Rituximab fixed retreatment versus on-demand retreatment in refractory rheumatoid arthritis: comparison of two B cell depleting treatment strategies

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.

Summarizing current refractory disease definitions in rheumatoid arthritis and polyarticular juvenile idiopathic arthritis: systematic review

OBJECTIVES

To identify how refractory disease (or relevant terminology variations) in RA and polyarticular JIA (polyJIA) is defined and establish the key components of such definitions.

METHODS

Searches were undertaken of English-language articles within six medical databases, including manual searching, from January 1998 to March 2020 (PROSPERO: CRD42019127142). Articles were included if they incorporated a definition of refractory disease, or non-response, in RA/polyJIA, with clear components to the description. Qualitative content analysis was undertaken to describe refractory disease in RA/polyJIA and classify each component within each definition.

RESULTS

Of 6251 studies screened, 646 met the inclusion criteria; 581 of these applied non-response criteria while 65 provided refractory disease definitions/descriptions. From the non-response studies, 39 different components included various disease activity measures, emphasizing persistent disease activity and symptoms, despite treatment with one or more biologic DMARD (bDMARD). From papers with clear definitions for refractory disease, 41 components were identified and categorized into three key themes: resistance to multiple drugs with different mechanisms of action, typically two or more bDMARDs; persistence of symptoms and disease activity; and other contributing factors. The most common term used was 'refractory' (80%), while only 16.9% reported explicitly how their definition was generated (e.g. clinical experience or statistical methods).

CONCLUSION

Refractory disease is defined as resistance to multiple drugs with different mechanisms of action by persistence of physical symptoms and high disease activity, including contributing factors. A clear unifying definition needs implementing, as the plethora of different definitions makes study comparisons and appropriate identification of patients difficult.

The multi-biomarker disease activity score tracks response to rituximab treatment in rheumatoid arthritis patients: a post hoc analysis of three cohort studies

BACKGROUND

A multi-biomarker disease activity (MBDA) score has been validated as an objective measure of disease activity in rheumatoid arthritis (RA) and shown to track response to treatment with several disease-modifying anti-rheumatic drugs (DMARDs). The objective of this study was to evaluate the ability of the MBDA score to track response to treatment with rituximab.

METHODS

Data were used from 57 RA patients from three cohorts treated with rituximab 1000 mg and methylprednisolone 100 mg at days 1 and 15. The MBDA score was assessed in serum samples obtained at baseline and 6 months. Spearman's rank correlation coefficients were calculated for baseline values, 6-month values, and change from baseline to 6 months (∆), between MBDA score and the following measures: disease activity score assessing 28 joints (DAS28) using erythrocyte sedimentation rate (ESR) or high-sensitivity C-reactive protein (hsCRP), ESR, (hs)CRP, swollen and tender joint counts assessing 28 joints (SJC28, TJC28), patient visual analogue scale for general health (VAS-GH), health assessment questionnaire (HAQ), and radiographic progression over 12 months using Sharp/van der Heijde score (SHS), as well as six bone turnover markers. Additionally, multivariable linear regression analyses were performed using these measures as dependent variable and the MBDA score as independent variable, with adjustment for relevant confounders. The association between ∆MBDA score and European League Against Rheumatism (EULAR) response at 6 months was assessed with adjustment for relevant confounders.

RESULTS

At baseline, the median MBDA score and DAS28-ESR were 54.0 (IQR 44.3-70.0) and 6.3 (IQR 5.4-7.1), respectively. MBDA scores correlated significantly with DAS28-ESR, DAS28-hsCRP, ESR and (hs)CRP at baseline and 6 months. ∆MBDA score correlated significantly with changes in these measures. ∆MBDA score was associated with EULAR good or moderate response (adjusted OR = 0.89, 95% CI = 0.81-0.98, p = 0.02). Neither baseline MBDA score nor ΔMBDA score correlated statistically significantly with ∆SHS (n = 11) or change in bone turnover markers (n = 23), although ∆SHS ≥ 5 was observed in 5 (56%) of nine patients with high MBDA scores.

CONCLUSIONS

We have shown, for the first time, that the MBDA score tracked disease activity in RA patients treated with rituximab and that change in MBDA score reflected the degree of treatment response.

