Rheumatoid factor positivity rather than anti-CCP positivity, a lower disability and a lower number of anti-TNF agents failed are associated with response to rituximab in rheumatoid arthritis

Mechanisms of Resistance to Rituximab Used for the Treatment of Autoimmune Blistering Diseases

Autoimmune blistering diseases represent a group of chronic severe, disabling, and potentially fatal disorders of the skin and/or mucous membranes, primarily mediated by pathogenic auto-antibodies. Despite their rarity, these diseases are associated with significant morbidity and mortality and profound negative impact on the patient's quality of life and impose a considerable economic burden. Rituximab, an anti-CD-20 monoclonal antibody, represents the first line of therapy for pemphigus, regardless of severity and a valuable off-label therapeutic alternative for subepidermal autoimmune blistering diseases as it ensures high rates of rapid, long-lasting complete remission. Nevertheless, disease recurrence is the rule, all patients requiring maintenance therapy with rituximab eventually. While innate resistance to rituximab in pemphigus patients is exceptional, acquired resistance is frequent and may develop even in patients with initial complete response to rituximab, representing a real challenge for physicians. We discuss the various resistance mechanisms and their complex interplay, as well as the numerous therapeutic alternatives that may be used to circumvent rituximab resistance. As no therapeutic measure is universally efficient, individualization of rituximab treatment regimen and tailored adjuvant therapies in refractory autoimmune blistering diseases are mandatory.

Factors Determining Retreatment Time Interval of Rituximab in Korean Patients With Rheumatoid Arthritis

Unlike other biologic agents for rheumatoid arthritis (RA) that are administered at regular intervals even without flare, rituximab can be administered according to the timing of retreatment determined by the physician. Recently, there has been a tendency to prefer on-demand administration for disease flares rather than regular retreatment. We aimed to investigate the retreatment patterns of rituximab in patients with RA and to identify factors associated with extension of the time interval between retreatment courses. This study included RA patients on rituximab treatment who were enrolled in the Korean Rheumatology Biologics registry (KOBIO) or treated at Ajou University Hospital. Previous or current concomitant conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), corticosteroids, number of previous biologic agents, withdrawal, and time intervals of rituximab retreatment were collected. In case of treatment failure, the reasons such as lack of efficacy, adverse events, and others, were also identified. A total of 82 patients were enrolled. The mean follow-up period from the first cycle of rituximab was 46.1 months, and the mean interval between the retreatment courses was 16.3 months. The persistent rates of rituximab after 5 years was 72.4%. Concomitant use of at least two csDMARDs (β = 4.672; 95% CI: 0.089-9.255, p = 0.046) and concomitant use of corticosteroids (β = 7.602; 95% CI: 0.924-14.28, p = 0.026) were independent factors for extending the time interval between the retreatment courses. In conclusion, RA patients treated with rituximab in Korea show high persistence rates. Concomitant use of two or more csDMARDs and concomitant use of corticosteroids with rituximab are associating factors of extending the retreatment time interval. These findings should be considered when selecting rituximab as a treatment for patients with RA.

The impact of seropositivity on the effectiveness of biologic anti-rheumatic agents: results from a collaboration of 16 registries

OBJECTIVES

RF and ACPA are used as diagnostic tools and their presence has been associated with clinical response to some biologic DMARDs (bDMARDs) in RA. This study compared the impact of seropositivity on drug discontinuation and effectiveness of bDMARDs in patients with RA, using head-to-head comparisons in a real-world setting.

METHODS

We conducted a pooled analysis of 16 observational RA registries. Inclusion criteria were a diagnosis of RA, initiation of treatment with rituximab (RTX), abatacept (ABA), tocilizumab (TCZ) or TNF inhibitors (TNFis) and available information on RF and/or ACPA status. Drug discontinuation was analysed using Cox regression, including drug, seropositivity, their interaction, adjusting for concomitant and past treatments and patient and disease characteristics and accounting for country and calendar year of bDMARD initiation. Effectiveness was analysed using the Clinical Disease Activity Index evolution over time.

RESULTS

Among the 27 583 eligible patients, the association of seropositivity with drug discontinuation differed across bDMARDs (P for interaction <0.001). The adjusted hazard ratios for seropositive compared with seronegative patients were 1.01 (95% CI 0.95, 1.07) for TNFis, 0.89 (0.78, 1.02)] for TCZ, 0.80 (0.72, 0.88) for ABA and 0.70 (0.59, 0.84) for RTX. Adjusted differences in remission and low disease activity rates between seropositive and seronegative patients followed the same pattern, with no difference in TNFis, a small difference in TCZ, a larger difference in ABA and the largest difference in RTX (Lundex remission difference +5.9%, low disease activity difference +11.6%).

CONCLUSION

Seropositivity was associated with increased effectiveness of non-TNFi bDMARDs, especially RTX and ABA, but not TNFis.

Influence of prognosis factors on the prescription of targeted treatments in rheumatoid arthritis: A Delphi survey

OBJECTIVES

To explore current evidence on the management of poor prognostic factors in rheumatoid arthritis (RA) and to investigate whether this evidence is taken into account by clinicians when deciding on treatment in daily clinical practice.

METHODS

We performed a systematic literature review (SLR) to analyse the effects of currently available biologic disease-modifying antirheumatic drugs (bDMARDs) and Janus kinase inhibitors (JAKi) on the classically accepted poor prognostic factors of RA. All randomized controlled trials reporting subgroup analyses about effects on prognostic factors were identified and synthesized. In a second phase, a two-round Delphi survey was carried out to contrast the SLR results with the grade of agreement of a large group of rheumatologists about the effectiveness of each drug class on each prognostic factor.

RESULTS

According to the Delphi results, the only prognostic factor that significantly influenced the selection of treatment was the presence of interstitial lung disease (ILD), being the preferred treatment in this scenario abatacept or rituximab. The rest of the poor prognostic factors (including high disease activity at baseline, disability as measured by the Health Assessment Questionnaire index, seropositivity, elevated acute-phase reactants, and evidence of erosions based on plain radiography or ultrasonography) did not seem to significantly influence rheumatologists when choosing a treatment. The results of the SLR results did not show solid evidence regarding the use of any specific therapy in the management of patients with specific poor factors, except in the case of RA-ILD, although the data in the literature in this regard are not free of bias.

CONCLUSIONS

The only prognostic factor that seems to significantly influence the selection of treatment is the presence of RA-ILD.

Response to interleukin-6 receptor antagonists in patients with rheumatoid arthritis is independent of the number of prior used TNF inhibitors: A systematic review and metaanalysis

OBJECTIVE

To investigate whether early response to tocilizumab (TCZ) and sarilumab (SAR) therapy in patients with active rheumatoid arthritis (RA) is influenced by previous use of biologic agents.

METHODS

We performed a systematic literature review and a meta-analysis of original studies that analyzed the effectiveness of TCZ or SRL in subgroups of RA patients, including biologic-naïve patients versus those with inadequate response to at least one biologic DMARD (bDMARD), and patients with failure to 1 versus≥2 bDMARDs.

RESULTS

The study selection process finally included 17 articles corresponding to 14 studies, including 7 randomized controlled trials (RCTs). Although the existing literature that compared the response in biologic-naïve patients versus those with inadequate response to at least one bDMARD showed conflicting results, meta-analysis of 6 published studies revealed a significantly higher likelihood of remission (RR=1.3; 95% CI: 1.2-1.5) and low activity disease (RR=1.3; 95% CI: 1.2-1.4) in the biologic-naïve group at week 24. However, differences between groups were not clinically meaningful in all studies and not always maintained after 6 to 12months of treatment. In addition, data from RCT RADIATE and TARGET suggest that the response to IL-6 pathway inhibitors seems to be similar, regardless of the number of tumor necrosis factor inhibitors (TNFis) previously tested.

