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

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

OBJECTIVE

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).

METHODS

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.

RESULTS

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.

CONCLUSION

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.

A heart transplant center experience with basiliximab induction strategies: A double edged sword?

BACKGROUND

The use of induction immunosuppression for heart transplantation (HT) is debated given the uncertain benefit and potential risks of infection and malignancy.

METHODS

This is a retrospective single-center analysis of 475 consecutive HT recipients from 2003 to 2020 grouped by use of induction with basiliximab group (BG) and the no basiliximab group (NBG). Subgroup analysis by era compared pre-2016 standard-basiliximab (BX) induction and 2016-2020 with selective-BX use as part of a calcineurin-inhibitor-sparing regimen.

RESULTS

When adjusted for confounders (sex, age, PRA, eGFR), the BG was less likely to have acute cellular rejection (ACR) (OR.42, p < .001), but had more antibody mediated rejection (AMR) (OR 11.7, p < .001) and more cardiac allograft vasculopathy (CAV) (OR 3.8, p = .04). There was no difference between BG and NBG in the incidence of malignancies or infections. When stratified by era (pre-2016 vs. 2016-2020), ACR remained less common in the BG than the NBG (36% vs. 50%, p = .045) groups, while AMR remained more common (9.7 vs. 0% p = .005). There was no significant difference in conditional survival comparing pre-and post-2016 NBG (HR 2.20 (95% CI.75-6.43); however, both pre-2016 BG and post-2016 BG have significantly higher mortality (HR 2.37 [95% CI 1.02-5.50) and HR 2.69 (95% CI 1.08-6.71), p = .045 and.03, respectively].

CONCLUSION

Basiliximab reduces the incidence of ACR but increases the risk of AMR, CAV, and may be associated with increased mortality. Mechanistic studies are needed to describe a potential T-cell-escape mechanism with enhanced humoral immunity.

Sustained post-rituximab B-cell depletion is common in ANCA-associated vasculitis and is affected by sex and renal function

OBJECTIVE

Despite the increasing use of rituximab in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), it remains unclear what the optimal dosing is, especially for maintenance of remission. A deeper understanding of post-rituximab B-cell repopulation patterns may aid better-tailored treatment.

METHODS

This is a monocentric, retrospective study including ANCA-positive AAV patients receiving a single course of rituximab induction. CD19+ B cells were longitudinally monitored with flow cytometry. B-cell repopulation was defined as CD19+ >10 cells/μL.

RESULTS

Seventy-one patients were included, the majority with microscopic polyangiitis (75%), myeloperoxidase-ANCA positivity (75%) and with renal involvement (79%). During a median follow-up of 54 months since the first rituximab infusion, 44 patients (62%) repopulated B cells, with a median time to repopulation of 39 months (range 7-102). Patients experiencing B-cell depletion lasting longer than the overall median time to repopulation (39 months) exhibited a lower risk of flare and higher risk of serious infection. In multivariate Cox regression, higher estimated glomerular filtration rate (eGFR) [hazard ratio (HR) 1.84, 95% confidence interval (CI) 1.13-2.98 per 30 mL/min/1.73 m2 eGFR] and female sex (HR 2.70, 95% CI 1.37-5.31) were independent predictors of increased rate of B-cell repopulation.

CONCLUSION

A subset of AAV patients develop sustained post-rituximab B-cell depletion, which associates with reduced risk of flare and increased risk of serious infection in the long term. Preserved renal function and female sex are associated with faster B-cell repopulation. These observations further highlight the need to personalize immunosuppression to improve clinical outcomes.

Rituximab treatment in myasthenia gravis

Myasthenia gravis (MG) is a chronic autoimmune disease mediated by antibodies against post-synaptic proteins of the neuromuscular junction. Up to 10%-30% of patients are refractory to conventional treatments. For these patients, rituximab has been used off-label in the recent decades. Rituximab is a monoclonal antibody against the CD20 protein that leads to B cell depletion and to the synthesis of new antibody-secreting plasma cells. Although rituximab was created to treat B-cell lymphoma, its use has widely increased to treat autoimmune diseases. In MG, the benefit of rituximab treatment in MuSK-positive patients seems clear, but a high variability in the results of observational studies and even clinical trials has been reported for AChR-positive patients. Moreover, few evidence has been reported in seronegative MG and juvenile MG and some questions about regimen of administration or monitoring strategies, remains open. In this review, we intend to revise the available literature on this topic and resume the current evidence of effectiveness of Rituximab in MG, with special attention to results on every MG subtype, as well as the administration protocols, monitoring strategies and safety profile of the drug.

B Cell Lymphocytosis in Juvenile Dermatomyositis

In this study, we determined if B lymphocytosis may serve as a JDM biomarker for disease activity. Children with untreated JDM were divided into two groups based on age-adjusted B cell percentage (determined through flow cytometry): 90 JDM in the normal B cell group and 45 in the high B cell group. We compared through T-testing the age, sex, ethnicity, duration of untreated disease (DUD), disease activity scores for skin (sDAS), muscle (mDAS), total (tDAS), CMAS, and neopterin between these two groups. The patients in the high B cell group had a higher tDAS (p = 0.009), mDAS (p = 0.021), and neopterin (p = 0.0365). Secondary analyses included B cell values over time and BAFF levels in matched patients with JM (juvenile myositis) and concurrent interstitial lung disease (ILD); JM alone and healthy controls Patient B cell percentage and number was significantly higher after 3-6 months of therapy and then significantly lower on completion of therapy (p =< 0.0001). The JM groups had higher BAFF levels than controls 1304 vs. 692 ng/mL (p = 0.0124). This study supports B cell lymphocytosis as a JDM disease-activity biomarker and bolsters the basis for B cell-directed therapies in JDM.

