A single dose of zoledronate preserves bone mineral density for up to 2 years after a second course of romosozumab

Verifying the effectiveness of romosozumab re-administration on bone mineral density

Upon completing romosozumab therapy for osteoporosis, sequential treatment with other agents is required. However, for patients at high fracture risk despite such therapy, re-administration of romosozumab might be a potent subsequent option to prevent additional fractures. Currently, there is insufficient real-world clinical data verifying the efficacy of romosozumab re-administration. This study evaluated its efficacy. We enrolled 72 osteoporosis patients who remained at high risk of fractures after a 12-mo course of romosozumab, followed by sequential therapy either with bisphosphonates, denosumab, or teriparatide. Patients were re-administered another 12-mo romosozumab to assess changes in bone mineral density (BMD) and the percentages of patients achieving a T-score > -2.5 at the completion. Our result exhibited that BMD at the lumbar spine and femoral neck increased significantly through the re-administration phase (p < .001). The percentage of patients achieving a T-score > -2.5 in the lumbar spine, total hip and femoral neck increased significantly compared to before initial romosozumab therapy, with the greatest improvement seen after re-administration (all p < .001). Bone formation markers increased significantly (p < .001) during re-administration, while resorption markers showed no significant change (p = .408). The impact of prior sequential therapy was also evaluated. BMD increased significantly at all sites for patients who received bisphosphonates as sequential therapy (p < .05). After denosumab therapy, significant BMD increases were observed only in the lumbar spine (p < .01), while the total hip and femoral neck showed no significant change. After teriparatide therapy, BMD temporarily decreased during the sequential period but increased significantly after romosozumab re-administration, especially in the lumbar spine and femoral neck (both p < .001). In conclusion, romosozumab re-administration is an effective treatment. Furthermore, its efficacy varies depending on the sequential therapy used, with the highest effectiveness seen in the order of teriparatide, bisphosphonates, and denosumab.

Can Bisphosphonate Therapy Reduce Overall Mortality in Patients With Osteoporosis? A Meta-analysis of Randomized Controlled Trials

BACKGROUND

For patients with osteoporosis, bisphosphonate therapy can reduce the risk of fractures, but its effect on reducing mortality remains unclear. Previous studies on this topic have produced conflicting results and generally have been too small to definitively answer the question of whether bisphosphonate therapy reduces mortality. Therefore, a meta-analysis may help us arrive at a more conclusive answer.

QUESTIONS/PURPOSES

In a large meta-analysis of placebo-controlled randomized controlled trials (RCTs), we asked: (1) Does bisphosphonate use reduce mortality? (2) Is there a subgroup effect based on whether different bisphosphonate drugs were used (zoledronate, alendronate, risedronate, and ibandronate), different geographic regions where the study took place (Europe, the Americas, and Asia), whether the study was limited to postmenopausal female patients, or whether the trials lasted 3 years or longer?

METHODS

We conducted a systematic review using multiple databases, including Embase, Web of Science, Medline (via PubMed), Cochrane Library, and ClinicalTrials.gov, with each database searched up to November 20, 2023 (which also was the date of our last search), following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included randomized, placebo-controlled clinical trials with participants diagnosed with osteoporosis and receiving bisphosphonate treatment. We excluded papers posted to preprint servers, other unpublished work, conference abstracts, and papers that were registered on ClinicalTrials.gov but were not yet published. We collected 2263 records. After excluding records due to study type, study content not meeting the inclusion criteria, and duplicates, our meta-analysis included 47 placebo-controlled RCTs involving 59,437 participants. Data extraction, quality assessment, and statistical analyses were performed. The evaluation of randomized trials for potential bias was conducted using the revised Cochrane Risk of Bias tool. This assessment encompassed factors such as sequence generation, allocation concealment, subject blinding, outcome assessor blinding, incomplete outcome data, and reporting bias. Some studies did not provide explicit details regarding random sequence generation, leading to a high risk of selection bias. A few studies, due to their open-label nature, were unable to achieve double-blind conditions for both the subjects and the researchers, resulting in intermediate performance bias. Nevertheless, the overall study quality was high. Due to the low heterogeneity among the studies, as evidenced by the low statistical heterogeneity (that is, a low I 2 statistic), we opted for a fixed-effects model, indicating that the effect size is consistent across the studies. In such cases, the fixed-effects model can provide more precise estimates. According to the results of the funnel plot, we did not find evidence of publication bias.

RESULTS

The use of bisphosphonates did not reduce the overall risk of mortality in patients with osteoporosis (risk ratio 0.95 [95% CI 0.88 to 1.03]). Subgroup analyses involving different bisphosphonate drugs (zoledronate, alendronate, risedronate, and ibandronate), regions (Europe, the Americas, and Asia), diverse populations (postmenopausal female patients and other patients), and trials lasting 3 years or longer revealed no associations with reduced overall mortality.

CONCLUSION

Based on our comprehensive meta-analysis, there is high-quality evidence suggesting that bisphosphonate therapy for patients with osteoporosis does not reduce the overall risk of mortality despite its effectiveness in reducing the risk of fractures. The primary consideration for prescribing bisphosphonates to individuals with osteoporosis should continue to be centered on reducing fracture risk, aligning with clinical guidelines. Long-term studies are needed to investigate potential effects on mortality during extended treatment periods.

LEVEL OF EVIDENCE

Level I, therapeutic study.

Romosozumab for the treatment of osteoporosis - a systematic review

INTRODUCTION

Romosozumab, a new treatment of osteoporosis, is a monoclonal antibody that targets sclerostin and thereby exhibits a dual mechanism of action by stimulating bone formation and inhibiting bone resorption. This systematic review aims to assess the clinical efficacy and safety of romosozumab for treatment of primary and secondary osteoporosis.

METHODS

A comprehensive literature search was conducted in October 2023 across multiple databases including Embase, PubMed and Cochrane Library. Randomized controlled trials (RCTs) and observational studies evaluating the impact of romosozumab on BMD, bone turnover markers (BTM), fracture outcomes, and its safety profile were included. Data extraction and quality assessment were performed independently by two reviewers in accordance with PRISMA guidelines.