CONCLUSION

Disease activity was more rapidly reduced in the early stages of treatment in biologic-naïve patients. However, near similar efficacy can be expected in patients who experienced a failure of at least one bDMARD (mainly TNFis) beyond the first 6 to 12months of treatment, suggesting that the response occurs independently of the number of prior TNFis.

Lessons for rituximab therapy in patients with rheumatoid arthritis

B-cell depletion therapy is an effective option for the treatment of rheumatoid arthritis but often does not result in complete B-cell depletion. Complete B-cell depletion after rituximab treatment is associated with clinical response, and this outcome leads to long-term maintenance of therapy. Low pretreatment plasmablast counts, concomitant treatment with disease-modifying antirheumatic drugs, no smoking exposure, the presence of anticitrullinated protein antibodies or rheumatoid factor, and a low interferon signature are all predictive of complete B-cell depletion and clinical response. Half of patients who initially show complete B-cell depletion and clinical response after rituximab treatment eventually lose responsiveness with further infusions. However three-quarters of these patients regain this outcome in their following treatment cycle, suggesting that loss of response is reversible and that patients can still benefit from rituximab retreatment. The efficacy of reduced doses of rituximab is being investigated, but preliminary results suggest that these strategies are best used for maintenance therapy, particularly in patients who suffer adverse events or who are at a high risk of infection. Infusion-related reactions are the most common adverse events associated with rituximab treatment, and monitoring of IgG concentrations is crucial, as low concentrations are correlated with an increased risk of infection.

Fetuin-A and thyroxin binding globulin predict rituximab response in rheumatoid arthritis patients with insufficient response to anti-TNFα

OBJECTIVES

Rheumatoid arthritis (RA) is a debilitating disease, but patient management and treatment have been revolutionized since the advent of bDMARDs. However, about one third of RA patients do not respond to specific bDMARD treatment without clear identified reasons. Different bDMARDs must be tried until the right drug is found. Here, we sought to identify a predictive protein signature to stratify patient responsiveness to rituximab (RTX) among patients with an insufficient response to a first anti-TNFα treatment.

METHODS

Serum samples were collected at baseline before RTX initiation. A proteomics study comparing responders and nonresponders was conducted to identify and select potential predictive biomarkers whose concentration was measured by quantitative assays. Logistic regression was performed to determine the best biomarker combination to predict good or nonresponse to RTX (EULAR criteria after 6 months' treatment).

RESULTS

Eleven biomarkers potentially discriminating between responders and nonresponders were selected following discovery proteomics. Quantitative immunoassays and univariate statistical analysis showed that fetuin-A and thyroxine binding globulin (TBG) presented a good capacity to discriminate between patient groups. A logistic regression analysis revealed that the combination of fetuin-A plus TBG could accurately predict a patient's responsiveness to RTX with an AUC of 0.86, sensitivity of 80%, and a specificity of 79%.

CONCLUSION

In RA patients for whom a first anti-TNFα treatment has failed, the serum abundance of fetuin-A and TBG before initiating RTX treatment is an indicator for their response status at 6 months. ClinicalTrials.gov identifier: NCT01000441. Key Points • Proteomic analysis revealed 11 putative predictive biomarkers to discriminate rituximab responder vs. nonresponder RA patients. • Fetuin-A and TBG are significantly differentially expressed at baseline in rituximab responder vs. nonresponder RA patients. • Algorithm combining fetuin-A and TBG accurately predicts response to rituximab in RA patients with insufficient response to TNFi.

In Human Autoimmunity, a Substantial Component of the B Cell Repertoire Consists of Polyclonal, Barely Mutated IgG+ve B Cells

B cells are critical for promoting autoimmunity and the success of B cell depletion therapy in rheumatoid arthritis (RA) confirms their importance in driving chronic inflammation. Whilst disease specific autoantibodies are useful diagnostically, our understanding of the pathogenic B cell repertoire remains unclear. Defining it would lead to novel insights and curative treatments. To address this, we have undertaken the largest study to date of over 150 RA patients, utilizing next generation sequencing (NGS) to analyze up to 200,000 BCR sequences per patient. The full-length antigen-binding variable region of the heavy chain (IgGHV) of the IgG B cell receptor (BCR) were sequenced. Surprisingly, RA patients do not express particular clonal expansions of B cells at diagnosis. Rather they express a polyclonal IgG repertoire with a significant increase in BCRs that have barely mutated away from the germline sequence. This pattern remains even after commencing disease modifying therapy. These hypomutated BCRs are expressed by TNF-alpha secreting IgG^+veCD27^-ve B cells, that are expanded in RA peripheral blood and enriched in the rheumatoid synovium. A similar B cell repertoire is expressed by patients with Sjögren's syndrome. A rate limiting step in the initiation of autoimmunity is the activation of B cells and this data reveals that a sizeable component of the human autoimmune B cell repertoire consists of polyclonal, hypomutated IgG^+ve B cells, that may play a critical role in driving chronic inflammation.

Rituximab in routine care of severe active rheumatoid arthritis : A prospective, non-interventional study in Germany

OBJECTIVE

To assess safety, effectiveness and onset of effect of rituximab (RTX) in routine clinical treatment of severe, active rheumatoid arthritis (RA).

METHODS

Prospective, multi-centre, non-interventional study in rheumatological outpatient clinics or private practices in Germany. RTX-naïve adult patients were to receive RTX according to marketing authorisation and at their physician's discretion. Also according to their physician's discretion, patients could receive a second cycle of RTX (re-treatment = treatment continuation). Major outcome was the change in Disease Activity Score based on 28-joints count and erythrocyte sedimentation rate (DAS28-ESR) over 24 weeks and during 6 months of re-treatment.

RESULTS

Overall, 1653 patients received at least one cycle RTX; 99.2% of these had received disease-modifying antirheumatic drugs (DMARD) pre-treatment and 75.5% anti-tumor necrosis factor(TNF)‑α pre-treatment. After a mean interval of 8.0 months, 820 patients received RTX re-treatment. Mean DAS28-ESR decreased from 5.3 at baseline to 3.8 after 24 weeks (-1.5 [95% confidence interval, CI: -1.6; -1.4]), and from 4.1 at start of cycle 2 to 3.5 at study end (change from baseline: -1.8 [95% CI: -2.0; -1.7]). Improvements in DAS28-ESR and Health Assessment Questionnaire (HAQ) score occurred mainly during the first 12 weeks of RTX treatment, with further DAS28-ESR improvement until week 24 or month 6 of re-treatment. Improvements in DAS28-ESR and EULAR responses were more pronounced in seropositive patients. RF was a predictor of DAS28-ESR change to study end. Safety analysis showed the established profile of RTX.

CONCLUSION

RTX was safe and effective in a real-life setting with rapid and sustained improvement in RA signs and symptoms.

A comprehensive review of rituximab therapy in rheumatoid arthritis patients

Rituximab (RTX) is an approved treatment for rheumatoid arthritis (RA) patients that do not respond adequately to disease-modifying antirheumatic drugs. However, different new concerns, such as efficacy, optimum dose, safety issues, prediction of response to RTX, and pregnancy outcomes have attracted a lot of attention. The PubMed database was systematically reviewed for the last published articles, new findings, and controversial issues regarding RTX therapy in RA using "Rheumatoid arthritis" AND "rituximab" keywords, last updated on June 18, 2019. From 1812 initial recorders, 162 studies met the criteria. Regarding the optimum dose, low-dose RTX therapy (2 × 500 mg) seems as effective as standard dose (2 × 1000 mg), safer, and more cost-effective. The most common reported safety challenges included de novo infections, false negative serologic tests of viral infections, reactivation of chronic infections, interfering with vaccination outcome, and development of de novo psoriasis. Other less reported side effects are infusion reactions, nervous system disorders, and gastrointestinal disorders. Lower exposure to other biologics, presence of some serological markers (e.g., anti-RF, anti-CCP, IL-33, ESR), specific variations in FCGR3A, FCGR2A, TGFβ1, IL6, IRF5, BAFF genes, and also EBV-positivity could be used to predict response to RTX. Although there is no evidence of the teratogenic effect of RTX, it is recommended that women do not expose themselves to RTX at least 6 months before the conception. Only a reversible reduction of B cell-count in the offspring may be the pregnancy-related outcome. Although RTX is an effective therapeutic option for RA, more studies on optimum doses, prevention of RTX-related side effects, prediction of RTX response, and safety during the pregnancy are required.

