Rituximab In Rheumatoid Arthritis Research Articles

Treat-to-target fixed dose rituximab retreatment versus fixed interval retreatment with disease activity-guided rituximab dose optimisation for patients with rheumatoid arthritis: study protocol for a multicentre randomised controlled superiority trial focusing on long-term disease impact (RITUXERA)

BackgroundThe optimal retreatment strategy with rituximab for rheumatoid arthritis (RA) remains a point of discussion. Depending on local guidelines, rituximab can either be administered at fixed intervals or when losing disease control, balancing therapeutic effectiveness with drug overexposure. However, treatment based on loss of disease control may significantly affect patients’ lives, provoking uncertainty and potentially leading to progressive joint damage. Moreover, as low-dose rituximab proved to be effective in treating RA while decreasing toxicity, drug exposure may be limited by tapering down rituximab doses guided by disease activity.MethodsRITUXERA is a 104-week open-label multicentre randomised controlled superiority trial. In total, 134 patients with RA treated with rituximab will be 1:1 randomised when in need of retreatment (DAS28-CRP ≥ 3.2 with previous rituximab administration at least 24 weeks earlier) to either a treat-to-target-driven fixed dose retreatment strategy (usual care group) or fixed interval disease-activity guided dose optimisation strategy (experimental group). The usual care group will be retreated with fixed rituximab doses (1 × 1000 mg IV) in case of loss of disease control (DAS28-CRP ≥ 3.2). The experimental group will receive a 24-weekly rituximab treatment while tapering down the dose in a decreasing sequence if DAS28-CRP ≤ 3.2: 1 × 1000 mg IV (maximal dose), 1 × 500 mg IV, and 1 × 200 mg IV (minimal dose). If DAS28-CRP exceeds 3.2 at the six-monthly retreatment, patients will receive and remain on the previous effective dose. Study visits are planned every 12 weeks. Primary outcome is the comparison of longitudinal patient-reported disease impact over 104 weeks, measured with the Rheumatoid Arthritis Impact of Disease (RAID) instrument, analysed using a linear mixed model. Main secondary outcome is the comparison of longitudinal disease activity (DAS28-CRP) over 104 weeks.DiscussionThe RITUXERA trial aims to explore the optimal retreatment strategy with rituximab for RA in terms of long-term patient-reported disease impact, by proposing a fixed interval disease activity-guided dose optimisation strategy as compared to a treat-to-target fixed dose strategy.Trial registrationCTIS 2023–506638-59–01 (registration date: 07 September 2023), ClinicalTrials.gov NCT06003283 (registration date: 17 August 2023).

Patients' and rheumatologists' perceptions on dose reduction of rituximab in rheumatoid arthritis.

The recommended dose of a rituximab course for the treatment of Rheumatoid Arthritis (RA) consists of two infusions of 1000mg with a 2-week interval. Evidence is growing that a lower dose could be as effective. We aimed to investigate patients' and rheumatologists' perceptions on dose reduction of rituximab. Patients with RA treated with rituximab, and rheumatologists were invited for a qualitative study via individual semi-structured interviews. Participants were recruited based on purposive sampling to ensure diversity. Interviews were analysed according to the principles of grounded theory and the constant comparative method. Sixteen patients and 13 rheumatologists were interviewed. Patients and rheumatologists perceived the benefits of rituximab dose reduction for reasons of safety and societal costs. Furthermore, available evidence for the effectiveness of lower doses was mentioned as an argument in favour, in addition to the possibility to tailor the dose based on the patients' clinical manifestations. However, patients and rheumatologists had concerns about the potential loss of effectiveness and quality of life. Moreover, some rheumatologists felt uncomfortable with dose reduction due to insufficient experience with rituximab in general. Patients and rheumatologists emphasised the importance of shared decision-making, underscoring the pivotal role of physicians in this process by explaining the reasoning behind dose reduction. Although some concerns on effectiveness were perceived, both patients and rheumatologists saw potential benefits of dose reduction in terms of safety, societal costs, and application of a personalised approach. As a result, most rheumatologists and patients showed a willingness to consider dose reduction strategies.

Long-term clinical and radiological effectiveness and safety of ultralow doses of rituximab in rheumatoid arthritis: observational extension of the REDO trial

BackgroundThe REDO trial (REtreatment with Rituximab in RhEmatoid arthritis: Disease Outcome after Dose Optimisation) showed similar disease activity for retreatment with ultralow doses (200 mg and 500 mg per 6...