Advanced immunophenotyping: A powerful tool for immune profiling, drug screening, and a personalized treatment approach

Various autoimmune diseases are characterized by distinct cell subset distributions and activation profiles of peripheral blood mononuclear cells (PBMCs). PBMCs can therefore serve as an ideal biomarker material, which is easily accessible and allows for screening of multiple cell types. A detailed understanding of the immune landscape is critical for the diagnosis of patients with autoimmune diseases, as well as for a personalized treatment approach. In our study, we investigate the potential of multi-parameter spectral flow cytometry for the identification of patients suffering from autoimmune diseases and its power as an evaluation tool for in vitro drug screening approaches (advanced immunophenotyping). We designed a combination of two 22-color immunophenotyping panels for profiling cell subset distribution and cell activation. Downstream bioinformatics analyses included percentages of individual cell populations and median fluorescent intensity of defined markers which were then visualized as heatmaps and in dimensionality reduction approaches. In vitro testing of epigenetic immunomodulatory drugs revealed an altered activation status upon treatment, which supports the use of spectral flow cytometry as a high-throughput drug screening tool. Advanced immunophenotyping might support the exploration of novel therapeutic drugs and contribute to future personalized treatment approaches in autoimmune diseases and beyond.

Tedavisi zor nefrotik sendromlu çocuklarda rituksimab tedavisi

Amaç: Rituksimab (RTX), tedavisi zor nefrotik sendromlu (sık tekrarlayan, steroide bağımlı ve steroide dirençli) hastalar için kurtarma tedavisi olarak önerilmektedir. Amacımız zor nefrotik sendromlu çocuklarda RTX tedavisinin etkinliğini ve uzun dönem sonuçlarını değerlendirmek ve deneyimlerimizi paylaşmaktır. Gereç ve Yöntem: RTX ile tedavi edilen zor nefrotik sendromlu çocukların tıbbi kayıtları geriye dönük olarak değerlendirildi. Oniki ayda nükssüz sağkalım oranı ve B hücre deplesyonun izlemi değerlendirildi. Bulgular: Çalışmaya 8'i steroide bağımlı (SBNS), 6'sı sık tekrarlayan (STNS) ve 6'sı steroide dirençli nefrotik sendromlu (SDNS) 20 çocuk dahil edildi. RTX tedavisi alan STNS/SBNS hastalarının tedavi öncesi ve sonrası 1 yıllık ortalama nüks sayısı karşılaştırıldı. Ortalama nüks sayısı 2 (1-4)’den 0 (0-1) kez/yıla geriledi. RTX tedavisi sonrası ortalama takip süresi 23 ay (12-59) ve 8 hastada nüks gelişti. RTX tedavisi sonrası nüks eden 5 hastaya, tekrarlayan dozlarda RTX uygulandı. Bu hastalarda, CD19+B hücreleri remisyon sırasında yeniden ortaya çıkarken, hafıza B hücrelerinin deplesyonu devam etti. Sonuç: RTX tedavisi, STNS/SBNS hastalarında remisyon süresini uzattı, ancak SDNS hastalarında etkisiz kaldı. Bu hastalarda remisyonun idamesi için RTX dozunun tekrarlanabileceği ve tekrarlama dozlarının zamanlamasında en iyi hafıza B hücre sayısının yardımcı olabileceği saptandı.

Use of rituximab in the treatment of mucous membrane pemphigoid: An analytic review

Mucous Membrane Pemphigoid (MMP) is a potentially fatal mucocutaneous autoimmune blistering disease. Autoantibodies are produced against various components of the dermo-epidermal or mucosal-submucosal junction are referred to as basement membrane zone (BMZ). The hallmark is deposition of of Ig and C3 on the perilesional tissues and in some patients detection of anti-BMZ autoantibodies. A unique characteristic of MMP is that as the blisters or erosions heal, they leave irreversible scarring. This scarring results in serious and catastrophic sequelae that affect the quality of life. Conventional therapy consists of anti-inflammatory and immunosuppressive agents (ISA). In patients who fail conventional therapy or develop significant side effects to them, rituximab (RTX) has been used off label. In this review, the clinical outcomes of patients with MMP treated with RTX were studied. 124 patients were identified, 47.58% being male. 72 patients were treated by the Lymphoma Protocol and 51 by Rheumatoid Arthritis (RA) protocol. Follow up for the entire cohort was 36 months (range 0.5-72). On follow-up 64 patients (51.61%) achieved complete clinical remission (CR) off therapy, 25 patients (20.16%) were in CR on therapy, 5 patients (4.03%) were non-responders, and 9 patients (7.25%) were failures. 52 patients (41.93%) experienced a relapse, after 36 months follow-up. Duration between last RTX infusion and relapse was 10.5 months (range 1-30). Most patients with relapses were treated with additional RTX. A statistically significant better outcome was observed in patients treated with RTX as monotherapy compared to those who received RTX with ISA. Clinical outcomes in patients treated with Lymphoma protocol were better than RA protocol at a statistically significant level. Data on CD20+ B cell depletion and repopulation was limited. Interestingly relapses were seen in patients with CD20+ B cell depletion and after repopulation. In the final analysis, 89 patients (71.77%) were in complete remission. Data in this review indicated that RTX was a useful agent to treat MMP. While a randomized control trial may not be practically possible, better and disease specific protocols need to be developed. When publishing, authors should attempt to provide complete and detailed information. In doing so, they will benefit their colleagues and the patients with MMP they treat with RTX.

Accuracy and tolerability of self-sampling of capillary blood for analysis of inflammation and autoantibodies in rheumatoid arthritis patients-results from a randomized controlled trial

BACKGROUND

Rheumatoid arthritis (RA) requires early diagnosis and tight surveillance of disease activity. Remote self-collection of blood for the analysis of inflammation markers and autoantibodies could improve the monitoring of RA and facilitate the identification of individuals at-risk for RA.

OBJECTIVE

Randomized, controlled trial to evaluate the accuracy, feasibility, and acceptability of an upper arm self-sampling device (UA) and finger prick-test (FP) to measure capillary blood from RA patients for C-reactive protein (CRP) levels and the presence of IgM rheumatoid factor (RF IgM) and anti-cyclic citrullinated protein antibodies (anti-CCP IgG).

METHODS

RA patients were randomly assigned in a 1:1 ratio to self-collection of capillary blood via UA or FP. Venous blood sampling (VBS) was performed as a gold standard in both groups to assess the concordance of CRP levels as well as RF IgM and CCP IgG. General acceptability and pain during sampling were measured and compared between UA, FP, and VBS. The number of attempts for successful sampling, requests for assistance, volume, and duration of sample collection were also assessed.