Assessing prognosis and prediction of treatment response in early rheumatoid arthritis: systematic reviews

BACKGROUND

Rheumatoid arthritis (RA) is a chronic, debilitating disease associated with reduced quality of life and substantial costs. It is unclear which tests and assessment tools allow the best assessment of prognosis in people with early RA and whether or not variables predict the response of patients to different drug treatments.

OBJECTIVE

To systematically review evidence on the use of selected tests and assessment tools in patients with early RA (1) in the evaluation of a prognosis (review 1) and (2) as predictive markers of treatment response (review 2).

DATA SOURCES

Electronic databases (e.g. MEDLINE, EMBASE, The Cochrane Library, Web of Science Conference Proceedings; searched to September 2016), registers, key websites, hand-searching of reference lists of included studies and key systematic reviews and contact with experts.

STUDY SELECTION

Review 1 - primary studies on the development, external validation and impact of clinical prediction models for selected outcomes in adult early RA patients. Review 2 - primary studies on the interaction between selected baseline covariates and treatment (conventional and biological disease-modifying antirheumatic drugs) on salient outcomes in adult early RA patients.

RESULTS

Review 1 - 22 model development studies and one combined model development/external validation study reporting 39 clinical prediction models were included. Five external validation studies evaluating eight clinical prediction models for radiographic joint damage were also included. c-statistics from internal validation ranged from 0.63 to 0.87 for radiographic progression (different definitions, six studies) and 0.78 to 0.82 for the Health Assessment Questionnaire (HAQ). Predictive performance in external validations varied considerably. Three models [(1) Active controlled Study of Patients receiving Infliximab for the treatment of Rheumatoid arthritis of Early onset (ASPIRE) C-reactive protein (ASPIRE CRP), (2) ASPIRE erythrocyte sedimentation rate (ASPIRE ESR) and (3) Behandelings Strategie (BeSt)] were externally validated using the same outcome definition in more than one population. Results of the random-effects meta-analysis suggested substantial uncertainty in the expected predictive performance of models in a new sample of patients. Review 2 - 12 studies were identified. Covariates examined included anti-citrullinated protein/peptide anti-body (ACPA) status, smoking status, erosions, rheumatoid factor status, C-reactive protein level, erythrocyte sedimentation rate, swollen joint count (SJC), body mass index and vascularity of synovium on power Doppler ultrasound (PDUS). Outcomes examined included erosions/radiographic progression, disease activity, physical function and Disease Activity Score-28 remission. There was statistical evidence to suggest that ACPA status, SJC and PDUS status at baseline may be treatment effect modifiers, but not necessarily that they are prognostic of response for all treatments. Most of the results were subject to considerable uncertainty and were not statistically significant.

LIMITATIONS

The meta-analysis in review 1 was limited by the availability of only a small number of external validation studies. Studies rarely investigated the interaction between predictors and treatment.

SUGGESTED RESEARCH PRIORITIES

Collaborative research (including the use of individual participant data) is needed to further develop and externally validate the clinical prediction models. The clinical prediction models should be validated with respect to individual treatments. Future assessments of treatment by covariate interactions should follow good statistical practice.

CONCLUSIONS

Review 1 - uncertainty remains over the optimal prediction model(s) for use in clinical practice. Review 2 - in general, there was insufficient evidence that the effect of treatment depended on baseline characteristics.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016042402.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Treatment outcomes in patients with seropositive versus seronegative rheumatoid arthritis in Phase III randomised clinical trials of tofacitinib

Objectives

Tofacitinib is an oral JAK inhibitor for the treatment of rheumatoid arthritis (RA). We examined response to tofacitinib 5 or 10 mg two times a day in patients with seropositive vs seronegative RA.

Methods

Data were pooled from five Phase III studies of conventional synthetic disease-modifying antirheumatic drug (csDMARD)- or biological DMARD-inadequate responders (ORAL Step [NCT00960440]; ORAL Scan [NCT00847613]; ORAL Solo [NCT00814307]; ORAL Sync [NCT00856544]; ORAL Standard [NCT00853385]). ‘Serotype’ subgroups were: anticyclic citrullinated peptide (CCP) and rheumatoid factor (RF) positive (anti-CCP+/RF+); anti-CCP+/RF negative (-); anti-CCP-/RF+; anti-CCP-/RF-. At month 3, ACR20/50/70 response rates, Disease Activity Score (DAS28-4[ESR])-defined remission (DAS28-4[ESR]<2.6) and low disease activity (LDA; DAS28-4[ESR]≤3.2), changes from baseline (CFB) in Health Assessment Questionnaire-Disability Index (HAQ-DI), Short Form-36 Health Survey (SF-36) physical functioning and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) were evaluated. Safety endpoints were compared.

Results

Baseline demographics/characteristics were similar across subgroups. Tofacitinib significantly improved ACR20/50/70 response rates, DAS28-4(ESR) LDA rates and CFB in HAQ-DI and FACIT-F vs placebo across subgroups. More anti-CCP+/RF+ than anti-CCP-/RF- patients had ACR20/50/70 responses (ACR20/50: both tofacitinib doses; ACR70: 10 mg two times a day). SF-36 physical functioning improved in anti-CCP+/RF+, anti-CCP+/RF- and anti-CCP-/RF+ patients (both tofacitinib doses) and anti-CCP-/RF- patients (10 mg two times a day) vs placebo. More anti-CCP+/RF+ and anti-CCP+/RF- than anti-CCP-/RF- patients achieved DAS28-4(ESR) remission and LDA with tofacitinib 10 mg two times a day. Frequency of adverse events (AEs), serious AEs and discontinuations due to AEs were similar across subgroups.

Conclusion

Generally, tofacitinib efficacy (ACR20/50/70 responses) and safety were similar across subgroups. DAS28-4(ESR) remission rates and SF-36 physical functioning appeared lower in anti-CCP- patients.