Treat-to-target vs fixed interval retreatment strategy with rituximab in rheumatoid arthritis: a retrospective cohort study.

To compare the effectiveness of retreatment of rheumatoid arthritis (RA) patients with rituximab (RTX) following the treat-to-target retreatment (TTr) or fixed interval retreatment (FIr) strategy. RA patients starting RTX treatment between January 2008 and June 2016, and receiving at least three infusion cycles were grouped by strategy (TTr, FIr or both). Primary outcome (between strategy difference in DAS28-CRP (Disease Activity Score in 28 joints calculated with C-reactive protein)) and secondary outcomes (flares, use of co-medication and mean yearly dose of RTX) were analyzed by group using linear mixed models to account for different strategies within patients. A total of 213 patients, 59 TTr (of whom 32 switched from TTr to FIr) and 186 FIr were included. No between-group difference in mean DAS28-CRP was found (0.10 DAS28-CRP point (95% CI -0.07 to 0.26)). The TTr strategy did not result in more flares (IRR 1.13, 95%CI 0.87 to 1.47), conventional synthetic disease-modifying antirheumatic drug use (difference -11.7%, 95%CI -26.3% to 2.9%), or lower mean yearly RTX dose (difference 172mg/yr, 95%CI -355 to 11.7 mg/yr). RTX retreatment with either a TTr or FIr strategy does not seem to lead to better disease control and/or less drug use when used in a DAS28-CRP treat-to-target context. Choice of either strategy can, therefore, be made based on patient and physician preferences and logistical context.

To flare or not to flare: patients' and rheumatologists' perceptions on the on-flare retreatment strategy of rituximab in rheumatoid arthritis.

Several retreatment strategies exist for rituximab in rheumatoid arthritis (RA). In some countries, reimbursement criteria require a loss of disease control for rituximab retreatment. Understanding the patients' and rheumatologists' perceptions regarding this retreatment strategy would be informative in identifying the optimal treatment administration schedule. This study aimed to uncover patients' and rheumatologists' perceptions regarding retreatment strategies of rituximab. Qualitative study - semi-structured interviews. Patients with RA, treated with rituximab, and rheumatologists were invited to participate in a qualitative study consisting of individual, in-depth, semi-structured interviews. Interviews were analysed according to the Qualitative Analysis Guide of Leuven. A total of 16 patients and 13 rheumatologists were interviewed. Benefits (e.g. decreased risk of overtreatment, cost savings and long-lasting effectiveness of rituximab) and barriers (e.g. fluctuating disease activity, slow mode of action and increased glucocorticoid use) of on-flare retreatment were identified. To effectively treat on-flare, flares must first be identified timely. Both stakeholder groups acknowledged that patients are capable of recognizing flares. However, the patient's ability to discriminate between inflammatory and other types of pain was perceived as difficult. Furthermore, patients and rheumatologists stressed that patients must timely seek professional help in case of a flare, followed by a swift response from the rheumatologists. Remarkably, retreatment was approached in various ways among rheumatologists, and not always adhering strictly to the on-flare reimbursement criteria. This study revealed that both stakeholder groups perceived the heterogeneity in recognition of and reaction to a flare as important in influencing the effectiveness of the on-flare retreatment strategy. Moreover, this study identified the benefits and barriers of treating on-flare, which could be informative for daily practice decisions.

Sudden Vision Loss: More than Just an Ophthalmic Diagnosis! A Case Report

Abstract A 66-year-old patient of asian background from the US was admitted with confusion and behavioral changes for the last 10 days. The patient was on rituximab for RA (Rheumatoid arthritis). He had a normal computed tomography (CT) head and blood tests showed hyponatremia and acute kidney injury. Cerebrospinal fluid (CSF) showed raised CSF pressure 30 cmH20, raised protein and considerably high lymphocyte count. Mycobacteria tuberculous was isolated from one of her sputum cultures after having several negative sputum cultures, and consequently, the patient was treated for tuberculous meningitis. During admission, he had worsening of GCS (Glasgow coma scale), and he was admitted to ITU (intensive care unit) where he developed acute ischaemic stroke. He was treated for acute infarct and TBM (tuberculous meningitis), and was discharged on anti-tuberculous medications. It was a unique presentation in an immunocompromised patient with sudden deterioration and confusion, however, without neck stiffness or typical meningitis features. His condition improved with the commencement of the anti-tuberculosis therapy and was discharged from the hospital, and the patient traveled back to the US (United States) following discharge. During his stay, he was started on anti-tuberculous therapy early on due to high suspicion of Tb. The positive sputum culture was reported only after he had traveled back to the US and the same was conveyed to the patient’s GP (general practitioner) in the US.