RESULTS

Fifty seropositive RA patients were included. 49/50 (98%) patients were able to successfully collect capillary blood. The overall agreement between capillary and venous analyses for CRP (0.992), CCP IgG (0.984), and RF IgM (0.994) were good. In both groups, 4/25 (16%) needed a second attempt and 8/25 (32%) in the UA and 7/25 (28%) in the FP group requested assistance. Mean pain scores for capillary self-sampling (1.7/10 ± 1.1 (UA) and 1.9/10 ± 1.9 (FP)) were significantly lower on a numeric rating scale compared to venous blood collection (UA: 2.8/10 ± 1.7; FP: 2.1 ± 2.0) (p=0.003). UA patients were more likely to promote the use of capillary blood sampling (net promoter score: +28% vs. -20% for FP) and were more willing to perform blood collection at home (60% vs. 32% for FP).

CONCLUSIONS

These data show that self-sampling is accurate and feasible within one attempt by the majority of patients without assistance, allowing tight monitoring of RA disease activity as well as identifying individuals at-risk for RA. RA patients seem to prefer upper arm-based self-sampling to traditional finger pricking.

TRIAL REGISTRATION

DRKS.de Identifier: DRKS00023526 . Registered on November 6, 2020.

Comparison of efficacy and cost-efficiency of an immunologically targeted low dose rituximab protocol with the conventional rheumatoid arthritis protocol in severe pemphigus

BACKGROUND

Various dosing protocols of rituximab have been used in pemphigus. B-cell repopulation post-rituximab can be considered a forerunner of clinical relapse. Immunologically-guided dosing may obviate the need of fixed timepoint maintenance dosing, hence proving more cost-effective and perhaps safer.

OBJECTIVE

Comparison of overall efficacy and cost-efficiency of low dose rituximab with immunologically-guided ultra-low (200mg) top-up infusions versus rheumatoid arthritis (RA) protocol with 500mg repeat infusion upon clinical relapse, in severe pemphigus over one-year period.

METHODS

23 patients of severe pemphigus were randomized into Group-A (RA protocol: 1000mg, 2 doses, 2 weeks apart) and Group-B (low-dose rituximab: 500mg, 2 doses, 2 weeks apart). Both groups also received short-term oral corticosteroids and were followed clinically and immunologically (3-monthly flowcytometric assessments of B-cell subtypes). While Group-A got a 500mg rituximab top-up upon clinical relapse; Group-B received an ultra-low top-up (200mg) on B-cell repopulation, intended to prevent clinical relapse. Outcome parameters [complete remission off treatment (CROT), relapse (clinical and immunological), total corticosteroid dose and direct cost of therapy] were compared.

RESULTS

Time to CROT (Group-A: 27±1.6 weeks; Group-B: 26±1.2 weeks, p=0.09) and cumulative prednisolone dose (p=0.28) were comparable. 10/11 (90.9%) patients in Group-B had B-cell repopulation (8.4±2.4 months) and a single 200mg top-up dose successfully prevented clinical relapse. In Group-A, 3/9 (33.3%) patients had clinical relapse (9.3±0.4 months). Overall cost of therapy was 37.4% cheaper in Group-B.

CONCLUSION

An immunologically- guided low dose rituximab regimen can be an equally effective yet affordable alternative to conventional rituximab regimens in pemphigus.

A novel digital PCR-based method to quantify (switched) B cells reveals the extent of allelic involvement in different recombination processes in the IGH locus

B cells fulfill an important role in the adaptive immunity. Upon activation and immunoglobulin (IG) class switching, these cells function in the humoral immunity compartment as plasma cells. For clinical applications, it can be important to quantify (switched) B cells accurately in a variety of body fluids and tissues of benign, inflammatory and malignant origin. For decades, flow cytometry and immunohistochemistry (IHC) have been the preferred methods for quantification. Although these methods are widely used, both depend on the accessibility of B cell epitopes and therefore require intact (fixed) cells. Whenever samples are low in quantity and/or quality, accurate quantification can be difficult. By shifting the focus from epitopes to DNA markers, quantification of B cells remains achievable. During differentiation and maturation, B cells are subjected to programmed genetic recombination processes like VDJ rearrangements and class switch recombination (CSR), which result in deletion of specific sequences of the IGH locus. These cell type-specific DNA "scars" (loss of sequences) in IG genes can be exploited as B cell markers in digital PCR (dPCR) based quantification methods. Here, we describe a novel, specific and sensitive digital PCR-based method to quantify mature and switched B cells in DNA specimens of benign and (copy number unstable) malignant origin. We compared this novel way of B cell quantitation with flow cytometric and immunohistochemical methods. Through cross-validation with flow cytometric sorted B cell subpopulations, we gained quantitative insights into allelic involvement in different recombination processes in the IGH locus. Our newly developed method is accurate and independent of the cellular context, offering new possibilities for quantification, even for (limited) small samples like liquid biopsies.

Severe COVID pneumonia and undetectable B cells after vaccination in patients previously treated with rituximab: a case series

INTRODUCTION

The risk of developing severe COVID-19 illness despite completing vaccination for patients who have previously received immunosuppressive therapy is unclear.

CASE PRESENTATION

We present three patients who received rituximab for treatment of autoimmune disorders who subsequently developed severe COVID-19 pneumonia post-vaccination requiring intensive care unit admission and found to have undetectable B cells.

DISCUSSION

While there have been concerns about the effectiveness of COVID-19 vaccines in this patient cohort, this is the first case series to report development of severe COVID-19 illness after completing vaccination in those who previously received rituximab. Guidelines for the optimal timing of COVID-19 vaccination in relation to immunosuppressive therapy have been recently published, albeit after many patients in this subpopulation have already been vaccinated.

CONCLUSION

This case series brings attention to the limited humoral response to vaccines in patients treated with rituximab, highlights existing guidelines and their limitations, and raises future considerations about the potential benefits to testing vaccine responsiveness.