FCGR2A/FCGR3A Gene Polymorphisms and Clinical Variables as Predictors of Response to Tocilizumab and Rituximab in Patients With Rheumatoid Arthritis

We evaluated the influence of clinical, biochemical, and genetic factors on response in 142 patients diagnosed with rheumatoid arthritis, of whom 87 patients were treated with tocilizumab (61.26%) and 55 patients were treated with rituximab (38.7%;) according to the variables European League Against Rheumatism (EULAR) response, remission, low disease activity, and improvement in Disease Activity Score, 28 joints (DAS28) at 6, 12, and 18 months. A retrospective prospective cohort study was conducted. Patients carrying the FCGR3A rs396991-TT genotype treated with tocilizumab showed higher EULAR response (OR, 5.075; 95%CI, 1.20-21.33; P = .027) at 12 months, those who were naive for biological disease-modifying antirheumatic drugs (bDMARDs) at the beginning of treatment showed satisfactory EULAR response, higher remission, and greater improvement in DAS28 at 6 months. Younger age at start of tocilizumab treatment was associated with satisfactory EULAR response at 18 months and greater remission at 6 and 18 months. Subcutaneous tocilizumab administration was associated with higher remission at 6 months and improved low disease activity rate at 12 months. In patients treated with rituximab, carriers of the FCGR2A rs1801274-TT genotype had higher EULAR response at 6 months (OR, 4.861; 95%CI, 1.11-21.12; P = .035), 12 months (OR, 4.667; p = 0.066, 95%CI, 0.90-24.12; P = .066), and 18 months (OR, 2.487; 95%CI, 0.35-17.31; P = .357), higher remission (OR: 10.625; p = 0.044, CI_95% : 1.07, 105.47) at 6 months, and greater improvement in DAS28 at 12 months (B = 0.782; 95%CI, -0.15 to 1.71; P = .098) and 18 months (B = 1.414; 95%CI, 0.19-2.63; P = .025). The FCGR3A rs396991-G allele was associated with improved low disease activity rate (OR, 4.904; 95%CI, 0.84-28.48; P = .077) and greater improvement in DAS28 (B = -1.083; 95%CI, -1.98 to -0.18; P = .021) at 18 months. Patients with a lower number of previous biological therapies had higher remission at 12 months. We suggest that the FCGR3A rs396991-TT genotype, higher baseline value of DAS28, subcutaneous tocilizumab administration, younger age at the beginning of treatment, and being bDMARD naive are associated with better response to tocilizumab. In patients treated with rituximab, we found better response in those patients with the FCGR2A rs1801274-TT genotype, the FCGR3A rs396991-G allele, and lower number of previous biological therapies.

Doses of rituximab for retreatment in rheumatoid arthritis: influence on maintenance and risk of serious infection

Objective

To investigate maintenance of rituximab (RTX) in RA patients re-treated with reduced doses compared with standard dose in a real life setting.

Methods

The Autoimmunity and Rituximab (AIR) registry is a nationwide prospective observational cohort investigating the long-term safety and efficacy of RTX in RA. The present study included patients from the AIR registry that have been re-treated with RTX after a first course of RTX standard dose (1000 mg × 2). Two groups were defined according to dose of RTX of the first retreatment course (i.e. second course): standard dose group and reduced dose group. Five years' maintenance and rate of serious infections of the retreatment period were compared between standard dose and reduced dose groups. Analyses used the inverse probability of treatment weighting propensity score adjusted method.

Results

Among the 1986 patients from the AIR registry, 1278 were included, 1093 (85.5%) treated with standard dose and 185 (14.5%) with reduced doses. Maintenance of RTX at 5 years in the standard and reduced groups was 55.5 and 53.8%, respectively, and did not significantly differ between groups in adjusted analyses (hazard ratio = 1.03; 95% CI: 0.81, 1.30), but the cumulative RTX dose received for retreatment [1.4 (0.6) vs 2.3 (1.0) g/year, P < 0.001] and the rate of serious infections were significantly lower in the reduced dose group (adjusted hazard ratio = 0.50; 95% CI: 0.27, 0.92; P = 0.02).

Conclusion

Use of reduced doses of RTX for retreatment did not alter the maintenance of RTX at 5 years in RA patients, but allowed a 39% total dose reduction and a lower rate of serious infections.

Clinically relevant discrepancies between different rheumatoid factor assays

Background:

Accurate measurements of rheumatoid factors (RFs), autoantibodies binding IgG, are important for diagnosing rheumatoid arthritis (RA) and for predicting disease course. Worldwide, various RF assays are being used that differ in technique and target antigens. We studied whether assay choice leads to clinically important discrepancies in RF status and level.

Methods:

RF measurements using four commercial RF assays were compared in 32 RF+ samples. Using enzyme-linked immunosorbent assays (ELISAs), the influence of the target antigen source – human IgG (hIgG) versus rabbit IgG (rIgG) – on measured RF levels was investigated in arthralgia patients and RA patients.

Results:

Substantial discrepancies were found between RF levels measured in the four commercial assays. Six samples (19%) with RF levels below or slightly above the cutoff in the rIgG-based Phadia assay were RF+ in three assays using hIgG as the target antigen, some with very high levels. Direct ELISA comparisons of RF reactivity against hIgG and rIgG estimated that among 173 ACPA+ arthralgia patients, originally RF negative in rIgG-based assays, up to 10% were single positive against hIgG. Monoclonal RFs binding to hIgG and rIgG or hIgG only supported these findings. In a cohort of 69 early RA patients, virtually all RF responses reacted with both targets, although levels were still variable.

Conclusions:

The use of RF assays that differ in technique and target antigen, together with the different specificities of RF responses, leads to discrepancies in RF status and levels. This has important consequences for patient care if RA diagnosis and disease progression assessments are based on RF test results.

Real-world predictors of 12-month intravenous abatacept retention in patients with rheumatoid arthritis in the ACTION observational study

INTRODUCTION

An understanding of real-world predictors of abatacept retention is limited. We analysed retention rates and predictors of abatacept retention in biologic-naïve and biologic-failure patients in a 12-month interim analysis of the 2-yearAbataCepTIn rOutiNe clinical practice (ACTION) study.

METHODS

ACTION was an international, observational study of patients with moderate-to-severe rheumatoid arthritis (RA) who initiated intravenous abatacept. In this 12-month interim analysis, crude abatacept retention rates, predictors of retention and European League Against Rheumatism (EULAR) response were evaluated in both biologic-naïve and biologic-failure patients. Retention by rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) status was also assessed, in patients with or without baseline radiographic erosions, and by body mass index (BMI).

RESULTS

Overall, 2350/2364 enrolled patients were evaluable (674 biologic naїve; 1676 biologic failure). Baseline characteristics were largely similar in biologic-naïve and biologic-failure groups. Crude retention rates (95% CI) at 12 months were significantly higher in biologic-naїve (78.1%(74.7% to 81.2%)) versus biologic-failure patients (69.9%(67.6% to 72.1%); P<0.001). RF/anti-CCP double positivity predicted higher retention in both patient groups, and remained associated with higher retention in patients with erosive disease. BMI did not impact abatacept retention in either patient group, irrespective of RF/anti-CCP serostatus. Good/moderate EULAR response rate at 12 months was numerically higher in biologic-naїve (83.8%) versus biologic-failure (73.3%) patients. There were no new safety signals.

CONCLUSION

High levels of intravenous abatacept retention in clinical practice were confirmed, particularly in biologic-naïve patients, including in those with poor RA prognostic factors. Retention was unaffected by BMI, regardless of RF/anti-CCP serostatus.

TRIAL REGISTRATION NUMBER

NCT02109666; retrospectively registered 8 April 2014.

Identification of IRX1 as a Risk Locus for Rheumatoid Factor Positivity in Rheumatoid Arthritis in a Genome-Wide Association Study

OBJECTIVE

Rheumatoid factor (RF) is a well-established diagnostic and prognostic biomarker in rheumatoid arthritis (RA). However, ∼20% of RA patients are negative for this anti-IgG antibody. To date, only variation at the HLA-DRB1 gene has been associated with the presence of RF. This study was undertaken to identify additional genetic variants associated with RF positivity.

METHODS

A genome-wide association study (GWAS) for RF positivity was performed using an Illumina Quad610 genotyping platform. A total of 937 RF-positive and 323 RF-negative RA patients were genotyped for >550,000 single-nucleotide polymorphisms (SNPs). Association testing was performed using an allelic chi-square test implemented in Plink software. An independent cohort of 472 RF-positive and 190 RF-negative RA patients was used to validate the most significant findings.

