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

Early predictive factors in routine clinical practice for rituximab therapy response in patients with rheumatoid arthritis

Introduction

Identifying early predictive factors of how rheumatoid arthritis (RA) patients respond to rituximab (RTX) treatment is crucial for both individual treatment outcome and the improvement of clinical practice overall. This study aimed to identify early predictive factors available in standard clinical practice for predicting RTX treatment outcomes in RA patients.

Material and methods

Data on seventy patients diagnosed with RA treated with RTX (two 1,000 mg doses 2 weeks apart or two 500 mg doses 2 weeks apart) were retrospectively collected. Baseline information collected at the initiation of RTX treatment included patient characteristics such as age, sex, disease duration, disease activity, Health Assessment Questionnaire score, erythrocyte sedimentation rate, C-reactive protein, and serological status regarding rheumatoid factor (RF) and anti-cyclic citrullinated protein antibodies (ACPA). Clinical responses were analyzed 6 months after RTX initiation using the European Alliance of Associations for Rheumatology criteria. Potential predictors associated with positive RTX response at 6 months were identified using a multivariate ordinal logistic regression model.

Results

The analysis showed that persistently active RA disease, Disease Activity Score with 28-joint count (DAS28) values at the treatment onset and after 3 months, along with erythrocyte sedimentation rate at treatment initiation, were negatively correlated with the response to RTX therapy (p < 0.05). All these correlations were statistically significant at the 99% confidence interval. The correlation and logistic regression analyses indicate that there are no significant association between RF and ACPA concerning therapy response, despite a higher number of RTX responders in the seropositive groups. Additionally, the study emphasizes the prognostic significance of the DAS28 value at treatment initiation in predicting therapy response at 6 months.

Conclusions

The optimal model for predicting RTX response at 6 months involves the interaction of all clinical factors examined in this study, as revealed by the analysis of multiple variables.

Anti-citrullinated protein antibody profiles predict changes in disease activity in patients with rheumatoid arthritis initiating biologics

OBJECTIVES

To determine whether an expanded antigen-specific ACPA profile predicts changes in disease activity in patients with RA initiating biologics.

METHODS

The study included participants from a prospective, non-randomized, observational RA cohort. For this sub-study, treatment groups of interest included biologic-naïve initiating anti-TNF, biologic-exposed initiating non-TNF, and biologic-naïve initiating abatacept. ACPAs to 25 citrullinated peptides were measured using banked enrolment serum. Principal component analysis (PCA) was performed and associations of resulting principal component (PC) scores (in quartiles) and anti-CCP3 antibody (≤15, 16-250 or >250 U/ml) with EULAR (good/moderate/none) treatment response at 6 months were examined using adjusted ordinal regression models.

RESULTS

Participants (n = 1092) had a mean age of 57 (13) years and 79% were women. At 6 months, 68.5% achieved a moderate/good EULAR response. There were three PCs that cumulatively explained 70% of variation in ACPA values. In models including the three components and anti-CCP3 antibody category, only PC1 and PC2 were associated with treatment response. The highest quartile for PC1 (odds ratio [OR] 1.76; 95% CI: 1.22, 2.53) and for PC2 (OR 1.74; 95% CI: 1.23, 2.46) were associated with treatment response after multivariable adjustment. There was no evidence of interaction between PCs and treatment group in EULAR responses (P-value for interaction >0.1).

CONCLUSION

An expanded ACPA profile appears to be more strongly associated with biologic treatment response in RA than commercially available anti-CCP3 antibody levels. However, further enhancements to PCA will be needed to effectively prioritize between different biologics available for the treatment of RA.

Real-World Sarilumab Use and Rule Testing to Predict Treatment Response in Patients with Rheumatoid Arthritis: Findings from the RISE Registry

INTRODUCTION

Clinical trial findings may not be generalizable to routine practice. This study evaluated sarilumab effectiveness in patients with rheumatoid arthritis (RA) and tested the real-world applicability of a response prediction rule, derived from trial data using machine learning (based on C-reactive protein [CRP] > 12.3 mg/l and seropositivity [anticyclic citrullinated peptide antibodies, ACPA +]).

