Biologic therapies for spondyloarthritis: what is new?

Effects of targeted therapies on bone in rheumatic and musculoskeletal diseases

Generalized bone loss (osteoporosis) and fragility fractures can occur in rheumatic and musculoskeletal diseases including rheumatoid arthritis and spondyloarthritis (SpA; including ankylosing spondylitis and psoriatic arthritis). In addition, rheumatoid arthritis can involve localized, periarticular bone erosion and, in SpA, local (pathological) bone formation can occur. The RANK-RANKL-osteoprotegerin axis and the Wnt-β-catenin signalling pathway (along with its inhibitors sclerostin and Dickkopf 1) have been implicated in inflammatory bone loss and formation, respectively. Targeted therapies including biologic DMARDs and Janus kinase (JAK) inhibitors can stabilize bone turnover and inhibit radiographic joint damage, and potentially also prevent generalized bone loss. Targeted therapies interfere at various points in the mechanisms of local and generalized bone changes in systemic rheumatic diseases, and they effect biomarkers of bone resorption and formation, bone mass and risk of fragility fractures. Studies on the effects of targeted therapies on rates of fragility fracture are scarce. The efficacy of biologic DMARDs for arresting bone formation in axial SpA is debated. Improved understanding of the most relevant therapeutic targets and identification of important targeted therapies could lead to the preservation of bone in inflammatory rheumatic and musculoskeletal diseases.

Both ASDAS and ADC are associated with spinal mobility in active axial spondyloarthritis: A comparison between early and later disease

OBJECTIVE

Using diffusion-weighted imaging (DWI)-derived apparent diffusion coefficient (ADC), we aimed to determine the relationship between intensity of spinal inflammation and mobility in patients with axial spondyloarthritis (SpA) in early and later stages of active disease. The Ankylosing Spondylitis Disease Activity Score (ASDAS) was also used for a more comprehensive evaluation.

METHODS

Participants with axial SpA and back pain were recruited from 10 rheumatology centers. Clinical, biochemical and radiological parameters were collected. Short tau inversion recovery (STIR) sequence magnetic resonance imaging (MRI) and DWI of the spine and sacroiliac (SI) joints were performed. ADC maps were generated. Participants were examined for Bath Ankylosing Spondylitis Metrology Index (BASMI). Linear regression models were used to determine associations between BASMI and various clinical, radiological, and MRI parameters in participants with active inflammation on spinal ADC maps.

RESULTS

One-hundred and twenty-seven participants were included in the analyses. Multivariate linear regression showed that mean ADC spine (ß = .16; P = .03), ASDAS-C-reactive protein (CRP) (ß = .29, P < .001), and ASDAS-erythrocyte sedimentation rate (ESR) (ß = .25, P < .01) were associated with BASMI. In participants with duration of back pain ≤3 years, mean spine ADC (ß = .37; P = .03), ASDAS-CRP (ß = .44; P = .01), and ASDAS-ESR (ß = .42; P = .01) were associated with BASMI after adjustment for confounding factors. In participants with duration of back pain >3 years, only ASDAS-CRP (ß = .25; P < .01) and ASDAS-ESR (ß = .20; P = .20) were associated with BASMI.

CONCLUSION

Intensity of inflammation and clinical disease activity were independently associated with impairment of spinal mobility. The associations were stronger in early (≤3 years) than later disease.

Pathogenesis and clinical perspectives of extraintestinal manifestations in inflammatory bowel diseases

A considerable number of patients with inflammatory bowel disease (IBD) experience extraintestinal manifestations (EIMs), which can present either before or after IBD diagnosis. Unraveling the pathogenic pathways of EIMs in IBD is challenging because of the lack of reliable criteria for diagnosis and difficulty in distinguishing EIMs from external pathologies caused by drugs or other etiologies. Optimizing treatment can also be difficult. Early diagnosis and management of EIM revolve around multidisciplinary teams, and they should have the resources necessary to make and implement appropriate decisions. In addition, specialists of the affected organs should be trained in IBD treatment. Furthermore, patient awareness regarding the extraintestinal symptoms of IBD is of paramount importance for improving patient understanding of disease and health outcomes. Herein, we review the pathogenesis and clinical perspectives of EIMs in IBD.

Features of trunk muscle weakness in patients with ankylosing spondylitis: A cross-sectional study

BACKGROUND

Ankylosing spondylitis (AS) is an inflammatory autoimmune disorder that manifested with sacroiliitis at its early stage and developed extensive inflammation with syndesmophytes of the lumbar, thoracic and cervical spines at its later stage. In the present study, we characterized the trunk isometric strength in patients with AS with different disease severity, defined by the radiological images.

