Romosozumab in Skeletally Mature Adults with a Fresh Unilateral Tibial Diaphyseal Fracture: A Randomized Phase-2 Study

Managing delayed union of fragility fractures of the pelvis successfully using romosozumab: A case report

Fragility fractures of the pelvis (FFPs) are typically caused by minor trauma or without any trauma in older individuals with osteoporosis. In recent years, FFP incidence has increased considerably owing to the increasing number of individuals in the aging population as well as impaired daily life. Surgeries are the main treatment options for some types of FFPs; however, the potential of the use of romosozumab, an FDA-approved humanized monoclonal antibody that can bind and inhibit sclerostin, is yet to be evaluated. Romosozumab substantially increases bone mineral density (BMD) in the spine and the hip, improves bone strength, and prevents the occurrence of new fractures. Previous studies have demonstrated the efficacy of romosozumab in promoting fracture healing, including the healing of nonunion in some fractures. Herein, we present a case of a 61-year-old woman who had FFP delayed union, after falling 4 months before visiting our hospital. She presented with bilateral buttock and leg pain. Baseline BMD measured using dual-energy X-ray absorptiometry revealed a T-score of -3.8 and -3.2 for the lumbar spine and total hip, respectively. As the patient's BMD indicated a high risk of fractures, romosozumab was administered. Her pain improved 3 months after the medication. Computed tomography taken after 3 months revealed that the fracture had healed, suggesting that romosozumab is an effective medication for treating FFP delayed union and nonunion.

Bone healing response to systemic bisphosphonate-prostaglandin E2 receptor 4 agonist treatment in female rats with a critical-size femoral segmental defect

Despite the wide body of research into prevention and treatment of nonunion, current bone fracture therapies remain suboptimal in their efficacy. Previous animal studies show that MES-1022, a bone-targeted prodrug that activates the prostaglandin E2 receptor EP4, stimulates bone healing when applied locally in uneventful defects. Here we investigated the healing capacity of systemically administered MES-1022 in a rat femoral critical size segmental defect. Ten-week-old female Sprague-Dawley rats (n = 8/group) underwent a 5 mm osteotomy of the left femoral midshaft, stabilized by a unilateral external fixator. Rats received weekly subcutaneous injections of MES-1022 at 5 mg/kg (MES1022-Hi), 1.7 mg/kg (MES1022-Lo), or Vehicle without a defect site scaffold. Serum bone markers and open field activity were measured pre-osteotomy and throughout the study. Rats were sacrificed after 12 weeks and osteotomized femora were imaged via microcomputed tomography (microCT) followed by histology and immunohistochemistry to assess healing. Complete bridging of the defect occurred in one rat from the MES1022-Hi group and zero from MES1022-Lo and Vehicle groups. However, healing outcomes in both MES-1022 groups for bone volume fraction, bone volume, bridging score, callus tissue composition, callus blood vessel density, P1NP levels, TRAcP-5b levels, and physical activity did not differ from Vehicle. Fracture callus osteoclast density and spleen weight were increased in MES1022-Hi rats relative to Vehicle. Overall, systemic administration of MES-1022 alone may not suffice for treatment of large segmental bone defects. Additional studies are needed to determine whether systemic MES-1022 is a useful therapeutic in conjunction with local scaffolds like bone graft substitutes.

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.

Assessment of evidence for the off-label application of osteoanabolic drugs in fracture healing and spinal fusion

Osteoanabolic drugs are sometimes prescribed off-label for "fracture healing and spinal fusion." This study examines the scientific validity of such practices by analyzing existing clinical reports. The purported bone union-promoting effect of teriparatide in fracture cases has been refuted in clinical trials. While teriparatide shows efficacy in accelerating spinal fusion after surgery for patients with osteoporosis, there is no scientific justification for its off-label use in patients without osteoporosis. For osteoporosis patients, no clear evidence suggests that teriparatide is superior to antiresorptive drugs, making the rationale for switching from antiresorptive drugs to teriparatide weak. The efficacy in postoperative spinal fusion may primarily be attributed to systemic improvements in bone quality and quantity, enhancing the mechanical engagement of implants. The clinical evidence for the off-label use of romosozumab, another osteoanabolic drug, in fracture healing and spinal fusion is insufficient to support its efficacy. In conclusion, osteoanabolic drugs, like antiresorptive drugs, primarily have systemic functions in osteoporosis patients, with limited evidence supporting their role in promoting localized bone formation in fractures or spinal fusions.

[Influencing fracture healing by specific osteoporosis medications]

BACKGROUND

Osteoporosis is a widespread disease defined by a reduction in bone mass and structure, thereby increasing the risk of fragility fractures. Treatment typically involves specific medications, which either inhibit bone resorption (antiresorptive) or stimulate bone formation (anabolic) and may potentially influence the healing of osteoporotic fractures. On the other hand, metabolic disorders, immune system dysfunctions or circulatory problems can impair fracture healing. Therefore, the targeted use of osteoporosis medications could be a strategy to promote the healing of impaired fractures.

OBJECTIVE

The aim of this study is to provide a current overview of the effects of osteoporosis medications approved in Germany on fracture healing. The focus is on the potential influence of these medications in the context of osteoporosis treatment. Additionally, the current state of research is examined to explore to what extent the targeted use of these medications could improve fracture healing.

MATERIAL AND METHODS

A literature search was conducted in the PubMed database using topic-specific keywords. Preclinical studies, clinical trials, review articles and meta-analyses were considered to present the current scientific knowledge with clinical relevance.

RESULTS

Preclinical and clinical studies suggest that specific osteoporosis medications do not have a clinically relevant negative impact on the healing of fragility fractures. Osteoanabolic substances even tend to have a positive effect on fracture healing in both normal and impaired healing processes; however, the available studies are limited and none of the medications have been approved for this specific use.

DISCUSSION

Osteoporosis medications with antiresorptive or osteoanabolic effects are primarily used to treat osteoporosis, especially after fragility fractures, to reduce the risk of further fractures. There is no clinically relevant impairment of fracture healing due to these medications. Further studies would be required to obtain approval for these medications specifically to improve fracture healing.