METHODS

Sarilumab initiators from the ACR-RISE Registry, with ≥ 1 prescription on/after its FDA approval (2017-2020), were divided into three cohorts based on progressively restrictive criteria: Cohort A (had active disease), Cohort B (met eligibility criteria of a phase 3 trial in RA patients with inadequate response/intolerance to tumor necrosis factor inhibitors [TNFi]), and Cohort C (characteristics matched to the phase 3 trial baseline). Mean changes in Clinical Disease Activity Index (CDAI) and Routine Assessment of Patient Index Data 3 (RAPID3) were evaluated at 6 and 12 months. In a separate cohort, predictive rule was tested based on CRP levels and seropositive status (ACPA and/or rheumatoid factor); patients were categorized into rule-positive (seropositive with CRP > 12.3 mg/l) and rule-negative groups to compare the odds of achieving CDAI low disease activity (LDA)/remission and minimal clinically important difference (MCID) over 24 weeks.

RESULTS

Among sarilumab initiators (N = 2949), treatment effectiveness was noted across cohorts, with greater improvement noted for Cohort C at 6 and 12 months. Among the predictive rule cohort (N = 205), rule-positive (vs. rule-negative) patients were more likely to reach LDA (odds ratio: 1.5 [0.7, 3.2]) and MCID (1.1 [0.5, 2.4]). Sensitivity analyses (CRP > 5 mg/l) showed better response to sarilumab in rule-positive patients.

CONCLUSIONS

In real-world setting, sarilumab demonstrated treatment effectiveness, with greater improvements in the most selective population, mirroring phase 3 TNFi-refractory and rule-positive RA patients. Seropositivity appeared a stronger driver for treatment response than CRP, although optimization of the rule in routine practice requires further data.

B cell depletion therapies in autoimmune diseases: Monoclonal antibodies or chimeric antigen receptor-based therapy?

Immune system detects foreign pathogens, distinguishes them from self-antigens and responds to defend human body. When this self-tolerance is disrupted, the overactive immune system attacks healthy tissues or organs and the autoimmune diseases develop. B cells and plasma cells contribute a lot to pathogenesis and persistence of autoimmune diseases in both autoantibody-dependent and autoantibody-independent ways. Accumulating data indicates that treatments aiming to eliminate antibody-secreting cells (B cells or plasma cells) are effective in a wide spectrum of autoimmune diseases. Monoclonal antibodies (mAbs) deplete B cell lineage or plasma cells by signaling disruption, complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). Engineered-T cells armed with chimeric antigen receptors (CARs) have been adopted from field of hematological malignancies as a method to eliminate B cells or plasma cells. In this review, we update our understanding of B cell depletion therapies in autoimmune diseases, review the mechanism, efficacy, safety and application of monoclonal antibodies and CAR-based immunotherapies, and discuss the strengths and weaknesses of these treatment options for patients.

Rheumatoid arthritis patients initiating rituximab with low number of previous bDMARDs failures may effectively reduce rituximab dose and experience fewer serious adverse events than patients on full dose: a 5-year cohort study

Background

Rituximab is used for the treatment of active rheumatoid arthritis. In the present study, we examined the long-term flare risk and safety of reduced doses of rituximab.

Patients-methods

This was a prospective, observational, single-center study of patients starting rituximab on standard dose (SD). Patients were switched to low dose (LD) (1 g every 6 months), based on the treating rheumatologist’s decision after having achieved sustained clinical responses, while the rest of the patients continued on standard dose (SD). During a 60-month period, we assessed (Kaplan–Meier survival analysis) the relapse rate (increase ≥ 1.2 in DAS28-ESR for ≥ 6 months) and discontinuations due to treatment failure in the low dose group, and we compared the incidence of serious adverse events (SAEs) between LD and SD groups.