METHODS

In a cross-sectional study conducted in a university-affiliated hospital, thirty-eight male AS patients (23 in the early AS group whose radiological findings showed no syndesmophyte, Modified Stoke Ankylosing Spinal Score (m-SASSS <3); and 15 in the syndesmophyte group, m-SASSS ≥24), and 22 healthy controls were recruited. All subjects received assessments of maximum isometric strength of trunk flexor and extensor muscles at a variety of trunk postures measured by an isokinetic device.

RESULTS

Under all examined trunk postures, the syndesmophyte AS patient group had the lowest isometric trunk muscle strength among the three groups. The flexion/extension ratio, defined by the ratio between isometric trunk flexor and extensor strengths, was highest among the three groups.

CONCLUSIONS

Trunk muscle strength significantly decreases in patients with syndesmophyte AS. The decrease of trunk muscle is inhomogeneous, which is more profound in extensor than in flexor muscles.

Full dose, half dose, or discontinuation of etanercept biosimilar in early axial spondyloarthritis patients: a real-world study in China

INTRODUCTION

To investigate the effect of dose maintenance, reduction, or discontinuation of the etanercept biosimilar Yisaipu (YSP) on early axial spondyloarthritis (axSpA) patients in remission with YSP 50 mg once weekly (QW).

MATERIAL AND METHODS

Patients were enrolled in three groups: full dose (YSP50), half dose (YSP25), and discontinuation (YSP0). Patients were assessed by the same rheumatologist every 8 weeks for 48 weeks. The primary endpoint was the proportion of non-failure patients in each group. If a flare occurred during the study period, the patient resumed YSP 50 mg QW or was switched to another tumor necrosis factor inhibitor.

RESULTS

A total of 144 patients were included and each group included 48 patients. The proportion of non-failure patients was significantly greater in the YSP50 group than in the YSP0 group at 48 weeks (91.7% vs. 72.9%, p = 0.032). The difference in the other two comparisons was not statistically significant (YSP50 vs. YSP25 group, p = 0.522; YSP25 vs. YSP0 group, p = 0.132). The median time to flare did not differ significantly between the three groups (p > 0.05). Most patients who flared regained remission rapidly after resuming YSP 50 mg QW or starting adalimumab 40 mg every other week.

CONCLUSIONS

For patients with early axSpA in remission on YSP for more than 12 weeks, continuation of YSP at full dose was superior to discontinuation of YSP, but not superior to halving the dose.

A Review of Extraintestinal Manifestations and Complications of Inflammatory Bowel Disease

Extraintestinal manifestations (EIMs) are common in inflammatory bowel disease (IBD), in both Crohn's disease and ulcerative colitis. Almost any organ system can be affected, including the musculoskeletal, dermatologic, renal, hepatopancreatobiliary, pulmonary and ocular systems. However, the musculoskeletal and dermatologic systems are the most commonly involved sites of manifestations. While some manifestations such as peripheral arthritis and erythema nodosum have an association with IBD activity, others such as axial arthropathy, pyoderma gangrenosum and primary sclerosing cholangitis have an independent disease course. This review provides a summary of the most common EIMs in IBD and their prevalence and management.

Cupping therapy for treating ankylosing spondylitis: The evidence from systematic review and meta-analysis

OBJECTIVE

Cupping therapy has been widely used in Eastern Asia, the Middle East, or Central and North Europe to manage the symptom of ankylosing spondylitis (AS). The aim of this systematic review was to review data from randomized controlled trials (RCTs) of cupping therapy for treating patients with AS.

METHODS

Databases that were searched from their inception until December 2017 included: MEDLINE, CINAHL, EMBASE, AMED, Cochrane Central Register of Controlled Trials, four Chinese databases [Chinese BioMedical Database, China National Knowledge Infrastructure, Wan-Fang Data, and the Chinese WeiPu Database], KoreaMed, The Korean National Assembly Library, Japana Centra Revuo Medicina (http://www.jamas.gr.jp/) and CiNii. In this systematic review, only RCTs that were related to the effects of cupping therapy on managing AS were included. A quantitative synthesis of RCTs will be conducted using RevMan 5.3 software. Study selection, data extraction, and validation were performed independently by two reviewers. Quantitative analysis of RCTs were performed using RevMan 5.3 software, and cochrane criteria for risk-of-bias were used to assess the methodological quality of the trials.

