Randomized trial of denosumab in patients receiving adjuvant aromatase inhibitors for nonmetastatic breast cancer

The use of denosumab in osteoporosis - an update on efficacy and drug safety

INTRODUCTION

Denosumab (Prolia) is a fully human monoclonal antibody against the receptor activator of the nuclear factor kappaB ligand. It is a potent antiresorptive agent that reduces osteoclastogenesis.

AREAS COVERED

Denosumab has been shown to improve bone mineral density and reduce the incidence of new fractures in postmenopausal women and men. It is also used in the treatment of glucocorticoid-induced osteoporosis, as well as for the prevention of bone loss and reduction of fracture risk in men receiving androgen deprivation therapy for non-metastatic prostate cancer and women receiving adjuvant aromatase inhibitor therapy for breast cancer. Initial safety concerns included infections, cancer, skin reactions, cardiovascular disease, hypocalcemia, osteonecrosis of the jaw, and atypical femur fractures; however, further study and experience provide reassurance on these issues. Anecdotal reports have raised concerns about an increased risk of multiple vertebral fractures following discontinuation of denosumab.

EXPERT OPINION

Although bisphosphonates are often selected as initial therapy for osteoporosis, denosumab may be an appropriate initial therapy in patients at high risk for fracture, including older patients who have difficulty with the dosing requirements of oral bisphosphonates, as well as patients who are intolerant of, unresponsive to, or have contraindications to other therapies. Additional data is needed to address questions regarding treatment duration and discontinuation.

Cancer treatment-induced bone loss

Cancer treatment-induced bone loss (CTBL) is associated with anti-tumor treatments, including endocrine therapies, chemotherapeutic treatments, radiotherapy, glucocorticoids, and tyrosine kinase inhibitors. Osteoporosis, characterized by the loss of bone mass, can increase the risk of fractures, leading to mortality and long-term disability, even after cancer remission. Cancer and osteoporosis have marked clinical and pathogenetic similarities. Both have a multifactorial etiology, affect the geriatric population, and markedly influence quality of life. Lifestyle management, including calcium and vitamin D supplementation, is recommended but the supporting evidence is limited. Oral and injectable bisphosphonates are effective for osteoporosis and malignant bone disease. Bisphosphonates increase bone mineral density (BMD) in patients with CTBL. Denosumab is also used in the management of CTBL; in clinical trials, it improved BMD and reduced the risk of fracture. Currently, there are no bone anabolic therapies for patients with cancer. Appropriate therapies are necessary to maintain optimal bone health, particularly in patients at heightened risk.

Bone-modifying agents for reducing bone loss in women with early and locally advanced breast cancer: a network meta-analysis

BACKGROUND

Bisphosphonates and receptor activator of nuclear factor-kappa B ligand (RANKL)-inhibitors are amongst the bone-modifying agents used as supportive treatment in women with breast cancer who do not have bone metastases. These agents aim to reduce bone loss and the risk of fractures. Bisphosphonates have demonstrated survival benefits, particularly in postmenopausal women.

OBJECTIVES

To assess and compare the effects of different bone-modifying agents as supportive treatment to reduce bone mineral density loss and osteoporotic fractures in women with breast cancer without bone metastases and generate a ranking of treatment options using network meta-analyses (NMAs).

SEARCH METHODS

We identified studies by electronically searching CENTRAL, MEDLINE and Embase until January 2023. We searched various trial registries and screened abstracts of conference proceedings and reference lists of identified trials.

SELECTION CRITERIA

We included randomised controlled trials comparing different bisphosphonates and RANKL-inihibitors with each other or against no further treatment or placebo for women with breast cancer without bone metastases.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the risk of bias of included studies and certainty of evidence using GRADE. Outcomes were bone mineral density, quality of life, overall fractures, overall survival and adverse events. We conducted NMAs and generated treatment rankings.

MAIN RESULTS

Forty-seven trials (35,163 participants) fulfilled our inclusion criteria; 34 trials (33,793 participants) could be considered in the NMA (8 different treatment options). Bone mineral density We estimated that the bone mineral density of participants with no treatment/placebo measured as total T-score was -1.34. Evidence from the NMA (9 trials; 1166 participants) suggests that treatment with ibandronate (T-score -0.77; MD 0.57, 95% CI -0.05 to 1.19) may slightly increase bone mineral density (low certainty) and treatment with zoledronic acid (T-score -0.45; MD 0.89, 95% CI 0.62 to 1.16) probably slightly increases bone mineral density compared to no treatment/placebo (moderate certainty). Risedronate (T-score -1.08; MD 0.26, 95% CI -0.32 to 0.84) may result in little to no difference compared to no treatment/placebo (low certainty). We are uncertain whether alendronate (T-score 2.36; MD 3.70, 95% CI -2.01 to 9.41) increases bone mineral density compared to no treatment/placebo (very low certainty). Quality of life No quantitative analyses could be performed for quality of life, as only three studies reported this outcome. All three studies showed only minimal differences between the respective interventions examined. Overall fracture rate We estimated that 70 of 1000 participants with no treatment/placebo had fractures. Evidence from the NMA (16 trials; 19,492 participants) indicates that treatment with clodronate or ibandronate (42 of 1000; RR 0.60, 95% CI 0.39 to 0.92; 40 of 1000; RR 0.57, 95% CI 0.38 to 0.86, respectively) decreases the number of fractures compared to no treatment/placebo (high certainty). Denosumab or zoledronic acid (51 of 1000; RR 0.73, 95% CI 0.52 to 1.01; 55 of 1000; RR 0.79, 95% CI 0.56 to 1.11, respectively) probably slightly decreases the number of fractures; and risedronate (39 of 1000; RR 0.56, 95% CI 0.15 to 2.16) probably decreases the number of fractures compared to no treatment/placebo (moderate certainty). Pamidronate (106 of 1000; RR 1.52, 95% CI 0.75 to 3.06) probably increases the number of fractures compared to no treatment/placebo (moderate certainty). Overall survival We estimated that 920 of 1000 participants with no treatment/placebo survived overall. Evidence from the NMA (17 trials; 30,991 participants) suggests that clodronate (924 of 1000; HR 0.95, 95% CI 0.77 to 1.17), denosumab (927 of 1000; HR 0.91, 95% CI 0.69 to 1.21), ibandronate (915 of 1000; HR 1.06, 95% CI 0.83 to 1.34) and zoledronic acid (925 of 1000; HR 0.93, 95% CI 0.76 to 1.14) may result in little to no difference regarding overall survival compared to no treatment/placebo (low certainty). Additionally, we are uncertain whether pamidronate (905 of 1000; HR 1.20, 95% CI 0.81 to 1.78) decreases overall survival compared to no treatment/placebo (very low certainty). Osteonecrosis of the jaw We estimated that 1 of 1000 participants with no treatment/placebo developed osteonecrosis of the jaw. Evidence from the NMA (12 trials; 23,527 participants) suggests that denosumab (25 of 1000; RR 24.70, 95% CI 9.56 to 63.83), ibandronate (6 of 1000; RR 5.77, 95% CI 2.04 to 16.35) and zoledronic acid (9 of 1000; RR 9.41, 95% CI 3.54 to 24.99) probably increases the occurrence of osteonecrosis of the jaw compared to no treatment/placebo (moderate certainty). Additionally, clodronate (3 of 1000; RR 2.65, 95% CI 0.83 to 8.50) may increase the occurrence of osteonecrosis of the jaw compared to no treatment/placebo (low certainty). Renal impairment We estimated that 14 of 1000 participants with no treatment/placebo developed renal impairment. Evidence from the NMA (12 trials; 22,469 participants) suggests that ibandronate (28 of 1000; RR 1.98, 95% CI 1.01 to 3.88) probably increases the occurrence of renal impairment compared to no treatment/placebo (moderate certainty). Zoledronic acid (21 of 1000; RR 1.49, 95% CI 0.87 to 2.58) probably increases the occurrence of renal impairment while clodronate (12 of 1000; RR 0.88, 95% CI 0.55 to 1.39) and denosumab (11 of 1000; RR 0.80, 95% CI 0.54 to 1.19) probably results in little to no difference regarding the occurrence of renal impairment compared to no treatment/placebo (moderate certainty).

AUTHORS' CONCLUSIONS

When considering bone-modifying agents for managing bone loss in women with early or locally advanced breast cancer, one has to balance between efficacy and safety. Our findings suggest that bisphosphonates (excluding alendronate and pamidronate) or denosumab compared to no treatment or placebo likely results in increased bone mineral density and reduced fracture rates. Our survival analysis that included pre and postmenopausal women showed little to no difference regarding overall survival. These treatments may lead to more adverse events. Therefore, forming an overall judgement of the best ranked bone-modifying agent is challenging. More head-to-head comparisons, especially comparing denosumab with any bisphosphonate, are needed to address gaps and validate the findings of this review.

Denosumab Prevents Bone Loss and Microarchitectural Deterioration in Premenopausal Women With Breast Cancer Receiving Estradiol Suppression Therapy: A Randomized Controlled Trial

PURPOSE

Suppression of ovarian function and aromatase inhibition (AI) increases disease-free survival in premenopausal women with estrogen receptor (ER)-positive early-stage breast cancer but accelerates bone loss. We therefore hypothesized that suppressing bone remodeling using denosumab (DMAB) would prevent bone loss in these women.

METHODS

In a 12-month double-blind randomized trial, 68 women with ER-positive early-stage breast cancer commencing ovarian function suppression and AI were randomly assigned to 60 mg DMAB (n = 34) or placebo (PBO; n = 34) once every 6 months (at 0 and 6 months). Volumetric bone mineral density (BMD), microarchitecture, and estimated bone strength of the distal tibia and distal radius were measured using high-resolution peripheral quantitative computed tomography, and spine and hip BMD were measured using dual-energy X-ray absorptiometry at 0, 6, and 12 months. The primary end point and treatment effect was the mean adjusted between group difference (MAD; [95% CI]) in distal tibial total volumetric BMD over 12 months, with a single P value tested over all time points. The study is registered with the Australian New Zealand Clinical Trials Registry (anzctr.org.au; identifier: ACTRN12616001051437).