Should complete B cell depletion be maintained in patients treated long-term with rituximab for rheumatoid arthritis?

To determine whether persistent complete B cell (BC) depletion was associated with a better clinical response in rheumatoid arthritis (RA) patients long-term treated with rituximab (RTX). We conducted a retrospective study including RA patients admitted for a new infusion between 2019 and 2021. The primary endpoint was the comparison of the mean disease activity score based on 28 joints (DAS28)-CRP at each of the four last infusion visits between patients with persistent complete BC depletion (mean CD19 counts <18/µl at each of the last four visits) or without persistent complete BC depletion (mean CD19 counts of the last four visits ≥18/µl). Secondary endpoints included DAS28, pain/fatigue visual analogue scale, CRP, gammaglobulins and the frequency of self-reported RA flares. Of the 126 patients in maintenance therapy with RTX [exposure period: 76 (5) months, 14 (7) infusions received], 43 (34%) had persistent complete BC depletion at each of the four last infusions. The mean DAS28-CRP calculated at each of the four last infusion visits did not significantly differ according to persistence or not of complete BC depletion. This result remained unchanged after adjusting for antibody status, number of previous therapies, number of RTX infusion and cumulative RTX dose. All secondary outcomes were also not significantly different between the two groups. Maintaining complete BC depletion does not appear to be a therapeutic target to achieve in RA patients in long-term maintenance therapy with RTX. There is a limited benefit of monitoring CD19 in RA patients long-term treated with RTX and having achieved low disease activity/remission.

Rituximab for rheumatoid arthritis-related interstitial lung disease: A systematic review and meta-analysis

Objectives: This systematic review and meta-analysis aimed at summarizing the evidence of efficacy and safety of rituximab in rheumatoid arthritis- related interstitial lung disease (RA-ILD). Materials and methods: PubMed and Embase databases were searched until June 22, 2022, to identify studies on RA-ILD treated with rituximab, confined to predefined inclusion and exclusion criteria. A systematic review and meta-analysis were performed on the included studies to assess the overall stabilization or improvement in ILD, changes in percent-predicted (%-predicted) forced vital capacity (FVC), and %-predicted diffusion capacity of lungs for carbon monoxide (DLCO) following rituximab therapy. Results: A total of 15 studies (4 prospective and 11 retrospective studies) were included, with a total of 314 patients. There were 105 (60.7%) females out of 173 subjects for whom sex details were available from seven studies. The overall pooled proportion of patients with stabilization or improvement in ILD was 0.88 [95% confidence interval (CI): 0.76-0.96, p=0.02]. Rituximab improved FVC from baseline by 7.50% (95% CI: 1.35-13.65; p=0.02, fixed effect). Similarly, rituximab improved DLCO by 6.39% (95% CI: 1.366-14.43; p=0.12, random-effect). Two retrospective studies reported reduced mortality with rituximab therapy compared to tumor necrosis factor-alpha inhibitors. Conclusion: Treatment with rituximab in RA-ILD was associated with a significant improvement in %-predicted FVC, as well as stabilization or improvement in ILD after one year of treatment.

Predictors of response of rituximab in rheumatoid arthritis by weighted gene co-expression network analysis.

The purpose of this study was to identify a biomarker that can predict the efficacy of rituximab (RTX) in the treatment of rheumatoid arthritis (RA) patients. Utilized weighted gene co-expression network analysis (WGCNA) and LASSO regression analysis of whole blood transcriptome data (GSE15316 and GSE37107) related to RTX treatment for RA from the GEO database, the critical modules, and key genes related to the efficacy of RTX treatment for RA were found. The biological functions were further explored through enrichment analysis. The area under the ROC curve (AUC) was validated using the GSE54629 dataset. WGCNA screened 71 genes for a dark turquoise module that were correlated with the efficacy of RTX treatment for RA (r = 0.42, P < 0.05). Through the calculation of gene significance (GS) and module membership (MM), 12 important genes were identified; in addition, 21 important genes were screened by the LASSO regression model; two key genes were obtained from the intersection between the important genes. Then, BANK1 (AUC = 0.704, P < 0.05) was identified as a potential biomarker to predict the efficacy of RTX treatment for RA by ROC curve evaluation of the treatment and validation groups. BANK1 gene expression was significantly decreased after RTX treatment, and a statistically significant difference was found (log FC = - 2.08, P < 0.05). Immune cell infiltration analysis revealed that the infiltration of CD4 + T cell memory subset was increased in the group with high BANK1 expression, and a statistically significant difference was found (P < 0.05). BANK1 can be used as a potential biomarker to predict the response of RTX treatment in RA patients. Key Points • Identifying the hub genes BANK1 as a potential biomarker to predict the response of RTX treatment in RA patients and confirming it in validation data. • Using the WGCNA approach and LASSO analyses to identify the BANK1 in a data set consisting of two GEO data merged and assessing the correlations between BANK1 and immune infiltration by CIBERSORT algorithm.