Results

Out of 361 patients [females 83.4%, mean age 61.9 (10.6) years, seropositive 50.3%, median total comorbidities count 4], 81 patients (22.4%) entered LD in a median time of 24 months (95% CI 18–30 months). Seropositivity (OR 1.823), more than 2 previous bDMARDs failures (OR 0.428), and DAS28 < 4.88 at 6 months (OR 2.329) predicted the odds of entering LD (p < 0.05 for all). During 60 months of follow-up, only 7.5% of patients on LD relapsed. Patients on LD had significantly less SAEs and all-cause hospitalizations as compared to the SD group (p < 0.05 for all). Linear regression analysis showed that previous hospitalization while on bDMARDs (p < 0.0001), use of prednisolone > 5 mg/day while on rituximab (p < 0.0001), and a history of ≥ 2 previous csDMARDs (p = 0.041) predicted the risk of SAEs.

Conclusion

In a cohort of patients with established RA and significant comorbidities who taper rituximab after substantial initial disease activity improvement, a low rate of relapses and lower risk of SAEs compared to SD were recorded. Seropositivity, a lower number of previous bDMARDs use, and lower DAS28 at 6 months predicted the probability of entering the LD regimen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02826-6.

Long-term drug effectiveness and survival for reference rituximab in rheumatoid arthritis patients in an ordinary outpatient clinic

To explore the long-term drug effectiveness and survival of reference rituximab (ref-RTX)-treated rheumatoid arthritis (RA) patients in an ordinary outpatient clinic. Second, we explored baseline predictors of drug effectiveness and survival, and third, we clarified reasons for stopping treatment. RA patients treated with ref-RTX between 2006 and 2020 in Norway were examined and monitored using recommended measures for disease activity and patient-reported outcomes (PROs). Drug effectiveness was assessed with random intercept linear mixed models; drug survival was assessed with Kaplan-Meier survival analysis. Reasons for discontinuation were ascertained. Baseline predictors of drug effectiveness and survival were estimated. Among 246 RA patients, at baseline, 17.1% were biologic disease-modifying anti-rheumatic drugs (bDMARDs) naïve, and 51.6% were currently using conventional synthetic DMARDs (csDMARDs). During the five-year follow-up, all disease activity and PRO measures improved significantly (p < 0.01), with more substantial changes noted in the second year. Drug survival was 83% after one year and declined to 34% after five years. The two most frequently reported reasons for discontinuation were the doctor's decision (36.2%) and lack or loss of effectiveness (19.2%). No significant difference was found between naïve and previous users of bDMARDs or between concomitant and nonconcomitant users of csDMARDs when analysing drug effectiveness and survival. Our real-life data show that ref-RTX-treated RA patients had satisfactory treatment responses; drug survival declined linearly over time. There was no significant difference between naïve and previous users of bDMARDs or between concomitant and nonconcomitant users of csDMARDs, both for drug effectiveness and survival.

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.

Tailoring biologic therapy for real-world rheumatoid arthritis patients

Introduction: The cornerstone of rheumatoid arthritis (RA) therapy relies on the treat-to-target strategy, which aims at dampening inflammation as soon as possible in order to achieve persistent low disease activity or, ideally, remission, according to validated disease activity measures. Traditional disease-modifying antirheumatic drugs (DMARDs) may be chosen in monotherapy or in combination as first-line therapy; in case of an unsatisfactory response after a 3-6-month trial, biologic therapy may be commenced.Areas covered: Real-life RA patients may present with concomitant comorbidities/complications or be in peculiar physiological states which raise more than one question as to which biotherapy may be more well suited considering the whole clinical picture. Therefore, a thorough literature search was performed to identify the most appropriate biologic therapy in each setting considered in this review.Expert opinion: Here we provide suggestions for the use of biologic drugs having a predictable better outcome in specific real-world conditions, so as to ideally profile the patient to the best of the current knowledge.

Peripheral B Cell Subsets in Autoimmune Diseases: Clinical Implications and Effects of B Cell-Targeted Therapies

Antibody-secreting cells (ASCs) play a fundamental role in humoral immunity. The aberrant function of ASCs is related to a number of disease states, including autoimmune diseases and cancer. Recent insights into activated B cell subsets, including naïve B cell to ASC stages and their resultant cellular disturbances, suggest that aberrant ASC differentiation occurs during autoimmune diseases and is closely related to disease severity. However, the mechanisms underlying highly active ASC differentiation and the B cell subsets in autoimmune patients remain undefined. Here, we first review the processes of ASC generation. From the perspective of novel therapeutic target discovery, prediction of disease progression, and current clinical challenges, we further summarize the aberrant activity of B cell subsets including specialized memory CD11c^hiT-bet⁺ B cells that participate in the maintenance of autoreactive ASC populations. An improved understanding of subgroups may also enhance the knowledge of antigen-specific B cell differentiation. We further discuss the influence of current B cell therapies on B cell subsets, specifically focusing on systemic lupus erythematosus, rheumatoid arthritis, and myasthenia gravis.