RESULTS

Intention-to-treat analysis included all 68 randomly assigned women. Over 12 months, compared with PBO, DMAB prevented the decrease in distal tibial total BMD (MAD, 20.8 mg HA/cm3 [95% CI, 17.3 to 24.2]), cortical BMD (42.9 mg HA/cm3 [95% CI, 32.1 to 53.9]), trabecular BMD (3.32 mg HA/cm3 [95% CI, 1.45 to 5.20], P = .004), estimated stiffness (11.6 kN/m [95% CI, 7.6 to 15.6]), and failure load (563 N [95% CI, 388 to 736]). Findings were similar at the distal radius. Decreases in BMD at the lumbar spine (MAD, 0.13 g/cm2 [95% CI, 0.11 to 0.15]), total hip (0.08 g/cm2 [95% CI, 0.07 to 0.09], and femoral neck (0.06 g/cm2 [95% CI, 0.05 to 0.07]) were also prevented. All P < .001 unless otherwise noted.

CONCLUSION

Treatment with DMAB at commencement of estradiol suppression therapy preserves BMD, bone microarchitecture, and estimated strength, and is likely to increase fracture-free survival.

Antiresorptive Medications Prior to Stereotactic Body Radiotherapy for Spinal Metastasis are Associated with Reduced Incidence of Vertebral Body Compression Fracture

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

Antiresorptive drugs are often given to minimize fracture risk for bone metastases, but data regarding optimal time or ability to reduce stereotactic body radiotherapy (SBRT)-induced fracture risk is limited. This study examines the association between antiresorptive use surrounding spinal SBRT and vertebral compression fracture (VCF) incidence to provide information regarding effectiveness and optimal timing of use.

METHODS

Patients treated with SBRT for spinal metastases at a single institution between 2009-2020 were included. Kaplan-Meier analysis was used to compare cumulative incidence of VCF for those taking antiresorptive drugs pre-SBRT, post-SBRT only, and none at all. Cox proportional hazards and Fine-Gray competing risk models were used to identify additional factors associated with VCF.

RESULTS

Of the 234 patients (410 vertebrae) analyzed, 49 (20.9%) were taking bisphosphonates alone, 42 (17.9%) were taking denosumab alone, and 25 (10.7%) were taking both. Kaplan-Meier analysis revealed a statistically significant lower VCF incidence for patients initiating antiresorptive drugs before SBRT compared to those taking none at all (4% vs 12% at 1 year post-SBRT, P = .045; and 4% vs 23% at 2 years, P = .008). On multivariate analysis, denosumab duration (HR: .87, P = .378) or dose (HR: 1.00, P = .644) as well as bisphosphonate duration (HR: .98, P= .739) or dose (HR: .99, P= .741) did not have statistical significance on VCF incidence.

CONCLUSION

Initiating antiresorptive agents before SBRT may reduce the risk of treatment-induced VCF. Antiresorptive drugs are underutilized in patients with spine metastases and may represent a useful intervention to minimize toxicity and improve long-term outcomes.

Preventing Bone Loss in Breast Cancer Patients: Designing a Personalized Clinical Pathway in a Large-Volume Research Hospital

BACKGROUND

We assess the impact of bone health clinical management in breast cancer (BC) patients receiving adjuvant endocrine therapy and design a personalized clinical pathway to reduce bone loss in an Italian research hospital.

METHODS

The primary endpoint was to assess (through the process improvement organizational method) the clinical pathway that post-surgical BC patients prescribed with endocrine therapy undergo to prevent bone loss. The secondary endpoint was to design a personalized clinical pathway for a prompt implementation of guidelines, to assess and possibly prescribe antiresorptive therapy.

RESULTS

During the first year of the execution of the new Diagnostic Therapeutic Assistance Pathway, a 60% increase in Dual-Energy X-ray Absorptiometry evaluations within 30 days and a 39.5% increase in antiresorptive therapy prescription within 90 days (since the prescription of endocrine therapy) were shown, thus increasing patients' compliance.

CONCLUSION

Case managers and bone health specialists in this context can improve patients' adherence to therapies and bone health, helping physicians to expand their collaboration.

Biologic Antiresorptive: Denosumab

Background

Osteoporosis is an age-related common bone disorder characterized by low bone mineral density and increased fragility fracture risk. Various Antiresorptive medications are being used to target osteoclast mediated bone resorption to prevent bone loss and reduce fracture risk.

About Denosumab

Denosumab is a novel biological antiresorptive drug that belongs to the class of monoclonal antibodies. It binds to and inhibits the cytokine receptor activator of nuclear factor kappa-B ligand (RANKL), which is requisite for osteoclast differentiation, function and survival.

Effectiveness

Denosumab has been shown to be a potent and effective therapy for osteoporosis, with clinical trial data demonstrating significant improvement in bone mineral density (BMD) and reductions in fracture risk at various skeletal sites for more than 10 years of treatment.

Safety Profile

Denosumab has a favourable benefit/risk profile, with low rates of complications such as infection, atypical femoral fracture and osteonecrosis of the jawbone.

Challenges

However, denosumab treatment requires continuous administration, as discontinuation leads to rapid bone mineral loss and increased risk of multiple vertebral fractures due to rebound of bone turnover. Therefore, modification to another anti-osteoporosis drug therapy after denosumab discontinuation is required to maintain bone health.

Conclusion

Denosumab is a promising biological antiresorptive therapy for osteoporosis that offers high efficacy and safety, but also poses challenges for long-term management.

Advances in the care of breast cancer survivors

Breast cancer survivors may experience significant after effects from diagnoses of breast cancer and cancer directed therapies. This review synthesizes the evidence about optimal management of the sequelae of a diagnosis of breast cancer. It describes the side effects of chemotherapy and endocrine therapy and evidence based strategies for management of such effects, with particular attention to effects of therapies with curative intent. It includes strategies to promote health and wellness among breast cancer survivors, along with data to support the use of integrative oncology strategies. In addition, this review examines models of survivorship care and ways in which digital tools may facilitate communication between clinicians and patients. The strategies outlined in this review are paramount to supporting breast cancer survivors' quality of life.

The recent progress of endocrine therapy-induced osteoporosis in estrogen-positive breast cancer therapy

Breast cancer is a significant global health concern, and the discovery of endocrine therapy has played a crucial role in the treatment of estrogen-positive breast cancer. However, these therapies are often associated with osteoporosis-related adverse events, which increase the risk of fractures in breast cancer patients and can result in limited mobility and reduced quality of life. Previous studies have shown that osteoporosis is essential side effects of the breast cancer therapy, although the exact mechanisms remain mostly unclear. Current clinical treatments, such as bisphosphonates, cause side effects and may impact the therapeutic response to endocrine drugs. In this review, we explore the likelihood of endocrine therapy-induced osteoporosis in estrogen-positive breast cancer therapy and discuss the involved mechanisms as well as the therapeutic potential of drugs and drug combination strategies.

Impact of CDK4/6 Inhibitors on Aromatase Inhibitor-Associated Musculoskeletal Syndrome (AIMSS) in the Adjuvant Setting

Background

Third-generation aromatase inhibitors (AIs) are the mainstay of treatment in hormone receptor (HR)-positive breast cancer. Even though it is considered to be a well-tolerated therapy, AI-induced musculoskeletal symptoms are common and may be accused for treatment discontinuation. Recently, selective cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors changed the therapeutic setting, and currently, ribociclib, palbociclib, and abemaciclib are all approved in combination with nonsteroidal AIs in patients with ER-positive, HER2-negative advanced or metastatic breast cancer. This systematic review aims to identify the frequency of aromatase inhibitor-associated musculoskeletal syndrome (AIMSS) in the adjuvant setting in patients under AI monotherapy compared to patients under combination therapy with AIs and CDK4/6 inhibitors and demonstrate the underlying mechanism of action.

Methods

This study was performed in accordance with PRISMA guidelines. The literature search and data extraction from all randomized clinical trials (RCTs) were done by two independent investigators. Eligible articles were identified by a search of MEDLINE and ClinicalTrial.gov database concerning the period 2000/01/01-2021/05/01.

Results

Arthralgia was reported in 13.2 to 68.7% of patients receiving AIs for early-stage breast cancer, while arthralgia induced by CDK4/6 inhibitors occurred in a much lower rate [20.5-41.2%]. Bone pain (5-28.7% vs. 2.2-17.2%), back pain (2-13.4% vs. 8-11.2%), and arthritis (3.6-33.6% vs. 0.32%) were reported less frequently in patients receiving the combination of CDK4/6 inhibitors with ET.

Conclusions

CDK4/6 inhibitors might have a protective effect against joint inflammation and arthralgia occurrence. Further studies are warranted to investigate arthralgia incidence in this population.

Adjuvant denosumab in early breast cancer: a systematic review and meta-analysis of randomized controlled clinical trials

Background

In early breast cancer (BC) the impact of denosumab on survival outcomes is still unclear. We undertook a systematic review and meta-analysis to assess efficacy and safety of adjuvant denosumab in addition to standard anticancer therapy.

Methods

PubMed, CENTRAL, Scopus, Embase, and oncological meetings websites were screened to identify potentially eligible randomized controlled trials (RCTs). Survival outcomes were disease-free survival (DFS), bone-metastasis-free survival (BMFS), and overall survival (OS). Fracture incidence and time to first fracture were bone-health outcomes. Osteonecrosis of the jaw (ONJ), atypical femur fractures (AFF), and other adverse events were also evaluated. Pooled hazard ratios (HRs) and risk ratios (RR) with respective 95% confidence interval (95% CI) were computed using a random-effects model. Exploratory subgroup analyses were performed.

