Romosozumab Treatment Converts Trabecular Rods into Trabecular Plates in Male Cynomolgus Monkeys

The effect of osteoporosis treatment on bone mass

Over the last two decades there have been significant developments in the pharmacotherapy of osteoporosis. The therapeutic arsenal has expanded with monoclonal antibodies which have been developed based on discoveries of the molecular mechanisms underlying bone resorption and bone formation. Denosumab, the antibody binding RANKL, inhibits bone resorption, and romosozumab, the antibody binding sclerostin, inhibits bone resorption and stimulates bone formation as well. Both antibodies have shown potent anti-fracture efficacy in randomized clinical trials and this review will discuss the preclinical and clinical studies focusing on the effects on bone mass. After discontinuation of these antibodies, bone mineral density quickly returns to baseline and in the case of denosumab, discontinuation can not only induce rebound bone loss, but also the occurrence of vertebral fractures. Therefore, sequential antiresorptive therapy to maintain bone mass gains and anti-fracture efficacy is of utmost importance and will also be discussed in this review.

Molecular Targeted Therapy for the Bone Loss Secondary to Pyogenic Spondylodiscitis Using Medications for Osteoporosis: A Literature Review

Pyogenic spondylodiscitis can cause severe osteolytic and destructive lesions in the spine. Elderly or immunocompromised individuals are particularly susceptible to infectious diseases; specifically, infections in the spine can impair the ability of the spine to support the trunk, causing patients to be bedridden, which can also severely affect the physical condition of patients. Although treatments for osteoporosis have been well studied, treatments for bone loss secondary to infection remain to be elucidated because they have pathological manifestations that are similar to but distinct from those of osteoporosis. Recently, we encountered a patient with severely osteolytic pyogenic spondylodiscitis who was treated with romosozumab and exhibited enhanced bone formation. Romosozumab stimulated canonical Wnt/β-catenin signaling, causing robust bone formation and the inhibition of bone resorption, which exceeded the bone loss secondary to infection. Bone loss due to infections involves the suppression of osteoblastogenesis by osteoblast apoptosis, which is induced by the nuclear factor-κB and mitogen-activated protein kinase pathways, and osteoclastogenesis with the receptor activator of the nuclear factor-κB ligand-receptor combination and subsequent activation of the nuclear factor of activated T cells cytoplasmic 1 and c-Fos. In this study, we review and discuss the molecular mechanisms of bone loss secondary to infection and analyze the efficacy of the medications for osteoporosis, focusing on romosozumab, teriparatide, denosumab, and bisphosphonates, in treating this pathological condition.

Osteoporosis Treatment with Anti-Sclerostin Antibodies-Mechanisms of Action and Clinical Application

Osteoporosis is characterized by reduced bone mass and disruption of bone architecture, resulting in increased risk of fragility fractures and significant long-term disability. Although both anti-resorptive treatments and osteoanabolic drugs, such as parathyroid hormone analogues, are effective in fracture prevention, limitations exist due to lack of compliance or contraindications to these drugs. Thus, there is a need for novel potent therapies, especially for patients at high fracture risk. Romosozumab is a monoclonal antibody against sclerostin with a dual mode of action. It enhances bone formation and simultaneously suppresses bone resorption, resulting in a large anabolic window. In this opinion-based narrative review, we highlight the role of sclerostin as a critical regulator of bone mass and present human diseases of sclerostin deficiency as well as preclinical models of genetically modified sclerostin expression, which led to the development of anti-sclerostin antibodies. We review clinical studies of romosozumab in terms of bone mass accrual and anti-fracture activity in the setting of postmenopausal and male osteoporosis, present sequential treatment regimens, and discuss its safety profile and possible limitations in its use. Moreover, an outlook comprising future translational applications of anti-sclerostin antibodies in diseases other than osteoporosis is given, highlighting the clinical significance and future scopes of Wnt signaling in these settings.

Efficacy and safety of Romosozumab in treatment for low bone mineral density: a systematic review and meta-analysis

Osteoporosis is a chronic skeletal disease with an increasing prevalence. Romosozumab, as a monoclonal anti-sclerostin antibody with a dual function, has been produced. In this meta-analysis, we aimed to examine the efficacy of Romosozumab in patients with low bone mineral density. A systematic search was conducted in the most important electronic search engines like Cochrane Library, PubMed, Web of Science, Scopus, Google Scholar, and ClinicalTrials.gov at the end of July 2019 to retrieve randomized controlled trials (RCTs), which evaluated the effect of Romosozumab in patients with osteoporosis and/or low bone mineral density. After evaluating the quality of articles with the Cochrane checklist, data related to the outcomes of bone mineral density (BMD) of lumbar spine, femoral neck, and total hip, risk of clinical, vertebral and non-vertebral fractures, and risk of adverse events were extracted. Quality of evidence was assessed according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Heterogeneity between studies was evaluated by I2 and Q statistics. The meta-analysis was performed using CMA v.2.0 software. Of all the 671 initially retrieved articles, seven articles were entered into the meta-analysis after removing duplicates and reviewing papers with inclusion and exclusion criteria. The results of the meta-analysis showed that Romosozumab 210, 140, and 70 mg compared with Alendronate, Teriparatide, and placebo can increase the bone mineral density in the lumbar spine, femoral neck, and total hip. The risk of adverse events like adjudicated cardiovascular serious adverse events and adjudicated cardiovascular death was more in Romosozumab 210 mg in comparison with placebo. However, this difference was not statistically significant. Treatment with anti-sclerostin antibodies can be a proper therapeutic option in patients with osteoporosis and low bone mineral density. Based on the results of this meta-analysis, it seems that Romosozumab, with its dual function, has a positive role in the treatment of osteoporosis and low bone mineral density.