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.

Latest on Anabolic Agents for Osteoporosis Treatment

In the last decades, novel therapeutics with anabolic bone properties have been developed and are currently used in the management of osteoporosis particularly in patients with high-risk of fragility fractures. These drugs include PTH-Related Analogues, teriparatide and abaloparatide, and the anti-sclerostin agent romosozumab, this latter drug currently approved only in female patients. Their efficacies in preventing fragility fractures are widely demonstrated and their potential serious side effects were progressively downgraded, including risk of malignancies in teriparatide- and cardiovascular events in romosozumab-users, respectively. Further data are warranted about their efficacy in glucocorticoids-induces osteoporosis and fracture healings.

Monoclonal antibody anti-sclerostin for treatment of pelvic insufficiency fractures in adult hypophosphatasia: A case report

Hypophosphatasia is a rare inherited metabolic disease leading to inhibition of bone and teeth mineralization that can be complicated by multiple insufficiency fractures. Treatment is currently limited to enzyme replacement therapy using bone-targeting recombinant human alkaline phosphatase, or asfotase alfa. Romosozumab is a monoclonal anti-sclerostin antibody originally indicated for the treatment of osteoporosis in postmenopausal women with high-risk of fracture. Recently its indication had been expanded to other metabolic bone disorders such as osteogenesis imperfecta. We report a unique case of a 67-yer-old female with hypophosphatasia complicated by multiple delayed-union and nonunion insufficiency fractures of the pelvis. After 12-month therapy with Romosozumab to address her osteoporosis, the patient healed her fractures and increased her bone mass density. Our case report shows interesting effects of Romozumab in an adult patient with hypophosphatasia. It not only helped increase bone density, but also help in the healing process of delayed-union and nonunion insufficiency fractures of the pelvis and prevented the occurrence of new fractures during the treatment period. To our knowledge, this is the first report describing the potential effect of Romosozumab on insufficiency fractures in patients with hypophosphatasia.

Treatment effects, adverse outcomes and cardiovascular safety of romosozumab - Existing worldwide data: A systematic review and meta-analysis

Background

Romosozumab is a novel monoclonal antibody that binds to sclerostin, and has dual effects of increasing bone formation and decreasing bone resorption, giving it a unique mechanism of action. The objective of this study was to perform a systematic review and meta-analysis based on existing worldwide data on treatment effects and safety of romosozumab in randomized controlled trials.

Methods

A systematic search was carried out on four databases including PubMed, Embase, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL). The keywords used for search was "(romosozumab) AND (osteoporosis OR safety)". Randomized controlled trial or post-hoc studies of the included randomized controlled trial which studied the effects and safety of romosozumab were included. The quality of selected studies was assessed with the Cochrane collaboration tool and the PEDro scale.

Results

20 studies were included for qualitative analysis. 14 studies were included for meta-analysis. In total, there were 13,507 (n = 13,507) participants with 637 men and 12,870 women from original cohorts. The overall mean difference was in favor of romosozumab treatment for lumbar spine (10.04 (95 % confidence interval (CI) = 7.51-12.57; p < 0.00001)), total hip (4.04 (95 % CI = 3.10-4.99; p < 0.00001)) and femoral neck bone mineral density (3.77 (95 % CI = 2.90-4.64; p < 0.00001)) at 12 months. There was significantly less likelihood of new vertebral fractures with romosozumab compared to control (odds ratio (OR) 0.42 (95 % CI = 0.20-0.89); p = 0.02) at 12 months of treatment. There was significantly less likelihood of new vertebral fracture at 24 months with 12 months of romosozumab followed by sequential treatment with anti-resorptive compared to control with only anti-resorptive agent use (OR 0.36 (95 % CI = 0.18-0.71); p = 0.003). There was no significant difference in serious adverse events and fatal adverse events with use of romosozumab compared with control in our meta-analyses. There were no significant differences in serious cardiovascular events in Asian population of romosozumab with control group with 12 months of romosozumab treatment followed by 24 months of anti-resorptive agent with OR 1.09 (95 % CI = 0.40-2.96; P = 0.86). There was no significant difference between romosozumab group and control group for the median time to radiographic healing. Our qualitative analysis on Quantitative Computed Tomography (QCT), Finite element analysis (FEA) and bone biopsy analyses demonstrated that romosozumab improved parameters and measures in these domains as well.

Conclusion

In conclusion, our study showed that romosozumab was an effective agent to treat osteoporosis with high quality evidence. There were no significant differences in the adverse events, serious adverse events, fatal adverse events identified. Further subgroup analysis of cardiovascular events and cardiovascular death in the total population showed no differences either.

The translational potential of this article

Given the results, romosozumab is an effective agent to treat patients with very-high risk of osteoporotic fractures.

β-catenin mRNA encapsulated in SM-102 lipid nanoparticles enhances bone formation in a murine tibia fracture repair model

Fractures continue to be a global economic burden as there are currently no osteoanabolic drugs approved to accelerate fracture healing. In this study, we aimed to develop an osteoanabolic therapy which activates the Wnt/β-catenin pathway, a molecular driver of endochondral ossification. We hypothesize that using an mRNA-based therapeutic encoding β-catenin could promote cartilage to bone transformation formation by activating the canonical Wnt signaling pathway in chondrocytes. To optimize a delivery platform built on recent advancements in liposomal technologies, two FDA-approved ionizable phospholipids, DLin-MC3-DMA (MC3) and SM-102, were used to fabricate unique ionizable lipid nanoparticle (LNP) formulations and then tested for transfection efficacy both in vitro and in a murine tibia fracture model. Using firefly luciferase mRNA as a reporter gene to track and quantify transfection, SM-102 LNPs showed enhanced transfection efficacy in vitro and prolonged transfection, minimal fracture interference and no localized inflammatory response in vivo over MC3 LNPs. The generated β-cateninGOF mRNA encapsulated in SM-102 LNPs (SM-102-β-cateninGOF mRNA) showed bioactivity in vitro through upregulation of downstream canonical Wnt genes, axin2 and runx2. When testing SM-102-β-cateninGOF mRNA therapeutic in a murine tibia fracture model, histomorphometric analysis showed increased bone and decreased cartilage composition with the 45 μg concentration at 2 weeks post-fracture. μCT testing confirmed that SM-102-β-cateninGOF mRNA promoted bone formation in vivo, revealing significantly more bone volume over total volume in the 45 μg group. Thus, we generated a novel mRNA-based therapeutic encoding a β-catenin mRNA and optimized an SM-102-based LNP to maximize transfection efficacy with a localized delivery.