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.

Targeting B Cells and Plasma Cells in Autoimmune Diseases

Success with B cell depletion using rituximab has proven the concept that B lineage cells represent a valid target for the treatment of autoimmune diseases, and has promoted the development of other B cell targeting agents. Present data confirm that B cell depletion is beneficial in various autoimmune disorders and also show that it can worsen the disease course in some patients. These findings suggest that B lineage cells not only produce pathogenic autoantibodies, but also significantly contribute to the regulation of inflammation. In this review, we will discuss the multiple pro- and anti-inflammatory roles of B lineage cells play in autoimmune diseases, in the context of recent findings using B lineage targeting therapies.

Antigenic burden and serum IgG concentrations influence rituximab pharmacokinetics in rheumatoid arthritis patients

AIMS

Rituximab is a monoclonal antibody directed against CD20, which is approved in rheumatoid arthritis (RA). This study aimed at assessing the influence of CD19+ cell counts as target-antigen amount, and of immunoglobulin G (IgG) serum concentrations on rituximab pharmacokinetics in RA patients.

METHODS

In a cohort of 64 RA patients who had received repetitive courses of rituximab, the influence of CD19+ cell count, IgG serum concentration, body surface area, sex and disease activity score in 28 joints on rituximab pharmacokinetic parameters was assessed using a population pharmacokinetic analysis.

RESULTS

A two-compartment model, with first-order distribution and elimination best described the data. The volume of distribution of central compartment and clearance of rituximab were estimated at 4.7 l and 0.56 l day^-1 , respectively. Distribution and elimination half-lives were 0.9 days and 17.3 days, respectively. As expected, the central volume of distribution increased with body surface area (P = 0.012) and was higher in male than in female (P = 0.004). We found that the elimination rate constant (k₁₀ ) increased with CD19+ count (P = 0.00022) and IgG concentration (P = 7.4 × 10^-8 ), and that k₁₀ decreased with time (P = 0.00015), partly explained by a change in target-antigen amount.

CONCLUSIONS

The association between CD19+ count and k₁₀ may be explained by target-mediated drug disposition, while the association between IgG serum concentration and k₁₀ may be explained by a saturation of the neonatal Fc receptor at high IgG concentrations, resulting in decreased recycling of rituximab.

Serum IL-33, a new marker predicting response to rituximab in rheumatoid arthritis

BACKGROUND

Recent works have suggested a possible link between interleukin (IL)-33 and B-cell biology. We aimed to study the possible association between serum IL-33 detection and response to rituximab (RTX) in rheumatoid arthritis (RA) patients in different cohorts with an accurate enzyme-linked immunosorbent assay (ELISA).

METHODS

Serum IL-33, rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), and high serum immunoglobulin (Ig)G levels were assessed in 111 RA patients receiving a first course of 2 g RTX (cohort 1) in an observational study and in 74 RA patients treated with the same schedule in routine care (cohort 2). Univariate and multivariate analyses identified factors associated with a European League Against Rheumatism (EULAR) response at 24 weeks.

RESULTS

At week 24, 84/111 (76%) and 54/74 (73%) patients reached EULAR response in cohorts 1 and 2, respectively. Serum IL-33 was detectable in only 33.5% of the patients. In the combined cohorts, the presence of RF or anti-CCP (odds ratio (OR) 3.27, 95% confidence interval (CI) 1.13-9.46; p = 0.03), high serum IgG (OR 2.32, 95% CI 1.01-5.33; p = 0.048), and detectable serum IL-33 (OR 2.40, 95% CI 1.01-5.72; p = 0.047) were all associated with RTX response in multivariate analysis. The combination of these three factors increased the likelihood of response to RTX. When serum IL-33 detection was added to seropositivity and serum IgG level, 100% of the patients with the three risk factors (corresponding to 9% of the population) responded to RTX (OR versus patients with none of the three risk factors 29.61, 95% CI 1.30-674.79; p = 0.034).

