OP0281 PHARMACODYNAMIC EFFECT OF SEQUENTIAL BELIMUMAB (BEL) AND RITUXIMAB (RTX) THERAPY IN PATIENTS (PTS) WITH SYSTEMIC LUPUS ERYTHEMATOSUS (SLE): THE PHASE 3, RANDOMISED, PLACEBO-CONTROLLED BLISS-BELIEVE STUDY

Background

BEL is approved for active SLE and lupus nephritis (adults only). Despite failed trials,1 RTX remains in the SLE treatment armamentarium. Sequential BEL and RTX therapy offers a promising strategy to target B cells by distinct but complementary mechanisms.

Objectives

To assess the pharmacodynamic effects of BEL and a single RTX cycle on immunologic biomarkers in adults with SLE.

Methods

In this 104-week (wk) study (NCT03312907), all pts with active SLE received subcutaneous BEL 200 mg/wk for 52 wks. Pts were randomised to receive intravenous (IV) RTX 1000 mg at Wks 4 + 6 (BEL/RTX), IV PBO at Wks 4 + 6 (BEL/PBO), or continued treatment with standard therapy (BEL/ST). For BEL/RTX and BEL/PBO pts, a 52-wk treatment-free observational phase followed the 52-wk treatment phase; BEL/ST pts continued to receive BEL for 104 wks. Changes from baseline (BL) in anti-dsDNA and C3/C4 levels, and counts of total B cells (CD19+) and B-cell subsets (CD20+; naïve; memory; activated B-cells), were analysed.

Results

292 pts received ≥1 study treatment dose (BEL/PBO n=72; BEL/RTX n=144; BEL/ST n=76). For pts assessed at Wk 52, reductions from BL in anti-dsDNA levels were seen in all 3 groups with a significant difference between BEL/RTX and BEL/PBO (p=0.0495). C3/C4 levels increased from BL to Wks 52 and 104 in all groups, with trends for greater increases with BEL/RTX versus BEL/PBO (Table 1). At Wk 52, total B cells and most B-cell subsets decreased in all 3 groups (Table 1), with significant differences between BEL/RTX and BEL/PBO (p<0.0001 for all). During the observation period, repopulation of total CD19+ B cells (comprising mostly of naïve CD20+CD27-) towards BL levels by Wk 104 was most evident with BEL/RTX, while low circulating CD20+CD27+ memory B cell levels remained relatively unchanged (Table 1).

Table 1.

Absolute changes in biomarkers for treatment phase completers*

Median (25th, 75thpercentile)Change from BLAt Wk 52At Wk 104BEL/PBOBEL/RTXBEL/STBEL/PBOBEL/RTXBEL/STn=54n=102n=58n=24n=44n=50Anti-dsDNA (IU/ml)-9 (-83, 1)-51 (-155, -3)-5 (-61, 0)-9.5 (-197, 2)-55 (-329, -2)-6.5 (-57, -1)C3 (md/dl)8.5 (-8, 21)15† (0, 30)1‡ (-6, 11)6 (-5.5, 19.5)11 (-7, 27)7.5 (-5, 23)C4 (md/dl)2 (0, 5)4† (2, 9)2‡ (-1, 4)1.5 (-1.5, 4.5)3 (0, 8)3 (1, 5)B cells and B-cell subsets (cells/ml)n=48n=93n=55n=20n=40n=47CD19+-57,570 (-120,810, -5861)-95,313 (-193,946, -44,240)-57,399 (-152,403, -12,562)-41,343 (-105,789, 23,819)-11,932 (-77,822, 45,773)-48,783 (-151,528, -15,603)CD20+-58,112 (-110,681, -3126)-93,482 (-189,567, -42,636)-57,428 (-147,094, -3590)-40,773 (-95,658, 25,547)-3986 (-75,942, 49,021)-45,110 (-143,321, -15,063)Naïve CD20+CD27--60,929 (-112,623, -15,316)-61,405 (-152,261, -28,496)-62,477 (-142,009, -16,191)-22,210 (-72,131, 28,335)6941 (-62,669, 67,355)-51,254 (-142,712, -14,736)Activated CD95+-5012 (-12,701, 278)-9991 (-17,900, -5560)-3895 (-10,068, -1347)-3834 (-13,274, 1490)-5821 (-11,216, -233)-5641 (-14,810, -3341)Memory CD20+CD27+9,586 (1500, 30,983)-15,076 (-42,880, -6376)5532 (-146, 14,393)-13,927 (-24,816, -3064)-11,534 (-25,646, -2958)-1229 (-8466, 7300)

*Excluded from analysis: all pts who discontinued the investigational product before Wk 52 and BEL/ST pts if discontinued before Wk 104, and BEL/PBO and BEL/RTX pts who re-started BEL after Wk 53; †n=101; ‡n=57.