RESULTS

A total of 36 articles met the inclusion criteria. Romosozumab significantly increased BMD at the lumbar spine, total hip, and femoral neck compared to placebo and active comparators in patients with primary osteoporosis. Sequential therapy with romosozumab followed by antiresorptives maintained or further increased BMD and reduced fracture risk. Romosozumab was generally well tolerated, however, an imbalance in cardiovascular adverse event was observed in one large clinical trial. Observational studies supported these findings. Specific subgroups of patients with secondary osteoporosis were assessed, demonstrating overall positive outcomes with romosozumab treatment.

CONCLUSION

Romosozumab effectively increases BMD and reduces fracture risk, particularly when used as initial therapy in high fracture-risk patients. Sequential therapy with subsequent antiresorptive treatment optimizes long-term benefits. While generally well-tolerated, its cardiovascular safety profile requires further long-term studies to ensure its safety in clinical practice. Additional studies are needed to confirm efficacy and safety in patients with secondary osteoporosis.

A practical approach for anabolic treatment of bone fragility with romosozumab

BACKGROUND

Romosozumab, a fully humanized anti-sclerostin-antibody, is a bone-builder stimulating osteoblasts and inhibiting osteoclast by activation of the canonical Wnt-beta catenin signaling. This unique mechanism of action has the potential to address unmet needs in osteoporosis management.

METHODS

The multifaceted practical clinical issues related to romosozumab are discussed, especially focusing on the rationale of employing a sclerostin inhibitor to target bone fragility as first line or second line treatment in post-menopausal osteoporosis and in males at increased risk of fractures.

RESULTS

Four randomized clinical trials with several post-hoc analyses and more than ten observational studies have consistently demonstrated that romosozumab is effective in rapidly increasing bone mineral density (BMD) and decreasing risk of vertebral, non-vertebral and hip fractures in post-menopausal women at very-high risk of fractures. In male osteoporosis, only data on BMD are available. Noteworthy, romosozumab was shown to be more effective and rapid than teriparatide in improving BMD, bone structure and strength at the hip, especially in women already treated with anti-resorptive drugs. Interestingly, even if romosozumab displays best results in treatment-naïve patients, its favourable effects on BMD were observed even in women previously treated with teriparatide or denosumab, although to a lesser extent.

CONCLUSIONS

Based on the available evidence, romosozumab could be proposed as ideal drug in several clinical settings, such as non-fractured post-menopausal women at very-high risk of fractures, patients with recent hip fracture, patients non responder to bisphosphonates and short-term denosumab therapy.

[Osteoporosis-Definition, risk assessment, diagnosis, prevention and treatment (update 2024) : Guidelines of the Austrian Society for Bone and Mineral Research]

BACKGROUND

Austria is among the countries with the highest incidence and prevalence of osteoporotic fractures worldwide. Guidelines for the prevention and management of osteoporosis were first published in 2010 under the auspices of the then Federation of Austrian Social Security Institutions and updated in 2017. The present comprehensively updated guidelines of the Austrian Society for Bone and Mineral Research are aimed at physicians of all specialties as well as decision makers and institutions in the Austrian healthcare system. The aim of these guidelines is to strengthen and improve the quality of medical care of patients with osteoporosis and osteoporotic fractures in Austria.

METHODS

These evidence-based recommendations were compiled taking randomized controlled trials, systematic reviews and meta-analyses as well as European and international reference guidelines published before 1 June 2023 into consideration. The grading of recommendations used ("conditional" and "strong") are based on the strength of the evidence. The evidence levels used mutual conversions of SIGN (1++ to 3) to NOGG criteria (Ia to IV).

RESULTS

The guidelines include all aspects associated with osteoporosis and osteoporotic fractures, such as secondary causes, prevention, diagnosis, estimation of the 10-year fracture risk using FRAX®, determination of Austria-specific FRAX®-based intervention thresholds, drug-based and non-drug-based treatment options and treatment monitoring. Recommendations for the office-based setting and decision makers and institutions in the Austrian healthcare system consider structured care models and options for osteoporosis-specific screening.

CONCLUSION

The guidelines present comprehensive, evidence-based information and instructions for the treatment of osteoporosis. It is expected that the quality of medical care for patients with this clinical picture will be substantially improved at all levels of the Austrian healthcare system.

Discovery of Novel Antiosteoporosis Leads with Bone Resorption Inhibition and Anabolic Promotion through a Chemotype-Assembly Approach

Developing a dual-efficiency agent with antiresorptive and anabolic applications is a promising strategy for treating osteoporosis. This study reports the discovery of dual antiosteoporosis agents via a chemotype-assembly approach. Chemotype analysis identified 12 antiresorptive and 12 anabolic chemotypes and 7 dual-function chemotype-assembly rules. Based on these assembly rules, a dual-functional compound S24 was discovered. S24 exhibits osteoclastogenesis inhibition with an IC50 value of 10.28 μM and osteoblast differentiation stimulation at 10 μM. S24 derivatives were designed and synthesized based on the activity relationship of the chemotypes. This yielded a more active compound, S24-14, with an osteoclastogenesis inhibition IC50 value of 0.40 μM and osteoblast differentiation stimulation at 1.0 μM; compound S24-14 also suppressed bone loss in vivo. These results prove that S24-14 can be a potential lead for antiosteoporosis drug development.

Romosozumab versus parathyroid hormone receptor agonists: which osteoanabolic to choose and when?

Osteoanabolic agents are used as a first line treatment in patients at high fracture risk. The PTH receptor 1 (PTH1R) agonists teriparatide (TPTD) and abaloparatide (ABL) increase bone formation, bone mineral density (BMD), and bone strength by activating PTH receptors on osteoblasts. Romosozumab (ROMO), a humanized monoclonal antibody against sclerostin, dramatically but transiently stimulates bone formation and persistently reduces bone resorption. Osteoanabolic agents increase BMD and bone strength while being more effective than antiresorptives in reducing fracture risk in postmenopausal women. However, direct comparisons of the antifracture benefits of osteoanabolic therapies are limited. In a direct comparison of TPTD and ABL, the latter resulted in greater BMD increases at the hip. While no differences in vertebral or non-vertebral fracture risk were observed between the two drugs, ABL led to a greater reduction of major osteoporotic fractures. Adverse event profiles were similar between the two agents except for hypercalcemia, which occurred more often with TPTD. No direct comparisons of fracture risk reduction between ROMO and the PTH1R agonists exist. Individual studies have shown greater increases in BMD and bone strength with ROMO compared with TPTD in treatment-naive women and in women previously treated with bisphosphonates. Some safety aspects, such as a history of tumor precluding the use of PTH1R agonists, and a history of major cardiovascular events precluding the use of ROMO, should also be considered when choosing between these agents. Finally, convenience of administration, reimbursement by national health systems and length of clinical experience may influence patient choice.