CONCLUSION

Detectable serum IL-33 may predict clinical response to RTX independently of, and synergistically with, auto-antibodies and serum IgG level.

TRIAL REGISTRATION

NCT01126541 ; 18 May 2010.

STAT6 and STAT1 Pathway Activation in Circulating Lymphocytes and Monocytes as Predictor of Treatment Response in Rheumatoid Arthritis

Objective

To find novel predictors of treatment response to disease-modifying antirheumatic drugs (DMARDs), we studied activation of STAT (signal transducers and activators of transcription) 6 and 1 in circulating leukocytes of patients with rheumatoid arthritis (RA).

Methods

19 patients with untreated recent-onset RA, 16 patients with chronic RA irresponsive to synthetic DMARDs and 37 healthy volunteers provided blood samples for whole blood flow cytometric determination of intracellular STAT6 and STAT1 phosphorylation, expressed as relative fluorescence units, in response to IL-4 and IFN-γ, respectively. Phosphorylation was restudied and treatment response (according to European League Against Rheumatism) determined after 1-year treatment with synthetic DMARDs in recent-onset RA and with biological DMARD in synthetic DMARD-irresponsive RA. Estimation-based exact logistic regression was used to investigate relation of baseline variables to treatment response. 95% confidence intervals of means were estimated by bias-corrected bootstrapping and the significance between baseline and follow-up values was calculated by permutation test.

Results

At baseline, levels of phosphorylated STAT6 (pSTAT6) induced by IL-4 in monocytes were higher in those who achieved good treatment response to synthetic DMARDs than in those who did not among patients with untreated RA (OR 2.74, 95% CI 1.05 to 9.47), and IFN-γ -stimulated lymphocyte pSTAT1 levels were higher in those who achieved good treatment response to a biological drug than in those who did not among patients with chronic RA (OR 3.91, 95% CI 1.12 to 20.68). During follow-up, in recent-onset RA patients with good treatment response to synthetic DMARDS, the lymphocyte pSTAT6 levels decreased (p = 0.011), and, consequently, the ratio of pSTAT1/pSTAT6 in lymphocytes increased (p = 0.042).

Conclusion

Cytokine-stimulated STAT6 and STAT1 phosphorylation in circulating leukocytes was associated with treatment response to DMARDs in this pilot study. The result, if confirmed in larger studies, may aid in developing personalized medicine in RA.

Differences in Predictive Factors for Sustained Clinical Remission with Abatacept Between Younger and Elderly Patients with Biologic-naive Rheumatoid Arthritis: Results from the ABROAD Study

OBJECTIVE

To differentiate predictive factors for sustained clinical remission between elderly and younger patients with rheumatoid arthritis (RA) receiving abatacept (ABA) as an initial biological disease-modifying antirheumatic drug.

METHODS

The study involved 277 biologic-naive patients with RA with high or moderate disease activity, who were treated with intravenous ABA and evaluated for 48 weeks in 43 Japanese hospitals and rheumatology clinics (the ABatacept Research Outcomes as a First-line Biological Agent in the Real WorlD study: UMIN000004651). Predictive factors associated with sustained clinical remission defined by the 28-joint Disease Activity Score with C-reactive protein (DAS28-CRP) during the 24-48-week or 36-48-week periods were determined in elderly (≥ 65 yrs, n = 148) and younger patient groups (< 65 yrs, n = 129) using logistic regression analysis.

RESULTS

Clinical remission was achieved at 24 and 48 weeks in 35.1% and 36.5% of patients in the elderly group and 34.9% and 43.4% in the younger group, respectively. In elderly patients, anticitrullinated protein antibody (ACPA) positivity and a lower DAS28-CRP score were significantly associated with sustained clinical remission; however, a lower Health Assessment Questionnaire-Disability Index (HAQ-DI) score was not related to sustained clinical remission. In younger patients, lower DAS28-CRP and HAQ-DI scores were predictive factors for sustained clinical remission, whereas ACPA positivity was not a useful predictive factor for sustained clinical remission.