Eficiency of different doses of rituximab in rheumatoid arthritis

OBJECTIVE

Evaluate the effectiveness, cost and safety of rituximab in patients with rheumatoid arthritis (RA) depending on the dose used.

MATERIAL AND METHODS

Retrospective observational study conducted on 52 patients with RA treated with at least one dose of rituximab for 135.3 patient-years were included. Three treatment groups were obtained: (G1) First course and following two 1g infusions separated by 15 days; (G2) First course 2 infusions of 1g followed by 2 infusions of 500mg; (G3) First course and followed by 2 infusions of 500mg separated by 15 days. Re-treatments were administered on-demand according to the clinical activity. The retention time (Log-Rank), retreats and adverse events rates (incidence rate ratio) and treatment costs per patient-month of rituximab were analysed by groups.

RESULTS

Group 2 showed a better cost-effectiveness ratio than group 1, as it was associated with a longer retention of rituximab (mean [95% CI] 65.7 [60.8 to 70.7] months vs 33.5 [22.7 to 44.3]; P<.001) and a lower rate of severe adverse events with only a slight increase in the rate of retreatment (courses/patient-year [95% CI] 1.66 [1.39 to 1.93] vs. 1.01 [0.69 to 1.34]; P=.005), and in the costs (median/patient-month, €484.89 vs. €473.45). Although group 3 was €41.20/patient-month cheaper than group 2, it was associated with a higher rate of re-treatments and shorter retention of rituximab (P<.001).

CONCLUSIONS

The use of full-dose rituximab at onset, followed by reduced doses in successive courses administered on-demand retreatment may be the most cost-effective option.

Rituximab for rheumatoid arthritis

BACKGROUND

Rituximab is a selective, B-cell depleting, biologic agent for treating refractory rheumatoid arthritis (RA). It is a chimeric monoclonal antibody targeted against CD 20 that is promoted as therapy for patients who fail to respond to other biologics. There is evidence to suggest that rituximab is effective and well tolerated when used in combination with methotrexate for RA.

OBJECTIVES

To evaluate the benefits and harms of rituximab for the treatment of RA.

SEARCH METHODS

We conducted a search (until January 2014) in electronic databases (The Cochrane Library, MEDLINE, EMBASE, CINAHL, Web of Science), clinical trials registries, and websites of regulatory agencies. Reference lists from comprehensive reviews were also screened.

SELECTION CRITERIA

All controlled trials comparing treatment with rituximab as monotherapy or in combination with any disease modifying anti-rheumatic drug (DMARD) (traditional or biologic) versus placebo or other DMARD (traditional or biologic) in adult patients with active RA.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and abstracted data from each study.