CTOTC-08: A multicenter randomized controlled trial of rituximab induction to reduce antibody development and improve outcomes in pediatric lung transplant recipients

We conducted a randomized, placebo-controlled, double-blind study of pediatric lung transplant recipients, hypothesizing that rituximab plus rabbit anti-thymocyte globulin induction would reduce de novo donor-specific human leukocyte antigen antibodies (DSA) development and improve outcomes. We serially obtained clinical data, blood, and respiratory samples for at least one year posttransplant. We analyzed peripheral blood lymphocytes by flow cytometry, serum for antibody development, and respiratory samples for viral infections using multiplex PCR. Of 45 subjects enrolled, 34 were transplanted and 27 randomized to rituximab (n = 15) or placebo (n = 12). No rituximab-treated subjects versus five placebo-treated subjects developed de novo DSA with mean fluorescence intensity >2000. There was no difference between treatment groups in time to the primary composite outcome endpoint (death, bronchiolitis obliterans syndrome [BOS] grade 0-p, obliterative bronchiolitis or listing for retransplant). A post-hoc analysis substituting more stringent chronic lung allograft dysfunction criteria for BOS 0-p showed no difference in outcome (p = .118). The incidence of adverse events including infection and rejection episodes was no different between treatment groups. Although the study was underpowered, we conclude that rituximab induction may have prevented early DSA development in pediatric lung transplant recipients without adverse effects and may improve outcomes (Clinical Trials: NCT02266888).

Rituximab Therapy for Adults with Nephrotic Syndromes: Standard Schedules or B Cell-Targeted Therapy?

Rituximab is a chimeric anti-CD20 monoclonal antibody. It acts mainly through complement-dependent cytotoxicity on B cells expressing the CD20 marker. In this review, we analyse the efficacy and possible pitfalls of rituximab to treat nephrotic syndromes by taking into account pharmacological considerations and CD19 marker testing utility. Despite the fact that the drug has been in use for years, efficacy and treatment schedules in adults with nephrotic syndrome are still a matter of debate. Clinical trials have proven the efficacy and safety of rituximab in idiopathic membranous nephropathy. Data from observational studies also showed the efficacy of rituximab in minimal change disease and focal segmental glomerulosclerosis. Rituximab use is now widely recommended by new Kidney Disease Improved Outcome (KDIGO) guidelines in membranous nephropathy and in frequent-relapsing, steroid-dependent minimal change disease or focal segmental glomerulosclerosis. However, rituximab response has a large interindividual variability. One reason could be that rituximab is lost in the urine at a higher extent in patients with nonselective nephrotic proteinuria, exposing patients to different rituximab plasma levels. Moreover, the association between CD19+ levels and clinical response or relapses is not always present, making the use of this marker in clinical practice complex. High resolution flow cytometry has increased the capability of detecting residual CD19+ B cells. Moreover, it can identify specific B-cell subsets (including IgG-switched memory B cells), which can repopulate at different rates. Its wider use could become a useful tool for better understanding reasons of rituximab failure or avoiding unnecessary retreatments.

Bruton's Tyrosine Kinase (BTK) Inhibitors and Autoimmune Diseases: Making Sense of BTK Inhibitor Specificity Profiles and Recent Clinical Trial Successes and Failures

Clinical development of BTK kinase inhibitors for treating autoimmune diseases has lagged behind development of these drugs for treating cancers, due in part from concerns over the lack of selectivity and associated toxicity profiles of first generation drug candidates when used in the long term treatment of immune mediated diseases. Second generation BTK inhibitors have made great strides in limiting off-target activities for distantly related kinases, though they have had variable success at limiting cross-reactivity within the more closely related TEC family of kinases. We investigated the BTK specificity and toxicity profiles, drug properties, disease associated signaling pathways, clinical indications, and trial successes and failures for the 13 BTK inhibitor drug candidates tested in phase 2 or higher clinical trials representing 7 autoimmune and 2 inflammatory immune-mediated diseases. We focused on rheumatoid arthritis (RA), multiple sclerosis (MS), and systemic lupus erythematosus (SLE) where the majority of BTK nonclinical and clinical studies have been reported, with additional information for pemphigus vulgaris (PV), Sjogren’s disease (SJ), chronic spontaneous urticaria (CSU), graft versus host disease (GVHD), and asthma included where available. While improved BTK selectivity versus kinases outside the TEC family improved clinical toxicity profiles, less profile distinction was evident within the TEC family. Analysis of genetic associations of RA, MS, and SLE biomarkers with TEC family members revealed that BTK and TEC family members may not be drivers of disease. They are, however, mediators of signaling pathways associated with the pathophysiology of autoimmune diseases. BTK in particular may be associated with B cell and myeloid differentiation as well as autoantibody development implicated in immune mediated diseases. Successes in the clinic for treating RA, MS, PV, ITP, and GVHD, but not for SLE and SJ support the concept that BTK plays an important role in mediating pathogenic processes amenable to therapeutic intervention, depending on the disease. Based on the data collected in this study, we propose that current compound characteristics of BTK inhibitor drug candidates for the treatment of autoimmune diseases have achieved the selectivity, safety, and coverage requirements necessary to deliver therapeutic benefit.

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.

Successful Treatment of Catastrophic Antiphospholipid Syndrome Using Rituximab: Case Report and Review of the Literature

BACKGROUND

Kidney involvement is a frequent complication of systemic lupus erythematosus (SLE) and kidney biopsy is essential in differentiating lupus nephritis (LN) from thrombotic microangiopathy (TMA) secondary to antiphospholipid autoantibodies (aPL). Association between antiphospholipid syndrome (APS) and acquired hemophilia due to inhibitors was very rarely described in SLE patients.

CASE PRESENTATION

We present the case of a 61-year-old male diagnosed with SLE who acquired deficiency of clotting factor VIII due to circulating inhibitors, admitted for acute kidney injury (AKI), microangiopathic hemolytic anemia, thrombocytopenia, and diplopia. Kidney biopsy showed TMA due to APS, but no signs of LN. Head computed tomography identified low dense areas in the white matter, suggesting small blood vessels' involvement. A diagnosis of probable catastrophic antiphospholipid syndrome (CAPS) was established and treatment with low molecular weight heparin, intravenous methylprednisolone, plasmapheresis, and rituximab was initiated, followed by resolution of AKI, diplopia, and TMA with complete depletion of CD19+B-lymphocytes (CD19+B-Ly) after one month. We further review the current knowledge regarding pathogenesis and management of CAPS in SLE patients.

CONCLUSIONS

Targeted therapy was possible after kidney biopsy, improving renal and general prognosis. CD19+B-Ly repopulation preceded biological relapse, so monitoring of CD19+B-Ly may serve as a tool to predict relapses and guide rituximab therapy.