RESULTS

In the discovery stage, a SNP in the IRX1 locus on chromosome 5p15.3 (SNP rs1502644) showed a genome-wide significant association with RF positivity (P = 4.13 × 10(-8) , odds ratio [OR] 0.37 [95% confidence interval (95% CI) 0.26-0.53]). In the validation stage, the association of IRX1 with RF was replicated in an independent group of RA patients (P = 0.034, OR 0.58 [95% CI 0.35-0.97] and combined P = 1.14 × 10(-8) , OR 0.43 [95% CI 0.32-0.58]).

CONCLUSION

To our knowledge, this is the first GWAS of RF positivity in RA. Variation at the IRX1 locus on chromosome 5p15.3 is associated with the presence of RF. Our findings indicate that IRX1 and HLA-DRB1 are the strongest genetic factors for RF production in RA.

A multi-parameter response prediction model for rituximab in rheumatoid arthritis

OBJECTIVES

To validate the IFN response gene (IRG) set for the prediction of non-response to rituximab in rheumatoid arthritis (RA) and assess the predictive performance upon combination of this gene set with clinical parameters.

METHODS

In two independent cohorts of 93 (cohort I) and 133 (cohort II) rituximab-starting RA patients, baseline peripheral blood expression of eight IRGs was determined, and averaged into an IFN score. Predictive performance of IFN score and clinical parameters was assessed by logistic regression. A multivariate prediction model was developed using a forward stepwise selection procedure. Patients with a decrease in disease activity score (ΔDAS28)≥1.8 after 6 months of therapy were considered responders.

RESULTS

The mean IFN score was higher in non-responders compared to responders in both cohorts, but this difference was most pronounced in patients who did not use prednisone, as described before. Univariate analysis in cohort I showed that baseline DAS28, IFN score, DMARD use and negativity for IgM-RF and/or ACPA were associated with rituximab non-response. The multivariate model consisted of DAS28, IFN score and DMARD use, which showed an area under the curve (AUC) of 0.82. In cohort II, this model revealed a comparable AUC in PREDN-negative patients (0.78), but AUC in PREDN-positive patients was significantly lower (0.63), which seemed due to effect modification of the IFN score by prednisone.

CONCLUSIONS

Combination of predictive parameters provided a promising model for the prediction of non-response to rituximab, with possibilities for optimization via definition of the exact interfering effect of prednisone on IFN score.

TRIAL REGISTRATION (COHORT II, SMART TRIAL)

NCT01126541, registered 18 May 2010.

Psoriasis, psoriatic arthritis, and rheumatoid arthritis: Is all inflammation the same?

OBJECTIVES

To review the pathophysiology, co-morbidities, and therapeutic options for psoriasis, psoriatic arthritis and rheumatoid arthritis in order to further understand the similarities and differences in treatment paradigms in the management of each disease. New targets for individualized therapeutic decisions are also identified with the aim of improving therapeutic outcome and reducing toxicity.

SEARCH STRATEGY

Using the PubMed database, we searched literature published from 2000 to 2015 using combinations of the key words "psoriasis," "psoriatic arthritis," "rheumatoid arthritis," "pathogenesis," "immunomodulation," and "treatment."

INCLUSION AND EXCLUSION CRITERIA

This was a non-systematic review and there were no formal inclusion and exclusion criteria.

DATA EXTRACTION

Abstracts identified in the search were screened for relevance and articles considered appropriate evaluated further. References within these selected articles were also screened. Information was extracted from 198 articles for inclusion in this report.

DATA SYNTHESIS

There was no formal data synthesis. Articles were reviewed and summarized according to disease area (psoriasis, psoriatic arthritis, and rheumatoid arthritis).

HEADLINE RESULTS

The pathophysiology of psoriasis, psoriatic arthritis, and rheumatoid arthritis involves chronic inflammation mediated by pro-inflammatory cytokines. Dysfunction in integrated signaling pathways affecting different constituents of the immune system result in varying clinical features in the three diseases. Co-morbidities, including cardiovascular disease, malignancies, and non-alcoholic fatty liver disease are increased. Increased understanding of the immunopathogenesis allowed development of targeted treatments; however, despite a variety of potentially predictive genetic, protein and cellular biomarkers, there is still significant unmet need in these three inflammatory disorders.

Repeated decrease of CD4+ T-cell counts in patients with rheumatoid arthritis over multiple cycles of rituximab treatment

Background

Significant peripheral blood CD4+ T-cell depletion has been observed after a first cycle of rituximab, a monoclonal antibody directed against the CD20 antigen, which is currently used in rheumatoid arthritis. Of note, an absence of CD4+ T-cell decrease has been observed in non-responders. Herein, we describe CD4+ T-cell changes over repeated cycles of rituximab and their relationship with clinical outcomes.

Methods

Patients with rheumatoid arthritis who started rituximab between July 2007 and July 2013 were analyzed up to November 2014. Lymphocyte phenotyping and clinical assessments were performed before, and 3 and 6 months after each cycle. Lymphocytes counts and disease activity were compared at each time point, using nonparametric tests.

Results

Patients received up to seven cycles of treatment during the study period. Mean CD4+ T-cell counts were above the upper limit of the reference range before each rituximab infusion and repeatedly reached the reference range at 6 months (and/or 3 months) post infusion. CD4+ T cells decreased concurrently with disease activity score.

Conclusions

CD4+ T-cell counts could be a relevant biomarker of response to rituximab in rheumatoid arthritis and could be considered in making decisions about the timing of retreatment.

A combination of cellular biomarkers predicts failure to respond to rituximab in rheumatoid arthritis: a 24-week observational study

BACKGROUND

Although B cell depletion with rituximab (RTX) is an effective treatment strategy in rheumatoid arthritis (RA), one third of patients do not achieve remission or low disease activity (LDA). Thus, identifying patients who will benefit from RTX is highly desirable. In the present study we investigated whether lymphocyte subsets other than B cells are predictors of a clinical response to RTX treatment.

METHODS

Patients with RA who were receiving RTX for the first time were included in an observatory registry. Clinical assessments, complete blood count and flow cytometry of lymphocyte subsets were obtained at baseline and at week 24 after RTX. Complete data were available for 44 patients. Logistic regression and receiver operating characteristic curve analyses were computed to analyze the predictive value of lymphocyte subsets for European League Against Rheumatism (EULAR) response and LDA (defined as disease activity score in 28 joints (DAS28) ≤3.2) at week 24.

RESULTS

EULAR responders had lower total lymphocyte counts (LC), T cells and CD4 + T cells at baseline. Although these parameters were independent predictors of EULAR response they failed in determining who would reach LDA. In contrast, LC >2910/μl or plasmablast frequency >2.85 % at baseline predicted a significantly higher DAS28 at week 24 after RTX and identified patients not achieving LDA at week 24 with sensitivity of 93.3 % and specificity of 44.8 %.

CONCLUSIONS

A combination of LC and plasmablast frequency identifies patients with RA who will not benefit from RTX with high probability.

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.

Personalized biological treatment for rheumatoid arthritis: a systematic review with a focus on clinical applicability

OBJECTIVES

To review studies that address prediction of response to biologic treatment in RA and to explore the clinical utility of the studied (bio)markers.

METHODS

A search for relevant articles was performed in PubMed, Embase and Cochrane databases. Studies that presented predictive values or in which these could be calculated were selected. The added value was determined by the added value on prior probability for each (bio)marker. Only an increase/decrease in chance of response ⩾15% was considered clinically relevant, whereas in oncology values >25% are common.

RESULTS

Of the 57 eligible studies, 14 (bio)markers were studied in more than one cohort and an overview of the added predictive value of each marker is presented. Of the replicated predictors, none consistently showed an increase/decrease in probability of response ⩾15%. However, positivity of RF and ACPA in case of rituximab and the presence of the TNF-α promoter 308 GG genotype for TNF inhibitor therapy were consistently predictive, yet low in added predictive value. Besides these, 65 (bio)markers studied once showed remarkably high (but not validated) predictive values.