Conclusion

An improvement in anti-dsDNA and C3/C4 levels was generally observed across all 3 treatment groups with greater reductions in anti-dsDNA antibodies following BEL/RTX versus BEL/PBO and BEL/ST. We believe that BEL induced a pharmacodynamic window for subsequent RTX treatment for a marked reduction in circulating memory B cells and other B-cell subsets. Our findings underscore the need for better understanding of the bridge from pharmacodynamic to clinical outcomes, given that BEL/RTX did not show an improvement in disease control over BEL/PBO.1

References

[1]Aranow C, et al. Arthritis Rheumatol 2021;73 (suppl 10).

Acknowledgements

This analysis of the GSK Study 205646 was funded by GlaxoSmithKline (GSK). Medical writing support was provided by Nicholas Thomas, PhD, Fishawack Indicia Ltd. UK, part of Fishawack Health, and was funded by GSK.

Disclosure of Interests

Y.K. Onno Teng Consultant of: GSK, Aurinia Pharmaceuticals, Novartis, KezarBio, Otsuka, Vifor Pharma, Grant/research support from: GSK, Vifor Pharma, Aurinia Pharmaceuticals, Andre van Maurik Shareholder of: GSK, Employee of: GSK, Kenneth L Clark Shareholder of: GSK, Employee of: GSK, Norma Lynn Fox Shareholder of: GSK, Employee of: GSK, Yun Irene Gregan Shareholder of: GSK, Employee of: GSK, James Groark Shareholder of: GSK, Employee of: GSK, Robert Henderson Shareholder of: GSK, Employee of: GSK, Josephine Ocran-Appiah Shareholder of: GSK, Employee of: GSK, David Roth Shareholder of: GSK, Employee of: GSK, Don Shanahan Shareholder of: GSK, Employee of: GSK, Paul-Peter Tak Shareholder of: GSK, Employee of: GSK, Cynthia Aranow Consultant of: BMS, Kezar, GSK, Grant/research support from: GSK

OP0099 INCREASED FREQUENCY OF CD4+ AND CD8+ FOLLICULAR HELPER T CELLS IN HUMAN LYMPH NODE BIOPSIES DURING THE EARLIEST STAGES OF RHEUMATOID ARTHRITIS

Background

Follicular T helper (Tfh) cells provide key help for B cell differentiation into plasma and memory B cells and are essential in germinal center formation and (auto) antibody generation (1).

Objectives

To gain more insights into the role of Tfh cells in RA development, we assessed whether Tfh cells have an altered frequency, phenotype and cytokine profile in peripheral blood, lymphoid and synovial tissues during the earliest stages of RA development.

Methods

Using flow cytometry, we analyzed the phenotpe, frequencies and cytokine profile of Tfh cells and B cells in peripheral blood and lymph node biopsies of healthy controls (HCs), autoantibody positive individuals at risk for developing RA (RA-risk individuals), and early RA patients. Using immunofluorescene we confirmed the presence of Tfh in B cell follicles of lymph nodes and synovial tissue biopsies of RA patients.

Results

In blood, the frequency of Tfh cells did not differ between study groups. In lymphoid and synovial tissue, Tfh cells were localized in B-cell areas, and their frequencies correlated strongly with the frequency of CD19+ B cells. Compared to lymphoid tissue of healthy controls, that of RA patients and RA-risk individuals, showed more CD19+ B cells and more CD4+CXCR5+ and CD8+CXCR5+ follicular T cells. Of note, compared to healthy controls, specifically lymph node Tfh cells of RA-risk and early RA patients produced less IL-21 upon ex-vivo stimulation.