Results

Two phase III RCTs were included, the Austrian Breast & Colorectal Cancer Study Group-18 (ABCSG-18) and the D-CARE trials, for a total of 7929 patients. In the ABCSG-18 trial, denosumab was administered every 6 months during endocrine therapy (for a median of seven cycles) while the D-CARE trial used an intensive schedule for a total treatment duration of 5 years. Adjuvant denosumab showed no difference in DFS (HR: 0.932; 95% CI: 0.748-1.162), BMFS (HR: 0.9896; 95% CI: 0.751-1.070), and OS (HR: 0.917; 95% CI: 0.718-1.171) compared to placebo in the overall population. In hormone receptor positive/human epidermal growth factor receptor 2 (HER2) negative BC patients, a DFS (HR: 0.883; 95% CI: 0.782-0.996) and BMFS (HR: 0.832; 95% CI: 0.714-0.970) benefit was observed and BMFS was prolonged in all hormone receptor positive patients (HR: 0.850; 95% CI: 0.735-0.983). Fracture incidence (RR: 0.787; 95% CI: 0.696-0.890) and time to first fracture (HR: 0.760; 95% CI: 0.665-0.869) were also improved. No increase in overall toxicity was seen with denosumab and no differences were observed for ONJ and AFF between the 60-mg every 6-month schedule and placebo.

Conclusion

Denosumab addition to anticancer treatment does not improve DFS, BMFS, or OS in the overall population, although a DFS improvement was observed in hormone receptor positive/HER2 negative BC patients and a BMFS improvement in all hormone receptor positive patients. Bone-health outcomes were improved with no added toxicity with the 60-mg schedule.

Registration

PROSPERO identifier: CRD42022332787.

Bone health in breast cancer

Early breast cancer is among the most common cancers worldwide. Recent advances continue to improve outcomes and increase long-term survivorship. However, therapeutic modalities are deleterious for patients' bone health. While antiresorptive therapy may partially negate this, consequent reduction in rates of fragility fractures remains unproven. Selective prescription of bisphosphonates or denosumab may be an amicable middle ground. Recent evidence also suggests a possible role of osteoclast inhibitors as adjuvant therapy, but the evidence is modest at best. In this narrative clinical review, we explore the impact of various adjuvant modalities on bone mineral density and fragility fracture rates of early breast cancer survivors. We also review optimal patient selection for antiresorptive agents, their impact on rates of fragility fractures, and the possible role of these agents as adjuvant therapy.

Management of cancer treatment-induced bone loss (CTIBL) in patients with breast cancer or prostate cancer

Breast cancer and prostate cancer are sex hormone-dependent cancers, and estrogen or androgen suppression therapy is the standard treatment. Cancer treatment-induced bone loss (CTIBL): bone loss and osteoporosis have become important side effects of these therapies. To summarize the current evidences, (1) Endocrine therapy for breast cancer and prostate cancer is associated with a significant decrease in bone mineral density. (2) Aromatase inhibitors (AI) for breast cancer are associated with a significant increase in fractures, and androgen deprivation therapy (ADT) for prostate cancer is likely to be associated with an increase in fractures. (3) Administration of bisphosphonates and denosumab increases bone mass in patients undergoing endocrine therapy for breast cancer. Administration of bisphosphonates, denosumab, and SERMs increased bone mass in patients undergoing ADT therapy for prostate cancer. (4) Bisphosphonates and denosumab reduce fracture risk in patients on AI for breast cancer, and toremifene and denosumab in patients on ADT for prostate cancer.

What Is Known about Breast Cancer in Young Women?

Breast cancer (BC) is the second leading cause of cancer-related death in women under the age of 40 years worldwide. In addition, the incidence of breast cancer in young women (BCYW) has been rising. Young women are not the focus of screening programs and BC in younger women tends to be diagnosed in more advanced stages. Such patients have worse clinical outcomes and treatment complications compared to older patients. BCYW has been associated with distinct tumour biology that confers a worse prognosis, including poor tumour differentiation, increased Ki-67 expression, and more hormone-receptor negative tumours compared to women >50 years of age. Pathogenic variants in cancer predisposition genes such as BRCA1/2 are more common in early-onset BC compared to late-onset BC. Despite all these differences, BCYW remains poorly understood with a gap in research regarding the risk factors, diagnosis, prognosis, and treatment. Age-specific clinical characteristics or outcomes data for young women are lacking, and most of the standard treatments used in this subpopulation currently are derived from older patients. More age-specific clinical data and treatment options are required. In this review, we discuss the epidemiology, clinicopathologic characteristics, outcomes, treatments, and special considerations of breast cancer in young women. We also underline future directions and highlight areas that require more attention in future studies.

Bone modifying agents in postmenopausal breast cancer patients treated with aromatase inhibitors: beyond bone protection?

Estrogen-receptor positive tumours represent the majority of breast cancers in postmenopausal women. Adjuvant endocrine therapy with aromatase inhibitors (AIs), continued for up to 10 years in high-risk patients, reduces by 40% the risk of recurrence. However, this therapy, among other side effects, is burdened with a higher incidence of osteoporotic bone fractures. To date, both bisphosphonates and denosumab are recognized as first-line drugs in the primary prevention of osteoporotic fractures in patients treated with AIs. They have demonstrated their effectiveness in increasing bone mineral density and in reducing the incidence of fractures, but they have also been shown to improve disease free survival (DFS).

Does the number of 6-monthly adjuvant zoledronate infusions received affect treatment efficacy for early breast cancer? A sub-study of ABCSG-12

BACKGROUND

The widespread adoption of adjuvant bisphosphonate therapy for postmenopausal early breast cancer (EBC) patients was based on results of the Early Breast Cancer Trialist Group (EBCTCG) meta-analysis. Despite multiple regimens evaluated, there was no signal of varying efficacy with type, dose/dose intensity of bisphosphonate administration. We evaluated the effect of early treatment cessation using long-term outcome data from the ABCSG-12 trial.

PATIENTS AND METHODS

ABCSG-12 randomized 1803 hormone-receptor positive EBC patients on ovarian suppression between 1999 and 2006 to receive 4 mg zoledronic acid 6-monthly or not (and tamoxifen or anastrozole, 2:2 factorial design). In the current study, we evaluated whether the number of zoledronate infusions had an impact on breast cancer-specific outcomes. We hypothesized that amongst patients who received at least one zoledronate infusion, the number of infusions had no effect on outcomes. Time-to-event endpoints were analysed with Cox models and Kaplan Meier curves starting from a 3-year landmark. BMD analysis was restricted to patients who participated in the BMD sub-study.

RESULTS

725 patients who received at least one zoledronate infusion were included in the time-to-event analysis. There was no statistically significant difference in disease-free or overall survival in the patients who received ≤6 zoledronate infusions (n = 170) compared to those who received ≥7 zoledronate infusions (n = 555).

CONCLUSIONS

Comparable to efforts to de-escalate treatment duration in metastatic bone disease, there was no evidence to indicate that a reduced number of zoledronate infusions is associated with reduced adjuvant efficacy. Further studies to define optimal regimens of adjuvant bone-targeted therapies are required.

Review of bone health in women with estrogen receptor-positive breast cancer receiving endocrine therapy

In estrogen-receptor-positive tumors, adjuvant endocrine therapy has been shown to be highly beneficial for both overall and disease-free survival. Estradiol is key in regulating bone and mineral physiology, and several studies found a strong correlation between these therapies and the risk of fractures. Since these therapies are often given for 5 through 10 years, the timing for bisphosphonates or denosumab initiation seems essential to managing bone metabolism. However, gray zones and discrepancies between guidelines remain as to the best threshold when to start antiresorptive treatment, or whether antiresorptive treatment should be administered to every woman undergoing adjuvant endocrine therapy, independent of their risk factors for fractures. Treatment options and strategies should be discussed at the start of hormone adjuvant therapy to come to a shared decision with the patient, with the final aim of reducing the risk of future fractures as much as possible. This review will cover present guidelines and literature on antiresorptive treatment in this setting, to provide clinicians with useful clues for managing these patients.

The clinical effectiveness of denosumab (Prolia®) in patients with hormone-sensitive cancer receiving endocrine therapy, compared to bisphosphonates, selective estrogen receptor modulators (SERM), and placebo: a systematic review and network meta-analysis

This systematic review (SR) assessed the use of denosumab (Prolia®) to treat osteoporosis in cancer patients receiving endocrine therapy. Denosumab was found to prevent vertebral fractures and improve bone mineral density in cancer patients with osteoporosis. This is the first SR to assess treating osteoporotic cancer patients with denosumab.

PURPOSE

This study assessed the effectiveness and safety of denosumab (Prolia®) compared to bisphosphonates (alendronate, ibandronate, risedronate, zoledronate), selective estrogen receptor modulators (SERMs) (bazedoxifene, raloxifene) and placebo for the treatment of osteoporosis in hormone-sensitive cancer patients receiving endocrine therapy (men with prostate cancer [MPC] on hormone ablation therapy [HAT], and women with breast cancer [WBC] on adjuvant aromatase inhibitor therapy [AAIT]).

METHODS

Systematic literature searches were conducted in three biomedical databases to identify randomized controlled trials (RCTs). Frequentist network meta-analyses and/or pairwise meta-analyses were performed on predetermined outcomes (i.e., vertebral/nonvertebral fractures, bone mineral density [BMD], mortality, treatment-related adverse events [AEs], serious AEs [SAEs], withdrawal due to treatment-related AEs).