Outcome measures and biomarkers in chronic inflammatory demyelinating polyradiculoneuropathy: from research to clinical practice

Introduction: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an immune-mediated syndrome characterized clinically by weakness and/or numbness that evolves over 2 months or more. The heterogeneity of clinical features necessitates an individualized approach to disease monitoring that takes lessons learned from clinical trials and applies them to clinical practice.Areas covered: This review discusses the importance of clinimetrics and biomarkers in CIDP diagnosis and disease monitoring. Highlighted are the challenges of defining responses to immunotherapy, the usefulness, and limitations of utilizing evidence-based clinical outcome measures during routine clinical care, and the evolving understanding of how diagnostic and disease activity biomarkers may reshape our treatment and disease monitoring paradigms.Expert opinion: Although disability and impairment outcome measures are commonly used in CIDP to indicate disease status, the nonspecific nature of these metrics limits the ability to attribute a change in any given metric to a change in CIDP. This interpretive challenge may be magnified by inconsistencies in the direction of change as well as a strong placebo effect. There is a need to improve our understanding of minimally important changes in existing outcome measures as a means to personalize treatment and to better assess disease activity status with biomarker discovery.

Factors Associated With Short-term Relapse in Patients With Pemphigus Who Receive Rituximab as First-line Therapy: A Post Hoc Analysis of a Randomized Clinical Trial

Importance

Rituximab and short-term corticosteroid therapy are the criterion standard treatments for patients with newly diagnosed moderate to severe pemphigus.

Objective

To examine factors associated with short-term relapse in patients with pemphigus treated with rituximab.

Design, Setting, and Participants

This post hoc analysis of a randomized clinical trial (Comparison Between Rituximab Treatment and Oral Corticosteroid Treatment in Patients With Pemphigus [RITUX 3]) conducted from January 1, 2010, to December 31, 2015, included patients from 20 dermatology departments of tertiary care centers in France from the RITUX 3 trial and 3 newly diagnosed patients treated according to the trial protocol. Data analysis was performed from February 1 to June 30, 2019.

Exposure

Patients randomly assigned to the rituximab group in the RITUX 3 trial and the 3 additional patients were treated with 1000 mg of intravenous rituximab on days 0 and 14 and 500 mg at months 12 and 18 combined with a short-term prednisone regimen.

Main Outcomes and Measures

Baseline (pretreatment) clinical and biological characteristics (Pemphigus Disease Area Index [PDAI] score, ranging from 0-250 points, with higher values indicating more severe disease) and changes in anti-desmoglein (DSG) 1 and anti-DSG3 values as measured by enzyme-linked immunosorbent assay during the 3 months after rituximab treatment were compared between patients with disease relapse and those who maintained clinical remission during the first 12 months after treatment. The positive and negative predictive values of these factors were calculated.

Results

Among 47 patients (mean [SD] age, 54.3 [17.0] years; 17 [36%] male and 30 [64%] female) included in the study, the mean (SD) baseline PDAI score for patients with relapsing disease was higher than that of the patients with nonrelapsing disease (54 [33] vs 28 [24]; P = .03). At month 3, 7 of 11 patients with relapsing disease (64%) vs 7 of 36 patients with nonrelapsing disease (19%) had persistent anti-DSG1 antibody values of 20 IU/mL or higher and/or anti-DSG3 antibody values of 130 IU/mL or higher (P = .01). A PDAI score of 45 or higher defining severe pemphigus and/or persistent anti-DSG1 antibody values of 20 IU/mL or higher and/or anti-DSG3 antibody values of 130 IU/mL or higher at month 3 provided a positive predictive value of 50% (95% CI, 27%-73%) and a negative predictive value of 94% (95% CI, 73%-100%) for the occurrence of relapse after rituximab.

Conclusions and Relevance

The findings suggest that initial PDAI score and changes in anti-DSG antibody values after the initial cycle of rituximab might help differentiate a subgroup of patients with high risk of relapse who might benefit from maintenance rituximab infusion at month 6 from a subgroup of patients with low risk of relapse who do not need early maintenance therapy.

Trial Registration

NCT00784589.

Safety of Newer Disease Modifying Therapies in Multiple Sclerosis

In the past decade, the therapeutic arsenal for multiple sclerosis has expanded greatly. Newer more potent disease modifying therapies (DMTs) with varying mechanisms of actions are increasingly used early in the disease course. These newer DMTs include oral therapies (teriflunomide, dimethyl fumarate, fingolimod, siponimod, ozanimod, and cladribine) and infusion therapies (natalizumab, alemtuzumab, and ocrelizumab), and are associated with better control of disease activity and long-term outcomes in patients with MS compared to older injectable therapies (interferon beta and glatiramer acetate). However, they are associated with safety concerns and subsequent monitoring requirements. Adverse events are initially observed in phase 2 and 3 clinical trials, and further long-term data are collected in phase 3 extension studies, case series, and post-marketing reports, which highlight the need to periodically re-evaluate and adjust monitoring strategies to optimize treatment safety in an individualized approach.

COVID-19 vaccine-readiness for anti-CD20-depleting therapy in autoimmune diseases

Although most autoimmune diseases are considered to be CD4 T cell- or antibody-mediated, many respond to CD20-depleting antibodies that have limited influence on CD4 and plasma cells. This includes rituximab, oblinutuzumab and ofatumumab that are used in cancer, rheumatoid arthritis and off-label in a large number of other autoimmunities and ocrelizumab in multiple sclerosis. Recently, the COVID-19 pandemic created concerns about immunosuppression in autoimmunity, leading to cessation or a delay in immunotherapy treatments. However, based on the known and emerging biology of autoimmunity and COVID-19, it was hypothesised that while B cell depletion should not necessarily expose people to severe SARS-CoV-2-related issues, it may inhibit protective immunity following infection and vaccination. As such, drug-induced B cell subset inhibition, that controls at least some autoimmunities, would not influence innate and CD8 T cell responses, which are central to SARS-CoV-2 elimination, nor the hypercoagulation and innate inflammation causing severe morbidity. This is supported clinically, as the majority of SARS-CoV-2-infected, CD20-depleted people with autoimmunity have recovered. However, protective neutralizing antibody and vaccination responses are predicted to be blunted until naive B cells repopulate, based on B cell repopulation kinetics and vaccination responses, from published rituximab and unpublished ocrelizumab (NCT00676715, NCT02545868) trial data, shown here. This suggests that it may be possible to undertake dose interruption to maintain inflammatory disease control, while allowing effective vaccination against SARS-CoV-29, if and when an effective vaccine is available.