MAIN RESULTS

We included eight studies with 2720 patients. For six studies selection bias could not be evaluated and two studies were considered to have low risk of bias. The level of evidence ranged from low to high, but was rated as moderate for most outcomes. We have prioritised reporting of rituximab (two 1000 mg doses) in combination with methotrexate since this is the approved dose and most commonly used combination. We also reported data on other combinations and doses as supplementary information in the results section of the review.American College of Rheumatology (ACR) 50 response rates were statistically significantly improved with rituximab (two 1000 mg doses) in combination with methotrexate compared with methotrexate alone at 24 to 104 weeks. The RR for achieving an ACR 50 at 24 weeks was 3.3 (95% CI 2.3 to 4.6); 29% of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate achieved the ACR 50 compared to 9% of controls. The absolute treatment benefit (ATB) was 21% (95% CI 16% to 25%) with a number needed to treat (NNT) of 6 (95% CI 4 to 9).At 52 weeks, the RR for achieving clinical remission (Disease Activity Score (DAS) 28 joints < 2.6) with rituximab (two 1000 mg doses) in combination with methotrexate compared with methotrexate monotherapy was 2.4 (95% CI 1.7 to 3.5); 22% of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate achieved clinical remission compared to 11% of controls. The ATB was 11% (95% CI 2% to 20%) with a NNT of 7 (95% CI 4 to 13).At 24 weeks, the RR for achieving a clinically meaningful improvement (CMI) in the Health Assessment Questionnaire (HAQ) (> 0.22) for patients receiving rituximab combined with methotrexate compared to patients on methotrexate alone was 1.6 (95% CI 1.2 to 2.1). The ATB was 24% (95% CI 12% to 36%) with an NNT of 5 (95% CI 3 to 13). At 104 weeks, the RR for achieving a CMI in HAQ (> 0.22) was 1.4 (95% CI 1.3 to 1.6). The ATB was 24% (95% CI 16% to 31%) with a NNT of 5 (95% CI 3 to 7).At 24 weeks, the RR for preventing radiographic progression in patients receiving rituximab (two 1000 mg doses) in combination with methotrexate was 1.2 (95% CI 1.0 to 1.4) compared to methotrexate alone; 70% of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate had no radiographic progression compared to 59% of controls. The ATB was 11% (95% CI 2% to 19%) and the NNT was 10 (95% CI 5 to 57). Similar benefits were observed at 52 to 56 weeks and 104 weeks.Statistically significantly more patients achieved a CMI on the physical and mental components of the quality of life, measured by the Short Form (SF)-36, in the rituximab (two 1000 mg doses) in combination with methotrexate-treated group compared with methotrexate alone at 24 to 52 weeks (RR 2.0, 95% CI 1.1 to 3.4; NNT 4, 95% CI 3 to 8 and RR 1.4, 95% CI 1.1 to 1.9; NNT 8, 95% CI 5 to 19, respectively); 34 and 13 more patients out of 100 showed an improvement in the physical component of the quality of life measure compared to methotrexate alone (95% CI 5% to 84%; 95% CI 7% to 8%, respectively).There was no evidence of a statistically significant difference in the rates of withdrawals because of adverse events or for other reasons (that is, withdrawal of consent, violation, administrative, failure to return) in either group. However, statistically significantly more people receiving the control drug withdrew from the study compared to those receiving rituximab (two 1000 mg doses) in combination with methotrexate at all times (RR 0.40, 95% CI 0.32 to 0.50; RR 0.61, 95% CI 0.40 to 0.91; RR 0.48, 95% CI 0.28 to 0.82; RR 0.58, 95% CI 0.45 to 0.75, respectively). At 104 weeks, 37% withdrew from the control group and 20% withdrew from the rituximab (two 1000 mg doses) in combination with methotrexate group. The absolute risk difference (ARD) was -20% (95% CI -34% to -5%) with a number needed to harm (NNH) of 7 (95% CI 5 to 11).A greater proportion of patients receiving rituximab (two 1000 mg doses) in combination with methotrexate developed adverse events after their first infusion compared to those receiving methotrexate monotherapy and placebo infusions (RR 1.6, 95% CI 1.3 to 1.9); 26% of those taking rituximab plus methotrexate reported more events associated with their first infusion compared to 16% of those on the control regimen with an ARD of 9% (95% CI 5% to 13%) and a NNH of 11 (95% CI 21 to 8). However, no statistically significant differences were noted in the rates of serious adverse events.

AUTHORS' CONCLUSIONS

Evidence from eight studies suggests that rituximab (two 1000 mg doses) in combination with methotrexate is significantly more efficacious than methotrexate alone for improving the symptoms of RA and preventing disease progression.

Spanish Rheumatology Society and Hospital Pharmacy Society Consensus on recommendations for biologics optimization in patients with rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis

OBJECTIVE

The aim of this study was to establish guidelines for the optimization of biologic therapies for health professionals involved in the management of patients with RA, AS and PsA.

METHODS

Recommendations were established via consensus by a panel of experts in rheumatology and hospital pharmacy, based on analysis of available scientific evidence obtained from four systematic reviews and on the clinical experience of panellists. The Delphi method was used to evaluate these recommendations, both between panellists and among a wider group of rheumatologists.

RESULTS

Previous concepts concerning better management of RA, AS and PsA were reviewed and, more specifically, guidelines for the optimization of biologic therapies used to treat these diseases were formulated. Recommendations were made with the aim of establishing a plan for when and how to taper biologic treatment in patients with these diseases.

CONCLUSION

The recommendations established herein aim not only to provide advice on how to improve the risk:benefit ratio and efficiency of such treatments, but also to reduce variability in daily clinical practice in the use of biologic therapies for rheumatic diseases.