CONCLUSION

We were unable to address clinically useful baseline (bio)markers for use in individually tailored treatment. Some predictors are consistently predictive, yet low in added predictive value, while several others are promising but await replication. The challenge now is to design studies to validate all explored and promising findings individually and in combination to make these (bio)markers relevant to clinical practice.

Rituximab for Rheumatoid Arthritis

Rituximab is a chimeric monoclonal antibody directed at the CD20 molecule on the surfaces of some but not all B cells. It depletes almost all peripheral B cells, but other niches of B cells are variably depleted, including synovium. Its mechanism of action in rheumatoid arthritis (RA) is only partially understood. Rituximab was efficacious in clinical trials of patients with RA, including those who are methotrexate naïve, those with an incomplete response to methotrexate, and those with an incomplete response to tumor necrosis factor inhibitors. The need for a concomitant traditional disease-modifying drug, the optimal dose of rituximab, and the optimal interval for retreatment remain somewhat uncertain. Rituximab seems to be most efficacious in seropositive patients and those with an incomplete response to only one tumor necrosis factor inhibitor. Rituximab has a reasonable safety profile, with a small risk of serious infectious events, which is stable over time and repeat courses. Opportunistic infections are rare. Reactivation of hepatitis B remains a concern. The possible association of rituximab and progressive multifocal leukoencephalopathy may still require vigilance. Malignancies and cardiovascular events do not appear to be increased. Infusion reactions are more likely with the initial infusion, and are usually mild. Rituximab may cause hypogammaglobulinemia, but any risk of subsequent risk of increased infectious events is not yet well established. Before initiating rituximab, patient screening for hypersensitivity to murine proteins, infections, congestive heart failure, pregnancy, and hypogammaglobulinemia is imperative. Vaccinations should be administered prior to treatment whenever possible. Rituximab has been a significant addition to the rheumatologists' armamentarium for the treatment of RA.

Restrictive IgG antibody response against mutated citrullinated vimentin predicts response to rituximab in patients with rheumatoid arthritis

Introduction

Antibodies against mutated citrullinated vimentin (AMCV) represent a useful diagnostic marker with correlation to disease activity in patients with rheumatoid arthritis (RA). Since seropositivity for citrullinated autoantibodies was predictive for response to B-cell depleting therapy (BCDT) with rituximab (RTX), we investigated whether differences in antibody fine reactivity and immunoglobulin (Ig) isotype kinetics among AMCV-positive patients could provide additional information about outcome.

Methods

A total of 50 AMCV IgG-positive RA patients (RTX responders (RRs) n = 37 and non-responders (NRRs) n = 13) were analyzed for reactivity against MCV epitopes and co-existent AMCV isotypes IgM and IgA. Antibody titers were determined by enzyme-linked immunosorbent assay at baseline and 24 weeks after the first cycle of RTX, and compared to kinetics of rheumatoid factor (RF) and antibodies against cyclic citrullinated peptide (ACCP).

Results

Recognized MCV epitopes by AMCV IgG of RRs and NRRs showed similar baseline patterns, with reducing reactivity in RRs and unchanged or even expanding reactivity in NRRs upon RTX treatment. At baseline, RRs were more frequently negative for AMCV subtypes, especially for IgA (68 %), compared to NRRs (31 %). Being AMCV IgA-negative at baseline indicated a good treatment response to RTX (negative predictive value = 0.86). Co-existence of AMCV IgA and IgG with stable titers upon treatment were associated with poorer responses to RTX. Furthermore, reductions of AMCV IgA levels upon RTX correlated with the improvement of 28-joint Disease Activity Score (DAS28). In comparison, subtypes of RF and ACCP were not of additional value for prediction of RTX response.

Conclusions

Restrictive IgG seropositivity against MCV with treatment-associated decline in fine reactivity and titers was predictive for response to RTX. Double-positivity for AMCV IgG and IgA was associated with failure to respond to BCDT, suggesting a pathogenetic and less sensitive IgA-producing B-cell subset in NRRs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0717-z) contains supplementary material, which is available to authorized users.

Usefulness of monitoring of B cell depletion in rituximab-treated rheumatoid arthritis patients in order to predict clinical relapse: a prospective observational study

Our objective was to evaluate the contribution of monitoring B cell subset depletion after rituximab in patients with rheumatoid arthritis (RA) in order to guide reintroduction to forestall relapse. This prospective, monocentre study included all RA patients receiving two 1-g rituximab infusions at a 15-day interval. The patients were followed clinically and biologically every 2 months until rituximab reintroduction. The physician was blinded to lymphocyte-typing results to diagnose relapse and, hence, retreatment. Among the 39 patients included between March 2010 and December 2011 and followed until April 2013, seven received two rituximab cycles, yielding a total of 46 cycles for analysis. After the two rituximab cycles, the total number of CD19(+) B cells decreased significantly (0·155 versus 0·0002 G/l, P < 0·0001), with complete depletions in all patients of CD19(+) CD38(++) CD24(++) (transitional) (P < 0·0001) and CD19(+) CD27(+) (memory) B lymphocytes. A significant majority of patients relapsed within the 4 months following repopulation of total B (P = 0·036), B transitional (P = 0·007) and B memory (P = 0·01) lymphocytes. CD19(+) B lymphocyte repopulation preceded clinical RA relapse and enabled its prediction 4 months in advance. Hence, monitoring of CD19(+) B lymphocytes could serve as a tool to predict those relapses.

Advances in the treatment of rheumatoid arthritis

The intense pursuit of novel therapies in rheumatoid arthritis has provided physicians with an assorted set of biologic drugs to treat patients with moderate to severe disease activity. Nine different biologic therapies are currently available: seven inhibitors of pro-inflammatory cytokines (five targeting tumor necrosis factor [TNF], one interleukin [IL]-1 and one IL-6), as well as a T- and a B-lymphocyte targeting agent. All these drugs have roughly similar efficacy profiles and are approved as first- or second-line therapy in patients who failed to respond to conventional disease-modifying anti-rheumatic drugs (DMARDs) and in most cases for first line use in rheumatoid arthritis as well. Despite the irrefutable clinical and radiological benefits of biologic therapies, there are still low rates of patients achieving stable remission. Therefore, the quest for new and more effective biologic therapies continues and every year new drugs are tested. Simultaneously, optimal use of established agents is being studied in different ways. Recently, the approval of the first small molecule targeting intracellular pathways has opened a new chapter in the treatment of rheumatoid arthritis. Other emerging treatment strategies include the activation of regulatory T cells as well as new cytokine-targeting therapies.

Epstein-Barr virus infection transforms CD25+ B cells into antibody-secreting cells in rheumatoid arthritis patients

Epstein-Barr virus (EBV) infection may initiate production of autoantibodies and development of cancer and autoimmune diseases. Here we outline phenotypic and functional changes in B cells of patients with rheumatoid arthritis (RA) related to EBV infection. The B-cell phenotype was analysed in blood and bone marrow (BM) of RA patients who had EBV transcripts in BM (EBV(+) , n = 13) and in EBV(-) (n = 22) patients with RA. The functional effect of EBV was studied in the sorted CD25(+) and CD25(-) peripheral B cells of RA patients (n = 18) and healthy controls (n = 9). Rituximab treatment results in enrichment of CD25(+) B cells in peripheral blood (PB) of EBV(+) RA patients. The CD25(+) B-cell subset displayed a more mature phenotype accumulating IgG-expressing cells. It was also enriched with CD27(+) and CD95(+) cells in PB and BM. EBV stimulation of the sorted CD25(+) B cells in vitro induced a polyclonal IgG and IgM secretion in RA patients, while CD25(+) B cells of healthy subjects did not respond to EBV stimulation. CD25(+) B cells were enriched in PB and synovial fluid of RA patients. EBV infection affects the B-cell phenotype in RA patients by increasing the CD25(+) subset and by inducing their immunoglobulin production. These findings clearly link CD25(+) B cells to the EBV-dependent sequence of reactions in the pathogenesis of RA.