Impact of osteoporosis and osteoporosis medications on fracture healing: a narrative review

Antiresorptive medications do not negatively affect fracture healing in humans. Teriparatide may decrease time to fracture healing. Romosozumab has not shown a beneficial effect on human fracture healing.

BACKGROUND

Fracture healing is a complex process. Uncertainty exists over the influence of osteoporosis and the medications used to treat it on fracture healing.

METHODS

Narrative review authored by the members of the Fracture Working Group of the Committee of Scientific Advisors of the International Osteoporosis Foundation (IOF), on behalf of the IOF and the Société Internationale de Chirurgie Orthopédique et de Traumatologie (SICOT).

RESULTS

Fracture healing is a multistep process. Most fractures heal through a combination of intramembranous and endochondral ossification. Radiographic imaging is important for evaluating fracture healing and for detecting delayed or non-union. The presence of callus formation, bridging trabeculae, and a decrease in the size of the fracture line over time are indicative of healing. Imaging must be combined with clinical parameters and patient-reported outcomes. Animal data support a negative effect of osteoporosis on fracture healing; however, clinical data do not appear to corroborate with this. Evidence does not support a delay in the initiation of antiresorptive therapy following acute fragility fractures. There is no reason for suspension of osteoporosis medication at the time of fracture if the person is already on treatment. Teriparatide treatment may shorten fracture healing time at certain sites such as distal radius; however, it does not prevent non-union or influence union rate. The positive effect on fracture healing that romosozumab has demonstrated in animals has not been observed in humans.

CONCLUSION

Overall, there appears to be no deleterious effect of osteoporosis medications on fracture healing. The benefit of treating osteoporosis and the urgent necessity to mitigate imminent refracture risk after a fracture should be given prime consideration. It is imperative that new radiological and biological markers of fracture healing be identified. It is also important to synthesize clinical and basic science methodologies to assess fracture healing, so that a convergence of the two frameworks can be achieved.

Romosozumab in patients who experienced an on-study fracture: post hoc analyses of the FRAME and ARCH phase 3 trials

Post hoc analysis of FRAME and ARCH revealed that on-study nonvertebral and vertebral fractures by Month 12 were less common in women initially treated with romosozumab versus placebo or alendronate. Recurrent fracture risk was also lower in romosozumab‑treated patients, and there were no fracture‑related complications. Results support continuing romosozumab treatment post‑fracture.

PURPOSE

Post hoc analysis evaluating efficacy and safety of romosozumab, administered in the immediate post‑fracture period, in the FRAME and ARCH phase 3 trials.

METHODS

In FRAME (NCT01575834) and ARCH (NCT01631214), postmenopausal women with osteoporosis were randomized 1:1 to romosozumab 210 mg monthly or comparator (FRAME, placebo; ARCH, alendronate 70 mg weekly) for 12 months, followed by antiresorptive therapy (FRAME, denosumab; ARCH, alendronate). In patients who experienced on-study nonvertebral or new/worsening vertebral fracture by Month 12, we report the following: fracture and treatment‑emergent adverse event (TEAE) incidence through 36 months, bone mineral density changes (BMD), and romosozumab timing. Due to the sample sizes employed, meaningful statistical comparisons between treatments were not possible.

RESULTS

Incidence of on-study nonvertebral and vertebral fractures by Month 12 was numerically lower in romosozumab- versus comparator-treated patients (FRAME, 1.6% and 0.5% versus 2.1% and 1.6%; ARCH, 3.4% and 3.3% versus 4.6% and 4.9%, respectively). In those who experienced on-study nonvertebral fracture by Month 12, recurrent nonvertebral and subsequent vertebral fracture incidences were numerically lower in patients initially treated with romosozumab versus comparator (FRAME, 3.6% [2/56] and 1.8% [1/56] versus 9.2% [7/76] and 3.9% [3/76]; ARCH, 10.0% [7/70] and 5.7% [4/70] versus 12.6% [12/95] and 8.4% [8/95], respectively). Among those with on-study vertebral fracture by Month 12, recurrent vertebral and subsequent nonvertebral fracture incidences were numerically lower with romosozumab versus comparator (FRAME, 0.0% [0/17] and 0.0% [0/17] versus 11.9% [7/59] and 8.5% [5/59]; ARCH, 9.0% [6/67] and 7.5% [5/67] versus 15.0% [15/100] and 16.0% [16/100], respectively). In patients with fracture by Month 12, no fracture‑related complications were reported in romosozumab-treated patients. BMD gains were numerically greater with romosozumab than comparators.

CONCLUSION

Data suggest support for the efficacy and safety of continuing romosozumab treatment following fracture.

TRIAL REGISTRATIONS

NCT01575834; NCT01631214.