Drug levels, anti-drug antibodies and B-cell counts were not predictive of response in rheumatoid arthritis patients on (ultra-)low-dose rituximab.

The REDO trial (REtreatment with Rituximab in RhEumatoid arthritis: Disease Outcome after Dose Optimisation) showed that ultra-low-dose rituximab (500 mg or 200 mg) was similarly effective to a 1000 mg dosage in the majority of RA patients. This pre-planned secondary analysis investigated (1) associations between rituximab dosage, drug levels, anti-drug antibodies (ADAs) and B-cell counts and (2) the predictive value of pharmacokinetic and pharmacodynamic parameters, and of patient, disease and treatment characteristics in relation to response to ultra-low-dose rituximab. For 140 RA patients from the REDO trial, differences in drug levels, ADAs and B-cell counts were examined at baseline, and at 3 and 6 months after dosing. Treatment response was defined as absence of flare and no extra rituximab or >1 glucocorticoid injection received during follow-up. The association between potential predictors and response was investigated using logistic regression analyses. Lower doses of rituximab resulted in lower drug levels but did not significantly affect ADA levels or B-cell counts, and 3 (10.7%), 12 (20.7%) and 7 (13.0%) patients failed to meet the response criteria in, respectively, the 1000 mg, 500 mg and 200 mg dosage groups. Drug levels, ADAs, B-cell counts, and patient, disease and treatment characteristics were not predictive for response to ultra-low-dose rituximab. The results of this study further support the hypothesis that continued treatment with 500 or 200 mg rituximab is similarly effective to a 1000 mg dosage in RA patients doing well on rituximab. These results, combined with lack of finding a clinical dose-response relationship in the original REDO study, suggest that 200 mg rituximab is not yet the lowest effective rituximab retreatment dose in RA.

The interferon gene signature as a clinically relevant biomarker in autoimmune rheumatic disease.

The interferon gene signature (IGS) is derived from the expression of interferon-regulated genes and is classically increased in response to type I interferon exposure. A raised whole blood IGS has increasingly been reported in rheumatic diseases as sequencing technology has advanced. Although its role remains unclear, we explore how a raised IGS can function as a clinically relevant biomarker, independent of whether it is a bystander effect or a key pathological process. For example, a raised IGS can act as a diagnostic biomarker when predicting rheumatoid arthritis in patients with arthralgia and anti-citrullinated protein antibodies, or predicting systemic lupus erythematous (SLE) in those with antinuclear antibodies; a theragnostic biomarker when predicting response for patients receiving disease modifying therapy, such as rituximab in rheumatoid arthritis; a biomarker of disease activity (early rheumatoid arthritis, dermatomyositis, systemic sclerosis, SLE); or finally a predictor of clinical characteristics, such as lupus nephritis in SLE or disease burden in primary Sjögren's syndrome. A high IGS does not uniformly predict worse clinical phenotypes across all diseases, as demonstrated by a reduced disease burden in primary Sjögren's syndrome, nor does it predict a universally poorer response to all therapies, as shown in rheumatoid arthritis. This dichotomy highlights both the complexity of type I interferon signalling in vivo and the current lack of standardisation when calculating the IGS. The IGS as a biomarker warrants further exploration, with beneficial clinical applications anticipated in multiple rheumatic diseases.