RESULTS

A total of 5 RCTs met the inclusion criteria, and most were of low methodological quality. Participants in cupping therapy plus Western medicine group showed significantly greater improvements in the response rate [RR = 1.13, 95%CI (1.06, 1.22), p < 0.01] with low heterogeneity (Chi² = 2.88, p = 0.41, I² = 0%). Moreover, when compared with western medicine alone, meta-analysis indicated favorable statistically significant effects of cupping therapy plus western medicine on the Bath Ankylosing Spondylitis Functional Index (BASFI) [MD = -16.63, 95%CI (-17.75, -15.51), p < 0.01] and Bath Ankylosing Disease Activity Index (BASDAI) [MD = -9.93, 95%CI (-10.34, -9.52), p < 0.01], with low heterogeneity (Chi² = 0.32, p = 0.85, I² = 0% in BASFI; (Chi² = 2.46, p = 0.29, I² = 19% in BASDAI). Furthermore, when compared with western medicine alone, meta-analysis demonstrated statistically significant effects of cupping therapy plus western medicine on the serum level of ESR [MD = -1.28, 95% CI (-1.44, -1.13), p < 0.01] and the serum level of CRP [MD = -3.97, 95%CI (-4.71, -3.22), p < 0.01], with low heterogeneity (Chi² = 0.50, p = 0.78, I² = 0% in the serum level of ESR; Chi² = 0.19, p = 0.91, I² = 0% in the serum level of CRP).

CONCLUSION

Taken together, only weak evidence supported the hypothesis that cupping therapy had potential benefits for patients with AS.

Serum C-reactive Protein Levels Demonstrate Predictive Value for Radiographic and Magnetic Resonance Imaging Outcomes in Patients with Active Ankylosing Spondylitis Treated with Golimumab

OBJECTIVE

Serum C-reactive protein (CRP) associates with radiographic progression in patients with ankylosing spondylitis (AS) untreated with tumor necrosis factor (TNF) antagonists. We assessed correlations between serum CRP and radiographic progression/magnetic resonance imaging (MRI)-detected inflammation after 2 years of anti-TNF therapy.

METHODS

Patients with active AS receiving golimumab (GOL)/placebo through Week 16 (early escape) or Week 24 (crossover by design), followed by GOL through 4 years, had sera/images obtained through Week 208. Lateral spinal radiographs and spinal MRI were scored with the modified Stoke AS Spine Score (mSASSS) and the AS spine MRI activity (ASspiMRI-a) score, respectively. ANOVA assessed differences based on CRP levels and mSASSS progression. The relationships between CRP levels and mSASSS/ASspiMRI-a were assessed by Spearman correlation and logistic regression.

RESULTS

Of the randomized GO-RAISE patients, 299 (84.0%) had pre- and posttreatment spinal radiographs. Larger proportions of patients with Week 104 CRP ≥ 0.5 mg/dl (n = 47) versus < 0.5 mg/dl (n = 236, 40.4% vs 22.9%, p = 0.0121) had mSASSS changes ≥ 2 at Week 104. Across several visits, serum CRP demonstrated weak associations with mSASSS change (rs ≤ 0.21, p < 0.05, n = 262-293) and moderate associations with ASspiMRI-a change (rs = -0.33 to 0.54, p < 0.05, n = 65-89). Higher baseline CRP was associated with increased risk for syndesmophytes at Week 104/Week 208, and large, short-term decreases in CRP from baseline to Week 14/Week 24 also yielded increased syndesmophyte formation risk.

CONCLUSION

Elevated CRP after 2 years of anti-TNF treatment correlated with greater radiographic progression risk at 4 years. Elevated CRP at baseline or Week 14/Week 24 of anti-TNF treatment weakly predicted subsequent radiographic progression and modestly predicted residual spinal inflammation in patients with AS treated with anti-TNF. Findings are useful regarding new treatment options in patients treated with anti-TNF. ClinicalTrials.gov: NCT00265083.

Serum Vascular Endothelial Growth Factor Levels Lack Predictive Value in Patients with Active Ankylosing Spondylitis Treated with Golimumab

OBJECTIVE

To assess vascular endothelial growth factor (VEGF) correlations with new bone formation and bone marrow edema in patients with ankylosing spondylitis (AS) treated with golimumab (GOL).