Close negative correlation of local and circulating Dickkopf-1 and Sclerostin levels during human fracture healing

Wnt signaling is critically involved in fracture healing. Existing data predominantly relies on rodent models. Here, we explored local and circulating Dickkopf-1 (DKK1) levels in patients with respect to fracture healing and explore its association to sclerostin (SOST). 69 patients after surgical stabilization of long bone fractures of which six patients had impaired fracture healing were included in this study. Life-style and patient related factors with a known effect on DKK1 and SOST were recorded. DKK1 and SOST concentrations were measured using enzyme-linked immunosorbent assay (ELISA) at the fracture site and in circulation. DKK1 and SOST showed a close inverse correlation. In fracture hematoma and immediately after trauma DKK1 levels were significantly reduced while SOST levels were significantly increased, compared to healthy control. Postoperatively, DKK1 peaked at week 2 and SOST at week 8, again demonstrating a close negative correlation. Age and smoking status affected the balance of DKK1 and SOST, while type 2 diabetes and sex did not demonstrate a significant influence. Early postoperative elevation of SOST without compensatory DKK1 decrease was associated with fracture non-union in younger patients (< 50a). The close inverse correlation and very rapid dynamics of DKK1 and SOST locally as well as systemically suggest their critical involvement during human fracture healing. Importantly, as immediate compensatory feedback mechanism are apparent, we provide evidence that dual-blockade of DKK1 and SOST could be critical to allow for therapeutic efficiency of Wnt targeted therapies for fracture healing.

Efficacy of Three Teriparatide Preparations and Romosozumab, Osteogenesis Promoters, in the Treatment of Fresh Vertebral Fractures: A Retrospective Observational Study

BACKGROUND

In Japan, daily, twice weekly, and weekly formulations of teriparatide (TPD) and monthly formulations of romosozumab (ROMO) are available as osteogenesis promoters for the treatment of osteoporosis with a high risk for fracture.

OBJECTIVE

To compare the effects of three TPD preparations and ROMO on fracture healing and low back pain after a fresh vertebral fracture.

METHODS

This was a retrospective observational study. Patients presenting with fresh osteoporotic vertebral fractures were treated subcutaneously with TPD daily (DTPD), twice weekly (2/WTPD), weekly (WTPD), or with ROMO monthly. Bone union, vertebral height changes, and low back pain in the injured vertebra were compared after 6 months of treatment.

RESULTS

Bone union and pain improvement were more frequent among those who received daily and twice weekly administration of TPD compared with those who received WTPD and ROMO administration. A comparison for multiplicity between the groups using the Steel-Dwass test showed significant differences between the DTPD and ROMO groups (p = 0.0029) and WTPD and ROMO groups (p = 0.0490), suggesting superior bone fusion in the DTPD and WTPD groups. Similarly, significant differences were noted between the DTPD and ROMO groups (p = 0.0001), WTPD and ROMO groups (p = 0.0341), and 2/WTPD and ROMO groups (p = 0.0009), indicating a higher degree of pain improvement in the DTPD, WTPD, and 2/WTPD groups compared with that in the ROMO group.

CONCLUSIONS

Daily, weekly, and twice-weekly administration of TPD may be superior to ROMO for promoting fresh vertebral fracture healing.

Romosozumab in osteoporosis: yesterday, today and tomorrow

Osteoporosis is a systemic bone disease characterized by low bone mass, microarchitectural deterioration, increased bone fragility, and fracture susceptibility. It commonly occurs in older people, especially postmenopausal women. As global ageing increases, osteoporosis has become a global burden. There are a number of medications available for the treatment of osteoporosis, categorized as anabolic and anti-resorptive. Unfortunately, there is no drugs which have dual influence on bone, while all drugs have limitations and adverse events. Some serious adverse events include jaw osteonecrosis and atypical femoral fracture. Recently, a novel medication has appeared that challenges this pattern. Romosozumab is a novel drug monoclonal antibody to sclerostin encoded by the SOST gene. It has been used in Japan since 2019 and has achieved promising results in treating osteoporosis. However, it is also accompanied by some controversy. While it promotes rapid bone growth, it may cause serious adverse events such as cardiovascular diseases. There has been scepticism about the drug since its inception. Therefore, the present review comprehensively covered romosozumab from its inception to its clinical application, from animal studies to human studies, and from safety to cost. We hope to provide a better understanding of romosozumab for its clinical application.

Dual Inhibition of the Wnt Inhibitors DKK1 and Sclerostin Promotes Fracture Healing and Increases the Density and Strength of Uninjured Bone: An Experimental Study in Nonhuman Primates

BACKGROUND

Fracture repair involves the reactivation of developmental signaling cascades, including Wnt signaling that stimulates bone formation and bone regeneration. Rodent data indicate that dual inhibition of the Wnt signaling antagonists sclerostin and Dickkopf-1 (DKK1) increases callus bone volume and strength while increasing bone mass systemically.

METHODS

We evaluated the effects of 16 weeks of subcutaneously administered carrier solution (vehicle, VEH), anti-sclerostin antibody (Scl-Ab), anti-DKK1 antibody (DKK1-Ab), or Scl-Ab plus DKK1-Ab combination therapy (COMBO) on ulnar osteotomy healing in nonhuman primates (cynomolgus monkeys; 20 to 22 per group).

RESULTS

Scl-Ab and COMBO therapy increased systemic markers of bone formation versus VEH, with COMBO leading to synergistic increases versus Scl-Ab or DKK1-Ab monotherapies. The COMBO and Scl-Ab groups showed reduced serum markers of bone resorption versus VEH. The COMBO and DKK1-Ab groups exhibited greater callus bone mineral density (BMD), torsional stiffness, and torsional rigidity versus VEH. Lumbar vertebrae from the Scl-Ab and COMBO groups showed greater BMD and bone formation rate versus VEH, and the femoral mid-diaphysis of the Scl-Ab and COMBO groups showed greater periosteal and endocortical bone formation rates versus VEH.

CONCLUSIONS

DKK1-Ab increased BMD and strength at the ulnar osteotomy site, Scl-Ab increased bone formation and BMD at uninjured skeletal sites, and Scl-Ab plus DKK1-Ab combination therapy induced all of these effects, in some cases to a greater degree versus 1 or both monotherapies. These results in nonhuman primates suggest that DKK1 preferentially regulates bone healing while sclerostin preferentially regulates systemic bone mass.

CLINICAL RELEVANCE

Combination therapy with antibodies against sclerostin and DKK1 may offer a promising therapeutic strategy for both fracture treatment and fracture prevention.