Enterovirus A71 causing meningoencephalitis and acute flaccid myelitis in a patient receiving rituximab

We present the case of a young woman being treated with rituximab for rheumatoid arthritis who developed a severe enteroviral meningoencephalitis and acute flaccid myelitis (AFM). Cerebrospinal fluid (CSF) and stool reverse transcription-polymerase chain reaction (RT-PCR) testing confirmed the diagnosis and additional sequencing studies performed at the CDC further characterized the enterovirus as enterovirus A71 (EV-A71). After treatment with intravenous immunoglobulin (IVIg) and fluoxetine (based on previous reports of possible efficacy) the patient experienced a remarkable improvement over time. This case highlights the importance of considering enteroviral infection in patients treated with rituximab, depicts a possible clinical course of enteroviral meningoencephalitis and AFM, and illustrates the importance of testing multiple sites for enterovirus infection (CSF, stool, nasopharyngeal swab, blood). Here we present the case with a brief review of the literature pertaining to EV-A71.

A retrospective comparison of respiratory events with JAK inhibitors or rituximab for rheumatoid arthritis in patients with pulmonary disease

Janus kinase inhibitors (JAKi) are an exciting option for the treatment of rheumatoid arthritis (RA) but little is known about their safety and tolerability in patients with existing respiratory disorders. The objective was to compare pulmonary safety of JAKi versus rituximab in patients with concurrent interstitial lung disease (ILD) or bronchiectasis. We performed a retrospective electronic patient record review of patients with known ILD or bronchiectasis commencing JAKi or rituximab for the treatment of RA. Patients initiating treatment from January 2016 to February 2020 were included. Respiratory events (hospitalization or death from a respiratory cause) were compared using Kaplan–Meier survival analysis. We analysed patients who received JAKi (n = 28) and rituximab (n = 19) for a mean (SD) of 1.1 (0.62) and 2.14 (1) years respectively. Patients were predominantly female (68%), anti-CCP antibody positive (94%) and non-smoking (89%) with a median (IQR) percentage predicted FVC at baseline of 100% (82–115%) and percentage predicted TLCO of 62% (54.5–68%). Respiratory events occurred in five patients treated with JAKi (18%; 5 hospitalizations, 2 deaths) and in four patients treated with rituximab (21%; 3 hospitalizations, 1 death). Respiratory event rates did not differ between groups (Cox-regression proportional hazard ratio = 1.38, 95% CI 0.36–5.28; p = 0.64). In this retrospective study, JAKi for the treatment of RA with existing ILD or bronchiectasis did not increase the rate of hospitalization or death due to respiratory causes compared to those treated with rituximab. JAK inhibition may provide a relatively safe option for RA in such patients.

Expert Panel consensus statements on the optimal usage of rituximab for the management of rheumatoid arthritis in India

Pharmacological management of rheumatoid arthritis (RA) includes synthetic and biological disease-modifying antirheumatic drugs (DMARDs). Biological DMARDs, also referred to as “biologics,” rapidly retard progression of the joint damage seen in RA. Rituximab is a well-established biologic for the management of RA with several biosimilar versions available. This document presents the consensus statements on the usage of rituximab for the management of RA developed by a group of 14 experienced rheumatologists from India. This expert panel identified areas of interests, collated and summarized relevant literature, developed, debated and refined and revised the statements which were voted upon at relevant stages. Subsequently, a wider consultative process including voting on the draft statements involved 18 more rheumatologists from across India. The approved final version has 28 consensus statements related to the following seven areas of rituximab therapy in RA, namely, contraindication, pretreatment screening, treatment schedule, evaluation of response, safety, and research agenda for future. It is envisaged that these consensus statements would help in optimizing the usage of rituximab in RA not only in India but also in other countries and benefit all stakeholders.

Hypogammaglobulinemia after rituximab for rheumatoid arthritis is not rare and is related with good response: 13 years real-life experience.

Rituximab (RTX) use in the treatment of RA can be complicated by decrease in IgG, IgM or IgA levels (hypogammaglobulinemia-HGG). The aim of this study was to define the frequency of HGG in RA patients treated with RTX and to identify associations between its occurrence and patients' characteristics, disease outcomes and serious infections rate. RA patients treated with RTX in two rheumatology centers from January 2007 to January 2020 were retrospectively examined. Demographical, clinical and laboratory parameters were recorded at baseline and at last visit. Eighty-three patients (84.3% females) with a mean age of 63.2 years were enrolled. They had baseline DAS28(CRP) of 5.2 (1.1) and received a median (range) of 8 (2-20) RTX cycles. A total of 43.4%, 24.1% and 31.3% developed 'any HGG', 'low IgG' and 'low IgM', respectively. Lower baseline IgG and IgM levels were predictors of 'low IgG' and 'low IgM' occurrence, respectively. Patients who developed 'low IgM' exhibited lower DAS28(CRP) and increased rates of remission and low disease activity compared with those with normal IgM levels. Patients who maintained normal IgG were receiving methotrexate more frequently. No differences were observed in serious infections rate among subgroups. HGG occurred in 43% of RTX-treated patients. Patients who developed low IgG or low IgM had lower baseline levels than those who did not. Concomitant DMARD and corticosteroid therapy was not associated with HGG. Low IgM, but not low IgG, development was associated with better disease outcomes. HGG was not associated with an increased incidence of serious infections.