Rituximab in adult minimal change disease and focal segmental glomerulosclerosis - What is known and what is still unknown?

Primary forms of minimal change disease and focal segmental glomerulosclerosis are rare podocytopathies and clinically characterized by nephrotic syndrome. Glucocorticoids are the cornerstone of the initial immunosuppressive treatment in these two entities. Especially among adults with minimal change disease or focal segmental glomerulosclerosis, relapses, steroid dependence or resistance are common and necessitate re-initiation of steroids and other immunosuppressants. Effective steroid-sparing therapies and introduction of less toxic immunosuppressive agents are urgently needed to reduce undesirable side effects, in particular for patients whose disease course is complex. Rituximab, a B cell depleting monoclonal antibody, is increasingly used off-label in these circumstances, despite a low level of evidence for adult patients. Hence, critical questions concerning drug-safety, long-term efficacy and the optimal regimen for rituximab-treatment remain unanswered. Evidence in the form of large, multicenter studies and randomized controlled trials are urgently needed to overcome these limitations.

Lessons for rituximab therapy in patients with rheumatoid arthritis

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

Clinical Response and Pattern of B cell Suppression with Single Low Dose Rituximab in Nephrology

Background

There is no consensus regarding dose and frequency of rituximab in nephrology with extrapolation of doses used in treating lymphoproliferative disorders. There are no guidelines on targeting initial and subsequent doses on the basis of CD19⁺ B cells.

Methods

Initially, 100 mg rituximab was given to 42 adults with steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS), idiopathic membranous nephropathy (MN), and high-immunologic-risk kidney transplantation. Absolute and percentage levels of CD19 B cells and clinical status were assessed at baseline, days 30, 90, and 180, and at 1 year. Subsequent doses of rituximab were on the basis of CD19 B cell reconstitution and clinical response.

Results

CD19 B cell percentage decreased from 16.3 ± 7.6 to 0.3 ± 0.3 (P≤0.001), 1.9 ± 1.7 (P≤0.001), and 4.0 ± 4.5 (P=0.005) by 30, 90, and 180 days, respectively. Suppression of CD19 B cell count below 1% at days 30, 90, and 180 was seen in 40 of 42 (95.2%), 18 of 42 (42.9%), and 7 of 42 (16.7%) patients, respectively. Of 30 with SDNS and FRNS followed up for 1 year, 29 (96.7%) went into remission at day 30. Remission was sustained in 23 (76.6%) at day 180 and 21 (70%) at 1 year. There was a significant decrease (P<0.001) in the dose of steroids needed to maintain remission at 180 days after rituximab (0.27 ± 0.02 mg/kg to 0.02 ± 0.00 mg/kg). CD19 B cell percentage at 90 days correlated with relapse (P=0.001; odds ratio 1.42; 95% confidence interval, 1.25 to 2.57). Eighteen (60%) required an additional dose. Of five with MN, four achieved remission by 6 months, which was sustained in three by 1 year. Of the seven kidney transplant recipients, two had antibody-mediated rejections, although CD19 B cells were suppressed even at 1 year.

Conclusions

Low-dose rituximab induces sustained depletion of CD19 B cells for up to 90 days. Its role in preventing relapses in SDNS, FRNS, MN, and rejection needs further study.

Accelerated Allograft Vasculopathy With Rituximab After Cardiac Transplantation

BACKGROUND

The CTOT-11 (Prevention of Cardiac Allograft Vasculopathy Using Rituximab Therapy in Cardiac Transplantation [Clinical Trials in Organ Transplantation-11]) study was a randomized, placebo-controlled, multicenter, double-blinded clinical trial in nonsensitized primary heart transplant (HTX) recipients.

OBJECTIVES

The study sought to determine whether B cell depletion therapy would attenuate the development of cardiac allograft vasculopathy.

METHODS

A total of 163 HTX recipients were randomized to rituximab 1,000 mg intravenous or placebo on days 0 and 12 post-transplant. Primary outcome was change in percent atheroma volume (PAV) from baseline to 1 year measured by intravascular ultrasound. Secondary outcomes included treated episodes of acute rejection, de novo anti-HLA antibodies (including donor-specific antibodies), and phenotypic differentiation of B cells.

RESULTS

There were no significant differences at study entry between the rituximab and placebo groups. Paired intravascular ultrasound measures were available at baseline and 1 year in 86 subjects (49 rituximab, 37 placebo). The mean ± SD change in PAV at 12 months was +6.8 ± 8.2% rituximab versus +1.9 ± 4.4% placebo (p = 0.0019). Mortality at 12 months was 3.4% rituximab versus 6.8% placebo (p = 0.47); there were no retransplants or post-transplant lymphoproliferative disorder. The rate of treated rejection was 24.7% rituximab versus 32.4% placebo (p = 0.28). Rituximab therapy effectively eliminated CD20⁺/CD19⁺ B cells followed by a gradual expansion of a CD19^- cell population in the rituximab-treated group.

CONCLUSIONS

A marked, unexpected increase in coronary artery PAV with rituximab was observed during the first year in HTX recipients. One-year mortality was not impacted; however, longer-term follow-up and mechanistic explanations are required. (Prevention of Cardiac Allograft Vasculopathy Using Rituximab [Rituxan] Therapy in Cardiac Transplantation; NCT01278745).

Flow Cytometry as a Diagnostic Tool in Primary and Secondary Immune Deficiencies

Flow cytometry is an incredibly powerful diagnostic tool in the evaluation of primary and secondary immune deficiencies. Assay design and setup involves a methodological consideration of specimen collection, marker and fluorochrome selection, antibody titration, instrumentation, compensation, gating, reference range development, and cross validation. Commonly used analyses for lymphocytes are the lymphocyte subset, T-cell subset, B-cell and T-cell naive/memory, double-negative T-cell, and plasmablast panels. Flow cytometry has direct clinical applicability to the workup of severe forms of primary immune deficiency disorders and is used diagnostically and for therapeutic monitoring in the context of secondary immune deficiency disorders.

Repeated low-dose rituximab treatment based on the assessment of circulating B cells in patients with refractory myasthenia gravis

Background:

The objective of this study was to evaluate the efficacy and safety of repeated low-dose rituximab treatment guided by monitoring circulating CD19+ B cells in patients with refractory myasthenia gravis (MG).