Conclusion

Tfh cells are localised in B-cell rich areas in lymphoid and synovial tissues of early RA patients. The analysis of lymph node tissue in early RA patients showed increased frequencies of Tfh cells, where they clearly associate with B cells. Interestingly, IL-21 production is already aberrant in the very early at risk phase of the disease. Our data suggest that Tfh cells may present a novel rationale for therapeutic targeting during the preclinical stage of RA to prevent further disease progression.

References

[1]Ise W, Fujii K, Shiroguchi K, Ito A, Kometani K, Takeda K, et al. T Follicular Helper Cell-Germinal Center B Cell Interaction Strength Regulates Entry into Plasma Cell or Recycling Germinal Center Cell Fate. Immunity. 2018;48(4):702-15.e4.

Acknowledgements

We thank the participants in the study, the radiology department at the Academic Medical Center (AMC) for lymph node sampling; the flow cytometry facility at the Hematology department at AMC, especially J.A. Dobber; and the core facility Cellular Imaging of the Amsterdam UMC, location AMC.

Disclosure of Interests

Dornatien Anang: None declared, Tamara H.Ramwadhdoebe: None declared, Janine Hahnlein: None declared, Bo van Kuijk: None declared, Smits Noortje: None declared, Krijn P. van Lienden: None declared, Mario Maas: None declared, Danielle Gerlag Employee of: Employee of UCB Pharma. UCB pharma was not involved in this study, Paul-Peter Tak Employee of: Employee of Candel therapeutics. Candel therapeutics was not involved in the study, Niek de Vries: None declared, Lisa van Baarsen: None declared.

AB1318-HPR VAGUS NERVE STIMULATION IN PATIENTS WITH RHEUMATOID ARTHRITIS: 48 MONTH SAFETY AND EFFICACY

Background:

Rheumatoid arthritis (RA) is a disease with significant remaining unmet medical needs for better treatments. Vagus nerve stimulation (VNS) to activate the inflammatory reflex (cholinergic anti-inflammatory pathway) represents a novel experimental therapy for RA.1Previously, we reported that inflammatory reflex activation by VNS reduced pro-inflammatory cytokine production and improved disease activity in a 17-patient rheumatoid arthritis (RA) proof-of-concept study using a reprogrammed epilepsy stimulator2; clinical improvement was sustained for 24 months without untoward safety signals.3Here we report the 48 months results from this long-term observational study.

Objectives:

Determine the long-term safety and efficacy of VNS for the treatment of RA

Methods:

In the primary study, a VNS device was implanted into 17 RA patients, mostly with insufficient response to multiple conventional and biologic DMARDs, on stable background of methotrexate (≤25 mg weekly) therapy2. The device electrically stimulated the vagus nerve, 1-4 min/day, over a 12-week open label period. On completion, subjects were offered to enroll into a follow-up study, where the study physicians were given flexibility to alter VNS dosing parameters and/or to add a biologic disease-modifying antirheumatic drug (DMARD) to the treatment regimen to induce disease remission. Clinical disease activity measures and safety were accessed over 4 years.

Results:

All patients electively continued VNS treatment in the long-term follow-up study, 4 subjects withdrew prior to month 48. Reasons for discontinuation were withdrawal of consent (N=3) and adverse event due to device discomfort (N=1). At the start of the follow-up study, the mean DAS28-CRP, CDAI and HAQ-DI were significantly reduced compared to the pre-implant baseline (mean difference± SD: DAS28-CRP=-1.60± 1.13, p<0.001; CDAI=-21.19± 13.5, p<0.001; HAQ-DI=-0.44± 0.49, p<0.01), and this effect was retained through 48 months. Patients using VNS monotherapy and those using a combination of VNS with biologic DMARDs exhibited stable improvements in DAS28-CRP, CDAI and HAQ-DI at month 48 (Table 1). Improvements were observed for patients who both previously had an insufficient response to targeted biological therapies as well those who had an insufficient response to standard DMARDs. No association was seen between DAS28-CRP and stimulation frequency (Range= 1X-8X/day). There was no difference in the adverse events profile between the two groups.

Table 1.

Efficacy of VNS treatment.