Pharmacological agents for bone fracture healing: talking points from recent clinical trials

INTRODUCTION

Pharmacological strategies might influence bone healing in terms of time to union or quality of mature bone. This expert opinion discussed the current level I evidence on the experimental pharmacological agents used to favor bone fracture healing.

AREAS COVERED

This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the 2020 PRISMA statement. In April 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, Embase. All the randomized clinical trials investigating pharmacological agents for bone fracture healing were accessed. No time constraint was set for the search. The search was restricted to RCTs. No additional filters were used in the database search. Data from 19 RCTs (4067 patients) were collected. 78% (3160 of 4067) were women. The mean length of the follow-up was 9.3 months (range, 1-26 months). The mean age of the patients was 64.4 years (range, 8-84 years).

EXPERT OPINION

Calcitonin could favor bone fracture healing. Bisphosphonates (alendronate, zoledronate, clodronate), monoclonal antibodies (denosumab, romosozumab), statins, vitamin D and calcium supplementation, strontium ranelate, and ibuprofen did not influence bony healing. Concerning the effect of parathormone, current level I evidence is controversial, and additional studies are required.

LEVEL OF EVIDENCE

Level I, systematic review of RCTs.

Post-Fracture Care Program: Pharmacological Treatment of Osteoporosis in Older Adults with Fragility Fractures

PURPOSE OF REVIEW

To present and discuss the recently published scientific evidence on the approach, mode of action, and timing of osteoporosis therapy initiation after fragility fractures.

RECENT FINDINGS

A comprehensive management approach is required to reduce mortality and morbidity associated with fragility fractures. This will help to reduce the risk of missing the diagnosis of osteoporosis as the underlying disorder while at the same time promoting the timely treatment of osteoporosis. The target is to minimize the incidence of post-traumatic disability and to reduce the imminent fracture risk. This article will present a Bone-Care algorithm for the diagnosis and management of fragility fractures in patients presenting for trauma surgery. This algorithm has been developed based on recently published national as well as international guidelines for implementation in standard clinical practice. International figures revealed that only a small proportion of those patients at high risk of sustaining a fragility fracture receive osteoporosis therapy. Based on the best currently available evidence, it is safe to start osteoporosis therapy in the acute post-fracture period (the optimal therapeutic window of romosozumab is the late endochondral phase/throughout bone remodeling). The right Bone-Care pathway ensures the delivery of a comprehensive management approach that meets the global call to action. All parameters including risk, benefit, compliance, and cost should be considered on an individual base for all kinds of therapy.

Fracture healing-orthobiologics: from basic science to clinical application

Orthopaedics as a field and a profession is fundamentally concerned with the treatment of musculoskeletal disease, in all of its many forms. Our collective understanding of the cellular mechanisms underlying musculoskeletal pathology resulting from injury continues to evolve, opening novel opportunities to develop orthobiologic treatments to improve care. It is a long path to move from an understanding of cellular pathology to development of successful clinical treatment, and this article proposes to discuss some of the challenges to achieving translational therapies in orthopaedics. The article will focus on challenges that clinicians will likely face in seeking to bring promising treatments forward to clinical practice and strategies for improving success in translational efforts.

Baicalin Nanocomplexes with an In Situ-Forming Biomimetic Gel Implant for Repair of Calvarial Bone Defects via Localized Sclerostin Inhibition

In situ-forming hydrogels are highly effective in covering complex and irregular tissue defects. Herein, a biomimetic gel implant (CS-GEL) consisting of methacrylated chondroitin sulfate and gelatin is obtained via visible light irradiation, which displays rapid gelation (∼30 s), suitable mechanical properties, and biological features to support osteoblast attachment and proliferation. Sclerostin is proven to be a viable target to promote osteogenesis. Hence, baicalin, a natural flavonoid with a high affinity to sclerostin, is selected as the therapeutic compound to achieve localized neutralization of sclerostin. To overcome its poor solubility and permeability, a baicalin nanocomplex (BNP) is synthesized using Solutol HS15, which is then dispersed in the CS-GEL to afford a nanocomposite delivery system, i.e., BNP-loaded gel (BNP@CS-GEL). In vitro, BNP significantly downregulated the level of sclerostin in MLO-Y4 osteocytes. In vivo, either CS-GEL or BNP@CS-GEL is proven to effectively promote osteogenesis and angiogenesis in a calvarial critical-sized bone defect rat model, with BNP@CS-GEL showing the best pro-healing effect. Specifically, the BNP@CS-GEL-treated group significantly downregulated the sclerostin level as compared to the sham group (p < 0.05). RANKL expression was also significantly suppressed by BNP in MLO-Y4 cells and BNP@CS-GEL in vivo. Collectively, our study offers a facile and viable gel platform in combination with nanoparticulated baicalin for the localized neutralization of sclerostin to promote bone regeneration and repair.

A Shifting Paradigm: Transformation of Cartilage to Bone during Bone Repair

While formation and regeneration of the skeleton have been studied for a long period of time, significant scientific advances in this field continue to emerge based on an unmet clinical need to improve options to promote bone repair. In this review, we discuss the relationship between mechanisms of bone formation and bone regeneration. Data clearly show that regeneration is not simply a reinduction of the molecular and cellular programs that were used for development. Instead, the mechanical environment exerts a strong influence on the mode of repair, while during development, cell-intrinsic processes drive the mode of skeletal formation. A major advance in the field has shown that cell fate is flexible, rather than terminal, and that chondrocytes are able to differentiate into osteoblasts and other cell types during development and regeneration. This is discussed in a larger context of regeneration in vertebrates as well as the clinical implication that this shift in understanding presents.