CONCLUSION

Although the effectiveness of ABA in biologic-naive patients with RA was equally recognized in elderly and younger patients, the baseline clinical characteristics associated with sustained clinical remission were substantially different.

Serum BAFF and APRIL Levels, T-Lymphocyte Subsets, and Immunoglobulins after B-Cell Depletion Using the Monoclonal Anti-CD20 Antibody Rituximab in Myalgic Encephalopathy/Chronic Fatigue Syndrome

Myalgic Encephalopathy/Chronic Fatigue Syndrome (ME/CFS) is a disease of unknown etiology. We have previously suggested clinical benefit from B-cell depletion using the monoclonal anti-CD20 antibody rituximab in a randomized and placebo-controlled study. Prolonged responses were then demonstrated in an open-label phase-II study with maintenance rituximab treatment. Using blood samples from patients in the previous two clinical trials, we investigated quantitative changes in T-lymphocyte subsets, in immunoglobulins, and in serum levels of two B-cell regulating cytokines during follow-up. B-lymphocyte activating factor of the tumor necrosis family (BAFF) in baseline serum samples was elevated in 70 ME/CFS patients as compared to 56 healthy controls (p = 0.011). There were no significant differences in baseline serum BAFF levels between patients with mild, moderate, or severe ME/CFS, or between responders and non-responders to rituximab. A proliferation-inducing ligand (APRIL) serum levels were not significantly different in ME/CFS patients compared to healthy controls at baseline, and no changes in serum levels were seen during follow-up. Immunophenotyping of peripheral blood T-lymphocyte subsets and T-cell activation markers at multiple time points during follow-up showed no significant differences over time, between rituximab and placebo groups, or between responders and non-responders to rituximab. Baseline serum IgG levels were significantly lower in patients with subsequent response after rituximab therapy compared to non-responders (p = 0.03). In the maintenance study, slight but significant reductions in mean serum immunoglobulin levels were observed at 24 months compared to baseline; IgG 10.6–9.5 g/L, IgA 1.8–1.5 g/L, and IgM 0.97–0.70 g/L. Although no functional assays were performed, the lack of significant associations of T- and NK-cell subset numbers with B-cell depletion, as well as the lack of associations to clinical responses, suggest that B-cell regulatory effects on T-cell or NK-cell subsets are not the main mechanisms for the observed improvements in ME/CFS symptoms observed in the two previous trials. The modest increase in serum BAFF levels at baseline may indicate an activated B-lymphocyte system in a subgroup of ME/CFS patients.

Anti-citrullinated peptide antibodies and their value for predicting responses to biologic agents: a review

Anti-citrullinated peptide antibodies (ACPAs) play an important pathogenic role both at the onset and during the disease course. These antibodies precede the clinical appearance of rheumatoid arthritis (RA) and are associated with a less favorable prognosis, both clinically and radiologically. The objective of this work was to conduct a comprehensive review of studies published through September 2015 of ACPAs' role as a predictor of the therapeutic response to the biological agents in RA patients. The review also includes summary of the biology and detection of ACPAs as well as ACPAs in relation to joint disease and CV disease and the possible role of seroconversion. The reviews of studies examining TNF inhibitors and tocilizumab yielded negative results. In the case of rituximab, the data indicated a greater probability of clinical benefit in ACPA(+) patients versus ACPA(-) patients, as has been previously described for rheumatoid factor. Nonetheless, the effect is discreet and heterogeneous. Another drug that may have greater effectiveness in ACPA(+) patients is abatacept. Some studies have suggested that the drug is more efficient in ACPA(+) patients and that those patients show greater drug retention. In a subanalysis of the AMPLE trial, patients with very high ACPA titers who were treated with abatacept had a statistically significant response compared to patients with lower titers. In summary, the available studies suggest that the presence of or high titers of ACPA may predict a better response to rituximab and/or abatacept. Evidence regarding TNFi and tocilizumab is lacking. However, there is a lack of studies with appropriate designs to demonstrate that some drugs are superior to others for ACPA(+) patients.