Rituximab-induced interleukin-15 reduction associated with clinical improvement in rheumatoid arthritis

Rituximab therapy alters all aspects of B-cell participation in the disturbed immune response of rheumatoid arthritis patients. To determine the impact of B-cell depletion on other immune compartments, we analysed levels of soluble and surface interleukin-15 (IL-15) along with the frequency of IL-15-related subsets after rituximab treatment. We then studied the correlation of observed changes with clinical activity. Heparinized blood samples from 33 rheumatoid arthritis patients were collected on days 0, 30, 90 and 180 after each of three rituximab cycles. Serum cytokine levels were determined by ELISA. Interleukin-15 trans-presentation was analysed by cytometry. Flow cytometry with monoclonal antibodies was performed to analyse circulating cell subsets. Interleukin-15 was detected in the serum of 25 patients before initiating the treatment. Rituximab then progressively reduced serum IL-15 (138 ± 21 pg/ml at baseline, 48 ± 18 pg/ml after third cycle, P = 0·03) along with IL-17 (1197 ± 203 pg/ml at baseline, 623 ± 213 pg/ml after third cycle, P = 0·03) and tended to increase the frequency of circulating regulatory T cells (3·1 ± 1 cells/μl at baseline, 7·7 ± 2 cells/μl after third cycle). Rituximab also significantly decreased IL-15 trans-presentation on surface monocytes of patients negative for IL-15 serum (mean fluorescence intensity: 4·82 ± 1·30 at baseline, 1·42 ± 0·69 after third cycle P = 0·05). Reduction of serum IL-15 was associated with decrease in CD8(+)  CD45RO(+) /RA(+) ratio (1·17 ± 0·21 at baseline, 0·36 ± 0·06 at third cycle, P = 0·02). DAS28, erythrocyte sedimentation rate and C-reactive protein correlated significantly with CD8(+)  CD45RO(+) /RA(+) ratio (R = 0·323, R = 0·357, R = 0·369 respectively, P < 0·001). Our results suggest that sustained clinical improvement after rituximab treatment is associated with IL-15/memory T-cell-related mechanisms beyond circulating B cells.

Progression of structural damage is not related to rituximab serum levels in rheumatoid arthritis patients

OBJECTIVE

The most cost-effective dosing regimen for rituximab treatment in RA is currently unknown. The objective of this study is to determine whether low rituximab serum levels are associated with progression of structural damage in RA patients.

METHODS

Sixty-two RA patients were treated with rituximab in three different centres. Structural damage was assessed on radiographs of hands and feet before and 1 year after therapy using the Sharp-van der Heijde scoring method (SHS). Patients were divided into progressors vs non-progressors based on different cut-off values. Rituximab serum levels were measured by sandwich ELISA after 4 and 12 weeks (Leiden University Medical Center and University Medical Centre, Utrecht cohorts) or 4 and 16 weeks (Academic Medical Center/University of Amsterdam cohort).

RESULTS

There was no difference in rituximab levels between progressors and non-progressors 4 weeks and 12 or 16 weeks after initiation of treatment in the different cohorts. There was also no correlation between rituximab levels at week 4 or week 12 or 16 and change in SHS score after 1 year.

CONCLUSION

Low rituximab serum levels are not associated with progression of structural damage in RA patients. The results do not support the use of dosages higher than 2 × 1000 mg rituximab to inhibit progression of joint destruction.

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.

Induction of long-term B-cell depletion in refractory rheumatoid arthritis patients preferentially affects autoreactive more than protective humoral immunity

Introduction

B-cell depletion has become a common treatment strategy in anti-TNF-refractory rheumatoid arthritis (RA). Although the exact mechanism of how B-cell depletion leads to clinical amelioration in RA remains to be elucidated, repetitive treatment with B-cell-depleting agents leading to long-term B-cell depletion has been reported to be beneficial. The latter has led to the hypothesis that the beneficial effects of B-cell depletion might act through their influence on pathogenic autoreactive plasma cells.

Methods

In this study, we investigated the effects of a fixed retreatment regimen with anti-CD20 mAbs on the humoral (auto)immune system in a cohort of therapy-refractory RA patients.