Methods:

Patients with refractory MG who had received rituximab treatment at two teaching hospitals between September 2013 and January 2017 were reviewed retrospectively. The treatment protocol consisted of an induction treatment with low-dose rituximab (375 mg/m² twice with a 2-week interval), followed by retreatment (375 mg/m² once). Retreatment was based on either circulating CD19+ B-cell repopulation or clinical relapse. Outcome measures included the MG Foundation of America (MGFA) clinical classification and postintervention status, prednisolone dose, CD19+ B-cell counts, clinical relapse, and adverse effects.

Results:

Of 17 patients, 11 (65%) achieved the primary endpoint, defined as the minimal manifestation or better status with prednisolone ⩽5 mg/day, after median 7.6 months (range, 2–17 months) following rituximab treatment. Over a median follow up of 24 months (range, 7–49 months), a total of 30 retreatments were undertaken due to clinical relapse without B-cell repopulation (n = 6), on the basis of B-cell repopulation alone (n = 16) and both (n = 8). B-cell recovery appeared to be in parallel with clinical relapse on the group level, although the individual-level association appeared to be modest, with B-cell repopulation observed only at 57% (8/14) of clinical relapses.

Conclusions:

The repeated low-dose rituximab treatment based on the assessment of circulating B-cell depletion could be a cost-effective therapeutic option for refractory MG. Further studies are needed to verify the potentially better cost-effectiveness of low-dose rituximab, and to identify biomarkers that help optimize treatment in MG patients.

Rituximab in autoimmune pemphigoid diseases: Indications, optimized regimens, and practice gaps

Rituximab is a monoclonal antibody targeting CD20 on B cells with proven efficacy for pemphigus vulgaris, now an FDA-approved indication. Other autoimmune bullous diseases can be challenging to treat and have significant associated morbidity and mortality, but data supporting the use of rituximab in pemphigoid group diseases remain limited. Although rituximab demonstrates efficacy for clinical improvement and remission in pemphigoid, concern for adverse events may also limit the use of this medication. We review the current evidence fo rthe use of rituximab in pemphigoid diseases, pertinent dosing schedules and laboratory monitoring, and the associated common and rare adverse events. Review of the literature to date not only supports consideration of rituximab for treatment of refractory pemphigoid group diseases but also reflects tolerability and an acceptable safety profile.

Secondary antibody deficiency in neurology

PURPOSE OF REVIEW

Induction of lymphocyte depletion is increasingly used as a therapeutic strategy for central and peripheral neuroinflammatory disease. However, there is also a growing recognition of the treatment-related complication of secondary antibody deficiency (SAD). Although the occurrence of hypogammaglobulinaemia is a recognized phenomenon during immunomodulation, robust data on the coexistence of impaired responses to immunization, and significant and/or atypical infections is scarce. Here we review the literature on SAD in anti-CD20 therapy.

RECENT FINDINGS

Several factors that may increase the incidence of SAD have now been identified, including low levels of immunoglobulins prior to the commencement of B-cell ablation therapy, duration of maintenance therapy, and concurrent or prior use of other immunosuppressing agents such as cyclophosphamide and steroids. Measurement of disease-specific antibodies and vaccine response are likely to be helpful adjuncts to measurement of serum immunoglobulin levels during B-cell depleting therapy. Supportive treatment may include amending the treatment schedule to limit cumulative dose.

SUMMARY

B-cell depleting agents offer considerable therapeutic benefit in neurology. We propose modifications in current practice that include risk stratification and early identification of SAD, with the aim of minimising morbidity and mortality related to this underappreciated condition.

Learning from other autoimmunities to understand targeting of B cells to control multiple sclerosis

Although many suspected autoimmune diseases are thought to be T cell-mediated, the response to therapy indicates that depletion of B cells consistently inhibits disease activity. In multiple sclerosis, it appears that disease suppression is associated with the long-term reduction of memory B cells, which serves as a biomarker for disease activity in many other CD20+ B cell depletion-sensitive, autoimmune diseases. Following B cell depletion, the rapid repopulation by transitional (immature) and naïve (mature) B cells from the bone marrow masks the marked depletion and slow repopulation of lymphoid tissue-derived, memory B cells. This can provide long-term protection from a short treatment cycle. It seems that memory B cells, possibly via T cell stimulation, drive relapsing disease. However, their sequestration in ectopic follicles and the chronic activity of B cells and plasma cells in the central nervous system may drive progressive neurodegeneration directly via antigen-specific mechanisms or indirectly via glial-dependent mechanisms. While unproven, Epstein-Barr virus may be an aetiological trigger of multiple sclerosis. This infects mature B cells, drives the production of memory B cells and possibly provides co-stimulatory signals promoting T cell-independent activation that breaks immune tolerance to generate autoreactivity. Thus, a memory B cell centric mechanism can integrate: potential aetiology, genetics, pathology and response to therapy in multiple sclerosis and other autoimmune conditions with ectopic B cell activation that are responsive to memory B cell-depleting strategies.

Trial Design and Statistical Considerations on the Assessment of Pharmacodynamic Similarity

Pharmacodynamics (PD) similarity is an important component to support the claim of similarity between two drugs or devices. This article investigates the trial design and statistical considerations in the equivalence test of PD endpoints. Using bone resorption marker CTX as a case study, the relationship between the PD readouts and drug potency was explored to evaluate the sensitivity of the PD endpoint and guide equivalence margin selection. For PD data that have high baseline variability, one conventional similarity assessment method was to apply baseline-normalization followed by the standard bioequivalence (BE) test (Lancet Haematol. 4:e350-61, 2017, Ann Rheum Dis. 2017). This study showcased the drawbacks of the conventional method for PD data that were close to inhibition saturation, as the baseline-normalization significantly skewed the distribution of the PD data toward non-log-normal. In such cases, the standard BE test can produce an inflated type I error. Alternatively, ANCOVA, when applied to the un-normalized PD data with the baseline as a covariate, produced a satisfactory type I error with sufficient power. Therefore, ANCOVA was recommended for equivalence test of PD markers that has a saturated inhibition profile and high variability at baseline. Moreover, the relationship between PD readouts and drug potency was used to explore the sensitivity of the PD endpoint and it could help justify the equivalence margins, since the standard 80% to 125% BE margin often does not apply to PD. Finally, a decision tree was proposed to help guide the design of the PD equivalence study in the choice of PD endpoints and statistical methods.