Treatment ReinitiatedN=9VNS MonotherapyN=8TotalN=17Mo. 24Mo. 36Mo.48Mo. 24Mo. 36Mo. 48Mo. 24Mo. 36Mo. 48Mean change from baseline (SD)DAS28-CRP-2.58 (1.0)***-2.40 (1.0)**-2.28 (1.3)**-2.61 (1.3)*-1.77 (1.8)-2.0(1.7)-2.59 (1.1)***-2.19(1.2)**-2.17(1.4)**CDAI-24.06 (8.3)***-18.02 (13.3) *-16.2 (19.6)-33.5 (11.1)***-27.8 (16.0)*-27.9 (12.7)*-28.20 (10.5)***-21.93 (14.5)*-20.83(17.5)*HAQ-DI-.60 (0.64)*-.63(0.45)*-.31(0.60)-.89 (0.69)*-.88 (0.92)-.88(0.61)-0.73(0.66)***-0.73(0.64)**-0.54(0.64)*

*P<0.05, **P<0.01, ***P<0.001 versus primary study baseline (month -3.5)

Conclusion:

VNS was safe, well-tolerated, and resulted in significant and clinically important improvements in disease activity measures that were maintained over 48 months. These results support development of VNS devices as a new therapeutic option for RA treatment.

References:

[1]van Maanen MA, et al.Nat Rev Rheum2009

[2]Koopman FA, et al.PNAS2016

[3]Koopman FA, et al.Arthritis Rheum2018

Disclosure of Interests:

Frieda Koopman: None declared, Anne Musters: None declared, Marieke Backer: None declared, Danielle Gerlag Shareholder of: GlaxoSmithKline, Employee of: GlaxoSmithKline, Sanda Miljko: None declared, Simeon Grazio Speakers bureau: Abbvie., Roche, MSD, Eli Lilly, Pfizer, Mylan, Amgen, Fresenius Kabi, Stada, Berlin-Chemie, Sekib Sokolovic: None declared, Yaakov Levine Shareholder of: SetPoint Medical, Employee of: SetPoint Medical, Emmett Glass Employee of: SetPoint Medical, David Chernoff Shareholder of: SetPoint Medical, Adamas Pharmaceuticals, Olly Nutrition, NAIA Pharma, Aquinox Pharma, Consultant of: Adamas Pharmaceuticals, Olly Nutrition, NAIA Pharma, Aquinox Pharma, Crescendo Bioscience, Employee of: SetPoint Medical, Niek de Vries Grant/research support from: AbbVie, Janssen, Ergomed Clinical Research, GlaxoSmithKline, Pfizer, Boehringer Ingelheim, Roche, Consultant of: MSD, Pfizer, Paul P. Tak Shareholder of: GlaxoSmithKline, Employee of: GlaxoSmithKline

Balancing the autonomic nervous system to reduce inflammation in rheumatoid arthritis

Imbalance in the autonomic nervous system (ANS) has been observed in many established chronic autoimmune diseases, including rheumatoid arthritis (RA), which is a prototypic immune-mediated inflammatory disease (IMID). We recently discovered that autonomic dysfunction precedes and predicts arthritis development in subjects at risk of developing seropositive RA. In addition, RA patients with relatively high vagus nerve tone (higher parasympathetic parameters, measured by heart rate variability) respond better to antirheumatic therapies. Together, these data suggest that the ANS may control inflammation in humans. This notion is supported by experimental studies in animal models of RA. We have found that stimulation of the so-called cholinergic anti-inflammatory pathway by efferent electrical vagus nerve stimulation (VNS) or pharmacological activation of the alpha7 subunit of nicotinic acetylcholine receptors (α7nAChR) improves clinical signs and symptoms of arthritis, reduces cytokine production and protects against progressive joint destruction. Conversely, increased arthritis activity was observed in alpha7nAChR knockout mice. These studies together with previous work in animal models of sepsis and other forms of inflammation provided the rationale for an experimental clinical trial in patients with RA. We could for the first time show that an implantable vagus nerve stimulator inhibits peripheral blood cytokine production in humans. VNS significantly inhibited TNF and IL-6 production and improved RA disease severity, even in some patients with therapy-resistant disease. This work strongly supports further studies using a bioelectronic approach to treat RA and other IMIDs.