Management of Osteoporosis Medication after Osteoporotic Fracture

The aim of this study was to provide helpful information for use in selection of an appropriate medication after osteoporotic fractures through conduct of a literature review. In addition, a review of the recommendations of several societies for prevention of subsequent fractures was performed and the appropriate choice of medication for treatment of atypical femur fractures was examined. Clinical perspective was obtained and an updated search of literature was conducted across PubMed and MEDLINE and relevant articles were selected. The articles were selected manually according to relevance, and the references for identified articles and reviews were also evaluated for relevance. The following areas are reviewed: Commonly prescribed osteoporosis medications: BPs (bisphosphonates), denosumab, and SERMs (selective estrogen receptor modulators) in antiresorptive medications and recombinant human parathyroid hormone teriparatide, recently approved Romosuzumab in anabolic agents, clinical practice guidelines for the management of osteoporosis, osteoporotic fracture, and atypical femur fracture. Most medications for treatment of osteoporosis do not delay fracture healing and the positive effect of teriparatide on fracture healing has been confirmed. In cases where an osteoporotic fracture is diagnosed, risk assessment should be performed for selection of very high-risk patients in order to prevent subsequent fractures, and administration of anabolic agents is recommended.

Fracture Healing in the Setting of Endocrine Diseases, Aging, and Cellular Senescence

More than 2.1 million age-related fractures occur in the United States annually, resulting in an immense socioeconomic burden. Importantly, the age-related deterioration of bone structure is associated with impaired bone healing. Fracture healing is a dynamic process which can be divided into four stages. While the initial hematoma generates an inflammatory environment in which mesenchymal stem cells and macrophages orchestrate the framework for repair, angiogenesis and cartilage formation mark the second healing period. In the central region, endochondral ossification favors soft callus development while next to the fractured bony ends, intramembranous ossification directly forms woven bone. The third stage is characterized by removal and calcification of the endochondral cartilage. Finally, the chronic remodeling phase concludes the healing process. Impaired fracture healing due to aging is related to detrimental changes at the cellular level. Macrophages, osteocytes, and chondrocytes express markers of senescence, leading to reduced self-renewal and proliferative capacity. A prolonged phase of "inflammaging" results in an extended remodeling phase, characterized by a senescent microenvironment and deteriorating healing capacity. Although there is evidence that in the setting of injury, at least in some tissues, senescent cells may play a beneficial role in facilitating tissue repair, recent data demonstrate that clearing senescent cells enhances fracture repair. In this review, we summarize the physiological as well as pathological processes during fracture healing in endocrine disease and aging in order to establish a broad understanding of the biomechanical as well as molecular mechanisms involved in bone repair.

Therapeutic approaches to activate the canonical Wnt pathway for bone regeneration

Activation of the canonical Wingless-related integration site (Wnt) pathway has been shown to increase bone formation and therefore has therapeutic potential for use in orthopedic conditions. However, attempts at developing an effective strategy to achieve Wnt activation has been met with several challenges. The inherent hydrophobicity of Wnt ligands makes isolating and purifying the protein difficult. To circumvent these challenges, many have sought to target extracellular inhibitors of the Wnt pathway, such as Wnt signaling pathway inhibitors Sclerostin and Dickkopf-1, or to use small molecules, ions and proteins to increase target Wnt genes. Here, we review systemic and localized bioactive approaches to enhance bone formation or improve bone repair through antibody-based therapeutics, synthetic Wnt surrogates and scaffold doping to target canonical Wnt. We conclude with a brief review of emerging technologies, such as mRNA therapy and Clustered Regularly Interspaced Short Palindromic Repeats technology, which serve as promising approaches for future clinical translation.

Diabetes and Impaired Fracture Healing: A Narrative Review of Recent Literature

PURPOSE OF THE REVIEW

Diabetes mellitus is a chronic metabolic disorder commonly encountered in orthopedic patients. Both type 1 and type 2 diabetes mellitus increase fracture risk and impair fracture healing. This review examines complex etiology of impaired fracture healing in diabetes.

RECENT FINDINGS

Recent findings point to several mechanisms leading to orthopedic complications in diabetes. Hyperglycemia and chronic inflammation lead to increased formation of advanced glycation end products and generation of reactive oxygen species, which in turn contribute to the disruption in osteoblast and osteoclast balance leading to decreased bone formation and heightening the risk of nonunion or delayed union as well as impaired fracture healing. The mechanisms attributing to this imbalance is secondary to an increase in pro-inflammatory mediators leading to premature resorption of callus cartilage and impaired bone formation due to compromised osteoblast differentiation and their apoptosis. Other mechanisms include disruption in the bone's microenvironment supporting different stages of healing process including hematoma and callus formation, and their resolution during bone remodeling phase. Complications of diabetes including peripheral neuropathy and peripheral vascular disease also contribute to the impairment of fracture healing. Certain diabetic drugs may have adverse effects on fracture healing. The pathophysiology of impaired fracture healing in diabetic patients is complex. This review provides an update of the most recent findings on how key mediators of bone healing are affected in diabetes.

The effects of romosozumab combined with active vitamin D3 on fracture healing in ovariectomized rats

Background

In this study, we investigated the potential acceleration of fracture healing and bone mineral density-increasing effects of romosozumab and active vitamin D₃ combination therapy for fractures in ovariectomized rats.

Methods

Ovariectomy was performed on 40 24-week-old female Sprague–Dawley rats. After 8 weeks, the rats were subjected to periosteum removal and osteotomy of the femoral shaft followed by osteosynthesis with intramedullary nailing to create fracture models. The rats were then divided into four groups: C group (control), R group (receiving romosozumab at 25 mg/kg once a month via subcutaneous injection), VD group (receiving active vitamin D₃ at 0.2 µg/kg twice a week via subcutaneous injection), and R + VD group. Further, 10 rats were included in a sham group. At 10 weeks after the intervention, both femurs were removed and blood samples were collected from all rats. Soft X-ray imaging was used to evaluate bone union, and microcomputed tomography (micro-CT) was used for bone morphometric evaluation. Toluidine blue staining was used for the histopathological evaluation of the undecalcified specimens, and bone turnover marker levels were measured using enzyme-linked immunosorbent assay.