Rituximab Use in the Management of Childhood Nephrotic Syndrome

Childhood nephrotic syndrome is a challenging and often persistent renal disorder, and its incidence varies between different ethnicities and regions. Corticosteroids have been the main treatment for decades and are effective in most children with idiopathic NS, although 10-15% of these children become steroid resistant. Furthermore, some initially steroid sensitive children follow a steroid dependent or frequently relapsing course and are therefore at increased risk for developing steroid toxicity. In such children, alternative immunosuppressive medications are used to induce and/or maintain remission of NS. One such drug, rituximab, is a monoclonal antibody directed against the B lymphocyte CD20 marker which induces depletion of B cells, and has shown promising results in the management of NS in children. In this review, we summarize recent studies on the efficacy and safety of rituximab in the different types of childhood nephrotic syndrome, the known and potential mechanisms of action of rituximab, its possible complications and side effects, and the available and potential biomarkers of rituximab activity.

Right drug, right patient, right time: aspiration or future promise for biologics in rheumatoid arthritis?

Individualising biologic disease-modifying anti-rheumatic drugs (bDMARDs) to maximise outcomes and deliver safe and cost-effective care is a key goal in the management of rheumatoid arthritis (RA). Investigation to identify predictive tools of bDMARD response is a highly active and prolific area of research. In addition to clinical phenotyping, cellular and molecular characterisation of synovial tissue and blood in patients with RA, using different technologies, can facilitate predictive testing. This narrative review will summarise the literature for the available bDMARD classes and focus on where progress has been made. We will also look ahead and consider the increasing use of 'omics' technologies, the potential they hold as well as the challenges, and what is needed in the future to fully realise our ambition of personalised bDMARD treatment.

Both cladribine and alemtuzumab may effect MS via B-cell depletion

Objective:

To understand the efficacy of cladribine (CLAD) treatment in MS through analysis of lymphocyte subsets collected, but not reported, in the pivotal phase III trials of cladribine and alemtuzumab induction therapies.

Methods:

The regulatory submissions of the CLAD Tablets Treating Multiple Sclerosis Orally (CLARITY) (NCT00213135) cladribine and Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis, study one (CARE-MS I) (NCT00530348) alemtuzumab trials were obtained from the European Medicine Agency through Freedom of Information requests. Data were extracted and statistically analyzed.

Results:

Either dose of cladribine (3.5 mg/kg; 5.25 mg/kg) tested in CLARITY reduced the annualized relapse rate to 0.16–0.18 over 96 weeks, and both doses were similarly effective in reducing the risk of MRI lesions and disability. Surprisingly, however, T-cell depletion was rather modest. Cladribine 3.5 mg/kg depleted CD4⁺ cells by 40%–45% and CD8⁺ cells by 15%–30%, whereas alemtuzumab suppressed CD4⁺ cells by 70%–95% and CD8⁺ cells by 47%–55%. However, either dose of cladribine induced 70%–90% CD19⁺ B-cell depletion, similar to alemtuzumab (90%). CD19⁺ cells slowly repopulated to 15%–25% of baseline before cladribine redosing. However, alemtuzumab induced hyperrepopulation of CD19⁺ B cells 6–12 months after infusion, which probably forms the substrate for B-cell autoimmunities associated with alemtuzumab.

Conclusions:

Cladribine induced only modest depletion of T cells, which may not be consistent with a marked influence on MS, based on previous CD4⁺ T-cell depletion studies. The therapeutic drug-response relationship with cladribine is more consistent with lasting B-cell depletion and, coupled with the success seen with monoclonal CD20⁺ depletion, suggests that B-cell suppression could be the major direct mechanism of action.

Theranostic of biopharmaceuticals

Monoclonal antibodies (mAbs) and fusion proteins with an Fc portion of immunoglobulin G (IgG) are emblematic of the remarkable expansion of biopharmaceuticals. Despite their biological origin, these products display an interindividual variability in their efficacy and/or side effects, which must be taken into consideration. Biological monitoring allowing for adapted prescription and dose adjustments may lead to therapeutic optimization and limitation of the high costs of these drugs. Herein, we review the biological theranostic of mAbs and Fc fusion proteins, including pre-treatment analyses, monitoring of efficacy, therapeutic drug monitoring, and monitoring of side effects. Supported by concrete evidence, a specific interest is given to individualised therapeutic monitoring that combines intention to treat, biomarkers of efficacy and adaptation of serum concentrations.

The role of anticitrullinated protein antibodies in the early stages of rheumatoid arthritis

PURPOSE OF REVIEW

This review provides an update on the recent discoveries on the role of anticitrullinated protein antibodies (ACPA) in early rheumatoid arthritis (RA).

RECENT FINDINGS

RA is characterized by an immune response against posttranslationally modified proteins, in particular citrullinated proteins. Recent studies have found that the ACPA response matures shortly before clinical disease manifests itself and is characterized by an increase in titre, isotype switching, antigen-recognition profile, and a change in the Fc-glycosylation pattern. To date, many citrullinated autoantigens have been identified and novel studies suggest that the human leucocyte antigen class II locus may directly influence the maturation of the ACPA response via antigen-specific T cells. Clinical studies have demonstrated that effective treatment of arthritis can lead to reduced ACPA levels or a change in composition of ACPA. In addition to ACPA, autoantibodies targeting other posttranslational modifications have been identified and may be associated with disease prognosis.

SUMMARY

Key studies have demonstrated that autoimmunity against citrullinated proteins is already present in preclinical RA and matures over time. Future studies are required to reveal whether autoantibodies and the B cells that produce them play a role in disease development or can function as biomarkers for disease maturation.

Refractory Autoimmune Hepatitis: Beyond Standard Therapy

Autoimmune hepatitis (AIH) can be difficult to control, particularly in some African-Americans. When standard therapy of prednisone and azathioprine is ineffective or poorly tolerated, alternative therapies are resorted to. We report two patients with AIH who were refractory to or intolerant of standard therapy. They initially responded to a combination of tacrolimus and MMF, but eventually developed acute flares of the disease that had to be managed with sirolimus, and in one case, rituximab, to achieve remission.

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

Introduction

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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