Prediction of Response to Targeted Treatment in Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune syndrome presenting with chronic inflammation of the joints. Patients with the same diagnosis can present with different phenotypes. In some patients severe joint inflammation and early joint destruction are observed, whereas a milder phenotype can be seen in others. Conversely, patients with the same signs and symptoms may exhibit different immunological and molecular abnormalities. Since the introduction of early treatment in clinical practice, the treat to target principle, and new medicines such as biologic disease-modifying antirheumatic drugs, clinical remission can be achieved early in the disease course, albeit not in all patients. The clinical response and efficacy of biologic disease-modifying antirheumatic drugs vary among different individuals. Therefore, there is a need to develop a more personalized approach toward treatment to achieve rapid remission in every patient to prevent disability and restore and maintain quality of life, without unnecessary adverse effects, in a cost-effective manner. The latest data from explorative studies of predictive markers of response are discussed here, together with a preliminary treatment algorithm based on currently available knowledge.

Single vagus nerve stimulation reduces early postprandial C-peptide levels but not other hormones or postprandial metabolism

A recent study in rheumatoid arthritis (RA) patients using electrical vagus nerve stimulation (VNS) to activate the inflammatory reflex has shown promising effects on disease activity. Innervation by the autonomic nerve system might be involved in the regulation of many endocrine and metabolic processes and could therefore theoretically lead to unwanted side effects. Possible effects of VNS on secretion of hormones are currently unknown. Therefore, we evaluated the effects of a single VNS on plasma levels of pituitary hormones and parameters of postprandial metabolism. Six female patients with RA were studied twice in balanced assignment (crossover design) to either VNS or no stimulation. The patients selected for this substudy had been on VNS therapy daily for at least 3 months and at maximum of 24 months. We compared 10-, 20-, and 30-min poststimulus levels to baseline levels, and a 4-h mixed meal test was performed 30 min after VNS. We also determined energy expenditure (EE) by indirect calorimetry before and after VNS. VNS did not affect pituitary hormones (growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, prolactin, follicle-stimulating hormone, and luteinizing hormone), postprandial metabolism, or EE. Of note, VNS reduced early postprandial insulin secretion, but not AUC of postprandial plasma insulin levels. Cortisol and catecholamine levels in serum did not change significantly. Short stimulation of vagal activity by VNS reduces early postprandial insulin secretion, but not other hormone levels and postprandial response. This suggests VNS as a safe treatment for RA patients.

Protein arginine deiminase 4 inhibition is sufficient for the amelioration of collagen-induced arthritis

Citrullination of joint proteins by the protein arginine deiminase (PAD) family of enzymes is recognized increasingly as a key process in the pathogenesis of rheumatoid arthritis. This present study was undertaken to explore the efficacy of a novel PAD4-selective inhibitor, GSK199, in the murine collagen-induced arthritis model of rheumatoid arthritis. Mice were dosed daily from the time of collagen immunization with GSK199. Efficacy was assessed against a wide range of end-points, including clinical disease scores, joint histology and immunohistochemistry, serum and joint citrulline levels and quantification of synovial autoantibodies using a proteomic array containing joint peptides. Administration of GSK199 at 30 mg/kg led to significant effects on arthritis, assessed both by global clinical disease activity and by histological analyses of synovial inflammation, pannus formation and damage to cartilage and bone. In addition, significant decreases in complement C3 deposition in both synovium and cartilage were observed robustly with GSK199 at 10 mg/kg. Neither the total levels of citrulline measurable in joint and serum, nor levels of circulating collagen antibodies, were affected significantly by treatment with GSK199 at any dose level. In contrast, a subset of serum antibodies reactive against citrullinated and non-citrullinated joint peptides were reduced with GSK199 treatment. These data extend our previous demonstration of efficacy with the pan-PAD inhibitor Cl-amidine and demonstrate robustly that PAD4 inhibition alone is sufficient to block murine arthritis clinical and histopathological end-points.

A Personalized Approach to Biological Therapy Using Prediction of Clinical Response Based on MRP8/14 Serum Complex Levels in Rheumatoid Arthritis Patients

Objectives

Measurement of MRP8/14 serum levels has shown potential in predicting clinical response to different biological agents in rheumatoid arthritis (RA). We aimed to develop a treatment algorithm based on a prediction score using MRP8/14 measurements and clinical parameters predictive for response to different biological agents.

Methods

Baseline serum levels of MRP8/14 were measured in 170 patients starting treatment with infliximab, adalimumab or rituximab. We used logistic regression analysis to develop a predictive score for clinical response at 16 weeks. MRP8/14 levels along with clinical variables at baseline were investigated. We also investigated how the predictive effect of MRP8/14 was modified by drug type. A treatment algorithm was developed based on categorizing the expected response per drug type as high, intermediate or low for each patient and optimal treatment was defined. Finally, we present the utility of using this treatment algorithm in clinical practice.