IDEAL-IQ combined with intravoxel incoherent motion diffusion-weighted imaging for quantitative diagnosis of osteoporosis

BACKGROUND

Osteoporosis (OP) is a common chronic metabolic bone disease characterized by decreased bone mineral content and microstructural damage, leading to increased fracture risk. Traditional methods for measuring bone density have limitations in accurately distinguishing vertebral bodies and are influenced by vertebral degeneration and surrounding tissues. Therefore, novel methods are needed to quantitatively assess changes in bone density and improve the accurate diagnosis of OP.

METHODS

This study aimed to explore the applicative value of the iterative decomposition of water and fat with echo asymmetry and least-squares estimation-iron (IDEAL-IQ) sequence combined with intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) for the diagnosis of osteoporosis. Data from 135 patients undergoing dual-energy X-ray absorptiometry (DXA), IDEAL-IQ, and IVIM-DWI were prospectively collected and analyzed. Various parameters obtained from IVIM-DWI and IDEAL-IQ sequences were compared, and their diagnostic efficacy was evaluated.

RESULTS

Statistically significant differences were observed among the three groups for FF, R2*, f, D, DDC values, and BMD values. FF and f values exhibited negative correlations with BMD values, with r=-0.313 and - 0.274, respectively, while R2*, D, and DDC values showed positive correlations with BMD values, with r = 0.327, 0.532, and 0.390, respectively. Among these parameters, D demonstrated the highest diagnostic efficacy for osteoporosis (AUC = 0.826), followed by FF (AUC = 0.713). D* exhibited the lowest diagnostic performance for distinguishing the osteoporosis group from the other two groups. Only D showed a significant difference between genders. The AUCs for IDEAL-IQ, IVIM-DWI, and their combination were 0.74, 0.89, and 0.90, respectively.

CONCLUSIONS

IDEAL-IQ combined with IVIM-DWI provides valuable information for the diagnosis of osteoporosis and offers evidence for clinical decisions. The superior diagnostic performance of IVIM-DWI, particularly the D value, suggests its potential as a more sensitive and accurate method for diagnosing osteoporosis compared to IDEAL-IQ. These findings underscore the importance of integrating advanced imaging techniques into clinical practice for improved osteoporosis management and highlight the need for further research to explore the full clinical implications of these imaging modalities.

Safety and efficacy of sequential treatments for postmenopausal osteoporosis: a network meta-analysis of randomised controlled trials

Background

The sequential anti-osteoporotic treatment for women with postmenopausal osteoporosis (PMO) is important, but the order in which different types of drugs are used is confusing and controversial. Therefore, we performed a network meta-analysis to compare the efficacy and safety of available sequential treatments to explore the most efficacious strategy for long-term management of osteoporosis.

Methods

In this network meta-analysis, we searched the PubMed, EMBASE, Web of Science, the Cochrane Library, and ClinicalTrials.gov from inception to September 19, 2023 to identify randomised controlled trials comparing sequential treatments for women with PMO. The identified trials were screened by reading the title and abstract, and only randomised clinical trials involving sequential anti-osteoporotic treatments and reported relevant outcomes for PMO were included. The main outcomes included vertebral fracture risk, the percentage change in bone mineral density (BMD) in different body parts, and all safety indicators in the stage after switching treatment. A frequentist network meta-analysis was performed using the multivariate random effects method and evaluated using the surface under the cumulative ranking curve (SUCRA). Certainty of evidence was assessed using the Confidence in the Network Meta-Analysis (CINeMA) framework. This study is registered with PROSPERO: CRD42022360236.

Findings

A total of 19 trials comprising 18,416 participants were included in the study. Five different sequential treatments were investigated as the main interventions and compared to the corresponding control groups. The intervention groups in this study comprised the following treatment switch protocols: switching from an anabolic agent (AB) to an anti-resorptive agent (AR) (ABtAR), transitioning from one AR to another AR (ARtAAR), shifting from an AR to an AB (ARtAB), switching from an AB to a combined treatment of AB and AR (ABtC), and transitioning from an AR to a combined treatment (ARtC). A significant reduction in the incidence of vertebral fractures was observed in ARtC, ABtAR and ARtAB in the second stage, and ARtC had the lowest incidence with 81.5% SUCRA. ARtAAR and ABtAR were two effective strategies for preventing fractures and improving BMD in other body parts. Especially, ARtAAR could improve total hip BMD with the highest 96.1% SUCRA, and ABtAR could decrease the risk of total fractures with the highest 94.3% SUCRA. Almost no difference was observed in safety outcomes in other comparisons.

Interpretation

Our findings suggested that the ARtAAR and ABtAR strategy are the effective and safe sequential treatment for preventing fracture and improving BMD for PMO. ARtC is more effective in preventing vertebral fractures.

Funding

The National Natural Science Foundation of China (82170900, 81970762), the Hunan Administration of Traditional Chinese Medicine, and the Hunan Province High-level Health Talents "225" Project.

Sequential Therapy for the Long-Term Treatment of Postmenopausal Osteoporosis

Osteoporosis is a chronic condition characterized by decreased bone mass, loss of skeletal integrity, and increased susceptibility to fracture. Drugs used to treat osteoporosis can be classified as those that block bone resorption (antiresorptive), stimulate bone formation (anabolic), or do both. While all currently approved medications reduce the risk of fragility fractures in high-risk populations, they are generally unable to fully restore bone strength in most patients with established disease. Thus, the majority of patients require disease management over many years. Unfortunately, the continuous use of a single drug has limitations, both in terms of efficacy and safety, and so sequential therapy is commonly required. Given the expanding list of pharmacological agents currently available, careful consideration needs to be given as to which drugs to use and in what sequence. This review will evaluate the differential effects of antiresorptive, bone-forming, and dual-acting drugs when used in specific sequences and will explore the current evidence favoring the initial use of bone-forming/dual-acting drugs followed by antiresorptive medications. This review will also examine the notion that long-term treatment with an antiresorptive drug may diminish the efficacy of subsequent treatment with a bone-forming/dual-acting drug. Finally, this review will explore the current evidence pertaining to the specific issue of how to best prevent the clinical ramifications of denosumab cessation.