RESULTS

A total of 14 RCTs (15 publications) were included. Denosumab was found to prevent vertebral fractures in cancer patients receiving endocrine therapy, relative to placebo. Similarly, denosumab, zoledronate, and alendronate improved BMD at the femoral neck (FN) and lumbar spine (LS) in MPC on HAT, relative to placebo. Denosumab, ibandronate and risedronate improved BMD at the LS and total hip (TH) in WBC on AAIT, relative to placebo. Denosumab and risedronate improved trochanteric (TRO) BMD in WBC on AAIT, relative to placebo. Similarly, denosumab improved FN BMD in WBC on AAIT.

CONCLUSION

In MPC on HAT, denosumab (relative to placebo) was effective at preventing vertebral fractures and improving BMD at the FN and LS. Moreover, in WBC on AAIT, denosumab (relative to placebo) improved BMD at the FN, LS, TH, and TRO, as well as prevent vertebral fracture.

Impact of Physical Rehabilitation on Bone Biomarkers in Non-Metastatic Breast Cancer Women: A Systematic Review and Meta-Analysis

Rehabilitation might improve bone health in breast cancer (BC) patients, but the effects on bone biomarkers are still debated. Thus, this meta-analysis of randomized controlled trials (RCTs) aims at characterizing the impact of rehabilitation on bone health biomarkers in BC survivors. On 2 May 2022, PubMed, Scopus, Web of Science, Cochrane, and PEDro were systematically searched for RCTs assessing bone biomarker modifications induced by physical exercise in BC survivors. The quality assessment was performed with the Jadad scale and the Cochrane risk-of-bias tool for randomized trials (RoBv.2). Trial registration number: CRD42022329766. Ten studies were included for a total of 873 patients. The meta-analysis showed overall significant mean difference percentage decrease in collagen type 1 cross-linked N-telopeptide (NTX) serum level [ES: -11.65 (-21.13, -2.17), p = 0.02)] and an increase in bone-specific alkaline phosphatase (BSAP) levels [ES: +6.09 (1.56, 10.62). According to the Jadad scale, eight RCTs were considered high-quality studies. Four studies showed a low overall risk of bias, according to RoBv.2. The significant effects of rehabilitation on bone biomarkers suggested a possible implication for a precision medicine approach targeting bone remodeling. Future research might clarify the role of bone biomarkers monitoring in rehabilitation management of cancer treatment induced bone-loss.

Efficacy and safety of COVID-19 vaccines for patients with spinal tumors receiving denosumab treatment: An initial real-clinical experience study

Background

Even if COVID-19 vaccine has gradually been adopted in the world, information of side effects and crosstalk in patients with spinal tumors is absent due to the exclusion from clinical research. In this research, we aimed to investigate the efficacy and safety for the patients with spinal tumors treated by denosumab.

Methods

In this retrospective research, 400 patients under treatment of denosumab against spinal tumors in real-clinical experience were grouped into two cohorts according to the treatment of COVID-19 vaccine. And linked hospital data, serum samples and unsolicited related adverse events had been collected from January 22nd 2021 to June 1st 2021 respectively.

Results

233 patients of all participants who received regular treatment of denosumab were vaccinated by mRNA or inactivated vaccine. Patients of metastatic disease and primary osseous spinal tumor showed similar distribution in both two groups. Over the study period, within 176 patients tested the status of serologic response of vaccine, 88(81.48%) and 41(87.23%) individuals injected one or two inactivated vaccines had effective antibody against SARS-CoV-2 infections. As 21 patients (85.71%) treated by mRNA vaccine did. Considering of the safety of vaccine, most common systemic adverse events were nausea or vomiting (45 events vs 23events). Interestingly, fewer participants in the vaccine group were statistically recorded in local adverse events than in the placebo group (16 events vs 33 events).

Conclusions

Our initial real-clinical experience suggests that COVID-19 vaccines are likely safe and effective in in patients with spinal tumors receiving denosumab treatment.

Managing Bone Health in Breast Cancer

OBJECTIVE

Osteoporosis is a common condition that can be caused or exacerbated by estrogen deficiency.

METHODS

This narrative review will discuss optimizing bone health in the setting of adjuvant endocrine treatments for hormone receptor-positive breast cancer and the current use of antiresorptive agents as adjuvant therapy and as bone modifying agents.

RESULTS

Adjuvant endocrine treatments for hormone receptor-positive breast cancer (tamoxifen and aromatase inhibitors) affect bone health. The exact effect depends on the agent used and the menopausal state of the woman. Antiresorptive medications for osteoporosis, bisphosphonates and denosumab, lower the risk of bone loss from aromatase inhibitors. Use of bisphosphonates as adjuvant treatment in breast cancer, regardless of hormone receptor status, is increasing because of benefits seen to cancer relapse and survival.

CONCLUSION

Optimizing bone health in women with breast cancer during and after cancer treatment is informed by an understanding of breast cancer treatment and its skeletal effect.

Long-Term Outcomes of Adjuvant Denosumab in Breast Cancer

BACKGROUND: Adjuvant aromatase inhibitors increase osteoporosis and fractures in patients with hormone receptor–positive breast cancer. We have previously reported outcomes of the ABCSG-18 (study 18 from the Austrian Breast & Colorectal Cancer Study Group) trial showing that adjuvant anti–receptor activator of nuclear factor-κB ligand denosumab treatment counteracts these adverse effects and may improve outcomes. We report here the final long-term outcomes. METHODS: ABCSG-18 is a prospective, double-blind, placebo-controlled, phase 3 trial in which 3425 postmenopausal patients with early hormone receptor–positive breast cancer receiving aromatase inhibitor therapy were randomly assigned in 58 trial centers to receive either denosumab 60 mg or placebo administered subcutaneously every 6 months. The primary end point was the time to first clinical fracture after randomization. Secondary disease outcome–related end points were disease-free survival (DFS), bone metastasis–free survival (BMFS), and overall survival (OS). RESULTS: For this final protocol-defined analysis, median follow-up is 8 years (interquartile range, 6 to 9.6 years). There were 309 versus 368 DFS events (hazard ratio, 0.83; 95% confidence interval [CI], 0.71 to 0.97) in the denosumab versus the placebo group, respectively, resulting in an absolute 9-year DFS benefit of 3.5 percentage points (79.4 vs. 75.9%). Adjuvant denosumab improved BMFS by 2.5 percentage points (88.9 vs. 86.4%; hazard ratio, 0.81; 95% CI, 0.65 to 1.00) and OS by 1.0 percentage point (90.9 vs. 89.9%; hazard ratio, 0.80; 95% CI, 0.64 to 1.01). No new toxicities for this dose of adjuvant denosumab were observed. CONCLUSIONS: DFS, BMFS, and OS continued to show benefit in this final long-term analysis of ABCSG-18. There were no new toxicities. (Funded by Amgen; ClinicalTrials.gov number, NCT00556374.)

Bone loss induced by cancer treatments in breast and prostate cancer patients

Cancer and cancer therapies are a major factor risk for osteoporosis due to bone loss and deterioration of bone microarchitecture. Both factors contribute to a decrease in bone strength and, consequently, increased bone fragility and risk of fracture. Cancer-associated bone loss is a multifactorial process, and optimal interdisciplinary management of skeletal health, accurate assessment of bone density, and early diagnosis are essential when making decisions aimed at reducing bone loss and fracture risk in patients who have received or are receiving treatment for cancer. In this document, a multidisciplinary group of experts collected the latest evidence on the pathophysiology of osteoporosis and its prevention, diagnosis, and treatment with the support of the Spanish scientific society SEOM. The aim was to provide an up-to-date and in-depth view of osteoporotic risk and its consequences, and to present a series of recommendations aimed at optimizing the management of bone health in the context of cancer.

Research progress of bone-targeted drug delivery system on metastatic bone tumors

Bone metastases are common in malignant tumors and the effect of conventional treatment is limited. How to effectively inhibit tumor bone metastasis and deliver the drug to the bone has become an urgent issue to be solved. While bone targeting drug delivery systems have obvious advantages in the treatment of bone tumors. The research on bone-targeted anti-tumor therapy has made significant progress in recent years. We introduced the related tumor pathways of bone metastases. The tumor microenvironment plays an important role in metastatic bone tumors. We introduce a drug-loading systems based on different environment-responsive nanocomposites for anti-tumor and anti-metastatic research. According to the process of bone metastases and the structure of bone tissue, we summarized the information on bone-targeting molecules. Bisphosphate has become the first choice of bone-targeted drug delivery carrier because of its affinity with hydroxyapatite in bone. Therefore, we sought to summarize the bone-targeting molecule of bisphosphate to identify the modification effect on bone-targeting. And this paper discusses the relationship between bisphosphate bone targeting molecular structure and drug delivery carriers, to provide some new ideas for the research and development of bone-targeting drug delivery carriers. Targeted therapy will make a more outstanding contribution to the treatment of tumors.

Cancer Treatment-Induced Bone Loss: Role of Denosumab in Non-Metastatic Breast Cancer

Chemotherapeutic agents, endocrine therapy and radiotherapy used in the management of breast cancer are known to cause decreased bone mineral density, and thus, increased incidence of fractures. A majority (~60%) of the breast cancer patients in India are either estrogen (ER) or progesterone hormone receptor (PR) positive. Adjuvant treatment with aromatase inhibitors (AIs) is the treatment mainstay for hormone-sensitive disease in postmenopausal (PM) women, with reduced bone mineral density (BMD), which results in increased fracture rates. Zoledronic acid, alendronate, risedronate and denosumab have been the agents of choice for managing bone loss. Denosumab 60 mg is approved for gaining bone mass in women with breast cancer who are at high risk for fracture following adjuvant AI treatment. The phase III HALT-BC data indicate an improvement in BMD with denosumab and a 50% reduction in clinical fractures, with significant improvements seen at the lumbar spine, distal third of the radius, and total hip. Denosumab has several advantages over other bone modifying agents such as subcutaneous self-administration by the patient themselves, no requirement of hospitalization, no dose modifications in renal impairment, and low incidence of acute phase anaphylactic reactions. We review the available evidence of denosumab for managing bone loss in non-metastatic breast cancer patients.