Results

The probability of response increased with higher baseline MRP8/14 complex levels (OR = 1.39), differentially between the TNF-blockers and rituximab (OR of interaction term = 0.78), and also increased with higher DAS28 at baseline (OR = 1.28). Rheumatoid factor positivity, functional disability (a higher HAQ), and previous use of a TNF-inhibitor decreased the probability of response. Based on the treatment algorithm 80 patients would have been recommended for anti-TNF treatment, 8 for rituximab, 13 for another biological treatment (other than TNFi or rituximab) and for 69 no recommendation was made. The predicted response rates matched the observed response in the cohort well. On group level the predicted response based on the algorithm resulted in a modest 10% higher response rate in our cohort with much higher differences in response probability in individual patients treated contrary to treatment recommendation.

Conclusions

Prediction of response using MRP8/14 levels along with clinical predictors has potential in personalizing treatment for RA patients starting biological anti-rheumatic treatment, and might increase cost-effectiveness.

Autonomic Dysfunction Precedes Development of Rheumatoid Arthritis: A Prospective Cohort Study

Background

Heart rate variability (HRV) is a validated method to establish autonomic nervous system (ANS) activity. Rheumatoid arthritis (RA) is accompanied by ANS imbalance. We hypothesized that ANS dysfunction may precede the development of RA, which would suggest that it plays a role in its etiopathogenesis.

Methods

First, we assessed HRV parameters in supine (resting) and upright (active) position in healthy subjects (HS, n = 20), individuals at risk of developing arthritis (AR subjects, n = 50) and RA patients (RA, n = 20). Next, we measured resting heart rate (RHR), a parasympathetic HRV parameter, in an independent prospective cohort of AR subjects (n = 45). We also evaluated expression levels of the parasympathetic nicotinic acetylcholine receptor type 7 (α7nAChR) on circulating monocytes.

Findings

Both AR subjects (68 beats per minute (bpm), interquartile range (IQR) 68–73) and RA patients (68 bpm, IQR 62–76) had a significantly higher RHR compared to HS (60 bpm, IQR 56–63). RHR was significantly higher at baseline in individuals who subsequently developed arthritis. Expression levels of α7nAChR were lower in AR subjects with RHR ≥ 70 bpm compared to those with RHR < 70 bpm, consistent with reduced activity of the parasympathetic cholinergic anti-inflammatory pathway.

Interpretation

These data support the notion that autonomic dysfunction precedes the development of RA.

•

Individuals at risk of developing RA show autonomic dysfunction similar to established RA patients.

•

Autonomic dysfunction is a predictor of development of arthritis in subjects at risk of RA, suggesting a role in its etiopathogenesis.

The autonomous nervous system is a neurological control system that acts largely unconsciously and regulates a variety of bodily functions. We found that dysfunction of this system may precede and predict the development of rheumatoid arthritis (RA), a chronic inflammatory disease with great unmet need. These findings provide important insights into the changes in the nervous system contributing to the development of this condition. They also open up the perspective of potential measures aimed at prevention of RA by restoring the balance in the nervous system before arthritis develops, which would have major implications for patients as well as society.

Safety and efficacy of atacicept in combination with rituximab for reducing the signs and symptoms of rheumatoid arthritis: a phase II, randomized, double-blind, placebo-controlled pilot trial

Objective

To explore the safety and tolerability of atacicept in combination with rituximab in patients with active rheumatoid arthritis (RA) receiving rituximab re‐treatment.

Methods

In this randomized, double‐blind, placebo‐controlled pilot trial, 2 infusions (1,000 mg per infusion) of intravenous rituximab, given 2 weeks apart, were followed by once‐weekly subcutaneous injections of 150 mg atacicept or placebo for 25 weeks. Primary end points were the nature, incidence, and severity of adverse events (AEs). Secondary end points were the effects on peripheral blood B cells, disease activity biomarkers, and American College of Rheumatology 20% (ACR20), 50% (ACR50), and 70% (ACR70) response rates.