Τhe story of sclerostin inhibition: the past, the present, and the future

Sclerostin inhibits osteoblast activity by hampering activation of the canonical Wnt signaling pathway and simultaneously stimulates osteoclastogenesis through upregulation of the receptor activator of NFκB ligand (RANKL). Thus, antibodies against sclerostin (Scl-Abs), besides promoting bone formation, suppress bone resorption and dissociate bone formation from resorption. This dual action results in remarkable increases of bone mineral density which are of a greater magnitude compared to the other antiosteoporotic treatments and are accompanied by decreases of fracture risk at all skeletal sites. The anabolic effect subsides after the first few months of treatment and a predominantly antiresorptive effect remains after this period, limiting its use to 12 months. Furthermore, these effects are largely reversible upon discontinuation; therefore, subsequent treatment with antiresorptives is indicated to maintain or further increase the bone gains achieved. Romosozumab is currently the only Scl-Ab approved for the treatment of severe postmenopausal osteoporosis. Indications for use in other populations, such as males, premenopausal women, and patients with glucocorticoid-induced osteoporosis, are pending. Additionally, the efficacy of Scl-Abs in other bone diseases, such as osteogenesis imperfecta, hypophosphatasia, X-linked hypophosphatemia, and bone loss associated with malignancies, is under thorough investigation. Cardiovascular safety concerns currently exclude patients at high cardiovascular risk from this treatment.

Zoledronic acid sequential to teriparatide may promote greater inhibition of bone resorption than zoledronic acid alone

Background

Teriparatide (TPTD) should be followed by an antiresorptive to maximize bone mineral density gain and anti-fracture protection. Infrequent zoledronic acid (ZOL) administration has demonstrated effectiveness. The duration of ZOL effect following TPTD is unknown.

Objective

To evaluate the effect of ZOL on bone resorption marker in a post-TPTD versus ZOL-alone scenario in osteoporotic patients.

Design

Retrospective cohort study.

Methods

Patients treated with TPTD followed by ZOL (TPTD-ZOL) or with a single ZOL infusion were identified in the database of a tertiary referral center. Clinical and laboratory data, including C-terminal telopeptide of type I collagen (CTX) following ZOL treatment, were compared.

Results

Twenty-six patients (93% women) treated with TPTD-ZOL and 41 with ZOL were comparable in age (median 70.1 versus 69.6 years, p = 0.6) and sex. Timing of CTX measurement post-ZOL was the same, median 1.0 year. CTX was lower following TPTD-ZOL (median 142.1 versus 184.2 pg/mL, p = 0.005). In a multivariable regression model (controlled for baseline characteristics), pretreatment with TPTD strongly predicted CTX <150 pg/mL, 1 year following ZOL (odds ratio = 7.5, 95% CI 1.3-58.1, p = 0.03). In a subgroup with sequential CTX measurements following one ZOL, significantly lower levels persisted in the TPTD-ZOL group for a median of 4.4 years follow-up.

Conclusion

ZOL-administered sequential to TPTD yielded deeper and more prolonged bone resorption suppression than ZOL alone. Prospective data are needed to confirm whether in a sequential treatment scenario, subsequent ZOL dosing interval should be less frequent.

Using sequential pharmacotherapy for the treatment of osteoporosis: an update of the literature

INTRODUCTION

Osteoporosis, which is characterized by compromised bone density and heightened susceptibility to fractures, is a substantial public health concern, especially among the aging population. Underdiagnosis, undertreatment, and therapy non-adherence contribute to its impact. Anabolic and dual-action agents like teriparatide, abaloparatide, and romosozumab have emerged as effective treatments, allowing rapid gains in bone mineral density (BMD) and reducing fracture risk. However, administering treatments in the correct order is paramount, with an 'anabolic first' approach gaining traction for patients at high risk of fractures. This strategy involves starting anabolic therapies, followed by antiresorptive agents as maintenance therapy. It is important to note that the effectiveness of anabolic agents differs between treatment-naive and previously treated patients: tailored treatment approaches are therefore necessary. This comprehensive strategy adheres to clinical guidelines, emphasizing individualized care, early intervention, and patient-centered management to mitigate the burden of osteoporosis and enhance patients' quality of life.

AREA COVERED

The aim of this review is to summarize recent evidence on the sequential treatment of osteoporosis and to provide recommendations on the best treatment strategies.

EXPERT OPINION

Effective treatments, such as anabolic agents, are key in high-risk patients, who require an 'anabolic first' approach. Sequential therapy, specifically tailored to a patient's history, can help to optimize prevention and management of fractures.

Pathophysiology of bone disease in chronic kidney disease: from basics to renal osteodystrophy and osteoporosis

Chronic kidney disease (CKD) is a highly prevalent disease that has become a public health problem. Progression of CKD is associated with serious complications, including the systemic CKD-mineral and bone disorder (CKD-MBD). Laboratory, bone and vascular abnormalities define this condition, and all have been independently related to cardiovascular disease and high mortality rates. The "old" cross-talk between kidney and bone (classically known as "renal osteodystrophies") has been recently expanded to the cardiovascular system, emphasizing the importance of the bone component of CKD-MBD. Moreover, a recently recognized higher susceptibility of patients with CKD to falls and bone fractures led to important paradigm changes in the new CKD-MBD guidelines. Evaluation of bone mineral density and the diagnosis of "osteoporosis" emerges in nephrology as a new possibility "if results will impact clinical decisions". Obviously, it is still reasonable to perform a bone biopsy if knowledge of the type of renal osteodystrophy will be clinically useful (low versus high turnover-bone disease). However, it is now considered that the inability to perform a bone biopsy may not justify withholding antiresorptive therapies to patients with high risk of fracture. This view adds to the effects of parathyroid hormone in CKD patients and the classical treatment of secondary hyperparathyroidism. The availability of new antiosteoporotic treatments bring the opportunity to come back to the basics, and the knowledge of new pathophysiological pathways [OPG/RANKL (LGR4); Wnt-ß-catenin pathway], also affected in CKD, offers great opportunities to further unravel the complex physiopathology of CKD-MBD and to improve outcomes.