Effect of Denosumab Added to 2 Different nab-Paclitaxel Regimens as Neoadjuvant Therapy in Patients With Primary Breast Cancer: The GeparX 2 × 2 Randomized Clinical Trial

Importance

Adjuvant denosumab might improve disease-free survival in hormone receptor (HR)-positive primary breast cancer (BC). The optimal neoadjuvant nab-paclitaxel schedule in terms of efficacy and safety is unclear.

Objective

To determine whether adding denosumab to anthracycline/taxane-containing neoadjuvant chemotherapy (NACT) increases the pathological complete response (pCR) rate and which nab-paclitaxel schedule is more effective in the NACT setting.

Design, Setting, and Participants

The GeparX was a multicenter, prospective, open-label, phase 2b, 2 × 2 randomized clinical trial conducted by GBG and AGO-B at 38 German sites between February 2017 and March 2019. The analysis data set was locked September 4, 2020; analysis was completed November 13, 2020. Patients had unilateral or bilateral primary BC, stage cT2-cT4a-d or cT1c, with either clinically node-positive or pathologically node-positive or HR-negative disease, or Ki-67 proliferation index greater than 20%, or ERBB2 (formerly HER2)-positive BC.

Interventions

Patients were randomized to receive or not receive denosumab, 120 mg subcutaneously every 4 weeks for 6 cycles, and either nab-paclitaxel, 125 mg/m2 weekly for 12 weeks or days 1 and 8 every 3 weeks for 4 cycles (8 doses), followed by 4 cycles of epirubicin/cyclophosphamide, 90/600 mg/m2 (every 2 weeks or every 3 weeks). Carboplatin was given in triple-negative BC (TNBC), and trastuzumab biosimilar ABP980 plus pertuzumab was given in ERBB2-positive BC (ERBB2-positive substudy).

Main Outcomes and Measures

The primary outcome was pCR rates between arms for each randomization.

Results

A total of 780 female (n = 779) and male (n = 1) patients (median [range] age, 49.0 [22-80] years) were randomized to the 4 treatment groups. The pCR (ypT0 ypN0) rate was 41.0% (90% CI, 37%-45%) with denosumab vs 42.8% (90% CI, 39%-47%) (P = .58) without denosumab, irrespective of BC subtype. Nab-paclitaxel weekly resulted in a significantly (significance level of α = .10) higher pCR rate of 44.9% (90% CI, 41%-49%) vs 39.0% (90% CI, 35%-43%) (P = .06) with nab-paclitaxel days 1 and 8 every 3 weeks. The pCR rates for nab-paclitaxel schedules in subgroups were only significantly different for TNBC (60.4% vs 50.0%; P = .06). Grade 3 to 4 toxic effects did not differ with or without denosumab. Nonhematologic toxic effects of grade 3 to 4 were higher with nab-paclitaxel weekly (33.7% vs 24.1%; P = .004).

Conclusions and Relevance

In this randomized clinical trial, denosumab added to anthracycline/taxane-based NACT did not improve pCR rates. Nab-paclitaxel at a dosage of 125 mg/m2 weekly significantly increased the pCR rate compared with the days 1 and 8, every-3-weeks schedule overall and in TNBC, but generated higher toxicity.

Trial Registration

ClinicalTrials.gov Identifier: NCT02682693.

Roles of the RANKL-RANK Axis in Immunity-Implications for Pathogenesis and Treatment of Bone Metastasis

A substantial amount patients with cancer will develop bone metastases, with 70% of metastatic prostate and breast cancer patients harboring bone metastasis. Despite advancements in systemic therapies for advanced cancer, survival remains poor for those with bone metastases. The interaction between bone cells and the immune system contributes to a better understanding of the role that the immune system plays in the bone metastasis of cancer. The immune and bone systems share various molecules, including transcription factors, signaling molecules, and membrane receptors, which can stimulate the differentiation and activation of bone-resorbing osteoclasts. The process of cancer metastasis to bone, which deregulates bone turnover and results in bone loss and skeletal-related events (SREs), is also controlled by primary cancer-related factors that modulate the intratumoral microenvironment as well as cellular immune process. The nuclear factor kappa B ligand (RANKL) and the receptor activator of nuclear factor kappa B (RANK) are key regulators of osteoclast development, bone metabolism, lymph node development, and T-cell/dendritic cell communication. RANKL is an osteoclastogenic cytokine that links the bone and the immune system. In this review, we highlight the role of RANKL and RANK in the immune microenvironment and bone metastases and review data on the role of the regulatory mechanism of immunity in bone metastases, which could be verified through clinical efficacy of RANKL inhibitors for cancer patients with bone metastases. With the discovery of the specific role of RANK signaling in osteoclastogenesis, the humanized monoclonal antibody against RANKL, such as denosumab, was available to prevent bone loss, SREs, and bone metastases, providing a unique opportunity to target RANKL/RANK as a future strategy to prevent bone metastases.

Efficacy of Antiresorptive Drugs on Bone Mineral Density in Post-Menopausal Women With Early Breast Cancer Receiving Adjuvant Aromatase Inhibitors: A Systematic Review of Randomized Controlled Trials

Background

Cancer treatment-induced bone loss (CTIBL) is a frequent complication of breast cancer therapies affecting both disability and health-related quality of life (HRQoL). To date, there is still a lack of consensus about the most effective approach that would improve bone health and HRQoL. Therefore, the aim of this systematic review of randomized controlled trials (RCTs) was to summarize the evidence on the effects of antiresorptive drugs on CTIBL in patients with early breast cancer.

Methods

PubMed, Scopus, and Web of Science databases were systematically searched up to April 30, 2021 to identify RCTs satisfying the following PICO model: P) Participants: postmenopausal women with early breast cancer receiving adjuvant aromatase inhibitors (AI), age >18 years; I) Intervention: antiresorptive drugs (i.e. bisphosphonates and/or denosumab); C) Comparator: any comparator; O) Outcome: bone mineral density (BMD) modifications. Moreover, a quality assessment was performed according to the Jadad scale.

Results

Out of the initial 2415 records, 21 papers (15 studies) were included in the data synthesis. According to the Jadad scale, 6 studies obtained a score of 5, 1 study obtained a score of 4, 13 studies obtained a score of 3, and 1 study with score 1. Although both bisphosphonates and denosumab showed to increase BMD, only denosumab showed significant advantages on fractures.

Conclusions

Bone health management in patients with early breast cancer receiving adjuvant AIs remains challenging, and the optimal therapeutic approach is not standardized. Further studies are needed to investigate CTIBL, focusing on both the need for antiresorptive drugs and their duration based on individual patients’ characteristics.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier CRD42021267107.

Early Denosumab for the prevention of osteoporotic fractures in breast cancer women undergoing aromatase inhibitors: A case-control retrospective study

BACKGROUND

Aromatase inhibitors (AIs) might have a detrimental impact on bone health in breast cancer (BC) women. Denosumab has been shown to reduce the risk of fractures, but the appropriate time for starting is yet to be clearly defined.

OBJECTIVE

To evaluate the effects of early treatment with Denosumab (⩽ 12 months after starting AIs) compared to a delayed treatment in BC women.

METHODS

In this retrospective case-control study, we included medical records of BC post-menopausal women, treated with AIs therapy; they were divided as: study group (starting Denosumab ⩽ 12 months after AIs) and control group (> 12 months). At the baseline (T0) and at 18 months (T1), we evaluated the lumbar spine (LS) Tscore and femoral neck (FN) Tscore. Furthermore, at T1 we assessed the incident fragility fractures.

RESULTS

Fifty-nine BC survivors (mean age: 61.5 ± 11.5 years) were included: 28 with Early Denosumab and 31 with Late Denosumab. At T1, the study group did not show any incident hip or vertebral fragility fracture, whereas the Late Denosumab group showed 2 incident hip fractures (6.5%) and 4 (12.9%) vertebral fragility fractures. Early Denosumab showed a significant positive effect on both LS (p= 0.044) and FN (p= 0.024) Tscore variations.

CONCLUSION

Taken together, our findings suggest that an early start of Denosumab might be considered for the osteoporosis management in BC women undergoing AIs.

Comparison of denosumab and zoledronic acid for the treatment of solid tumors and multiple myeloma with bone metastasis: a systematic review and meta-analysis based on randomized controlled trials

Objective

To compare the efficacy and safety between denosumab and zoledronic acid for advanced cancer with bone metastasis.

Methods

MEDLINE, EMBASE, and the Cochrane library databases were searched for randomized controlled trials up to December 2020 that compared denosumab and zoledronic acid in the treatment of advanced cancer with bone metastasis. The following clinical outcomes were extracted for analysis: time to first skeletal-related event, time to first-and-subsequent skeletal-related events, overall survival, and disease progression. Safety outcomes including incidence of adverse events, serious adverse events, acute-phase reactions, renal toxicity, osteonecrosis of the jaw, and hypocalcemia were also extracted.

Results

Four randomized controlled trials involving 7201 patients were included. The overall analysis showed that denosumab was superior to zoledronic acid in delaying time to first skeletal-related event (hazard ratio = 0.86; 95% confidence interval, 0.80–0.93; P < 0.01) and time to first-and-subsequent skeletal-related events (risk ratio 0.87; 95% confidence interval 0.81–0.93; P < 0.01). Denosumab was associated with lower incidence of renal toxicity (risk ratio 0.69; 95% confidence interval 0.54–0.87; P < 0.01) and acute phase reaction (risk ratio 0.47; 95% confidence interval 0.38–0.56; P < 0.01), but higher incidence of hypocalcemia (risk ratio 1.78; 95% confidence interval 1.33–2.38; P < 0.01) and osteonecrosis of the jaw (risk ratio 1.41; 95% confidence interval 1.01–1.95; P = 0.04). No significant differences were found in overall survival, time to disease progression, or incidence of adverse events and serious adverse events between denosumab and zoledronic acid.