Predictive factors of response to biological disease modifying antirheumatic drugs: towards personalized medicine

Many therapies are now available for patients with rheumatoid arthritis (RA) who have an inadequate response to methotrexate including tumor necrosis factor inhibitors, abatacept, tocilizumab, and rituximab. Clinical response to drugs varies widely between individuals. A part of this variability is due to the characteristics of the patient such as age, gender, concomitant therapies, body mass index, or smoking status. Clinical response also depends on disease characteristics including disease activity and severity and presence of autoantibodies. Genetic background, cytokine levels, and immune cell phenotypes could also influence biological therapy response. This review summarizes the impact of all those parameters on response to biological therapies.

Rheumatoid factors: clinical applications

Rheumatoid factors are antibodies directed against the Fc region of immunoglobulin G. First detected in patients with rheumatoid arthritis 70 years ago, they can also be found in patients with other autoimmune and nonautoimmune conditions, as well as in healthy subjects. Rheumatoid factors form part of the workup for the differential diagnosis of arthropathies. In clinical practice, it is recommended to measure anti-cyclic citrullinated peptide antibodies and rheumatoid factors together because anti-cyclic citrullinated peptide antibodies alone are only moderately sensitive, and the combination of the two markers improves diagnostic accuracy, especially in the case of early rheumatoid arthritis. Furthermore, different rheumatoid factor isotypes alone or in combination can be helpful when managing rheumatoid arthritis patients, from the time of diagnosis until deciding on the choice of therapeutic strategy.

[Personalized medicine in rheumatology]

In rheumatology, especially in arthritides, early diagnosis and aggressive therapy may open up new dimensions of expectations, such as improvement of pain, prevention of structural, functional damage and better quality of life. Targeted (biological) therapy has brought new horizons in rheumatology. As it is a rather expensive treatment modality, it has been urgent to develop tools suitable for the prediction of therapeutic responses. Several clinical, immunological and genetic biomarkers have been established for this purpose. Among clinical markers, male sex, younger age, lower or even higher disease activity at baseline, combination treatment and quitting smoking may lead to better treatment outcome. Immunological biomarkers, such as C-reactive protein, seropositivity, peripheral blood or synovial cellular content have been associated with therapeutic responses. Finally, numerous genes or gene signatures may also predict the efficacy or safety of immunosuppressive drugs. Although sometimes there have been only few studies conducted that led to some controversy, some biomarkers have also been validated. This may lead us to optimism in terms of wider acceptance of personalized medicine in rheumatology.

Predictive factors of rituximab response in rheumatoid arthritis: results from a French university hospital

OBJECTIVE

To study the influence of several factors (rheumatoid factor [RF], anti-cyclic citrullinated peptide [anti-CCP], serum Ig level, and Epstein-Barr virus [EBV] load) on clinical response to rituximab (RTX) after 6 months in rheumatoid arthritis (RA) patients.

METHODS

Sixty-four patients receiving RTX (two 1-gm doses 2 weeks apart) for active RA were prospectively included. RF, anti-CCP, gamma globulin level, and EBV load were assessed prior to the first RTX cycle. Clinical responses were analyzed 6 months after RTX initiation using the European League Against Rheumatism criteria. Univariate and multivariate analyses were performed to identify factors associated with RTX response at 6 months.

RESULTS

The mean disease duration was 16.4 years and 46 patients (71.9%) had already received at least 1 anti-tumor necrosis factor agent prior to RTX. At 6 months, 46 patients (71.9%) had a good to moderate response to RTX. Anti-CCP positivity was associated with a good to moderate response (odds ratio [OR] 4, 95% confidence interval [95% CI] 1.04-15.5; P = 0.04). RF positivity (P = 0.26) and positive initial EBV load (P = 0.16) were not associated with a good to moderate response. Hyperimmunoglobulin was correlated with a poorer response to RTX than normal Ig levels (OR 0.04, 95% CI 0.005-0.28; P = 0.002).

CONCLUSION

Anti-CCP positivity was a predictor of good to moderate response to RTX in RA patients. On the other hand, high Ig levels were associated with a poorer outcome in contrast to previous findings. Further support from larger studies is necessary so as to optimize the management of the RA patients with high Ig levels.

Longterm effects of rituximab on B cell counts and autoantibody production in rheumatoid arthritis: use of high-sensitivity flow cytometry for more sensitive assessment of B cell depletion

OBJECTIVE

To assess the efficacy and safety of longterm rituximab (RTX) therapy for rheumatoid arthritis (RA) and study correlations among B cell depletion, clinical response, and autoantibody production.

METHODS

Seventy-seven patients with moderate or high RA activity received RTX and were re-treated every 6 months regardless of clinical response. All patients received at least 5 cycles. We assessed 28-joint Disease Activity Score (DAS28), IgM rheumatoid factor (RF), and anticitrullinated protein antibody (ACPA) levels at baseline, after 15 days, and then every 6 months for 24 months. Absolute CD19+ B lymphocyte counts were determined in 50 patients using high-sensitivity flow cytometry (hsFACS) by reading 100,000 events.

RESULTS

After 6, 12, 18, and 24 months, 51.6%, 51.9%, 73.3%, and 83.8% of patients, respectively, showed good European League Against Rheumatism responses. Significant and sustained decreases in IgM RF and ACPA levels were observed as early as 6 months and 12 months, respectively. The baseline mean absolute B cell number was 0.234 g/l. B cell numbers diminished significantly after the very first infusion by Day 15 (0.104 g/l; p = 0.007); they further decreased until 24 months (0.0013 g/l; p < 0.001). One RTX infusion resulted in incomplete depletion in 76.7% of patients. Upon RTX treatment, changes in CD19+ B cell numbers positively correlated with changes in DAS28 (r = 0.963, p = 0.008) and IgM RF (r = 0.859, p = 0.028), but not with changes in ACPA production (r = 0.726, p = 0.102). The correlations between B cell numbers and DAS28 were observed in both ACPA-seropositive (r = 0.999, p < 0.0001) and ACPA-negative patient subpopulations (r = 0.962, p = 0.009). The correlation between CD19+ cell numbers and IgM RF was observed only in the ACPA-positive population (r = 0.944, p = 0.005) but not in seronegative patients (r = 0.398, p = 0.435). No safety issues arose.

CONCLUSION

In RA, clinical response to RTX is associated with the extent of B cell depletion and with autoantibody production. Changes in CD19+ B cell numbers correlate with those in disease activity and, in seropositive patients, also with IgM RF, but not with ACPA production. We found that hsFACS may be a useful method to more accurately assess incomplete B cell depletion.

The TTTT B lymphocyte stimulator promoter haplotype is associated with good response to rituximab therapy in seropositive rheumatoid arthritis resistant to tumor necrosis factor blockers

OBJECTIVE

To investigate the polymorphisms in the promoter region of the B lymphocyte stimulator (BLyS) gene as markers of response to rituximab (RTX) in rheumatoid arthritis (RA).

METHODS

The study was first conducted in 152 Italian RA patients and then replicated in an additional 117 RA patients (73 Italian, 44 British). The European League Against Rheumatism response criteria were used to evaluate the response rate at months 4 and 6 after the first cycle of RTX, by means of the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate; patients were classified according to the best response shown between months 4 and 6. BLyS promoter polymorphisms were analyzed by polymerase chain reaction followed by the analysis of the restriction fragments, BLyS promoter haplotypes were analyzed using the expectation-maximization algorithm, and BLyS serum levels were analyzed using enzyme-linked immunosorbent assay. Odds ratios (ORs) were calculated with 95% confidence intervals (95% CIs).