Fracture risk reduction and safety by osteoporosis treatment compared with placebo or active comparator in postmenopausal women: systematic review, network meta-analysis, and meta-regression analysis of randomised clinical trials

OBJECTIVE

To review the comparative effectiveness of osteoporosis treatments, including the bone anabolic agents, abaloparatide and romosozumab, on reducing the risk of fractures in postmenopausal women, and to characterise the effect of antiosteoporosis drug treatments on the risk of fractures according to baseline risk factors.

DESIGN

Systematic review, network meta-analysis, and meta-regression analysis of randomised clinical trials.

DATA SOURCES

Medline, Embase, and Cochrane Library to identify randomised controlled trials published between 1 January 1996 and 24 November 2021 that examined the effect of bisphosphonates, denosumab, selective oestrogen receptor modulators, parathyroid hormone receptor agonists, and romosozumab compared with placebo or active comparator.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials that included non-Asian postmenopausal women with no restriction on age, when interventions looked at bone quality in a broad perspective. The primary outcome was clinical fractures. Secondary outcomes were vertebral, non-vertebral, hip, and major osteoporotic fractures, all cause mortality, adverse events, and serious cardiovascular adverse events.

RESULTS

The results were based on 69 trials (>80 000 patients). For clinical fractures, synthesis of the results showed a protective effect of bisphosphonates, parathyroid hormone receptor agonists, and romosozumab compared with placebo. Compared with parathyroid hormone receptor agonists, bisphosphonates were less effective in reducing clinical fractures (odds ratio 1.49, 95% confidence interval 1.12 to 2.00). Compared with parathyroid hormone receptor agonists and romosozumab, denosumab was less effective in reducing clinical fractures (odds ratio 1.85, 1.18 to 2.92 for denosumab v parathyroid hormone receptor agonists and 1.56, 1.02 to 2.39 for denosumab v romosozumab). An effect of all treatments on vertebral fractures compared with placebo was found. In the active treatment comparisons, denosumab, parathyroid hormone receptor agonists, and romosozumab were more effective than oral bisphosphonates in preventing vertebral fractures. The effect of all treatments was unaffected by baseline risk indicators, except for antiresorptive treatments that showed a greater reduction of clinical fractures compared with placebo with increasing mean age (number of studies=17; β=0.98, 95% confidence interval 0.96 to 0.99). No harm outcomes were seen. The certainty in the effect estimates was moderate to low for all individual outcomes, mainly because of limitations in reporting, nominally indicating a serious risk of bias and imprecision.

CONCLUSIONS

The evidence indicated a benefit of a range of treatments for osteoporosis in postmenopausal women for clinical and vertebral fractures. Bone anabolic treatments were more effective than bisphosphonates in the prevention of clinical and vertebral fractures, irrespective of baseline risk indicators. Hence this analysis provided no clinical evidence for restricting the use of anabolic treatment to patients with a very high risk of fractures.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019128391.

Comparison of the Efficacy of Zoledronate Acid or Denosumab After Switching from Romosozumab in Japanese Postmenopausal Patients

We aimed to compare the efficacy of switching from romosozumab (RMAb) to denosumab (DMAb) or zoledronic acid (Zol) with respect to changes in bone mineral density (BMD) and bone metabolism. We also aimed to determine predictors of changes in BMD among patients who received sequential therapy from RMAb. One hundred patients who received RMAb therapy were recruited for this study. A total 49 patients received bisphosphonate (BP) pre-treatment and 51 received active vitamin D3 analog pre-treatment or no treatment. Forty-two patients were switched to Zol (BP-RMAb-Zol; 20 and RMAb-Zol; 22), and 58 patients were switched to DMAb (BP-RMAb-DMAb; 29 and RMAb-DMAb; 29). Longitudinal changes in bone metabolic markers (P1NP and TRACP-5b) and BMD were also evaluated. In the BP-RMAb-Zol group, TRACP-5b increased after administration of Zol, and the mean BMD of the lumbar spine (LS) was significantly lower than those in the BP-RMAb-DMAb, RMAb-Zol and RMAb-DMAb groups at 24 months. The % changes in BMD of the LS after 24 months were associated with TRACP-5b values at baseline and at 12 months in patients who received Zol therapy, and with TRACP-5b value at baseline in patients who received DMAb therapy. The DMAb follow-on regimen could be considered more effective than Zol as a sequential agent for the enhancement of BMD after RMAb in patients with BP pretreatment. TRACP-5b, especially the baseline value, may predict the efficacy of sequential therapy from RMAb, as well as previous treatments.

Management of bone loss due to endocrine therapy during cancer treatment

Bone modifying agents BMAs (oral and IV bisphosphonates, denosumab) are used to treat bone loss due to endocrine therapy in patients with hormone receptor positive (HR +) early breast cancer and non-metastatic prostate cancer (NMPC). Timely initiation of appropriate sequential therapy is imperative to reduce cancer treatment-induced bone loss (CTIBL). This narrative review summarizes current literature regarding management of CTIBL in HR + early breast cancer and NMPC patients. Risk factors for fragility fractures, screening strategies, optimal timing for the treatment, dosing/duration of therapy, and post treatment monitoring have not been clearly defined in HR + early breast and NMPC patients receiving endocrine therapy. This review aims to discuss the utility of fracture risk assessment (FRAX) tool for the prevention and management of CTIBL, osteoanabolic therapy for imminent fracture risk reduction, and sequential therapy options. Using predefined terms, PubMed, MEDLINE, and Google Scholar were searched for studies on CTIBL in HR + breast and NMPC patients. We included randomized clinical trials, meta-analysis, evidence-based reviews, observational studies, and clinical practice guidelines. Fracture risk assessment tools (FRAX) guide therapy for osteoporosis in patients with early HR + breast cancer and NMPC. BMAs to prevent bone loss should be initiated at higher T-score than recommended by FRAX in premenopausal HR + breast cancer patients with chemotherapy-induced ovarian failure, oophorectomy and gonadotropin releasing hormone (GnRH) therapy, post-menopausal women with HR + breast cancer receiving aromatase inhibitor therapy, and NMPC patients with androgen deprivation therapy. Sequential therapy with osteoanabolic agents as first line treatment offers a potential therapeutic strategy in patients with high imminent fracture risk. Due to limited data in cancer patients regarding management of osteoporosis, a dosing schedule similar to osteoporosis is considered appropriate. Risk stratification to identify vulnerable patient population, choosing the appropriate sequential therapy, and close monitoring of patients at the risk of bone loss can potentially reduce the mortality, morbidity, and health care cost related to CTIBL.

