Recommendations for the optimal use of bone forming agents in osteoporosis

PTH1 receptor agonists for fracture risk: a systematic review and network meta-analysis

Osteoporosis, defined by reduced bone mineral density and macro- and micro-architectural degradation, leads to increased fracture risk, particularly in aging populations. While randomized controlled trials (RCTs) demonstrate that PTH1 receptor agonists, teriparatide and abaloparatide, are effective at reducing fracture risk, real-world evidence (RWE) remains sparse. This study reviews and compares the anti-fracture efficacy of these agents, against each other and against other osteoporosis treatments using both RCTs and RWE. We systematically searched Medline, Embase, and Cochrane up to May 2024, focusing on RCTs and RWE studies reporting reduction in vertebral, non-vertebral, hip, or all fractures as primary endpoint. A network meta-analysis (NMA) was conducted, first through pairwise meta-analyses of teriparatide versus abaloparatide, then a Bayesian NMA comparing each to other treatments. Safety assessments included adverse events classified by MedDRA, with a particular attention to hypercalcemia and cardiac events. Seventeen studies (11 RCTs, 6 RWE) met inclusion criteria. Teriparatide and abaloparatide were effective in reducing vertebral and non-vertebral fractures in all pairwise meta-analyses versus placebo. Abaloparatide showed an advantage over teriparatide for non-vertebral fractures (OR: 0.87, 95% CI: 0.80-0.95) and hip fractures (OR: 0.81, 95% CI: 0.71-0.93). In the NMA model, teriparatide and abaloparatide were superior to placebo, raloxifene, and calcitonin in reducing vertebral fracture while teriparatide was further superior to denosumab and risedronate. For non-vertebral fracture, abaloparatide was better than any other treatment while teriparatide was only superior to alendronate or placebo. PTH1 analogs were better than placebo at reducing all fractures while no difference was observed for the risk of hip fracture. Both abaloparatide and teriparatide demonstrate comparable safety to other osteoporosis treatments, with no increased cardiovascular risk. This review highlights that PTH1 receptor agonists effectively reduce fracture risk, with abaloparatide offering enhanced benefits for non-vertebral and hip fractures compared to teriparatide. Both agents exhibit acceptable safety profiles, suggesting their valuable role in managing osteoporosis, particularly for high-risk patients.

Bone mineral density and microarchitecture improvement in a young patient with Hajdu-Cheney syndrome and autosomal dominant polycystic kidney disease treated with alendronate

Introduction

Osteoporosis, typically seen in postmenopausal women, can also affect younger individuals, a condition known as Early-Onset Osteoporosis (EOOP). EOOP may be secondary to various conditions or arise from rare genetic disorders such as Hajdu-Cheney Syndrome (HCS), characterized by systemic bone involvement and fragility fractures.

Case Report

A 14-year-old male presented with a distal left femur fragility fracture. His medical history included spina bifida and bilateral tarsal coalition, with no family history of osteoporosis, and polycystic kidneys associated with a positive family history of autosomal dominant polycystic kidney disease (ADPKD). Laboratory tests were unremarkable, but dual X-ray absorptiometry (DXA) revealed low bone mineral density (BMD), and high resolution peripheral quantitative computed tomography (HR-pQCT) showed decreased volumetric bone density (vBMD), particularly in the cortical bone. At age 17, his kidneys were cystic and mildly enlarged. Whole exome sequencing revealed a pathogenic variant in NOTCH2, confirming the diagnosis of HCS, and a very likely causative variant in PKD1, supporting the diagnosis of ADPKD.The treatment regimen included weekly alendronate, impact exercise, a calcium-rich diet, and vitamin D supplementation. After 3 years, follow-up DXA and HR-pQCT demonstrated significant improvements in BMD and vBMD, mainly in the cortical bone.

Discussion

This case highlights the effectiveness of alendronate in managing osteoporosis in a patient with HCS and ADPKD, despite the current lack of strong supportive evidence. Long-term monitoring revealed substantial improvements in bone density and microarchitecture, underscoring the importance of early diagnosis and intervention for genetic causes of osteoporosis to prevent fracture-related morbidity.