RESULTS

The TTTT BLyS promoter haplotype appeared to be significantly associated with response to RTX only in the subset of seropositive patients (those positive for rheumatoid factor and/or anti-cyclic citrullinated peptide). The replication study confirmed that this association was limited to seropositive RA patients in whom treatment with anti-tumor necrosis factor (anti-TNF) agents had previously failed. In the whole series of seropositive patients in whom anti-TNF agents had previously failed, patients carrying the TTTT BLyS promoter haplotype were more prevalent in good responders (18 of 43 [41.9%]) than in moderate responders (20 of 83 [24.1%]) or in nonresponders (1 of 21 [4.8%]) (for good responders versus nonresponders, OR 14.4 [95% CI 1.77-117.39], P=0.0028). Furthermore, multivariate analysis selected the TTTT BLyS promoter haplotype as an independent marker of good response to RTX (for good responders versus nonresponders, OR 16.2 [95% CI 1.7-152.5], P=0.01; for good responders versus moderate responders and nonresponders combined, OR 3.1 [95% CI 1.2-7.8], P=0.02). The relationship between BLyS polymorphisms and BLyS serum levels remained unclear.

CONCLUSION

BLyS promoter genotyping may be suitable for identifying seropositive RA patients who may have a good response to RTX after anti-TNF agents have failed.

A rheumatoid factor paradox: inhibition of rituximab effector function

Introduction

Rituximab (RTX) therapy of rheumatoid arthritis (RA) exhibits enhanced effectiveness in seropositive patients. Using patient sera, we tested if this improved efficacy was associated with enhanced RTX mediated complement-dependent cytotoxicity (RTX-CDC).

Methods

We developed an in vitro assay for RTX-CDC using patient sera and the Daudi human B cell line. Using propidium iodide uptake and flow cytometry, we compared RTX-CDC with rheumatoid factor (RF)+ sera relative to normal volunteer, non-RA and RF- sera. Additional studies examined mixing studies of RF+ and RF- sera, as well as the effect of monoclonal IgA or IgM RF. Finally, the effect of RF on RTX mediated trogocytosis of normal B cells was evaluated.

Results

Using human sera, addition of RTX resulted in rapid and profound (> 50%) Daudi cell death that was complement dependent. Surprisingly, RF+ patient sera exhibited reduced RTX-CDC relative to RF- sera, with an inverse relationship of RTX-CDC and RF titer. Mixing studies indicated the presence of an inhibitor of RTX-CDC in RF+ sera. The addition of monoclonal IgM or IgA RF to RF- sera markedly inhibited RTX-CDC. This effect was specific for RF binding to the Fc portion of RTX as it was not apparent with the F(ab)' domains of RTX engineered onto IgG3 heavy chain. RF also modestly inhibited RTX mediated trogocytosis.

Conclusions

Contrary to expectations, RF+ sera exhibits reduced RTX-CDC due to the presence of RF. The enhanced efficacy of RTX in seropositive RA patients cannot be attributed to improved B cell depletion through CDC. This result indicates that high RF levels may potentially modulate the efficacy of any therapeutic monoclonal antibody dependent on Fc effector function.

Rheumatoid factor as predictor of response to abatacept, rituximab and tocilizumab in rheumatoid arthritis: Systematic review and meta-analysis

OBJECTIVE

To identify if rheumatoid factor (RF) is predictor of response to rituximab (RTX), abatacept (ABT), and tocilizumab (TCZ) in rheumatoid arthritis (RA).

METHODS

Systematic review and meta-analysis of clinical trials and observational studies based on a sensitive search. Meta-regression was used to explore causes of heterogeneity. Unpublished data of clinical trials provided by the authors were also included.

RESULTS

The electronic search captured 3221 references and 422 meeting abstracts. By hand search, four additional articles were also identified. A total of 23 studies meet the purpose of the study and were included in the review. RF positivity at starting predicts better ACR20 [OR, 1.95 (1.24, 3.08)], ACR50 [OR, 5.38 (2.50, 11.60)] and EULAR response [OR, 3.52 (1.66, 7.45)] in 14 studies with RTX, and better ACR20 [OR, 1.51 (1.21, 1.90)] in 6 studies with TCZ. In 3 studies with ABT, no association was found between response and RF [OR 1.36 (0.97, 1.90)]. No asymmetries in the funnel plots or significant variables were found in the meta-regression.

CONCLUSION

In RA, RF positivity predicts better response to RTX and TCZ but not to ABT.

Association of the FCGR3A-158F/V gene polymorphism with the response to rituximab treatment in Spanish systemic autoimmune disease patients

Rituximab is being used as treatment for systemic autoimmune diseases. The objective of this study was to determine whether the genetic variant in the Fc gamma-receptor III a (FCGR3A) gene, 158F/V, contributes to the observed variation in response to rituximab in patients with systemic autoimmune diseases. DNA samples from 132 Spanish patients with different systemic autoimmune diseases receiving rituximab were genotyped for FCGR3A-158F/V (rs396991) gene polymorphism using the TaqMan(®) allelic discrimination technology. Six months after infusion with rituximab we evaluated the response to the drug: 61% of the patients showed a complete response, partial 27% and 12% did not respond to the treatment. A statistically significant difference was observed in V allele frequency between responder (38%) and nonresponder (16%) patients (p=0.01; odds ratio [OR]=3.24, 95% confidence interval [CI] 1.17-11.1). Rituximab was also more effective in V allele carriers (94%) than in homozygous FF patients (81%): p=0.02; OR=3.96, 95% CI 1.10-17.68. These results suggest that FCGR3A-158F/V (rs396991) gene polymorphism play a role in the response to rituximab in autoimmune diseases. Validation of these findings in independent cohorts is warranted.

Biomarkers of good EULAR response to the B cell depletion therapy in all seropositive rheumatoid arthritis patients: clues for the pathogenesis

Objective

To find out whether a high number of auto-antibodies can increase the probability of a “good-EULAR response” and to identify the possible biomarkers of response in seropositive rheumatoid arthritis (RA) patients undergoing the B cell depletion therapy (BCDT).

Patients and Methods

One hundred and thirty-eight patients with long standing RA (LSRA), 75% non or poorly responsive to one or more TNFα blockers, all seropositive for at least one autoantibody (AAB) (RF-IgM, RF-IgA, RF-IgG, anti-MCV, ACPA-IgG, ACPA-IgA, ACPA-IgM) received one full course of BCDT. The major outcomes (moderate or good-EULAR response) were assessed after 6 months of therapy. The IL6 and BAFF levels were also determined.

Results

At a 6-month follow-up, 33 (23.9%) of the RA patients achieved a good EULAR response. Having up to 5-AABs positivity increased the chances for treatment response. After a logistic regression analysis, however, only 4 baseline factors arose as associated with a good-EULAR response: no steroid therapy (OR = 6.25), a lymphocyte count <1875/uL (OR = 10.74), a RF-IgG level >52.1 IU/ml (OR = 8.37) and BAFF levels <1011 pg/ml (OR = 7.38). When all the AABs, except for RF-IgM and ACPA-IgG, were left in the analysis, the two final predictors were no-steroid therapy and low lymphocyte count.

Discussion

The number of AABs increased the chances of being a “good-EULAR” responder. The only predictors, however, at the baseline of a good response in this seropositive cohort of RA patients were 2 simple variables – no steroids and lymphocyte count – and two laboratory assays – IgG-RF and BAFF.