Identifying the preferable rheumatoid arthritis subgroups for intervention with the anti-RANKL antibody denosumab to reduce progression of joint destruction

Role of denosumab in bone erosions in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by systemic inflammation and synovitis which evolve into joint destruction and deformity. Bone abnormalities are represented by marginal bone erosions and iuxta-articular and generalized osteoporosis. Overactivation of osteoclasts along with dysregulation of osteoblasts are the key events. Bone resorption is mediated by the receptor activator of nuclear factor (NF)-κB (RANK) ligand (RANK-L), responsible for the differentiation, proliferation, and activation of osteoclasts. RANK-L binds its receptor RANK, localized on the surface of preosteoclasts and mature osteoclasts promoting osteoclastogenesis. High levels of RANK-L were demonstrated in active RA patients. Denosumab, a fully human monoclonal antibody, binds RANK-L and suppresses the RANK-RANK-L signaling pathway leading to the inhibition of osteoclastogenesis. A retrospective analysis of published studies such as clinical trials evidenced the efficacy of denosumab in preventing bone erosion progression in RA patients. Key messages Key questions to answer in future include the following: Could denosumab be associated with other biologic therapies in RA patients? Could denosumab block the progression of bone damage in RA? Could denosumab be used for the prevention of bone erosion in RA?

BML-111 inhibits osteoclast differentiation by suppressing the MAPK and NF-κB pathways, alleviating deterioration of the knee joints in a CIA rat model

Irreversible destruction of joints is the hallmark of rheumatoid arthritis (RA). Osteoclasts are the only bone-resorbing cells and play an important role in joint rebuilding. BML-111 (5(S),6(R),7-trihydroxyheptanoic acid methyl ester, C₈ H₁₆ O₅ ) is a synthetic lipoxin A4 agonist with antioxidant and anti-inflammatory properties. The present study aimed to investigate the effect of BML-111 on osteoclasts in vivo and in vitro, to investigate its therapeutic effect on joint destruction in RA. Cell Counting Kit-8 assay and flow cytometry were used to exclude cytotoxic effects of BML-111 to bone marrow-derived macrophages (BMMs). Then, osteoclasts were differentiated in vitro from BMMs by used macrophage colony-stimulating factor and receptor activator of nuclear factor-κB ligand, and osteoclasts were observed following tartrate-resistant acid phosphatase staining with or without BML-111 treatment. Meanwhile, absorption pit assay and immunofluorescence staining of the fibrous actin ring were used to observe osteoclast function. Moreover, we examined mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation. We established collagen-induced arthritis in a rat model and, after treatment with BML-111, joint swelling was measured and the knee joints were processed for histology. We also examined serum and tissue for osteoclastogenesis-related markers. BML-111 inhibited osteoclast formation and differentiation in a time- and concentration-dependent manner, and downregulated the expression levels of MAPK and NF-κB in vitro. Meanwhile, BML-111 effectively alleviated joint structural damage and inhibited osteoclast formation in vivo. BML-111 inhibited osteoclast formation and differentiation in vitro and in vivo, and delayed the progression of joint destruction.

Bone resorption during therapy with denosumab in patients with rheumatoid arthritis, positive for the main immunological markers

Objective. Inflammation in rheumatoid arthritis (RA) leads to the development of local and generalized bone loss. Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (ACCP) are believed to play a negative role in the radiological progression of RA. The use of such antiresorptive therapy as denosumab – monoclonal antibodies to RANKL (receptor activator of nuclear factor kappa-B ligand), reduces the activity of osteoclasts, increases bone mineral density (BMD), and also potentially affects the erosive process at RA. The aim of the study is to evaluate the effect of denosumab therapy on BMD and erosion count in patients with RA and osteoporosis (OP) in consideration of the positivity in the RF and ACCP in serum and the baseline RA activity. Materials and methods. The 12-month prospective study of the efficacy of denosumab therapy (60 mg subcutaneously every 6 months) in patients with RA and OP included 66 postmenopausal women; age – 59.4±7.5 years, duration of RA – 17.8±10.6 years, RF-positive – 47 (72%) patients, ACCP-positive – 48 (74%) patients. At baseline and after 12 months, dual-energy X-ray absorptiometry was performed with an assessment of BMD in the lumbar spine (L1– L4), proximal femur (hip neck and total hip), distal forearm; X-ray of the hands and distal parts of the feet in direct projection, followed by assessment of erosive-destructive changes according to the Sharp/van der Heijde method. Results. A significant increase in BMD was established in all studied sites of the skeleton despite the positivity of the RF and ACCP (for the hip neck p=0.05), while a significant increase in BMD in the RF- and ACCP-negative group was detected only in L1–L4 site. The progression of the increase in erosion count was noted in the RF- and ACCP-positive group while in the RF- and ACCP-negative group this indicator did not change. Regardless of the baseline activity of RA (by DAS28 (Disease Activity Score 28)) the BMD of most parts of the skeleton were stabilized. In patients with moderate RA activity, BMD increased significantly in L1–L4 in both groups: RF- and ACCP-positive and -negative , as well as in the total hip – in RF- and ACCP-positive group. The dynamics of the erosion count in RA patients did not depend on the baseline degree of DAS28 activity, no significant changes were detected in the analyzed groups. Conclusions. RF and ACCP positivity in serum in patients with RA and OP treated with denosumab did not have a negative effect on the dynamics of BMD, while the number of erosions increased. The baseline RA activity level did not affect the dynamics of the erosion count and the dynamics of BMD in most subgroups – BMD levels have been increased or stabilized.