Cost-effectiveness of opportunistic osteoporosis screening using chest radiographs with deep learning in Germany

BACKGROUND

Osteoporosis is often underdiagnosed due to limitations in traditional screening methods, leading to missed early intervention opportunities. AI-driven screening using chest radiographs could improve early detection, reduce fracture risk, and improve public health outcomes.

AIMS

To assess the cost-effectiveness of deep learning models (hereafter referred to as AI-driven) applied to chest radiographs for opportunistic osteoporosis screening in German women aged 50 and older.

METHODS

A decision tree and microsimulation Markov model were used to calculate the cost per quality-adjusted life year (QALY) gained (€2024) for screening with AI-driven chest radiographs followed by treatment, compared to no screening and treatment. Patient pathways were based on AI model accuracy and German osteoporosis guidelines. Women with a fracture risk below 5% received no treatment, those with 5-10% risk received alendronate, and women 65 + with a risk above 10% received sequential treatment starting with romosozumab. Data was validated by a German clinical expert, incorporating real-world treatment persistence, DXA follow-up rates, and treatment initiation. Sensitivity analyses assessed parameter uncertainty.

RESULTS

The cost per QALY gained from screening was €13,340, far below the typical cost-effectiveness threshold of €60,000. Optimizing follow-up, treatment initiation, and medication adherence further improved cost-effectiveness, with dominance achievable by halving medication non-persistence, and in women aged 50-64.

CONCLUSION

AI-driven chest radiographs for opportunistic osteoporosis screening is a cost-effective strategy for German women aged 50+, with the potential to significantly improve public health outcomes, reduce fracture burdens and address healthcare disparities. Policymakers and clinicians should consider implementing this scalable and cost-effective screening strategy.

Engineered Extracellular Vesicles Derived from Juvenile Mice Enhance Mitochondrial Function in the Aging Bone Microenvironment and Achieve Rejuvenation

Aging-related bone degeneration and impaired healing capacity remain significant challenges in regenerative medicine, necessitating innovative, efficient, and targeted strategies to restore bone health. Here, we engineered extracellular vesicles (EVs) derived from the serum of pretreated juvenile mice, with the goals of reversing aging, enhancing osteogenic potential, and increasing bioavailability to rejuvenate the aging bone environment. First, we established bone healing models representing different phases of healing to identify the EV type with the highest potential for improving the bone microenvironment in older individuals. Second, we employed DSS6 for bone targeting to enhance the biological effects of the selected EVs in vivo. The engineered EVs effectively targeted bone repair sites and promoted fracture healing more effectively than unmodified EVs in older mice. RNA sequencing revealed that the translocase of outer mitochondrial membrane 7 (Tomm7) is crucial for the underlying mechanism. Silencing Tomm7 significantly diminished the positive regulatory effects of the EVs. Specifically, the engineered EVs may enhance mitochondrial function in aging cells by activating the Tomm7-mediated Pink1/Parkin mitophagy pathway, promoting stemness recovery in aging bone marrow stromal cells (BMSCs) and reversing the adverse conditions of the aging bone microenvironment. Overall, the developed engineered EVs derived from serum from juvenile mice offer an alternative approach for treating aging bones. The identified underlying biological mechanisms provide a valuable reference for precision treatment of aging bones in the future.