Results

Eighteen patients were randomized to receive atacicept and 9 to receive placebo. AEs occurred in 17 atacicept‐treated patients (94.4%) and in all 9 placebo‐treated patients (100%). There were no infection‐related serious adverse events. Hypersensitivity and injection site reactions were more common, and more patients withdrew due to AEs, in the atacicept group. Median reductions in Ig levels from baseline to week 32 were greater with atacicept (median change in IgG −31.2%, IgM −60.9%, and IgA −56.4%) than with placebo (median change in IgG −4.4%, IgM −15.9%, and IgA −8.2%). Peripheral B cell numbers remained low in all patients after rituximab‐mediated B cell depletion, limiting comparison of time to recovery between treatment groups. There were no between‐group differences in ACR20, ACR50, and ACR70 response rates.

Conclusion

In this exploratory trial, atacicept in combination with rituximab showed no new safety issues. Peripheral B cell counts remained too low to determine whether atacicept delayed B cell re‐expansion following rituximab‐mediated depletion. Despite clear biologic effects, adding atacicept to rituximab in patients with active RA was not associated with clinical benefit.

Vagus nerve stimulation: a new bioelectronics approach to treat rheumatoid arthritis?

There has been a marked improvement in the treatment of rheumatoid arthritis (RA), but most patients do not achieve disease remission. Therefore, there is still a need for new treatments. By screening an adenoviral short hairpin RNA library, we discovered that knockdown of the nicotinic acetylcholine receptor type 7 (α7nAChR) in RA fibroblast-like synoviocytes results in an increased production of mediators of inflammation and degradation. The α7nAChR is intimately involved in the cholinergic anti-inflammatory pathway (CAP). This led us to study the effects of α7nAChR activation in an animal model of RA, and we could show that this resulted in reduced arthritis activity. Accordingly, stimulation of the CAP by vagus nerve stimulation improved experimental arthritis. Conversely, we found aggravation of arthritis activity after unilateral cervical vagotomy as well as in α7nAChR-knockout mice. Together, these data provided the basis for exploration of vagus nerve stimulation in RA patients as a novel anti-inflammatory approach.

Preclinical characterisation of the GM-CSF receptor as a therapeutic target in rheumatoid arthritis

Objective

Previous work has suggested that the granulocyte macrophage colony stimulating factor (GM-CSF)–GM-CSF receptor α axis (GM-CSFRα) may provide a new therapeutic target for the treatment of rheumatoid arthritis (RA). Therefore, we investigated the cellular expression of GM-CSFRα in RA synovial tissue and investigated the effects of anti-GM-CSFRα antibody treatment in vitro and in vivo in a preclinical model of RA.

Methods

We compared GM-CSFRα expression on macrophages positive for CD68 or CD163 on synovial biopsy samples from patients with RA or psoriatic arthritis (PsA) to disease controls. In addition, we studied the effects of CAM-3003, an anti-GM-CSFR antibody in a collagen induced arthritis model of RA in DBA/1 mice. The pharmacokinetic profile of CAM-3003 was studied in naïve CD1(ICR) mice (see online supplement) and used to interpret the results of the pharmacodynamic studies in BALB/c mice.

Results

GM-CSFRα was expressed by CD68 positive and CD163 positive macrophages in the synovium, and there was a significant increase in GM-CSFRα positive cells in patients in patients with RA as well as patients with PsA compared with patients with osteoarthritis and healthy controls. In the collagen induced arthritis model there was a dose dependent reduction of clinical arthritis scores and the number of F4/80 positive macrophages in the inflamed synovium after CAM-3003 treatment. In BALB/c mice CAM-3003 inhibited recombinant GM-CSF mediated margination of peripheral blood monocytes and neutrophils.

Conclusions

The findings support the ongoing development of therapies aimed at interfering with GM-CSF or its receptor in various forms of arthritis, such as RA and PsA.

Features of the synovium of individuals at risk of developing rheumatoid arthritis: implications for understanding preclinical rheumatoid arthritis

OBJECTIVE

Findings from previous studies have suggested that subclinical inflammation of the synovium does not coincide with the appearance of rheumatoid arthritis (RA)-specific autoantibodies. This study was undertaken to examine the relationship between the presence of autoantibodies, changes in the synovium, and development of arthritis over time in a markedly larger, prospective study.