METHODS

Following placebo control (through weeks 16 and 24), GO-RAISE (A Multicenter Randomized, Double-blind, Placebo-controlled Trial of Golimumab, a Fully Human Anti-TNF-α Monoclonal Antibody, Administered Subcutaneously, in Subjects with Active Ankylosing Spondylitis; ClinicalTrials.gov: NCT00265083) all patients received GOL; sera/images were available at weeks 0, 104, and 208. Lateral spinal radiographs and magnetic resonance imaging (MRI) were scored using the modified Stokes Ankylosing Spondylitis Spine Score (mSASSS) and the Ankylosing Spondylitis Spinal MRI activity score, respectively.

RESULTS

VEGF levels and the mSASSS did not significantly correlate. Logistic regression analyses showed no association between VEGF levels and an increased risk of syndesmophyte formation at weeks 104 and 208. Pretreatment/Week 14 VEGF did not predict MRI scores/changes at Week 104.

CONCLUSION

Serum VEGF did not predict radiographic progression/spinal inflammation in patients receiving antitumor necrosis factor.

Wnt/β-catenin signaling plays a key role in the development of spondyloarthritis

Spondyloarthritis (SpA) is a group of diseases consisting of psoriatic arthritis (PsA), reactive arthritis, arthritis related to inflammatory bowel disease (a subgroup of juvenile idiopathic arthritis), and ankylosing spondylitis (the prototype of SpA). Axial bone formation and the combination of concurrent erosion and new bone formation are specific characteristics of SpA disease. The use of antiproinflammatory cytokines, such as inhibitors of tumor necrosis factor α (TNF-α), appears to be the greatest advance in the treatment of SpA over the past 20 years. However, TNF-α blockers do not halt new bone formation. Recent clinical observations and animal studies demonstrate that Wnt signaling proteins and natural Wnt inhibitors, such as DKK1 and sclerostin, are likely to play important roles in the process of ankylosis in SpA, and could potentially serve as therapeutic targets for the treatment of SpA.

Pain in systemic inflammatory rheumatic diseases

The sometimes intense, persistent and disabling pain associated with rheumatoid arthritis (RA) and spondyloarthritis frequently has a multifactorial, simultaneously central and peripheral origin, and it may be due to currently active inflammation or joint damage and tissue destruction caused by a previous inflammatory condition. The symptoms of inflammatory pain symptoms can be partially relieved by non-steroidal anti-inflammatory drugs, but many patients continue to experience moderate pain due to alterations in central pain regulation mechanisms, as in the case of the chronic widespread pain (CWP) characterising fibromyalgia. The importance of distinguishing CWP from inflammatory pain is underlined by the fact that drugs such as tumour necrosis factor inhibitors are expensive, and direct costs are higher in patients with concomitant CWP than in those without. The management of pain requires a combination approach that includes pharmacological analgesia, and biological and non-biological treatments because, although joint replacement surgery can significantly improve RA-related pain, it may only be available to patients with the most severe advanced disease.

Inflammatory diseases: Integrating biosimilars into clinical practice

OBJECTIVES

To discuss considerations regarding the selection, prescribing, and monitoring of biosimilars in the clinical management of patients with inflammatory disorders.

METHODS

A search of the Internet as well as PubMed was conducted through August 2014 for information related to the clinical use of biosimilars in chronic inflammatory disorders using the keywords biosimilar, rheumatoid arthritis, juvenile idiopathic arthritis, psoriasis, psoriatic arthritis, Crohn׳s disease, ulcerative colitis, and ankylosing spondylitis. The European Medicines Agency (EMA) and US Food and Drug Administration (FDA) websites were searched for biosimilar guidelines.

RESULTS

Articles and guidelines relating to integrating biosimilars into the clinical management of patients with inflammatory disorders have been published by regulatory agencies, professional associations, healthcare providers, and others.

CONCLUSIONS

The recent approval of the biosimilar infliximab in some countries makes biosimilars a reality for rheumatologists and others involved in the care of patients with inflammatory disorders. To successfully and confidently integrate biosimilars into clinical practice, physicians must understand factors such as variation in innovator/reference products, extrapolation of data, naming and labeling, interchangeability and automatic substitution, and pharmacovigilance.