Results

Fixed retreatment led to long-term B-cell depletion in peripheral blood, bone marrow and, to a lesser extent, synovium. Also, pathologic autoantibody secretion (that is, anticitrullinated peptide antibodies (ACPAs)) was more profoundly affected by long-term depletion than by physiological protective antibody secretion (that is, against measles, mumps and rubella). This was further illustrated by a significantly shorter estimated life span of ACPA-IgG secretion compared to total IgG secretion as well as protective antibody secretion.

Conclusion

By studying plasma cell function during an extensive 2-year period of B-cell depletion, autoantibody secretion was significantly shorter-lived than physiologically protective antibody secretion. This suggests that the longevity of autoreactive plasma cells is different from protective long-lived plasma cells and might indicate a therapeutic window for therapies that target plasma cells.

Suppression of bone turnover by B-cell depletion in patients with rheumatoid arthritis

The role of B cells in inflammatory bone formation and resorption is controversial. We investigated this in patients with rheumatoid arthritis (RA) treated with rituximab, a B-cell depleting antibody. We found a significant suppression in bone turnover, possibly a direct effect or as a consequence of a reduction in inflammation and disease activity.

INTRODUCTION

RA is the most prevalent inflammatory joint disease, in which B cells play an important role. However, the role of B cells in bone turnover is controversial and RA subjects treated with rituximab, a B-cell depleting monoclonal antibody, provide an ideal model for determining the role of B cells in inflammatory bone resorption.

METHODS

Serum from 46 RA patients, collected pre- and post-rituximab therapy, was analysed for biomarkers of bone turnover (procollagen type I amino-terminal propeptide [P1NP], osteocalcin, β-isomerised carboxy-terminal telopeptide of type 1 collagen [βCTX] and osteoprotegerin [OPG]).

RESULTS

A significant decrease in bone resorption was observed 6 months after rituximab (median change βCTX -50 ng/L, 95%CI -136, -8 p < 0.001, this equates to -37%; 95%CI -6, -49), mirrored by a reduction in disease activity. Similarly, there was a significant increase in P1NP, a marker of bone formation (median change P1NP 5.0 μg/L, 95%CI -1.0, 11.2, p = 0.02; 13%; 95%CI -3, 39), but no significant change in osteocalcin or OPG levels. The percentage change from baseline of βCTX in a subgroup of patients (not on prednisolone or bisphosphonate) was significantly correlated with the percentage reduction in DAS28 score (r (s) = 0.570, p = 0.014).

CONCLUSIONS

In conclusion, we have found that B-cell depletion increases bone formation and decreases bone resorption in RA patients; this may be a direct effect on osteoblasts and osteoclasts, respectively, and be at least partially explained by the decreased inflammation and disease activity.

[Consensus on the Use of Rituximab in Rheumatoid Arthritis. A document with evidence-based recommendations. Grupo de Expertos en Rituximab. ]

INTRODUCTION

Rituximab has been employed successfully for the treatment of Rheumatoid Arthritis (RA). However, its particular mechanism of action, as well as a lack of concrete guidelines for its management have generated doubts on its use.

OBJECTIVE

To establish recommendations that facilitates the use of rituximab in common clinical practice.

METHODS

In a first Delphi round, 9 expert rheumatologists got together to develop questions on those subjects generating most doubts on the efficacy and safety of the drug. These were adapted to perform a systematic review of the evidence, which was presented in a second meeting. Nominal groups were formed to respond to each question and give a recommendation. These recommendations were presented in a second Delphi round to a larger group of experts in rheumatology. Once again recommendations were discussed, modified and voted upon. Once approved, a vote on the degree of agreement for each recommendation was carried out.

RESULTS

17 recommendations were established, 10 regarding efficacy and 7 safety. All of the efficacy recommendations except 3 presented a good or moderate degree of evidence. Among the safety recommendations, 3 had a good or moderate degree of evidence while in the rest it was indirect, scarce or non-existent and a product of expert recommendation. The degree of agreement between experts was elevated for most of the recommendations.

CONCLUSIONS

These recommendations attempt to clear doubts on the use of rituximab and establish guidelines for its use in daily practice. Efficacy recommendations have a high degree of evidence, allowing the clinician to be guided in therapeutic decisions. Safety recommendations have a lower degree of evidence.