Clinical Utility of Romosozumab in the Management of Osteoporosis: Focus on Patient Selection and Perspectives

As one of the most potent osteoanabolic agents with a unique mechanism of action, romosozumab has high efficacy for osteoporosis treatment. It is a monoclonal antibody against sclerostin, a natural inhibitor of the Wnt signaling pathway, and by inhibiting sclerostin, activation of Wnt signaling occurs with a cascade of changes ultimately leading to bone mineral density (BMD) gains. Romosozumab stimulates bone modeling and has a dual effect of activating bone formation while inhibiting bone resorption. With this unique mechanism of action, treatment with romosozumab leads to a rapid and significant gain in BMD; these gains are higher than seen with bisphosphonates, denosumab, or parathyroid hormone (PTH) analogs. The FRAME and ARCH studies represent two pivotal trials demonstrating the efficacy of romosozumab in treating osteoporosis. Treatment with romosozumab should be followed by an antiresorptive agent, as this approach has demonstrated maintenance of or greater increases in BMD and reduced fracture risk even after finishing romosozumab treatment. As an osteoanabolic agent, romosozumab has shown superiority to alendronate in reducing fracture risk, increasing bone density, and potentially more rapid fracture risk reduction. Recent data have suggested that romosozumab prior to antiresorptive therapy may be the ideal treatment sequence, especially in high-risk patients and patients at imminent risk of fracture. Carrying a black box warning, romosozumab should be avoided in patients who have had myocardial infarction or stroke in the past year. Further studies are needed to clarify the increased cardiovascular risk attributed to this drug. Romosozumab has expanded our osteoporosis armamentarium and has enabled novel approaches, including "treat to target." Future studies are needed to evaluate the optimal use sequence and to assess its safety, especially in patients with cardiovascular risk factors.

The why and how of sequential and combination therapy in osteoporosis. A review of the current evidence

It is now well recognized that over the lifetime of a patient with osteoporosis, more than one medication will be needed to treat the disease and to decrease fracture risk. Though current gaps in osteoporosis therapy can be potentially mitigated with sequential and combination regimens, how to move seamlessly amongst the multiple treatments currently available for osteoporosis for sustained efficacy is still unclear. Data from recent studies show that an anabolic agent such as teriparatide or romosozumab followed by an antiresorptive affords maximal gain in BMD and possibly better and earlier fracture risk reduction compared to a regimen which follows the opposite sequence. Sequentially moving to a bisphosphonate such as alendronate from an anabolic agent such as abaloparatide has also been shown to preserve the fracture reduction benefits seen with the latter. This sequence of an anabolic agent followed by an antiresorptive should especially be considered in the high-risk patient with imminent fracture risk to rapidly reduce the risk of subsequent fractures. The data surrounding optimum timing of initiation of bisphosphonate therapy following denosumab discontinuation is still unclear. Though data suggests that combining a bisphosphonate with teriparatide does not provide substantial BMD gains compared to monotherapy, the concomitant administration of denosumab with teriparatide has been shown to significantly increase areal BMD as well as to increase volumetric BMD and estimated bone strength. This narrative review explores the available evidence regarding the various sequential and combination therapy approaches and the potential role they could play in better managing osteoporosis.

EXTENSIVE EXPERTISE IN ENDOCRINOLOGY: Osteoporosis management

Fractures occur in about half of older White women, and almost a third of older White men. However, 80% of the older individuals who have fractures do not meet the bone density definition of osteoporosis, suggesting that this definition is not an appropriate threshold for offering treatment. Fracture risk can be estimated based on clinical risk factors with or without bone density. A combination of calculated risk, fracture history, and bone density is used in treatment decisions. Medications available for reducing fracture risk act either to inhibit bone resorption or to promote bone formation. Romosozumab is unique in that it has both activities. Bisphosphonates are the most widely used interventions because of their efficacy, safety, and low cost. Continuous use of oral bisphosphonates for >5 years increases the risk of atypical femoral fractures, so is usually punctuated with drug holidays of 6-24 months. Denosumab is a further potent anti-resorptive agent given as 6-monthly s.c. injections. It is comparable to the bisphosphonates in efficacy and safety but has a rapid offset of effect after discontinuation so must be followed by an alternative drug, usually a bisphosphonate. Teriparatide stimulates both bone formation and resorption, substantially increases spine density, and reduces vertebral and non-vertebral fracture rates, though data for hip fractures are scant. Treatment is usually limited to 18-24 months, followed by the transition to an anti-resorptive. Romosozumab is given as monthly s.c. injections for 1 year, followed by an anti-resorptive. This sequence prevents more fractures than anti-resorptive therapy alone. Because of cost, anabolic drugs are usually reserved for those at very high fracture risk. 25-hydroxyvitamin D levels should be maintained above 30 nmol/L, using supplements if sunlight exposure is limited. Calcium intake has little effect on bone density and fracture risk but should be maintained above 500 mg/day using dietary sources.