Conclusions

Compared with zoledronic acid, denosumab is associated with delayed first-and-subsequent skeletal-related events, lower incidence of renal toxicity, and acute phase reaction, but higher incidence of hypocalcemia and osteonecrosis of the jaw. Hence, denosumab seems to be a promising choice for advanced cancer with bone metastasis. Nonetheless, more randomized controlled trials are needed for further evaluation.

Denosumab Discontinuation in Patients Treated for Low Bone Density and Osteoporosis

Denosumab (DMAB) is a potent antiresorptive treatment used for treatment of osteoporosis and low bone mineral density (BMD) in those at high risk for fracture. In postmenopausal women with osteoporosis, DMAB treatment for 10 years has been studied, with results showing continued gains in BMD, sustained fracture risk reduction, and low risk of adverse events. However, upon discontinuation of DMAB, there is a rapid reversal of effect, with increase in bone turnover, loss of BMD, and in a subset of patients, a greater risk for multiple vertebral fractures.

Bone-modifying Agents (BMAs) in Breast Cancer

Bone-modifying agents (BMAs) are mainstays in breast cancer and prevent and treat osteoporosis in early-stage disease and reduce skeletal metastases complications in advanced disease. There is some evidence to support that BMA also prevents skeletal metastases and improves overall survival. Bone loss occurs with chemotherapy-induced ovarian failure, gonadotrophin-releasing hormone (GnRH) agonists, and aromatase inhibitors. In some women, the bone loss will be of sufficient magnitude to increase the risks of osteoporosis or fractures. Recommended steps in osteoporosis prevention or treatment include risk factor assessment, taking adequate amounts of calcium and vitamin D3, and periodic evaluations with dual-energy x-ray absorptiometry scanning. If clinically indicated by the T-scores and fracture-risk prediction algorithms treat with oral, IV bisphosphonates or subcutaneous denosumab (DEN). Zoledronic acid (ZA) or DEN reduces skeletal metastases complications, including pathological fracture, spinal cord compression, or the necessity for radiation or surgery to bone. Also, both of these drugs have the side-effect of osteonecrosis at a similar incidence. Monthly administration of ZA or DEN is standard, but several recent randomized trials show noninferiority between ZA monthly and every 3-month ZA. Every 3-month ZA is a new standard of care. Similar trials of the schedule of DEN are ongoing. ZA anticancer effect is only in postmenopausal women or premenopausal women rendered postmenopausal by GnRH agonists or bilateral oopherectomy. High-risk women, either postmenopausal or premenopausal, receiving GnRH/oopherctomy should consider adjuvant ZA. There are insufficient data to support DEN in this setting. Herein, this narrative review covers the mechanism of action of BMA, randomized clinical trials, and adverse events, both common and rare.

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

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

Efficacy and Safety of Denosumab in Osteoporosis or Low Bone Mineral Density Postmenopausal Women

Denosumab, a human monoclonal antibody, acts against the receptor activator of nuclear factor-κB ligand and is a promising antiresorptive agent in patients with osteoporosis. This study aimed to update the efficacy and safety of denosumab vs. placebo in osteoporosis or low bone mineral density (BMD) postmenopausal women. PubMed, Embase, Cochrane library, and ClinicalTrials.gov were searched for randomized controlled trials (RCTs) reporting the efficacy and safety data of denosumab vs. placebo in osteoporosis or low BMD postmenopausal women. A random-effects model was used to calculate pooled weight mean differences (WMDs) or relative risks (RRs) with corresponding 95% confidence intervals (CIs) for treatment effectiveness of denosumab vs. placebo. Eleven RCTs including 12,013 postmenopausal women with osteoporosis or low BMD were preferred for the final meta-analysis. The summary results indicated that the percentage change of BMD in the denosumab group was greater than that of BMD in placebo at 1/3 radius (WMD: 3.43; 95%CI: 3.24–3.62; p < 0.001), femoral neck (WMD: 3.05; 95%CI: 1.78–4.33; p < 0.001), lumbar spine (WMD: 6.25; 95%CI: 4.59–7.92; p < 0.001), total hip (WMD: 4.36; 95%CI: 4.07–4.66; p < 0.001), trochanter (WMD: 6.00; 95%CI: 5.95–6.05; p < 0.001), and total body (WMD: 3.20; 95%CI: 2.03–4.38; p < 0.001). Moreover, denosumab therapy significantly reduced the risk of clinical fractures (RR: 0.57; 95%CI: 0.51–0.63; p < 0.001), nonvertebral fracture (RR: 0.83; 95%CI: 0.70–0.97; p = 0.018), vertebral fracture (RR: 0.32; 95%CI: 0.25–0.40; p < 0.001), and hip fracture (RR: 0.61; 95%CI: 0.37–0.98; p = 0.042). Finally, denosumab did not cause excess risks of adverse events. These findings suggested that postmenopausal women receiving denosumab had increased BMDs and reduced fractures at various sites without inducing any adverse events.

Perils of prolonged ovarian suppression and hypoestrogenism in the treatment of breast cancer: Is the risk of treatment worse than the risk of recurrence?

Premenopausal breast cancer is usually estrogen receptor positive, and hence, prolonged ovarian suppression by medical or surgical means to prevent recurrence has become standard of management to improve disease-free survival. Ten-year adjuvant tamoxifen therapy is associated with 3.5% fewer recurrences compared to five years. The SOFT trial demonstrated small but statistically significant incremental improvements in long-term disease-free survival by the addition of gonadotropin-releasing hormone analog treatment (triptorelin) to an aromatase inhibitor (exemestane). Profound hypoestrogenism in the premenopausal age group may not be well tolerated due to a host of bothersome side effects (primarily vasomotor symptoms, musculoskeletal complaints, genitourinary syndrome of menopause, and mood disorders). Prolonged hypoestrogenism in younger women is associated with premature development of cardiovascular disease, bone loss, cognitive decline, and all-cause mortality. This paper explores multi-system consequences of prolonged hypoestrogenism in premenopausal women derived from studies of women with and without breast cancer. Pretreatment counseling in estrogen receptor positive breast cancer should emphasize the benefit of prolonged estrogen suppression on breast cancer recurrence and established risks of lifelong hypoestrogenism on quality of life and all-cause mortality. Future genomic research may help identify the best candidates for extended ovarian suppression to avoid treating many women when only a minority benefit.

Denosumab Treatment for Giant Cell Tumors, Aneurysmal Bone Cysts, and Fibrous Dysplasia-Risks and Benefits

PURPOSE OF REVIEW

This review summarizes current understanding of the role of denosumab, an inhibitor of receptor activator of nuclear kappa-B ligand (RANKL), in the management of 3 skeletal neoplasms: giant cell tumors, aneurysmal bone cysts, and fibrous dysplasia.

RECENT FINDINGS

A growing body of literature supports denosumab use in giant cell tumors, a neoplasm in which RANKL plays a clear pathogenic role. Comparatively less data is available in aneurysmal bone cysts and fibrous dysplasia; however, the pathogenic similarity of these disorders to giant cell tumors, as well as encouraging preliminary data, suggests denosumab may be useful. Denosumab's inhibitory effects on bone turnover are fully reversible after drug discontinuation. This raises important unanswered questions for clinical management, including potential risks of tumor recurrence and bone turnover rebound. Denosumab is a promising potential treatment for skeletal neoplasms. However, its clinical use is impacted by ongoing safety concerns related to postdiscontinuation rebound, particularly in children. There is a critical need to understand denosumab treatment and discontinuation effects on tumor recurrence and to develop strategies for long-term treatment in patients who cannot be managed surgically.

Is denosumab associated with an increased risk for infection in patients with low bone mineral density? A systematic review and meta-analysis of randomized controlled trials

AIM

Denosumab increases bone mineral density through inhibition of the receptor activator of nuclear factor κ-Β ligand (RANKL). RANKL has known immunomodulatory effect. The largest study to date that reviewed denosumab efficacy in osteoporosis demonstrated an increased incidence of serious adverse events of infection (SAEI). We aimed to further evaluate risk of infection and SAEI in denosumab-treated patients.

METHOD

PubMed, Embase, Cochrane Central Register of Controlled Trials, and Web of Science were searched for randomized controlled trials. Studies comparing denosumab 60 mg every 6 months with placebo or bisphosphonate for treatment of low bone mineral density were included. Trials were excluded for use of denosumab in cancer patients treated for skeletal-related events, immunosuppressed patient populations, or for comparison to teriparatide. Risk ratios (RR) with a 95% confidence interval (CI) were pooled using a fixed effects model, or a random effects model if heterogeneity occurred.

RESULTS

Twenty-four randomized controlled trials (20 470 patients) were analyzed. An increased incidence of any infection (RR 1.11; 95% CI 1.02-1.20; P = 0.02) was observed in denosumab-treated patients compared with bisphosphonates, but not when compared with placebo. In contrast, a higher incidence of SAEI (RR 1.21; 95% CI 1.03-1.43; P = 0.02) was seen with denosumab when compared with placebo, but not compared with bisphosphonates.

CONCLUSION

Denosumab-treated patients with low bone mineral density have slightly increased incidence of SAEI compared with placebo, but not when compared with bisphosphonates. Application of these results requires consideration of the entire body of data available regarding denosumab safety.

Adjuvant bisphosphonate use in patients with early stage breast cancer: a physician survey

Purpose

Despite the increasing use of adjuvant bone-modifying agents (BMAs) such as zoledronate and clodronate in the treatment of patients with early stage breast cancer (EBC), little is known about real world practice patterns. A physician survey was performed to address this deficit and determine interest in clinical trials of alternative strategies for BMA administration.