Novel biomarkers in bone pathophysiology: Establishing reference intervals and biological variations estimates for serum leptin, sclerostin, lipocalin-2, osteoprotegerin, resistin and Dickkopf-related protein-1 from the European biological variation study (EuBIVAS) populations

A range of biomarkers of bone metabolism are thought to mediate adipose tissue-bone crosstalk and fulfil a homeostatic role. While considered clinically relevant, their utility and application appears limited by lack of data characterising biological variability and reference intervals rather than by analytical issues. We have therefore studied the biological variation (BV) of these biomarkers. Concentrations of Dikkopf-related protein 1, leptin, osteoprotegerin, sclerostin, lipocalin2 (Lcn2) and resistin were measured by Luminex assays in serum samples from the EuBIVAS study. Samples were taken once per week, over 10 consecutive weeks, from 91 subjects in cohorts from 5 European countries. Estimates of analytical variation (CVA), within-subject (CVI) and between-subject (CVG) BV were calculated and analytical imprecision (CVAPS) and analytical bias (BAPS) specifications, index of individuality (II), reference change values (RCV) for increase and decrease and the number of samples required to estimate the homeostatic set points (NHSPs) were derived. Mean concentrations differed between males and females for leptin, osteoprotegerin, and sclerostin, and for osteoprotegerin and sclerostin between females in fertile and menopausal ages. No male-to-female differences were observed in CVI estimates. Index of individuality was below 0.6, for all measurands. Determination of reference intervals (RI) limits indicated that all, with the exception Lcn2, described data which were non-gaussian distributed and that only leptin differed between sexes. Availability of high-quality biological variation enables objective assessment of the bone metabolism biomarker results which may enhance their clinical utility. The data indicates that they exhibit significant individuality.

Executive Summary: Treatment of Osteoporosis and Osteoarthritis in the Oldest Old

This is the executive summary of a work by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) (Nicholas Fuggle et al. in Drugs, 2024).

A Real-Life Study in Sequential Therapy for Severe Menopausal Osteoporosis

Background: Teriparatide (TPT) acts against severe primary (postmenopausal) osteoporosis (MOP), and it requires continuation with another anti-resorptive drug to conserve or enhance the effects on fracture risk reduction. Objective: To analyse the sequential pharmacotherapy in MOP who were treated upon a 24-month daily 20 µg TPT protocol (24-mo-TPT) followed by another 12 months of anti-resorptive drugs (12-mo-AR) amid real-life settings. Hypotheses: 1. TPT candidates had a more severe fracture risk profile versus those who did not fulfil the TPT criteria according to the national protocol of TPT initiation; 2. Patients treated with TPT improved their DXA profile after 24 mo; 3. After 1 year of therapy since the last TPT injection, the improved bone profile and fracture risk at the end of the TPT protocol were conserved; 4. The mineral metabolism assays and fracture risk status were similar at TPT initiation between those who finished the 24 mo protocol and those who prematurely stopped it. Methods: This was a longitudinal, retrospective, multicentre study in MOP. The entire cohort (group A) included the TPT group (B) versus the non-TPT group (non-B). Group B included subjects who finished 24-mo-TPT (group P) and early droppers (ED), and then both continued 12-mo-AR. Results: Group B (40.5%) from cohort A (N = 79) vs. non-B had lower T-scores, increased age and years since menopause. A similar profile of demographic features, BTM, and prevalent fractures (73%, respectively, 57%) was found in group P (72%) vs. ED (21.8%). Group P: osteocalcin was statistically significantly higher at 12 mo (+308.39%), respectively, at 24 mo (+171.65%) vs. baseline (p < 0.001 for each), while at 12-mo-AR became similar to baseline (p = 0.615). The cumulative probability of transient hypercalcemia-free follow-up of protocol had the highest value of 0.97 at 6 mo. An incidental fracture (1/32) was confirmed under 24-mo-TPT. BMD had a mean percent increase at the lumbar spine of +8.21% (p < 0.001), of +12.22% (p < 0.001), respectively, of +11.39% (p < 0.001). The pharmacologic sequence for 12-mo-AR included bisphosphonates (24.24% were oral BP) or denosumab (13%). BTM showed a suppression at 12-mo-AR (p < 0.05), while all BMD/T-scores were stationary. No incidental fracture was registered during 12-mo-AR. Conclusions: All research hypotheses were confirmed. This study in high-risk MOP highlighted an effective sequential pharmacotherapy in reducing the fracture risk as pinpointed by BMD/T-score measurements and analysing the incidental fractures profile.