METHODS

Fifty-five individuals who were IgM rheumatoid factor positive and/or anti-citrullinated protein antibody (ACPA) positive (detected by the anti-cyclic citrullinated peptide antibody test) and who were without any evidence of arthritis upon physical examination were included in the study. ACPAs were subsequently also detected using a multiplex chip-based assay. All individuals underwent magnetic resonance imaging and mini-arthroscopic synovial biopsy sampling of a knee joint at inclusion and were prospectively followed up. Proportional hazards regression analysis was performed to investigate whether changes in the synovium were associated with the onset of arthritis.

RESULTS

Fifteen individuals (27%) developed arthritis after a median followup time of 13 months (interquartile range 6-27 months; range 1-47 months). No overt synovial inflammation was observed, but CD3+ T cell numbers in the biopsy tissue showed a borderline association with subsequent development of clinically manifest arthritis (hazard ratio 2.8, 95% confidence interval [95% CI] 0.9-9.1; P = 0.088). In addition, the presence of CD8+ T cells was associated with ACPA positivity (odds ratio [OR] 16.0, 95% CI 1.7-151.1) and with the total number of ACPAs present (OR 1.4, 95% CI 1.0-1.8).

CONCLUSION

These findings confirm and extend previous results showing the absence of clearcut synovial inflammation in individuals having systemic autoimmunity associated with RA. However, subtle infiltration by synovial T cells may precede the signs and symptoms of arthritis in preclinical RA.

Fms-like tyrosine kinase 3 ligand-dependent dendritic cells in autoimmune inflammation

Dendritic cells (DCs) are specialized in capture, processing and presentation of antigens to T cells. Depending on the type of DC and its activation state, the interaction of DCs with naive T cells can lead to different types of immune response, or to T-cell tolerance. The existence of many specialized subtypes of DCs with particular functions has raised the need to distinguish DCs formed in steady-state from those produced during an inflammatory response. In patients with autoimmune disease and in experimental animal models of autoimmunity, DCs show abnormalities in both numbers and activation state, expressing immunogenic levels of co-stimulatory molecules and pro-inflammatory cytokines. Initial in vitro studies of cytokines in DC development revealed distinct and important roles for the receptor tyrosine kinases, granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF, also called CSF1) and fms-like tyrosine kinase 3 ligand (Flt3L) in the generation of DCs. Flt3L is critical for instructing DC generation throughout different organs and regulates DC development from Flt3(+) lymphoid and myeloid-committed progenitors to DCs in vivo. The aim of this review is to provide an overview of the role of Flt3L-dependent DCs in the immunopathogenesis of autoimmunity and chronic inflammation and its potential as therapeutic targets.

Absence of Fms-like tyrosine kinase 3 ligand (Flt3L) signalling protects against collagen-induced arthritis

OBJECTIVE

Comprehending the mechanisms that regulate activation of autoreactive T cells and B cell antibody production is fundamental for understanding the breakdown in self-tolerance and development of autoimmunity. Here we studied the role of Fms-like tyrosine kinase 3 ligand (Flt3L) signalling in the pathogenesis of collagen-induced arthritis (CIA).

METHODS

CIA was induced in mice lacking Flt3L (Flt3L(-/-)) and wild-type (WT) littermates (C57/BL6, 8-10 weeks old). Mice were killed in the initial phase (acute phase: experiment 1) and late phase (chronic phase: experiment 2) of the disease. Arthritis severity was assessed using a semiquantitative scoring system (0-4), and histological analysis of cellular infiltration, cartilage destruction and peptidoglycan loss was performed. Phenotypic and functional analysis of T and B cells, FoxP3 expression, activation and lymphocyte costimulatory markers, and cytokine production were performed ex vivo by flow cytometry in lymph nodes. Serum collagen type II (CII)-specific antibodies were measured by ELISA.

RESULTS

Flt3L(-/-) mice showed a marked decrease in clinical arthritis scores and incidence of arthritis in both acute and chronic phases of CIA compared with WT mice. Moreover, decreased synovial inflammation and joint destruction was observed. Both the magnitude and quality of T cell responses were altered in Flt3L(-/-). In the acute phase, the amount of CII-specific IgG2a antibodies was lower in Flt3L(-/-) than WT mice.

CONCLUSIONS

These results strongly suggest a role for Flt3L signalling in the development of arthritis.