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.

Assessment of free light chains in HCV-positive patients with mixed cryoglobulinaemia vasculitis undergoing rituximab treatment

BACKGROUND & AIMS

Mixed cryoglobulinaemia (MC) is an HCV-related lymphoproliferative disorder characterized by the presence of circulating immune complexes called cryoglobulins. Treatment with anti-CD20 monoclonal antibody rituximab is proved to be very useful, especially in patients ineligible to interferon-based antiviral therapy. Recently, free light chain (FLC) κ/λ ratio and FLC patterns were associated with MC. The aim of this study was to evaluate changes in FLC-κ, FCL-λ, FLC ratio following rituximab treatment in patients with HCV-related MC and to correlate FLC-κ, FCL-λ and FLC ratio values with therapy response.

PATIENTS AND METHODS

We retrospectively enrolled 46 patients with HCV infection (26 females, 20 males), including 10 patients without signs/symptoms of MC-related vasculitis, 36 with MC vasculitis. Clinical and biological data were recorded at baseline and 6 months after RTX treatment. Nephelometric measurement of serum FLCs was taken.

RESULTS

The mean serum FLC-κ level and FLC ratio were significantly higher in patients with MC, compared to HCV patients without MC and to blood donors. An abnormal FLC ratio at baseline correlated with the presence of cryoglobulins, C4 consumption, higher RF level and higher vasculitis rate. To evaluate the predictive value of FLCs, patients with MC were divided into two groups according to RTX therapy outcome (responders and no/partial responders). Abnormal baseline FLC ratio was significantly associated with no/partial response.

CONCLUSIONS

RTX treatment in HCV-related MC induces a reduction in FLC-κ and RF levels. Moreover, pretreatment FLC ratio, which can be easily assessed by a routine test, may be useful to predict response to this expensive treatment for patients with HCV-related MC ineligible to IFN-based therapy.

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.

Anti-citrullinated peptides as autoantigens in rheumatoid arthritis-relevance to treatment

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the presence of rheumatoid factor (RF) and anti-citrullinated protein/peptide autoantibodies (ACPAs). Citrulline derives from arginine by peptidyl arginine deiminases, and ACPAs are directed against different citrullinated antigens, including fibrinogen, fibronectin, α-enolase, collagen type II, histones. ACPAs are present in two thirds of RA patients have higher specificity than RF for RA, and are associated with joint radiographic damage and extra-articular manifestations and they are detected years before the onset clinical arthritis. Recent studies suggest that citrullinated antigens are most likely arthritogenic autoantigens in RA. ACPA production is associated with the HLA-DRB1 shared epitope (HLA-DRB1 SE) and accounts for the well-known RA-HLA-DRB1 SE association, as T cells recognize citrullinated peptides. Smoking and periodontitis, known environmental risk factors for RA promote protein citrullination and ACPA production. Cirullinated proteins are capable of inducing arthritis in transgenic mice carrying HLA-DRB1 SE genes, and ACPAs induce macrophage TNF-α production, osteoclastogenesis and complement activation. They also induce the formation of neutrophil extracellular traps (NETs). NETs, increased in RA, are a source of citrullinated autoantigens in RA and induce fibroblast interleukin-8 production. This knowledge is likely to have therapeutic implications, as there is a need of matching therapy with patient profile. Abatacept, a T cell activation modulator, is the best therapy for ACPA(+) RA patients, although clinical data are sparse at present. Rituximab, a monoclonal antibody that depletes B cells, is also the best therapy for ACPA(+) RA patients, and clinical data support this view.

Rituximab-induced T cell depletion in patients with rheumatoid arthritis: association with clinical response

OBJECTIVE

Rituximab, a monoclonal antibody specifically targeting CD20, induces B cell depletion and is effective in the treatment of rheumatoid arthritis (RA). This study was undertaken to evaluate whether routine monitoring of lymphocyte subpopulations, especially T cells, may be useful in patients receiving rituximab for RA.