Management of arthropathy in inflammatory bowel diseases

The most common extra-intestinal manifestation in patients with inflammatory bowel disease (IBD) is articular involvement, with a prevalence ranging between 17% and 39%. It is frequently characterized by an involvement of the axial joints but may also be associated with peripheral arthritis. The target of therapy in the management of arthritis associated with IBD is to reduce the inflammation and prevent any disability and/or deformity. This requires active cooperation between gastroenterologist and rheumatologist. The treatment of axial involvement has focused on the combination of exercise with nonsteroidal anti-inflammatory drugs. Immunomodulators have been efficacious in patients with peripheral arthritis and other extra-intestinal manifestations, but they are not effective for the treatment of axial symptoms of spondylitis. Tumor necrosis factor (TNF) α inhibitors have been proven to be highly effective in the treatment of IBD patients which are steroid-dependent or refractory to conventional therapy and in patients with associated articular manifestations. The treatment of peripheral involvement and/or enthesitis and/or dactylitis is based on local steroid injections, while sulfasalazine and/or low doses of systemic steroids may be useful in case of inadequate response to intra-articular steroids. Sulfasalazine induces only a little improvement in peripheral arthritis. Immunomodulators such as methotrexate, azathioprine, cyclosporine and leflunomide show their efficacy in some patients with peripheral arthritis and other extra-intestinal components. TNF-α inhibitors should be considered the first-line therapeutic approach when moderate-to-severe luminal Crohn's disease or ulcerative colitis is associated with polyarthritis. The aim of this review is to provide a fair summary of current treatment options for the arthritis associated with IBD.

Effectiveness and safety of infliximab in two cases of severe chondrocalcinosis: nine years of follow-up

Objectives. To investigate the efficacy of infliximab in the treatment of severe calcium pyrophosphate deposition diseases (CPPD). Methods. Two patients with severe CPPD and diffuse idiopathic skeletal hyperostosis- (DISH-) like phenotype are described. Both patients were resistant to therapy with nonsteroidal anti-inflammatory drugs (NSAIDs). Both patients were treated with infliximab, a TNF-α receptor antagonist, for nine years. Results. Treatment with infliximab resulted in major clinical and laboratory improvements without relevant side effects. Conclusions. These results suggest that infliximab may be an effective treatment of severe CPDD.

How good is the coverage and how accurate are exposure data in the Swedish Biologics Register (ARTIS)?

OBJECTIVES

To assess the coverage of the Swedish Biologics Register (Anti-Rheumatic Therapy in Sweden, ARTIS) across indications, and the accuracy of the registered information on treatment with biologics.

METHOD

Through cross-reference of ARTIS to almost complete national health registers on prescriptions (adalimumab and etanercept), outpatient visits, and death/residency during 2008-2010, we assessed: the treatment coverage of ARTIS for each treatment indication, the validity of the registered start and stop dates, ARTIS treatments with no corresponding drug dispensations, and the accuracy of the registered information on concomitant anti-rheumatic therapies.

RESULTS

According to the national health registers, 3945 individuals with a spondyloarthropathy (SpA) and 8032 patients with rheumatoid arthritis (RA) had filled at least one adalimumab or etanercept prescription during the study period. Of these, 86% of those with SpAs and 95% of patients with RA were also found in ARTIS with the corresponding treatment. Tumour necrosis factor (TNF) inhibitor prescriptions had been filled by 95% of patients between the ARTIS start and stop dates (allowing a 90-day window). More than 60 days before and more than 60 days after the registered start date in ARTIS, 5% and 4% respectively of patients had filled their first TNF inhibitor prescription. More than 90 days after the registered stop date in ARTIS, 8% of patients had filled one or more TNF inhibitor prescriptions.

CONCLUSIONS

We observed a high coverage and accuracy of ARTIS data on biologics exposure, for both SpAs and RA. The combination of data from clinical registers such as ARTIS with data from national health registers offers a high quality measurement of actual treatment.

Chronic inflammatory diseases: do immunological patterns drive the choice of biotechnology drugs? A critical review

Chronic inflammatory diseases represent a heterogeneous group of conditions that can affect practically any organ or system. An increasing number of biologic agents have been developed to selectively target the cell populations and signaling pathways involved in chronic inflammation, including cytokines, monoclonal antibodies and engineered receptors. This approach has been remarkably successful in alleviating some of the signs and symptoms of refractory autoimmune diseases. The use of this therapeutic strategy is likely to increase with the introduction of biosimilar agents. The different nature of these biological products makes the comparison of their pharmaceutical and clinical characteristics difficult, including safety and potency and these issues may be particularly relevant in the case of biosimilars. In addition, the heterogeneity of autoimmune diseases and of autoimmune patients, further adds to the complexity of choosing the right drug for each patient and predicting efficacy and safety of the treatment. In this review, we summarize actual knowledge about current biological agents and their use in autoimmune diseases, with a special emphasis for rheumatoid arthritis, inflammatory bowel diseases and psoriasis. The purpose of this analysis is to address the most critical issues raised by the rapid advancements in this field over recent years, and to acknowledge the potentially valuable gains brought about by the increasing availability of these new biologic agents.