Verification of efficacy and safety of ibandronate or denosumab for postmenopausal osteoporosis after 12-month treatment with romosozumab as sequential therapy: The prospective VICTOR study

Romosozumab is a potent drug for treating postmenopausal osteoporosis but has a limited dosing period of 12 months. Bone mineral density (BMD) decreases soon after romosozumab discontinuation, thus emphasizing the importance of appropriate sequential treatment. The present VICTOR randomized controlled study compared the efficacy of ibandronate and denosumab as sequential therapy options following 12-month romosozumab treatment. Subjects completing 12 months of romosozumab administration for severe postmenopausal osteoporosis were randomly assigned to receive either ibandronate or denosumab for an additional 12 months. The primary outcome of interest was the percentage changes in BMD at the lumbar spine, total hip, and femoral neck from 12 months (completion of romosozumab) to 18 and 24 months of total treatment (6 and 12 months, respectively, after the conversion to sequential therapy). Secondary outcomes included alterations in serum bone turnover markers and the incidence of adverse events. Sixty-two subjects each in the ibandronate and denosumab groups completed the sequential therapy. The respective percentage changes in BMD at the lumbar spine from 12 months to 24 months were 2.5 % in the ibandronate group and 5.4 % in the denosumab group. At 24 months, we observed significant differences versus 12 months for both groups as well as between the groups (all P < 0.01), showing a superior ability to increase BMD at the lumbar spine for denosumab over ibandronate. BMD gains at the total hip and femoral neck exhibited comparably favorable trends. P1NP and TRACP-5b were significantly decreased from 12 to 24 months (-64.9 % and - 26.8 % in the ibandronate group and - 67.4 % and - 36.3 % in the denosumab group, respectively; all P < 0.001 versus 12 months). Several minor adverse events were recorded in both groups, none of which led to the discontinuation of the trial. The VICTOR study revealed that denosumab could be considered more effective than ibandronate, with few severe adverse events, for the enhancement of BMD as a sequential agent after romosozumab in postmenopausal osteoporosis patients.

Management of patients at very high risk of osteoporotic fractures through sequential treatments

Osteoporosis care has evolved markedly over the last 50 years, such that there are now an established clinical definition, validated methods of fracture risk assessment and a range of effective pharmacological agents. Currently, bone-forming (anabolic) agents, in many countries, are used in those patients who have continued to lose bone mineral density (BMD), patients with multiple subsequent fractures or those who have fractured despite treatment with antiresorptive agents. However, head-to-head data suggest that anabolic agents have greater rapidity and efficacy for fracture risk reduction than do antiresorptive therapies. The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) convened an expert working group to discuss the tools available to identify patients at high risk of fracture, review the evidence for the use of anabolic agents as the initial intervention in patients at highest risk of fracture and consider the sequence of therapy following their use. This position paper sets out the findings of the group and the consequent recommendations. The key conclusion is that the current evidence base supports an "anabolic first" approach in patients found to be at very high risk of fracture, followed by maintenance therapy using an antiresorptive agent, and with the subsequent need for antiosteoporosis therapy addressed over a lifetime horizon.

Drug therapy for osteoporosis in older adults

The goal of osteoporosis management is to prevent fractures. Several pharmacological agents are available to lower fracture risk, either by reducing bone resorption or by stimulating bone formation. Bisphosphonates are the most widely used anti-resorptives, reducing bone turnover markers to low premenopausal concentrations and reducing fracture rates (vertebral by 50-70%, non-vertebral by 20-30%, and hip by ~40%). Bisphosphonates bind avidly to bone mineral and have an offset of effect measured in months to years. Long term, continuous use of oral bisphosphonates is usually interspersed with drug holidays of 1-2 years, to minimise the risk of atypical femoral fractures. Denosumab is a monoclonal antibody against RANKL that potently inhibits osteoclast development and activity. Denosumab is administered by subcutaneous injection every 6 months. Anti-fracture effects of denosumab are similar to those of the bisphosphonates, but there is a pronounced loss of anti-resorptive effect from 7 months after the last injection, which can result in clusters of rebound vertebral fractures. Two classes of anabolic drugs are now available to stimulate bone formation. Teriparatide and abaloparatide both target the parathyroid hormone-1 receptor, and are given by daily subcutaneous injection for up to 2 years. Romosozumab is an anti-sclerostin monoclonal antibody that stimulates bone formation and inhibits resorption. Romosozumab is given as monthly subcutaneous injections for 1 year. Head-to-head studies suggest that anabolic agents have greater anti-fracture efficacy and produce larger increases in bone density than anti-resorptive drugs. The effects of anabolic agents are transient, so transition to anti-resorptive drugs is required. The optimal strategy for cycling anabolics, anti-resorptives, and off-treatment periods remains to be determined.

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.

Risks vs. benefits of switching therapy in patients with postmenopausal osteoporosis

Introduction: Osteoporosis is characterized by the fragility of bones, leading to fractures and, consequently, the deterioration of functional capacity and quality of life. Postmenopausal women, in particular, are prone to osteoporosis and often require anti-osteoporosis treatment. In the last few decades, various anti-osteoporosis drugs have been approved for clinical use. In an aging society, osteoporosis cannot be treated using a single agent; therefore, switching therapy is an important treatment strategy.Areas covered: This review covers switching therapy in patients with postmenopausal osteoporosis. It's extremely important to understand the characteristics of each drug including; limitations on the duration of use, side effects due to long-term use (such as atypical femur fracture and osteonecrosis of the jaw) or discontinuation (such as rebound phenomenon), compliance, and ability to prevent fractures. We review and summarize the risks and benefits of switching therapy.Expert opinion: When switching therapy, the order of drug administration is important. Routine monitoring should be continued after switching treatments. We recommend first using osteoanabolic agents in postmenopausal women with severe osteoporosis. In addition, identifying predictors of the efficacy and side effects of treatment may help prevent the inappropriate use of drugs for the treatment of osteoporosis.

Recent Progresses in the Treatment of Osteoporosis

Osteoporosis (OP) is a chronic bone disease characterized by aberrant microstructure and macrostructure of bone, leading to reduced bone mass and increased risk of fragile fractures. Anti-resorptive drugs, especially, bisphosphonates, are currently the treatment of choice in most developing countries. However, they do have limitations and adverse effects, which, to some extent, helped the development of anabolic drugs such as teriparatide and romosozumab. In patients with high or very high risk for fracture, sequential or combined therapies may be considered with the initial drugs being anabolic agents. Great endeavors have been made to find next generation drugs with maximal efficacy and minimal toxicity, and improved understanding of the role of different signaling pathways and their crosstalk in the pathogenesis of OP may help achieve this goal. Our review focused on recent progress with regards to the drug development by modification of Wnt pathway, while other pathways/molecules were also discussed briefly. In addition, new observations made in recent years in bone biology were summarized and discussed for the treatment of OP.