Results

Bone morphometry analysis via micro-CT revealed increased mineral density of the trabecular bone in the R + VD group femurs, demonstrating the effectiveness of romosozumab plus active vitamin D₃ combination therapy. However, there were no differences in bone union evaluated using soft X-ray imaging, indicating no acceleration of fracture healing.

Conclusions

Although romosozumab and active vitamin D₃ combination therapy increased trabecular bone volume, there was no evidence on its ability to accelerate fracture healing.

Graphical abstract

Drug discovery of sclerostin inhibitors

Sclerostin, a protein secreted from osteocytes, negatively regulates the WNT signaling pathway by binding to the LRP5/6 co-receptors and further inhibits bone formation and promotes bone resorption. Sclerostin contributes to musculoskeletal system-related diseases, making it a promising therapeutic target for the treatment of WNT-related bone diseases. Additionally, emerging evidence indicates that sclerostin contributes to the development of cancers, obesity, and diabetes, suggesting that it may be a promising therapeutic target for these diseases. Notably, cardiovascular diseases are related to the protective role of sclerostin. In this review, we summarize three distinct types of inhibitors targeting sclerostin, monoclonal antibodies, aptamers, and small-molecule inhibitors, from which monoclonal antibodies have been developed. As the first-in-class sclerostin inhibitor approved by the U.S. FDA, the monoclonal antibody romosozumab has demonstrated excellent effectiveness in the treatment of postmenopausal osteoporosis; however, it conferred high cardiovascular risk in clinical trials. Furthermore, romosozumab could only be administered by injection, which may cause compliance issues for patients who prefer oral therapy. Considering these above safety and compliance concerns, we therefore present relevant discussion and offer perspectives on the development of next-generation sclerostin inhibitors by following several ways, such as concomitant medication, artificial intelligence-based strategy, druggable modification, and bispecific inhibitors strategy.

Enhancing fracture repair: cell-based approaches

Fracture repair is based both on the macrolevel modulation of fracture fragments and the subsequent cellular activity. Surgeons have also long recognized other influences on cellular behavior: the effect of the fracture or subsequent surgery on the available pool of cells present locally in the periosteum, the interrelated effects of fragment displacement, and construct stiffness on healing potential, patient pathophysiology and systemic disease conditions (such as diabetes), and external regulators of the skeletal repair (such as smoking or effect of medications). A wide variety of approaches have been applied to enhancing fracture repair by manipulation of cellular biology. Many of these approaches reflect our growing understanding of the cellular physiology that underlies skeletal regeneration. This review focuses on approaches to manipulating cell lineages, influencing paracrine and autocrine cell signaling, or applying other strategies to influence cell surface receptors and subsequent behavior. Scientists continue to evolve new approaches to pharmacologically enhancing the fracture repair process.

Successful treatment of humeral shaft nonunion with romosozumab: A case report

Romosozumab is a humanized monoclonal anti-sclerostin antibody (Scl-Ab) that binds and inhibits sclerostin, thereby increasing bone formation and decreasing bone resorption. In 2019, the Japanese Ministry of Health, Labor and Welfare, and the FDA approved romosozumab for treating osteoporosis in men and in postmenopausal women at high risk of fracture. In the past decade, pharmacological systemic treatments using molecules in use for the treatment of the osteoporosis have been reported. Herein we reported the case of a 67-year-old woman with nonunion of humerus shaft fracture, in whom bone union could not be achieved after 11 months of conservative treatment; however, successful bone healing was achieved after once-a-month administration of romosozumab for 6 months. To our knowledge, this is the first case reporting the successful use of romosozumab for treating established nonunion. Romosozumab can aid in promoting bone healing of nonunion in patients not willing to undergo surgical intervention.

Effects of sclerostin antibody on bone healing

Promoting bone healing after a fracture has been a frequent subject of research. Recently, sclerostin antibody (Scl-Ab) has been introduced as a new anabolic agent for the treatment of osteoporosis. Scl-Ab activates the canonical Wnt (cWnt)-β-catenin pathway, leading to an increase in bone formation and decrease in bone resorption. Because of its rich osteogenic effects, preclinically, Scl-Ab has shown positive effects on bone healing in rodent models; researchers have reported an increase in bone mass, mechanical strength, histological bone formation, total mineralized callus volume, bone mineral density, neovascularization, proliferating cell nuclear antigen score, and bone morphogenic protein expression at the fracture site after Scl-Ab administration. In addition, in a rat critical-size femoral-defect model, the Scl-Ab-treated group demonstrated a higher bone healing rate. On the other hand, two clinical reports have researched Scl-Ab in bone healing and failed to show positive effects in the femur and tibia. This review discusses why Scl-Ab appears to be effective in animal models of fracture healing and not in clinical cases.

Osteoanabolic therapy for osteoporosis in women

Therapy to activate bone formation is required to reverse and restore the damaged bone architecture found in women with postmenopausal osteoporosis. The osteoanabolic drugs include teriparatide, which has been available for several years, and abaloparatide and romosozumab, novel osteoanabolic drugs that have become available more recently. By stimulating bone formation, these drugs produce greater increases in bone mass and bone strength, and they do so more quickly compared to the commonly used anti-remodeling (also called antiresorptive) drugs such as bisphosphonates. In head-to-head trials, teriparatide and romosozumab reduce fracture risk more effectively than do oral bisphosphonates in women with osteoporosis and high fracture risk. Osteoanabolic drugs have little role in the prevention of bone loss during early menopause, but they have an important place in the treatment of women at very high risk of fracture or who remain at high fracture risk after a course of bisphosphonate therapy. Primarily because of the high cost of the drugs, these therapies are initiated by specialists rather than primary-care physicians in most countries. This review will present the evidence for efficacy and safety of these drugs so that clinicians may discern their appropriate use when caring for postmenopausal women with osteoporosis.