Safety and clinical outcomes of rituximab therapy in patients with different autoimmune diseases: experience from a national registry (GRAID)

INTRODUCTION

Evidence from a number of open-label, uncontrolled studies has suggested that rituximab may benefit patients with autoimmune diseases who are refractory to standard-of-care. The objective of this study was to evaluate the safety and clinical outcomes of rituximab in several standard-of-care-refractory autoimmune diseases (within rheumatology, nephrology, dermatology and neurology) other than rheumatoid arthritis or non-Hodgkin's lymphoma in a real-life clinical setting.

METHODS

Patients who received rituximab having shown an inadequate response to standard-of-care had their safety and clinical outcomes data retrospectively analysed as part of the German Registry of Autoimmune Diseases. The main outcome measures were safety and clinical response, as judged at the discretion of the investigators.

RESULTS

A total of 370 patients (299 patient-years) with various autoimmune diseases (23.0% with systemic lupus erythematosus, 15.7% antineutrophil cytoplasmic antibody-associated granulomatous vasculitides, 15.1% multiple sclerosis and 10.0% pemphigus) from 42 centres received a mean dose of 2,440 mg of rituximab over a median (range) of 194 (180 to 1,407) days. The overall rate of serious infections was 5.3 per 100 patient-years during rituximab therapy. Opportunistic infections were infrequent across the whole study population, and mostly occurred in patients with systemic lupus erythematosus. There were 11 deaths (3.0% of patients) after rituximab treatment (mean 11.6 months after first infusion, range 0.8 to 31.3 months), with most of the deaths caused by infections. Overall (n = 293), 13.3% of patients showed no response, 45.1% showed a partial response and 41.6% showed a complete response. Responses were also reflected by reduced use of glucocorticoids and various immunosuppressives during rituximab therapy and follow-up compared with before rituximab. Rituximab generally had a positive effect on patient well-being (physician's visual analogue scale; mean improvement from baseline of 12.1 mm).

CONCLUSIONS

Data from this registry indicate that rituximab is a commonly employed, well-tolerated therapy with potential beneficial effects in standard of care-refractory autoimmune diseases, and support the results from other open-label, uncontrolled studies.

Relationship between the type I interferon signature and the response to rituximab in rheumatoid arthritis patients

OBJECTIVE

To analyze the relationship between the type I interferon (IFN) signature and clinical response to rituximab in rheumatoid arthritis (RA) patients.

METHODS

Twenty RA patients were treated with rituximab (cohort 1). Clinical response was defined as a decrease in the Disease Activity Score evaluated in 28 joints (DAS28) and as a response according to the European League Against Rheumatism (EULAR) criteria at week 12 and week 24. The presence of an IFN signature was analyzed in peripheral blood mononuclear cells by measuring the expression levels of 3 IFN response genes by quantitative polymerase chain reaction analysis. After comparison with the findings in healthy controls, patients were classified as having an IFN high or an IFN low signature. The data were confirmed in a second independent cohort (n = 31). Serum IFNα bioactivity was analyzed using a reporter assay.

RESULTS

In cohort 1, there was a better clinical response to rituximab in the IFN low signature group. Consistent with these findings, patients with an IFN low signature had a significantly greater reduction in the DAS28 and more often achieved a EULAR response at weeks 12 and 24 as compared with the patients with an IFN high signature in cohort 2 versus cohort 1. The pooled data showed a significantly stronger decrease in the DAS28 in IFN low signature patients at weeks 12 and 24 as compared with the IFN high signature group and a more frequent EULAR response at week 12. Accordingly, serum IFNα bioactivity at baseline was inversely associated with the clinical response, although this result did not reach statistical significance.

CONCLUSION

The type I IFN signature negatively predicts the clinical response to rituximab treatment in patients with RA. This finding supports the notion that IFN signaling plays a role in the immunopathology of RA.