Rituximab for rheumatoid arthritis-associated large granular lymphocytic leukemia, a retrospective case series

ObjectivesTo assess the efficacy and tolerance profile of rituximab in rheumatoid arthritis (RA)-associated large granular lymphocyte leukemia (LGLL). MethodsMulticenter retrospective case series. Inclusion criteria were RA defined by the ACR/EULAR 2010 criteria and LGLL defined by absolute LGL count ≥ 0.3 × 109/L with evidence of an expanded clonal LGL population (flow cytometry, TCR-γ polymerase chain reaction, or Stat3 mutation). ResultsFourteen patients (10 women, mean age 55.2 ± 14.2 years) included; 13 were seropositive for anti-cyclic citrullinated peptides (n = 11) or rheumatoid factor (n = 10). LGLL diagnosis was made 9.5 [IQR: 3.25;15.5] years after RA diagnosis. Thirteen patients had T-LGLL. Rituximab was the first-line therapy for LGLL for 4 patients. Previous treatment lines included methotrexate (n = 7), cyclophosphamide (n = 2), cyclosporin A (n = 1), or granulocyte colony-stimulating factor (n = 4). Rituximab was used in monotherapy (n = 8) or associated to methotrexate (n = 3), granulocyte colony-stimulating factor (n = 2), or alkylating agents (n = 1). The number of rituximab cycles ranged from 1 to 11 (median 6), with high heterogeneity in dosing regimens. Median duration response after rituximab initiation was 35 [IQR: 23.5;41] months. The overall response rate was 100%: 8 patients experienced complete response (normalization of blood count and LGL ≤ 0.3 × 109/L) and 6 experienced partial responses (improvement in blood counts without complete normalization). The tolerance profile was good, with no infectious complications. Conclusionrituximab appears as a valuable therapeutic option for RA-associated LGLL.

Factors associated with long-term persistence of rituximab in rheumatoid arthritis in clinical practice: RITAR Study

Background and objectiveTreatment of rheumatoid arthritis with rituximab (RTX) requires repeated cycles, but there is no well-established retreatment regimen in dose and frequency. The objective was to analyse the persistence of RTX treatment and factors that influence in terms of routine clinical practice. MethodsRituximab in rheumatoid arthritis (RITAR Study) is an observational, retrospective study that analyses the persistence of RTX in a cohort from 2003 to 2015. Persistence was calculated by the Kaplan–Meier analysis; curves were compared with the Log-Rank test. Cox regression was used to quantify the risk of discontinuation and multivariate analyses were conducted to determine the factors associated with the persistence of the treatment. Results454 cycles of RTX in 114 patients were included. Median survival was 10.0 years and incidence rate of discontinuation was 7.7 per 100patients/year. Factors associated with persistence were autoantibody positivity and use of RTX in combination with csDMARDs. Sex, age, number of comorbidities, rheumatoid arthritis evolution, number of complications, basal DAS28, basal HAQ, number of lines of treatment, fixed or on demand retreatment and year of RTX starting were not associated. Multivariable models confirmed the relationship between autoantibody positivity, monotherapy and persistence of RTX. ConclusionsThe persistence of RTX in clinical practice is higher in seropositive patients and in those who are treated with RTX associated with a csDMARD. Dose per cycle and retreatment frequency do not have a decisive role in rituximab persistence.