Bone healing of distal radius nonunion treated with bridge plating with bone graft substitutes in combination with systemic romosozumab administration: A case report

Romosozumab is a humanized, anti-sclerostin monoclonal antibody used to treat osteoporosis, which increases bone formation and decreases bone resorption. It enhances fracture healing and systemic romosozumab administration may have therapeutic potentials for accelerating bone healing of even nonunion. Herein, a 61-year-old heavy smoker male with distal radius nonunion who achieved successful bone union by combination therapy of romosozumab and spanning distraction plate fixation with bone graft substitutes was presented. Through the dorsal approach, atrophic comminuted nonunion of the distal radius was sufficiently debrided. Reduction of the distal radius was performed using indirect ligamentotaxis, and a 14-hole locking plate was fixed from the third metacarpal to the radial shaft. A beta (β) tricalcium phosphate block was mainly packed into the substantial metaphyseal bone defect with additional bone graft from the resected ulnar head. Postoperatively, systemic administration of monthly romosozumab was continued for six months. Complete bone union was achieved 20 weeks postoperatively and the plate was, then, removed. Wrist extension and flexion improved to 75o and 55o, respectively, without pain, and grip strength increased 52 weeks postoperatively from 5.5 kg to 22.4 kg. During romosozumab treatment, bone formation marker levels increased rapidly and finally returned to baseline, and bone resorption marker levels remained low. In conclusion, combination of systemic romosozumab administration and grafting β-tricalcium phosphate with bridge plating provides an effective treatment option for difficult cases of comminuted distal radius nonunion with risk factors such as smoking, diabetes, and fragility.

Molecular enhancement of fracture healing - Is there a role for Bone Morphogenetic Protein-2, parathyroid hormone, statins, or sclerostin-antibodies?

Enhancement of fracture healing has been a hot topic over the last two decades. This narrative review article is aimed to provide an update on current clinical use and evidence on four clinically available agents in the treatment of fracture healing: bone morphogenetic proteins-2 (BMP-2), parathyroid hormone, statins and sclerostin-antibodies. After first promising results from animal and clinical studies in the early 2000s, BMP-2 was studied mainly in open tibia shaft fractures treated with intramedullary nailing. There are conflicting results from different randomized clinical trials (RCTs) regarding fracture healing time and complications compared to BMP-2 free control treatment in open tibia fractures, as BMP-2 could not show significant differences in patients treated with reamed nails compared to BMP-2 free control treatment with reamed nailing only. Given that fact, its official use was limited in Europe to open tibia shaft fractures treated with unreamed tibial nailing by the European Medical Agency (EMA). Another more recent RCT failed to show equivalence of BMP- 2 together with allograft versus autograft for the treatment of tibia fractures with critical size defects. Recombinant human parathyroid hormone has proven anabolic effects on bone metabolism and is commonly used in treatment of severe osteoporosis. Different animal trials suggested an enhancement effect in fracture healing by PTH. In several clinical trials, PTH seems to have a stimulative effect for lower limb fractures. Statins, commonly used in treatment of dyslipidemia, could also enhance fracture healing in animal trials, especially when they were applied locally at the fracture site. For statins, there is only one RCT that failed to show significant effects for the oral administration of statins in undisplaced distal radius fractures. The role of sclerostin in fracture healing has more and more been understood. Application of sclerostin antibodies has been shown to be beneficial for fracture healing in animal trials. However, no RCTs on the effect of sclerostin antibodies on fracture healing have been performed yet. In conclusion, the "magic bullet" for molecular enhancement of fracture healing has not been identified yet, at least not with its optimal dosage and delivery method.

Experimental agents to improve fracture healing: utilizing the WNT signaling pathway

The process of bone healing largely recapitulates bone development in the embryo and ideally achieves complete restoration of bone shape and structure. However, because successful fracture healing requires tight interactions of numerous cell types and signaling molecules, any disruption of this highly coordinated processes can result in delayed healing or even non-union formation. The rate of fracture healing complications in orthopedic patients is reported to be 5-20%. Therefore, there is a need for new therapeutic strategies to improve fracture healing in patients with healing complications. One treatment strategy would include the easy and safe application of a pharmacological agent inducing osteoanabolic effects during fracture healing. One potential promising molecular target is the osteoanabolic WNT signaling pathway. This pathway plays an important role during embryonic bone development, homeostasis, mechanotransduction, development of osteoporosis and bone regeneration. This review focuses on preclinical studies targeting WNT signaling molecules to accelerate fracture healing. The three main investigated antagonists of the WNT signaling pathway, which can be blocked experimentally by antibodies, are Sclerostin, Dickkopf-1 and Midkine. Treating animals with antibodies against these proteins enhanced bone formation in the fracture callus. This indicates a therapeutic potential for these antibodies to accelerate fracture healing in patients with orthopedic complications.

Bone fracture healing: perspectives according to molecular basis

Fractures have a great impact on health all around the world and with fracture healing optimization; this problem could be resolved partially. To make a practical contribution to this issue, the knowledge of bone tissue, cellularity, and metabolism is essential, especially cytoskeletal architecture and its transformations according to external pressures. Special physical and chemical characteristics of the extracellular matrix (ECM) allow the transmission of mechanical stimuli from outside the cell to the plasmatic membrane. The osteocyte cytoskeleton is conformed by a complex network of actin and microtubules combined with crosslinker proteins like vinculin and fimbrin, connecting and transmitting outside stimuli through EMC to cytoplasm. Herein, critical signaling pathways like Cx43-depending ones, MAPK/ERK, Wnt, YAP/TAZ, Rho-ROCK, and others are activated due to mechanical stimuli, resulting in osteocyte cytoskeletal changes and ECM remodeling, altering the tissue and, therefore, the bone. In recent years, the osteocyte has gained more interest and value in relation to bone homeostasis as a great coordinator of other cell populations, thanks to its unique functions. By integrating the latest advances in relation to intracellular signaling pathways, mechanotransmission system of the osteocyte and bone tissue engineering, there are promising experimental strategies, while some are ready for clinical trials. This work aims to show clearly and precisely the integration between cytoskeleton and main molecular pathways in relation to mechanotransmission mechanism in osteocytes, and the use of this theoretical knowledge in therapeutic tools for bone fracture healing.

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.

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.