Methods

Canadian oncologists treating patients with EBC were surveyed via an anonymized online survey. The survey collected information on: physician demographics, knowledge and interpretation of adjuvant bisphosphonate guidelines, and real world prescribing practices. Questions also determined thoughts around the design of future adjuvant BMA trials.

Results

Of 127 surveyed physicians, 53 eligible invitees responded (response rate 42%). The majority of physicians are offering high-risk postmenopausal patients adjuvant BMAs. The most common BMA regimen was adjuvant zoledronate (45/53, 85%) every 6 months for 3 years. Concerns around toxicities and repeated visits to the cancer centre were perceived as the greatest barriers to adjuvant bisphosphonate use. Respondents were interested in future trials of de-escalation of BMAs comparing a single infusion of zoledronate vs. 6-monthly zoledronate for 3 years. The most favoured primary endpoints for such a trial included disease recurrence and fragility fracture rates.

Conclusion

Questions around optimal use of adjuvant bisphosphonates in patients with EBC still exist. There is interest among physicians in performing trials of de-escalation of these agents. The results of this survey will assist in designing pragmatic clinical trials to address this question.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06147-1.

Profiling of three H3F3A-mutated and denosumab-treated giant cell tumors of bone points to diverging pathways during progression and malignant transformation

Giant cell tumor of bone (GCTB) is a locally aggressive lesion of intermediate malignancy. Malignant transformation of GCTB is a rare event. In 2013, the humanized monoclonal antibody against receptor activator of nuclear factor-κb-Ligand (RANKL) denosumab was approved for treatment of advanced GCTB. Since then, several reports have questioned the role of denosumab during occasional malignant transformation of GCTB. We report on three patients with H3F3A-mutated GCTBs, treated with denosumab. The tissue samples were analysed by histomorphology, immunohistochemistry, and in two instances by next generation panel sequencing of samples before and after treatment. One patient had a mutation of ARID2 in the recurrence of the GCTB under treatment with denosumab. One patient developed a pleomorphic sarcoma and one an osteoblastic osteosarcoma during treatment. Sequencing revealed a persisting H3F3A mutation in the osteosarcoma while the pleomorphic sarcoma lost the H3F3A mutation; however, a FGFR1 mutation, both in the recurrence and in the pleomorphic sarcoma persisted. In addition, the pleomorphic sarcoma showed an AKT2 and a NRAS mutation. These data are inconclusive concerning the role denosumab plays in the event of malignant progression/transformation of GCTB and point to diverging pathways of tumor progression of GCTB associated with this treatment.

Denosumab is not associated with risk of malignancy: systematic review and meta-analysis of randomized controlled trials

The immunomodulatory effects of denosumab have raised concerns for risk of malignancy. This meta-analysis of 25 randomized controlled trials (21,523 patients) shows similar risk of malignancy between denosumab (60 mg every 6 months, up to 48 months) and any comparator. Post-marketing surveillance may detect rare or late-occurring drug effects. Possible increased risk of malignancy in patients treated with denosumab has been concerned due to inhibition of the immune modulator receptor activator of nuclear factor κ-Β ligand (RANKL). We aimed to assess the risk of malignancy associated with denosumab treatment. PubMed and Cochrane Central Register of Controlled Trials were searched up to May 27, 2019 to include all randomized controlled trials of denosumab (60 mg every 6 months) versus any comparator. Trials using higher drug doses for prevention of skeletal-related events were excluded. Data were independently extracted by two reviewers and analyzed using a fixed-effect model to pool risk ratios (RRs) with 95% confidence intervals (CI). Twenty-five trials (21,523 patients) were included. The risk of malignancy was similar between denosumab and other comparators (absolute risk difference 0%, RR 1.08 [95% CI, 0.93-1.24], I² = 0%). Sensitivity analysis based on adequate allocation concealment showed similar results. The risk of malignancy did not differ between groups in any of the subgroup analyses, including stratification by race, individual comparators, indications for treatment, and longer drug exposure (≥ 24 months, 9 studies). The risk ratio of malignancy-related death was similar between groups. Early concerns about a potential increased risk of malignancy resulting from an immunomodulatory effect of denosumab are not supported by evidence from this meta-analysis of 25 RCTs with drug exposure of up to 48 months. Since RCTs with longer observation for safety outcomes are not expected, post-marketing surveillance will be the main means for detection of rare or late-occurring events.

The effect of denosumab in breast cancer patients receiving adjuvant aromatase inhibitors: 36-month results

INTRODUCTION

Aromatase inhibitor (AI)-associated bone loss increases the risk of bone fracture and reduces patients' quality of life, making it a critical issue worldwide. We conducted a prospective non-randomized clinical trial (UMIN-CTR, UMIN 000016173) to assess the effect of denosumab on bone loss in patients treated with adjuvant AI and have previously reported the results at 12 and 24 months. This study aimed to present the results at 36 months of treatment with denosumab for osteopenia in breast cancer patients who were undergoing treatment with adjuvant AI; 36 months is the longest denosumab treatment period reported so far.

MATERIALS AND METHODS

Patients received 60-mg denosumab subcutaneously every 6 months. Daily supplements containing 500-mg elemental calcium and at least 400 international units of vitamin D were highly recommended throughout the study period. The levels of bone mineral density (BMD) and bone turnover markers, serum tartrate-resistant acid phosphatase isoform 5b, and bone alkaline phosphatase were determined at baseline and 6, 12, 18, 24, and 36 months.

RESULTS

At 36 months, the bone mineral density of the lumbar spine, right femoral neck, and left femoral neck were found to increase by 8.8% (95% confidence interval CI 7.6-10.1), 4.3% (95% CI 3.0-5.5), and 3.1% (95% CI 2.1-4.1), respectively. No non-traumatic clinical fractures occurred in patients receiving AI and denosumab.

CONCLUSION

Twice-yearly administration of denosumab to the breast cancer patients treated with adjuvant AI, regardless of the skeletal site, resulted in consistent increases in BMD without severe adverse events at 36 months.

Cardiovascular Safety of Denosumab Across Multiple Indications: A Systematic Review and Meta-Analysis of Randomized Trials

The cardiovascular safety of denosumab has not yet been evaluated in a systematic review. This systematic review and meta-analysis sought to quantify the number of randomized controlled trials (RCTs) of denosumab (against comparators) reporting cardiovascular adverse events (CAEs) and examine the balance of CAEs between treatment arms. MEDLINE, Embase, and clinicaltrials.gov were searched from inception to October 26, 2019, for RCTs of denosumab versus comparators for any indication. Included trials were randomized, enrolled ≥100 participants, and reported bone-related outcomes. Primary outcome for analysis was all CAEs, a composite endpoint representing summation of all CAEs as reported by included trials. Secondary outcomes included major adverse cardiovascular events (MACE). Data were pooled using a fixed effects model to determine relative risk (RR) and 95% confidence interval (95% CI). Risk of bias was assessed using the Cochrane risk-of-bias tool. Of 554 records screened, 49 were included, while 36 reported CAEs. Twenty-seven included trials (12 eligible for meta-analysis) were conducted in 13,202 postmenopausal women. Compared with bisphosphonates, there was a 46% (95% CI 1.05 to 2.02) increase in CAEs (85/2136 events in denosumab-treated versus 58/2131 events in bisphosphonate-treated; seven trials). There was a similar imbalance in a five-point (stroke, myocardial infarction, cardiovascular death, heart failure, atrial fibrillation) MACE endpoint (28/2053 versus 12/2050; RR = 2.33 [1.19 to 4.56]). Compared with placebo-treated women, there was no imbalance in total CAEs (439/4725 events in denosumab versus 399/4467 in placebo; RR = 0.79 [0.41 to 1.52]; seven trials). No imbalance in total AEs (versus bisphosphonates: 0.98 [0.92 to 1.04]; versus placebo: 0.99 [0.98 to 1.01]) occurred. Other indications showed no statistically significant results. The excess CAEs in postmenopausal women treated with denosumab compared with bisphosphonates, but not placebo, indirectly supports claims that bisphosphonates may suppress CAEs. Future trials should use standardized CAE reporting to better describe cardiovascular effects of bone active medications. (PROSPERO: CRD42019135414.) © 2020 American Society for Bone and Mineral Research (ASBMR).

The safety profile of denosumab in oncology beyond the safety of denosumab as an anti-osteoporotic agent: still more to learn

INTRODUCTION

Initially endorsed as an antiosteoporotic agent, denosumab ‒ human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL)‒ has currently shown an anticancer potential, rationalizing its exploitation in oncology. A prerequisite for leveraging denosumab in oncology is a favorable safety profile.

AREAS COVERED

The present review provides an overview of the adverse events of denosumab in oncology, with a focus on hypocalcemia, medication-related osteonecrosis of the jaw, atypical femoral fracture(s), post-denosumab vertebral fractures, increased risk of infections, and excess of second primary cancer. Representative studies addressing the safety and efficacy of denosumab compared to bisphosphonates in oncology are summarized. Critical gaps in the literature concerning the safety of denosumab in oncology are highlighted as opposed to plenty of available safety data on denosumab as an antiosteoporotic agent.

EXPERT OPINION

Despite the generally acceptable safety profile of denosumab in oncology, many issues remain unresolved. Further research is mandatory to counteract current challenges, namely: (i) validation of risk factors for adverse events; (ii) elucidation of the pathophysiology of the adverse events in search of actionable molecular pathways; (iii) illumination of the association of denosumab with increased risk of infections and/or second primary cancer; (iv) establishment of optimal diagnostic, and therapeutic protocols.

Feasibility outcomes of a randomised, multicentre, pilot trial comparing standard 6-monthly dosing of adjuvant zoledronate with a single one-time dose in patients with early stage breast cancer

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Adjuvant bisphosphonates are an established standard in postmenopausal breast cancer.