Personalized Therapeutic Strategies in the Management of Osteoporosis in Patients with Autoantibody-Positive Rheumatoid Arthritis

Bone mineral density (BMD) reduction and fragility fractures still represent a major source of morbidity in rheumatoid arthritis (RA) patients, despite adequate control of the disease. An increasing number of clinical and experimental evidence supports the role of autoantibodies, especially anti-citrullinated protein antibodies (ACPAs), in causing localized and generalised bone loss in ways that are both dependent on and independent of inflammation and disease activity. The human receptor activator of nuclear factor kappa B and its ligand—the so-called RANK-RANKL pathway—is known to play a key role in promoting osteoclasts’ activation and bone depletion, and RANKL levels were shown to be higher in ACPA-positive early untreated RA patients. Thus, ACPA-positivity can be considered a specific risk factor for systemic and periarticular bone loss. Through the inhibition of the RANK-RANKL system, denosumab is the only antiresorptive drug currently available that exhibits both a systemic anti-osteoporotic activity and a disease-modifying effect when combined with conventional synthetic or biologic disease-modifying anti-rheumatic drugs (DMARDs). Thus, the combination of DMARD and anti-RANKL therapy could be beneficial in the prevention of fragility fractures and structural damage in the subset of RA patients at risk of radiographic progression, as in the presence of ACPAs.

Therapeutic efficacy of denosumab for rheumatoid arthritis: a systematic review and meta-analysis

OBJECTIVES

Denosumab is used for osteoporosis because it inhibits osteoclast maturation and suppresses bone resorption. Although denosumab is expected to inhibit the bone erosion in RA, its therapeutic efficacy is not well established. The aim of this study was to estimate the effects of denosumab on RA through a meta-analysis.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. PubMed, Web of Science and Scopus were searched for original studies providing information on BMD, joint destruction and disease activity in denosumab-treated RA. A random-effects model was used in the meta-analysis.

RESULTS

Of the 367 studies identified, 18 met the selection criteria. The BMDs of the lumbar spine, total hip and femoral neck at 12 months after denosumab treatment increased by 5.27% (95% CI: 4.37, 6.18), 2.82% (2.46, 3.18) and 3.07% (2.66, 3.48), respectively. In the sensitivity analysis, age and sex tended to influence the effect of denosumab therapy on the rate of variation of BMD, but not glucocorticoid use. The changes in the modified total sharp, erosion and joint space narrowing scores at 12 months after denosumab treatment were significantly smaller with denosumab than with placebo, although the DAS did not change after denosumab treatment.

CONCLUSION

Although denosumab has an inhibitory effect on the bone resorption in RA, its effects might be influenced by the age and sex of RA patients, but not by glucocorticoid use.

Effect of denosumab switched from bisphosphonates in preventing joint destruction in postmenopausal rheumatoid arthritis patients with anti-cyclic citrullinated peptide antibodies

INTRODUCTION

This study aimed to determine the effects of denosumab treatment on the joint destruction of Japanese females with rheumatoid arthritis (RA) and anti-cyclic citrullinated peptide (CCP) antibodies.

MATERIALS AND METHODS

This retrospective longitudinal study included 56 patients treated with denosumab and 50 patients treated with bisphosphonate. All participants were positive for anti-CCP antibodies. All patients also had a history of osteoporosis treatment with bisphosphonate, which was either continued or switched to 60 mg of subcutaneous denosumab injection every 6 months. To assess the progression of joint destruction, hand and foot radiographs were taken, and changes in modified total Sharp score (mTSS), erosion score (ERO), and joint space narrowing score (JSN) were evaluated at 12 months and 24 months. The changes in BMD of the lumbar spine and hip were also assessed at 12 months.

RESULTS

At 12 months, there were significant differences in the change of ERO (p = 0.015) and mTSS (p = 0.01). Similarly, there were significant differences in the change of ERO (p = 0.013) and mTSS (p = 0.003) at 24 months. In contrast, no significant difference was observed in the changes of JSN and clinical parameters. There were significant differences in the changes in BMD in the femoral neck (p = 0.011) and total hip (p = 0.012).

CONCLUSION

Denosumab treatment might be effective for the inhibition of bone erosion progression in the patients with RA, and it potentially contributes to the treatment of osteoporosis and prevention of destructive arthritis in patients with switching treatment from bisphosphonate.