One Year of Romosozumab Followed by Two Years of Denosumab Maintains Fracture Risk Reductions: Results of the FRAME Extension Study

Romosozumab, a humanized monoclonal antibody that binds and inhibits sclerostin, has the dual effect of increasing bone formation and decreasing bone resorption. As previously reported in the pivotal FRActure study in postmenopausal woMen with ostEoporosis (FRAME), women with a T-score of ≤ -2.5 at the total hip or femoral neck received subcutaneous placebo or romosozumab once monthly for 12 months, followed by open-label subcutaneous denosumab every 6 months for an additional 12 months. Upon completion of the 24-month primary analysis period, eligible women entered the extension phase and received denosumab for an additional 12 months. Here, we report the final analysis results through 36 months, including efficacy assessments of new vertebral, clinical, and nonvertebral fracture; bone mineral density (BMD); and safety assessments. Of 7180 women enrolled, 5743 (80%) completed the 36-month study (2851 romosozumab-to-denosumab; 2892 placebo-to-denosumab). Through 36 months, fracture risk was reduced in subjects receiving romosozumab versus placebo for 12 months followed by 24 months of denosumab for both groups: new vertebral fracture (relative risk reduction [RRR], 66%; incidence, 1.0% versus 2.8%; p < 0.001), clinical fracture (RRR, 27%; incidence, 4.0% versus 5.5%; p = 0.004), and nonvertebral fracture (RRR, 21%; incidence, 3.9% versus 4.9%; p = 0.039). BMD continued to increase for the 2 years with denosumab treatment in both arms. The substantial difference in BMD achieved through 12 months of romosozumab treatment versus placebo was maintained through the follow-up period when both treatment arms received denosumab. Subject incidence of adverse events, including positively adjudicated serious cardiovascular adverse events, were overall balanced between groups. In conclusion, in postmenopausal women with osteoporosis, 12 months of romosozumab led to persistent fracture reduction benefit and ongoing BMD gains when followed by 24 months of denosumab. The sequence of romosozumab followed by denosumab may be a promising regimen for the treatment of osteoporosis. © 2018 American Society for Bone and Mineral Research.

Novel therapies in osteoporosis: PTH-related peptide analogs and inhibitors of sclerostin

Bone-forming approaches to treat patients with severe osteoporosis are effective, but treatment options are limited, and there is an unmet clinical need for additional drugs. This review discusses two novel and advanced anabolic therapeutic concepts that have successfully completed phase 3 trials. Romosozumab is a monoclonal antibody that targets the Wnt inhibitor sclerostin. Two phase 3 trials (FRAME and ARCH) of romosozumab for the treatment of postmenopausal osteoporosis have been completed. Both trials successfully reached their primary endpoint by reducing vertebral fractures by 75% compared to placebo (FRAME trial) and 48% compared to alendronate (ARCH trial), respectively. Abaloparatide is a PTH-related protein (PTHrP) analog that has displayed bone anabolic activity. In the phase 3 ACTIVE trial, abaloparatide was compared to placebo and teriparatide for 18 months in postmenopausal women who had already experienced an osteoporotic fracture. Abaloparatide successfully reduced the rate of new vertebral fractures by 86% compared to placebo. Furthermore, abaloparatide achieved greater BMD increases at all measured sites compared to both placebo and teriparatide. Based on these results, abaloparatide was FDA approved in April 2017. This review discusses available data of both agents with regard to efficacy and safety as well as their possible future application.

Sclerostin antibodies in osteoporosis: latest evidence and therapeutic potential

Sclerostin is an osteocyte-derived glycoprotein that inhibits Wnt/β-catenin signaling and activation of osteoblast function, thereby inhibiting bone formation. It plays a vital role in the regulation of skeletal growth. In adults, sclerostin secretion is modulated by skeletal loading (increased secretion with immobilization; less with weight bearing) and by hormonal/cytokine actions on the osteocyte. Sclerostin deficiency syndromes in humans and animals are characterized by high bone mass of normal quality. In animal models of osteoporosis, inhibition of sclerostin by monoclonal antibodies induces osteoblast activity and new bone formation, normalizing bone mass and improving bone architecture and strength. In recently completed clinical trials, anti-sclerostin antibody therapy results in marked increases in bone mineral density and rapid and substantial reduction in fracture risk. This review will focus on these recent studies and anticipate the role of anti-sclerostin therapy in the management of patients with osteoporosis.