Skeletal responses to romosozumab after 12 months of denosumab

Romosozumab, a monoclonal anti‐sclerostin antibody that has the dual effect of increasing bone formation and decreasing bone resorption, reduces fracture risk within 12 months. In a post hoc, exploratory analysis, we evaluated the effects of romosozumab after 12 months of denosumab in postmenopausal women with low bone mass who had not received previous osteoporosis therapy. This phase 2 trial (NCT00896532) enrolled postmenopausal women with a lumbar spine, total hip, or femoral neck T‐score ≤ −2.0 and ≥ −3.5. Individuals were randomized to placebo or various romosozumab dosing regimens from baseline to month 24, were re‐randomized to 12 months of denosumab or placebo (months 24–36), and then all received romosozumab 210 mg monthly for 12 months (months 36–48). Results for the overall population have been previously published. Here, we present results for changes in bone mineral density (BMD) and levels of procollagen type I N‐terminal propeptide (P1NP) and β‐isomer of the C‐terminal telopeptide of type I collagen (β‐CTX) from a subset of women who were randomized to placebo for 24 months, were re‐randomized to receive denosumab (n = 16) or placebo (n = 12) for 12 months, and then received romosozumab for 12 months. In women who were randomized to placebo followed by denosumab, romosozumab treatment for 12 months maintained BMD gained during denosumab treatment at the total hip (mean change from end of denosumab treatment of 0.9%) and further increased BMD gains at the lumbar spine (mean change from end of denosumab treatment of 5.3%). Upon transition to romosozumab (months 36–48), P1NP and β‐CTX levels gradually returned to baseline from their reduced values during denosumab administration. Transitioning to romosozumab after 12 months of denosumab appears to improve lumbar spine BMD and maintain total hip BMD while possibly preventing the rapid increase in levels of bone turnover markers above baseline expected upon denosumab discontinuation. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Role of bone-forming agents in the management of osteoporosis

Recent evidence confirms the superiority of osteoanabolic therapy compared to anti-remodeling drugs for rapid improvement in bone density and fracture risk reduction, providing strong justification for the use of these anabolic agents as the initial therapy in high-risk patients, to be followed by anti-remodeling therapy. This review will highlight the results of recent studies and define the current status of osteoanabolic therapy for osteoporosis.

Skeletal Aging and Osteoporosis: Mechanisms and Therapeutics

Bone is a dynamic organ maintained by tightly regulated mechanisms. With old age, bone homeostasis, which is maintained by an intricate balance between bone formation and bone resorption, undergoes deregulation. Oxidative stress-induced DNA damage, cellular apoptosis, and cellular senescence are all responsible for this tissue dysfunction and the imbalance in the bone homeostasis. These cellular mechanisms have become a target for therapeutics to treat age-related osteoporosis. Genetic mouse models have shown the importance of senescent cell clearance in alleviating age-related osteoporosis. Furthermore, we and others have shown that targeting cellular senescence pharmacologically was an effective tool to alleviate age- and radiation-induced osteoporosis. Senescent cells also have an altered secretome known as the senescence associated secretory phenotype (SASP), which may have autocrine, paracrine, or endocrine function. The current review discusses the current and potential pathways which lead to a senescence profile in an aged skeleton and how bone homeostasis is affected during age-related osteoporosis. The review has also discussed existing therapeutics for the treatment of osteoporosis and rationalizes for novel therapeutic options based on cellular senescence and the SASP as an underlying pathogenesis of an aging bone.

[Osteoporosis-Update 2021]

The state of the art of osteoporosis management and treatment is being continuously refined according to recent progress in data availability, drug development and strategies as determined by health authorities. The recent approval of the sclerostin-antibody romosozumab as a novel first in class anabolic drug is another milestone that enriches our therapeutic portfolio. Neutralisation of the wnt-pathway inhibitor sclerostin by romosozumab leads to rapid stimulation of bone formation and a rise in bone mineral density that translates into robust > 70 % reduction of fracture risk at the lumbar spine. Already after one year of treatment romosozumab is stopped and followed by antiresorptive maintenance treatment. The indication for this strategy is severe osteoanabolic compounds can now be applied as a first line treatment without prior antiresorptive medication. The new data helped in alleviating restrictions by the authorities for first line use of anabolic strategies. Romosozumab and teriparatide represent two anabolic strategies that differ in their mode of action although the molecular mechanisms are partially overlapping. Teriparatide is primarily active as a remodeling agent whereas romosozumab exerts bone mass gains mainly via modeling. Differential therapeutic strategies throughout a patient "career" may take into account these differences as well as adverse effects and individual contraindications. Based on all our recent progress and achievement we can more and more individualize the long term management of osteoporosis over decades applying an individual "treat to target" strategy. Basically, osteoporosis is a chronic disease and has to be treated as such. If however for whatever reason treatment regimens using biologicals are being discontinued we have to be aware that such situations need to be stabilized using long-acting bisphosphonates to maintain the therapeutic success and avoid rapid bone loss and fracture risk.

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.

Anti-Sclerostin Antibodies in Osteoporosis and Other Bone Diseases

The Wnt pathway is a key element of bone remodeling; its activation stimulates bone formation and inhibits bone resorption. The discovery of sclerostin, a natural antagonist of the Wnt pathway, promoted the development of romosozumab, a human monoclonal antibody directed against sclerostin, as well as other anti-sclerostin antibodies. Phase 3 studies have shown the efficacy of romosozumab in the prevention of fractures in postmenopausal women, against placebo but also against alendronate or teriparatide and this treatment also allows bone mineral density (BMD) increase in men. Romosozumab induces the uncoupling of bone remodeling, leading to both an increase in bone formation and a decrease in bone resorption during the first months of treatment. The effect is attenuated over time and reversible when stopped but transition with anti-resorbing agents allows the maintenance or reinforcement of BMD improvements. Some concerns were raised about cardiovascular events. Therefore, romosozumab was recently approved in several countries for the treatment of severe osteoporosis in postmenopausal women with high fracture risk and without a history of heart attack, myocardial infarction or stroke. This review aims to outline the role of sclerostin, the efficacy and safety of anti-sclerostin therapies and in particular romosozumab and their place in therapeutic strategies against osteoporosis or other bone diseases.