Osteoarticular manifestations: specific treatments and/or treating intestinal disease?

Osteoarticular manifestations in inflammatory bowel diseases (IBD) belong to the concept of spondyloarthritis (SpA) including an axial and peripheral SpA according to predominant symptoms (inflammatory back pain vs. peripheral arthritis and enthesopathy). Careful examination of sacroiliac joints on MRI plays a crucial role in the recognition of an early axial SpA in young patients with inflammatory back pain and spinal inflammation on MRI but without structural changes on radiography (non-rx SpA). In this early form of SpA, chronic gut inflammation was already found in about 30% of patients. Moreover, more pronounced bone marrow edema was found in patients with axial SpA and chronic gut inflammation. Identification of a therapeutic window in patients with early gut and spine inflammation is important since anti-TNF suppresses inflammation and seems to prevent evolution to structural changes. Shared genetic factors probably predispose to both diseases. Careful analysis of the effect of medication on gut and spine inflammation in SpA and IBD patients is recommended in order to find new therapeutic agents.

Reduction of biological agent dose in rheumatic diseases: descriptive analysis of 153 patients in clinical practice conditions

OBJECTIVE

To analyze the frequency and characteristics of dose reduction of biological agents in a cohort of patients with chronic arthritis, in clinical practice conditions in a tertiary level hospital.

MATERIAL AND METHODS

Descriptive, cross-sectional study, which included all patients, followed consecutively during 6 months (June 2011-November 2011), by one investigator, with patients who at least have received one dose of biological agents in 2011.

RESULTS

We included 153 patients: Rheumatoid arthritis (RA) (n=82), ankylosing spondylitis (n=29), psoriatic arthritis (n=20), and miscellaneous group (n=22). Mean disease duration was 14.9±7.7 years. At the time of analysis, 70 patients (45.7%) were receiving low doses of biological therapy (50% in miscellaneous group group, 50% in psoriatic arthritis, 48.2% in ankylosing spondylitis, and 42.6% in RA). Mean time of dosage reduction was 17.4±17.5 months. The most common biological agents used in low dose were: etanercept, adalimumab and tocilizumab; 57.6%, 54.9% and 40% respectively, in patients with a reduced dose of biological therapy. The patients at low dose of biological therapy compared with standard dose, had similar mean disease duration, but received significantly less DMARDs, glucocorticoids and NSAIDs, and similar biological agent duration. RA patients with reduced biological treatment, at the time of analysis, had higher remission rates versus patients receiving a standard dose (82.9% vs 34%, p<0.0001). The medical decision at the time of analysis was to maintain low-dosage biological treatment in almost all patients.

CONCLUSION

In our clinical practice, 45.7% of our chronic arthritis patients receive low dose of biological therapy, after achieving remission or low activity at standard doses, maintaining a good control of the disease.

Immature dendritic cells in multiple myeloma are prone to osteoclast-like differentiation through interleukin-17A stimulation

Interleukin 17A (IL17A), a cytokine involved in allergy, inflammation and osteoclastogenesis, was investigated in multiple myeloma (MM) to assess its role in the osteoclast (OC)-like activity of marrow immature dendritic cells (iDCs). Comparing nine MM patients with control subjects affected by monoclonal gammopathy of undetermined significance, we found high IL17A expression in the marrow plasma of MM patients in parallel with its deposits within the stromal matrix. Increased expression of the IL17A receptor (IL17RA) was also found in primary myeloma iDCs, which underwent OC-like transdifferentiation after IL17A stimulation. To assess the role of IL17A, we measured the activity of the IL17/IL17RA pathway in IL17A-transdifferentiated iDCs and the expression of functional OC genes by Western blotting and real-time polymerase chain reaction. These cells showed increased RNA transcription of genes enrolled in the maturation of OCs, while NFATC1 and FOS were induced by IL17A, independently of NFKB1 phosphorylation. Moreover, the concurrent phosphorylation of the Lip isoform of CEBPB and the down-regulation of MAFB supported the activation of IL17RA pathway in OC-like transdifferentiated iDCs that was apparently unrelated to TNFRSF11A signalling. These data emphasize the involvement of iDCs in MM hyperactive osteoclastogenesis and suggest that their bone resorption activity is also regulated, at least in vitro, by IL17RA.