be carefully monitored and stratified for fracture risk. Although there is a strong evidence of efficacy in prevention of bone loss and reduction of fracture risk for many drugs approved for postmenopausal osteoporosis (PMO) and male osteoporosis, for CTIBL there are actually no drugs approved for this indication.

Functions of nuclear factor kappaB in bone

Nuclear factor kappaB (NF-kappaB) is a set of multifunctional transcription factors that regulate expression of genes involved in numerous normal cellular activities. They also are activated in many inflammatory and neoplastic conditions in which their expression may be stimulated by proinflammatory cytokines. NF-kappaB, in turn, regulates the expression of cytokines and so can mediate autocrine self-amplifying cycles of cytokine release and NF-kappaB activation, leading to maintenance of inflammatory reactions beyond the initial stimulus, as seen in rheumatoid arthritis and asthma. Since discovery of the requirement of NF-kappaB for basal and cytokine-induced osteoclast formation in the mid-1990s, much has been learned about the role of NF-kappaB in bone. NF-kappaB has roles in skeletal development, endochondral ossification, osteoclast and osteoblast functions, and common bone diseases. NF-kappaB inhibitors have been developed, but none have made it to clinical trials for the treatment of common bone diseases. Here we review the roles for NF-kappaB in bone and in common bone diseases.