Therapeutic targeting of B cells for rheumatic autoimmune diseases

Autoreactive B cells are characterized by their ability to secrete autoantibodies directed against self-peptides. During the last decade, it has become increasingly apparent that B lymphocytes not only produce autoantibodies but also exert important regulatory roles independent of their function as antibody-producing cells. This is especially relevant in the context of autoimmunity, because autoreactive B cells have been shown to possess the ability to activate pathogenic T cells, to produce pro-inflammatory cytokines, and to promote the formation of tertiary lymphoid tissue in target organs. The production of monoclonal antibodies against B-cell-surface molecules has facilitated the characterization of several distinct B lymphocyte subsets. These cell-surface molecules have not only served as useful cell differentiation markers but have also helped to unravel the important biological functions of these cells. Some of these molecules, all of which are expressed on the cell surface, have proven to be effective therapeutic targets. In both animal models and in clinical assays, the efficient elimination of B lymphocytes has been shown to be useful in the treatment of rheumatoid arthritis and other autoimmune diseases. The treatment of most rheumatic autoimmune diseases relies mainly on the use of cytotoxic immunosuppressants and corticosteroids. Although this has resulted in improved disease survival, patients may nonetheless suffer severe adverse events and, in some cases, their relapse rate remains high. The increasing need for safer and more effective drugs along with burgeoning new insights into the pathogenesis of these disorders has fueled interest in biological agents; clinical trials involving the B-cell depletion agent rituximab have been especially promising. This article reviews the current knowledge of B-cell biology and pathogenesis as well as the modern therapeutic approaches for rheumatic autoimmune diseases focusing in particular on the targeting of B-cell-specific surface molecules and on the blocking of B-cell activation and survival.

The Belgian MIRA (MabThera In Rheumatoid Arthritis) registry: clues for the optimization of rituximab treatment strategies

INTRODUCTION

This study describes the results of the Belgian 'MabThera In Rheumatoid Arthritis (MIRA)' registry: effectiveness, safety and evaluation of the current retreatment practice on the background of the Belgian reimbursement criteria for rituximab.

METHODS

All Belgian rheumatologists had the possibility to participate in the study. Patients entered the registry in November 2006 and the entry is still open.

RESULTS

By mid-September 2009, 401 patients had entered the registry with a mean follow-up time of 70 weeks. Overall, DAS28-ESR decreased from 6.0 at baseline to 4.2 at week 16. Further decrease of disease activity was observed at the end of year 1 and year 2 with mean DAS28-ESR of 4.0 and 3.7 at these respective time points. More than 80% of patients showed a EULAR response at week 16. Patients could be retreated if they had DAS scores of > 3.2 at least 6 months after the previous course. Second and third courses were given in 224 and 104 patients, respectively. At month 6 after the second course, significantly lower DAS28-ESR values were observed compared to the first course. This was especially the case for patients who were retreated before they showed an obvious flare (DAS increase > 1.2).

CONCLUSIONS

This study describes the follow-up of a daily clinical practice cohort of 401 RA patients with long-standing refractory disease treated with rituximab. Relatively high DAS28 values at the start of each retreatment, compared to values 6 months after each treatment course, were noted. Moreover, further decrease of DAS28 scores after the second course was significantly more pronounced in those patients who didn't show an obvious flare. These two elements suggest that treatment of RA patients with rituximab could be optimized by earlier retreatment.

Clinical Manifestations but not Cytokine Profiles Differentiate Adult-onset Still’s Disease and Sepsis

Objective.

To analyze clinical manifestations, serum ferritin, and serum cytokine levels in patients with adult-onset Still’s disease (AOSD) or bacterial sepsis and to evaluate their potential use for differential diagnosis.

Methods.

Twenty-two consecutive patients with the first flare of AOSD and 6 patients with an established diagnosis of AOSD under immunosuppressive therapy were compared with 14 patients with bacterial sepsis. Clinical manifestations were scored in a Pouchot AOSD activity score including elevated serum ferritin levels to obtain a modified Pouchot score. Serum cytokine profiles were analyzed from each patient.

Results.