P231 B-cell depletion therapy with rituximab in RA: UCLH/UCL 20 years of experience

Abstract Background B-cell depletion therapy based on rituximab in patients with seropositive rheumatoid arthritis (RA) was pioneered at UCLH/UCL in 1998. The positive results of the initial open-label UCLH/UCL trials led to the Phase IIa proof of concept trial confirming efficacy and safety for rituximab in the treatment of patients with RA. A Phase III trial followed and licensing in 2006. We report a service evaluation of the UCLH/UCL cohort of RA patients treated with rituximab over the last 20 years. Methods A retrospective review of electronic records from all patients with RA treated with rituximab followed up in a dedicated clinic at UCLH/UCL (1998-2019) were included. Data on gender, age at first treatment, previous DMARDs, concomitant therapy at the time of the first rituximab cycle, total number of rituximab cycles and length of follow-up while on rituximab were collected. For patients currently on rituximab, further information was collected at last follow-up, including concomitant therapy, swollen and tender joint count, global VAS, CRP and ESR. DAS28ESR was calculated. Results 296 patients had received rituximab therapy since November 1998, with 105 remaining on rituximab at final data collection (14/10/2019). Median follow-up was 77.5 months. Clinical data is shown in Table 1. Information for previous DMARDs was only available for 196 patients in the whole cohort, and for 70 patients currently on rituximab. The most common concomitant DMARD at first cycle was methotrexate with a similar percentage receiving methotrexate at last follow-up. The median number of previous DMARDs were 4 and 3 respectively. Within both cohorts approximately 31% of patients received rituximab as their first biologic. Conclusion This retrospective service evaluation of 296 patients with RA who had undergone rituximab therapy since 1998 showed that more than one third remained on rituximab at last follow-up. Of these, 70.2% of patients were in clinical remission or with low disease activity. Most patients (94%) remaining on rituximab were receiving only 1 or no concomitant therapies. Multiple cycles of treatment with rituximab have thus proved to be an effective therapeutic strategy for patients with RA resulting in long-term and highly favourable control of their disease. Disclosures C.M. Norris-Grey None. S. Moore None. G. Cambridge None. V. Reedy None. M. Leandro Consultancies; Genentech: consultancy fees for attending meeting on obinutuzumab trial in lupus nephritis.

Risk factor of infusion-related reactions of rituximab in rheumatoid arthritis: single-center experience of 459 infusions over 5 years

目的：探討接受莫須瘤治療之類風濕性關節炎患者發生輸注反應的可能相關因素。方法：將五年內曾經接受莫須瘤治療之類風濕性關節炎患者，以病歷回顧之方式記錄發生輸注反應發生的嚴重程度與處置方式，並加以分析。結果：本研究共收錄68位類風濕性關節炎患者，共459次莫須瘤輸注。針對每位患者第一次輸注作分析，可發現過去曾經接受其他種類生物製劑的患者（n=35），有輸注反應發生7人（20%）；比較未曾接受過其他生物製劑者（n=33），輸注反應發生1人（3%）。進一步依據輸注流速做存活分析，納入459次莫須瘤輸注，接受其他種類生物製劑的患者之輸注反應存活曲線有顯著與未曾接受者分開 。結論：過去曾經接受其他種類生物製劑的類風濕性關節炎患者，接受莫須瘤輸注治療時，有較高機會發生輸注反應。

CD4+ count-dependent concentration-effect relationship of rituximab in rheumatoid arthritis.

Rituximab is approved in rheumatoid arthritis (RA). A substantial decrease in CD4+ count was observed in responders after a single cycle of treatment. This study aimed to describe and quantifying the influence of CD4+ count depletion on the concentration-response relationship of rituximab in RA patients. In this retrospective monocentric observational study, 52 patients were assessed. Repeated measurements of rituximab concentrations (pharmacokinetics), CD4+ counts (biomarker) and disease activity score in 28 joints (DAS28, clinical response) were made. Rituximab pharmacokinetics was described using a 2-compartment model, and CD4+ cell counts and DAS28 measurements were described using indirect turnover and direct Emax pharmacokinetic-pharmacodynamic models, respectively. Delay between rituximab concentrations and responses was accounted for by including biophase compartments. Elimination half-life of rituximab was 18 days. The pharmacokinetic-pharmacodynamic model showed that DAS28 response to rituximab was partly associated with CD4+ cell depletion. At 6 months, a deeper DAS28 decrease was observed in patients when CD4+ cell count is decreased: median [interquartile range] of DAS28 was 3.7 [2.9-4.4] and 4.5 [3.7-5.3] in patients with and without CD4+ decrease, respectively. This is the first study to quantify the relationship between rituximab concentrations, CD4+ count and DAS28 in RA patients. This model showed that approximately 75% of patients had CD4+ count decrease, and that the clinical improvement is 2-fold higher in patients with CD4+ cells decrease than in others.