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Guidelines note the need to explore different agents, doses, and intervals of bisphosphonates.

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Feasibility of randomizing to 6-monthly vs one dose of IV zoledronate was demonstrated.

Background

Adjuvant zoledronate is widely used in patients with early stage breast cancer (EBC), but its optimal duration and dosing interval is still unknown. While a single-dose of zoledronate can improve bone density for many years, a proper evaluation of its effects on breast cancer-related outcomes would require a large trial. In this pilot study we evaluated the feasibility of performing such a trial.

Methods

Eligible patients with EBC were randomised to receive either one dose of zoledronate or 7 doses (6-monthly dosing for 3 years). Feasibility was assessed by a combination of primary outcomes including: activation of at least 6 Ontario sites within a year, active participation (i.e. approaching eligible patients for study participation) of at least half of the medical oncologists, and enrolment of at least 100 patients across all sites within 9 months of the sixth site being activated.

Results

All 6 sites were activated within 1 year and of 47 medical oncologists, 27 (57%) approached patients. Between November 2018 and April 2020, 211 eligible patients were randomised, 106 (50.2%) to a single dose of zoledronate and 105 (49.8%) to 6-monthly dosing. Baseline characteristics of randomised patients included; median age 59 (range 36–88), ER and/or PR positive (85%), Her2 positive (23%), menopausal status (premenopausal [19%], perimenopausal [6.7%] and postmenopausal [74%]) and 74% received neo/adjuvant chemotherapy.

Conclusions

All study feasibility endpoints were met in this trial comparing alternative schedules for adjuvant zoledronate. We will now seek funding for performing a larger efficacy trial.

Trial registration: NCT03664687.

Repurposing denosumab in breast cancer beyond prevention of skeletal related events: Could nonclinical data be translated into clinical practice?

INTRODUCTION

Denosumab is a human monoclonal antibody inhibiting the receptor activator of nuclear factor kappa-B ligand (RANKL). Initially approved as antiosteοporotic agent, denosumab is being currently pursued as a candidate for drug repurposing in oncology, especially breast cancer.

AREAS COVERED

The present review provides an overview of the therapeutic potential of denosumab in breast cancer beyond prevention of skeletal-related events (SREs), with focus on prevention of carcinogenesis in BRCA mutation carriers and on adjuvant treatment in early breast cancer patients. Study search was conducted on the following electronic databases: PubMed, Google scholar, Scopus.com, ClinicalTrials.gov, and European Union Clinical Trials Register from 2008 until June 2020.

EXPERT OPINION

Nonclinical data have established links between RANKL signaling and breast cancer initiation and progression, rationalizing exploring the potential bone-independent anticancer role of denosumab beyond SREs prevention. Preclinical and preliminary clinical data show that denosumab may inhibit carcinogenesis in BRCA mutation carriers. Denosumab adjuvant in early breast cancer has been shown, though inconsistently, to provide a disease-free survival benefit for a subgroup of patients. Despite promising results, the incorporation of denosumab in preventive and therapeutic protocols of breast cancer beyond prevention of SREs cannot be endorsed until further research consolidates its efficacy.

Integration of denosumab therapy in the management of giant cell tumors of bone

A review of the literature indicated denosumab is gaining favorability in the oncology community, particularly with increasing frequency in GCTB. Will denosumab be the breakthrough GCTB treatment? Here, we provide a pertinent case example, a review of the literature regarding the history and basic science behind the use of denosumab for GCTB, highlight the newest insights into the dosing and duration of treatment, and note advancements in the field.

Osteoporosis: A Long-Term and Late-Effect of Breast Cancer Treatments

Simple Summary

Osteoporosis is a prevalent condition affecting 200 million individuals world-wide. Estimates are about one in three women will experience a fragility fracture of hip, spine or wrist. Common breast cancer treatments, such as aromatase inhibitors in postmenopausal women and chemotherapy-induced ovarian failure in premenopausal women, cause bone loss that in some women will lead to osteoporosis and fragility fractures. Fragility fractures cause morbidity and mortality and are entirely preventable. Prevention or treatment of osteoporosis includes lifestyle modifications (e.g., reducing smoking and excessive alcohol consumption, and increasing physical activity), taking calcium and vitamin D3, screening for osteoporosis with dual-energy absorptiometry, and treatment, if clinically indicated, with ether oral bisphosphonates, intravenous zoledronic acid, or subcutaneous denosumab. This chapter reviews the pathogenesis of osteoporosis, the magnitude of bone loss related to common breast cancer treatments, osteoporosis risk factor assessment and screening, and the specific drugs to treat or prevent osteoporosis.

Abstract

Osteoporosis is both a long-term effect (occurs during treatment and extends after treatment) and a late-effect (occurs after treatment ends) of breast cancer treatments. The worldwide prevalence of osteoporosis is estimated to be some 200 million patients. About one in three postmenopausal women will experience an osteoporotic (or fragility) fracture of the hip, spine, or wrist. breast cancer treatments, including gonadotropin-releasing hormone (GnRH) agonists, chemotherapy-induced ovarian failure (CIOF), and aromatase inhibitors (AIs), cause bone loss and increase the risks of osteoporosis. Also, breast cancer is a disease of aging, and most of the “one in eight” lifetime risks of breast cancer are in women in their sixth, seventh, and eighth decades. The majority of women diagnosed with breast cancers today will be long-term survivors and experience personal cures. It is the coalescence of osteoporosis with breast cancer, two common and age-related conditions that make osteoporosis relevant in women with breast cancer throughout the continuum from diagnosis, treatment, and survivorship. It is critical to remember that women (and men) will lose bone after age thirty years. However, only certain women will lose bone of sufficient magnitude to merit treatment with anti-osteoporosis drugs. The narrative review is intended for medical, surgical, radiation oncologists, and other mid-level providers, and provides an overview of bone loss and the prevention and treatment of osteoporosis.

The Role of the RANKL/RANK Axis in the Prevention and Treatment of Breast Cancer with Immune Checkpoint Inhibitors and Anti-RANKL

The receptor activator of nuclear factor-κB (RANK) and the RANK ligand (RANKL) were reported in the regulation of osteoclast differentiation/activation and bone homeostasis. Additionally, the RANKL/RANK axis is a significant mediator of progesterone-driven mammary epithelial cell proliferation, potentially contributing to breast cancer initiation and progression. Moreover, several studies supported the synergistic effect of RANK and epidermal growth factor receptor (EGFR) and described RANK's involvement in epidermal growth factor receptor 2 (ERBB2)-positive carcinogenesis. Consequently, anti-RANKL treatment has been proposed as a new approach to preventing and treating breast cancer and metastases. Recently, RANKL/RANK signaling pathway inhibition has been shown to modulate the immune environment and enhance the efficacy of anti-CTLA-4 and anti-PD-1 monoclonal antibodies against solid tumors. Clinical and experimental trials have emerged evaluating RANKL inhibition as an enhancer of the immune response, rendering resistant tumors responsive to immune therapies. Trials evaluating the combinatorial effect of immune checkpoint inhibitors and anti-RANKL treatment in double-positive (RANK+/ERBB2+) patients are encouraging.

Challenges in Preventing Bone Loss Induced by Aromatase Inhibitors

CONTEXT

Aromatase inhibitors have become a mainstay in the adjuvant treatment regimen in postmenopausal women with hormone receptor-positive breast cancer. While many of these patients have an excellent long-term prognosis, adverse effects on bone represent an emerging complication of aromatase inhibitor treatment, resulting in substantial bone loss and fragility fractures. Treatment approaches to prevent aromatase inhibitor-induced bone loss typically consist of an antiresorptive approach with bisphosphonates or the RANKL antibody denosumab. However, different guidelines vary with respect to treatment thresholds, duration, and dosing. The choice of antiresorptive regime is further complicated by comorbidities and potential disease-modifying effects of individual agents.

OBJECTIVE

This review summarizes the evidence of how aromatase inhibitors affect bone health and provides an update of clinical approaches to preserve bone strength in affected women. (J Clin Endocrinol Metab XX: 0-0, 2020).

OPG-Fc treatment partially rescues low bone mass phenotype in mature Bgn/Fmod deficient mice but is deleterious to the young mouse skeleton

Biglycan (Bgn) and Fibromodulin (Fmod) are small leucine rich proteoglycans (SLRPs) which are abundant in the extra-cellular matrix (ECM) of mineralized tissues. We have previously generated a Bgn/Fmod double knock-out (DKO) mouse model and found it has a 3-fold increase in osteoclastogenesis compared with Wild type (WT) controls, resulting in a markedly low bone mass (LBM) phenotype. To try and rescue/repair the LBM phenotype of Bgn/Fmod DKO mice by suppressing osteoclast formation and activity, 3- and 26-week-old Bgn/Fmod DKO mice and age/gender matched WT controls were treated with OPG-Fc for 6 weeks after which bone parameters were evaluated using DEXA, micro-computed tomography (μCT) and serum biomarkers analyses. In the appendicular skeleton, OPG-Fc treatment improved some morphometric and geometric parameters in both the trabecular and cortical compartments in Bgn/Fmod DKO female and male mice, especially in the repair module. For many of the skeletal parameters analyzed, the Bgn/Fmod DKO mice were more responsive to the treatment than their WT controls. In addition, we found that OPG-Fc treatment was not able to prevent or ameliorate the formation of ectopic ossification, which are common lesions seen in aged joints and are one of the phenotypical hallmarks of our Bgn/Fmod DKO model. Analysis of skull bones, specifically the occipital bone, showed the treatment recovered some parameters of LBM phenotype in the craniofacial skeleton, more so in the younger rescue module. Using OPG-Fc as treatment alleviated, yet did not completely restore, the severe osteopenia and mineralized tissue structural abnormalities that Bgn/Fmod DKO mice suffer from.