The scores of clinical manifestations using a modified Pouchot activity score were significantly higher in patients with active untreated AOSD (mean 5.60 ± 1.93) compared with patients with chronic AOSD (mean 1.16 ± 0.98; p < 0.001) and patients with sepsis (mean 2.38 ± 1.19; p < 0.001). A modified Pouchot score ≥ 4 shows a sensitivity of 92% and a specificity of 93% for active AOSD. Serum cytokine levels of interleukin 1ß (IL-1ß), IL-6, IL-8, IL-10, IL-12, IL-18, interferon-γ, tumor necrosis factor-α, and calprotectin were elevated in acute AOSD and sepsis. Significant differences were detected only in patients with sepsis who had higher levels of IL-6 and IL-8. The overlap of the 2 groups limits the use of cytokines for differential diagnosis in individual patients.

Conclusion.

A modified Pouchot AOSD activity score including elevated serum ferritin levels was more useful to confirm the diagnosis of AOSD compared to patients with sepsis. Elevated serum cytokines correlate with inflammation but are of limited use to differentiate between active AOSD and bacterial sepsis.

B cells in the pathogenesis and treatment of rheumatoid arthritis

PURPOSE OF REVIEW

Our understanding of the multiple physiological and pathogenic functions of B cells in rheumatoid arthritis (RA) continues to expand. In turn, the availability of effective agents targeting the B cell compartment increases. In this review, we discuss novel insights into the roles of B cells in RA and recent evidence regarding the efficacy of B cell depletion and biomarkers of treatment response.

RECENT FINDINGS

Recent data have further elucidated the requirements for the generation of ectopic lymphoid structures in the rheumatoid synovium, their frequency, and role in pathogenesis. Additional studies have described the phenotype of infiltrating B cells in the synovium and the unexpected role for B cells in bone homeostasis. In addition to pathogenic roles for B cells, there is also mounting evidence for regulatory B cell subsets that may play a protective role. New data on radiographic progression, efficacy in early disease, the role of retreatment, and biomarkers of treatment response continue to refine the role of B cell depletion in the treatment armamentarium.

SUMMARY

The past few years have seen new advances in immunology applied to the study of RA with surprising observations and interesting new insights into cause and pathogenesis.

Monoclonal antibodies and fusion proteins and their complications: targeting B cells in autoimmune diseases

The immune system consists of a complex array of immunocompetent cells and inflammatory mediators that exist in complex networks. These components interact through cascades and feedback circuits, maintaining physiologic inflammation and immunosurveillance. In various autoimmune conditions, a foreign or auto-antigen may upset this fine balance, leading to dysregulated immunity, persistent inflammation, and ultimately pathologic sequelae. In recent years, there has been tremendous progress delineating the specific components of the immune system that contribute to normal immunity and specific disease states. With this greater understanding of pathogenesis coupled with advances in biotechnology, many immunomodulatory agents, commonly called biologic agents, have been introduced. The 2 most common classes of biologic agents are monoclonal antibodies and fusion proteins. These agents can inhibit targets with exquisite specificity to optimize outcomes and minimize toxicity. B cells contribute significantly to the initiation and perpetuation of the immune responses. B cells not only can produce potentially pathologic autoantibodies and proinflammatory cytokines but also can present antigens to T cells and provide costimulatory signals essential for T-cell activation, clonal expansion, and effector function. This review focuses on biologic agents targeting B cells in the treatment of rheumatoid arthritis and systemic lupus erythematosus.

Update on the use of rituximab for intractable rheumatoid arthritis

It has been 3 years since rituximab, a mouse x human chimeric anti-CD20 monoclonal antibody that selectively depleted B cells, was approved by the FDA for the treatment of moderate to severe rheumatoid arthritis (RA) with an inadequate response to anti-TNF therapies. Since approval rituximab has become a part of standard treatment, and additional data have become available on long-term efficacy and safety both from clinical trials and from post-marketing surveillance. In open long-term follow-up from clinical trials, patients treated with multiple courses of rituximab continued to respond in terms of signs and symptoms, and damage assessed radiographically was significantly inhibited. Moreover, the rate of serious infectious events was not increased as the number of courses increased. However, because of case reports of progressive multifocal leukoencephalopathy in patients treated with rituximab for non-malignant conditions, a black box warning has been added. Studies on the immunologic correlates of response to rituximab treatment including B cell subsets in peripheral blood and synovial biopsies are providing clues into how rituximab works for autoimmune disease. However, at this time we are not able to explain why some patients do not respond and cannot predict who will respond. Future challenges for the further development of rituximab for intractable RA will be discussed.