METHODS

We examined data on all RA patients receiving rituximab between July 2007 and November 2012 in our center. Peripheral blood CD3+, CD4+, CD8+, CD3-CD56+, and CD19+ lymphocyte counts before and during the first course of rituximab were measured by flow cytometry. The Mann-Whitney nonparametric test was used to compare lymphocyte subpopulation counts before and during treatment.

RESULTS

Data on 52 patients were examined. Rituximab induced unexpected and substantial depletion of T cells, mainly CD4+ cells, in most patients. The CD4+ cell count decreased by a mean ± SD of 37 ± 33% as compared to baseline at week 12, reaching <200 cells/μl in 3 patients. Importantly, lack of CD4+ cell depletion was associated with no clinical response. Therefore, the mechanism of action of rituximab may depend at least in part on T cells.

CONCLUSION

Rituximab induces substantial T cell depletion, mainly of CD4+ cells, which is associated with the clinical response in RA. Routine monitoring of T cells may be useful in the clinical setting of RA.

Rituximab for the treatment of rheumatoid arthritis: an update

Rituximab is a chimeric monoclonal antibody that targets the CD20 molecule expressed on the surface of B cells. It was first used in the treatment of non-Hodgkin's lymphoma and later approved for the treatment of rheumatoid arthritis (RA) that does not respond adequately to disease-modifying antirheumatic drugs, including the anti-tumor-necrosis-factor (TNF) biologics. Sustained efficacy in RA can be achieved by repeated courses of rituximab. However, the optimal dose and retreatment schedule of rituximab in RA remains to be established. Seropositivity, complete B cell depletion shortly after treatment, and previous failure to no more than one anti-TNF agent are three factors associated with greater clinical benefits to rituximab. Infusion reaction to the first dose of rituximab occurs in approximately 25% of RA patients, and the incidence reduces with subsequent exposure. Immunogenicity to the chimeric compound occurs in 11% of RA patients, but this does not correlate with its efficacy in B cell depletion. Extended observation of randomized controlled trials in RA does not reveal a significant increase in the incidence of serious infections related to rituximab compared to placebo groups, and the infection rate remains static over time. Repeated treatment with rituximab is associated with hypogammaglobulinemia, which may increase the risk of serious, but rarely opportunistic, infections. Reactivation of occult hepatitis B infection has been reported in RA patients receiving rituximab, but no increase in the incidence of tuberculosis was observed. Screening for baseline serum immunoglobulin G level and hepatitis B status (including occult infection) is important, especially in Asian countries where hepatitis B infection is prevalent. The rare but fatal progressive multifocal leukoencephalopathy linked to the use of rituximab has to be noted. Postmarketing surveillance and registry data, particularly in Asia, are necessary to establish the long-term efficacy and safety of rituximab in the treatment of RA.

Plasma level of neopterin as a marker of disease activity in treated rheumatoid arthritis patients: association with gender, disease activity and anti-CCP antibody

Immune system activation is known to be involved in the progression of rheumatoid arthritis (RA). The pro-inflammatory cytokine interferon-γ in various cells, including monocytes, induces neopterin production. Plasma level of neopterin has been measured in many autoimmune diseases and can be used as a marker of cellular immunity activation. In this study we measured the plasma level of neopterin in 418 treated RA patients and 398 age and sex matched healthy people by high pressure liquid chromatography (HPLC) method. Disease activity score was calculated in all patients by DAS-CRP method. Plasma level of neopterin was compared between RA and control groups. We also determined the association between neopterin level with gender and disease activity score in RA patients. Significantly higher level of neopterin was observed in RA patients compared to healthy controls. Moreover, there was higher neopterin level in male RA patients versus female patients. Plasma neopterin level was increased in patients with active disease and also was correlated with disease activity parameters. There was a significant correlation of plasma level of neopterin with age in both RA and control group and also age of onset and disease duration in RA patients. Anti-CCP positive patients had higher level of neopterin in comparison to anti-CCP negative patients and there was a significant correlation between neopterin level and anti-CCP titer. Our results indicated that neopterin is a sensitive marker for assaying background inflammation and disease activity score in RA patients and may be used as a marker for evaluation of therapy efficacy.