Efficacy and safety of rituximab biosimilar (CT-P10) in IgG4-related disease: an observational prospective open-label cohort study

A protocol for targeted B-lymphocyte depletion for the treatment of IgG4-related disease

OBJECTIVES

To determine the clinical outcomes of patients with immunoglobulin 4-related disease (IgG4-RD) treated with a defined B-cell depletion protocol using rituximab.

METHODS

Patients were included if they had (i) an IgG4-RD diagnosis at Imperial College Healthcare NHS Trust between February 2017 and October 2022, and (ii) >9 months of follow-up data available following the first rituximab dose. The rituximab protocol targeted B-cell depletion to <10 cells/microliter for a maintenance period of two years. Electronic records were used to define patient demographics, serological and radiological variables and treatment responses according to the IgG4-RD responder index (RI).

RESULTS

Forty-five patients received induction treatment with rituximab. Two patients had insufficient follow-up data for outcome analysis. All patients responded to rituximab therapy according to the IgG4-RD RI. Most patients (25/43, 58%) were also treated with low-dose glucocorticoids at the time of rituximab induction (median prednisolone dose 5 mg daily) and 4/25 (16%) remained on prednisolone at two years (median prednisolone dose 5 mg daily). Disease flares occurred in 11/43 (26%) patients; 9/11 flares occurred in the presence of B-cell repopulation; 2/11 (18.1%) flares occurred in the absence of B-cell repopulation (>10 cells/uL). All flares re-treated with rituximab (7/7, 100%) responded positively.

CONCLUSION

Rituximab administration targeting B-cell depletion for a two-year period is an effective treatment strategy for IgG4-RD and can limit the cumulative glucocorticoid exposure. Flares are uncommon and typically occur in the setting of B-cell repopulation, with good clinical responses to further rituximab administration.

IgG4-related disease and other fibro-inflammatory conditions

IgG4-related disease (IgG4-RD) is a fibro-inflammatory disorder usually characterized by multi-organ involvement. Its pathogenesis is complex and involves genetic and environmental factors, while immune responses usually mediate organ damage and promote fibrosis, which is a key feature of the disease. IgG4 responses, however, are not exclusive to IgG4-RD and can be encountered in other diseases with phenotypes that partially overlap that of IgG4-RD. Although IgG4-RD has clinical and histological hallmarks, the lack of validated diagnostic criteria often makes the diagnosis challenging, requiring a multi-dimensional approach that integrates clinical, radiological and serological data. The present Review covers recent advances in the understanding of disease drivers and its clinical phenotypes, mainly focusing on the differential diagnosis with potential IgG4-RD mimickers, namely histiocytoses, lymphoproliferative disorders, systemic vasculitides and other immune-mediated conditions. The Review also provides a schematic approach to IgG4-RD treatment, including a brief overview of glucocorticoid-sparing agents and emerging therapies, from B cell-depleting monoclonal antibodies to cytokine-targeting drugs, the majority of which are currently under investigation in randomized clinical trials.

Increased prevalence of malignancies in patients with IgG4-related disease: implications for clinical care

OBJECTIVES

The association between cancer and IgG4-related disease (IgG4-RD) is evolving. The primary aim of this study was to investigate the prevalence of malignancies in IgG4-RD. The secondary aim was to describe the epidemiological and clinical characteristics of IgG4-RD patients with a history of cancer.

METHODS

Two hundred and ten patients with IgG4-RD were included in this retrospective study. IgG4-RD phenotypes, clinical and serological variables were analysed. The prevalence of cancer in IgG4-RD was compared with that in the Italian population using the registry of the Global Cancer Observatory (GCO) of the World Health Organization. The Standardized Incidence Ratio (SIR) for cancer in IgG4-RD was obtained based on the 5-year Limited Duration Prevalence (2015-2020) of tumours in the Italian population.

RESULTS

Thirty-seven/210 patients (18%) developed cancer before or after the diagnosis of IgG4-RD. Solid and haematologic tumours were more frequently observed in pancreato-biliary IgG4-RD. The SIR for malignancy in IgG4-RD patients was 2.54 higher than the general Italian population (P = 0.007). The SIR was 2.78 higher for males (P = 0.005) and 1.15 higher for females (P > 0.05). Thirty-two malignancies were diagnosed before and 16 after IgG4-RD diagnosis. Interval 'from IgG4-RD to cancer' was shorter than that 'from cancer to IgG4-RD'. Most tumours occurring after IgG4-RD developed within 36 months from diagnosis of IgG4-RD.

CONCLUSIONS

The prevalence of cancer in patients with IgG4-RD is increased compared with the Italian population and mechanistically suggests a possible paraneoplastic association. Close surveillance is warranted for the first 36 months after IgG4-RD diagnosis.

Pharmacological Management of IgG4-Related Disease: From Traditional to Mechanism-Based Targeted Therapies

IgG4-related disease (IgG4-RD) is an immune-mediated disorder characterized by organ enlargement and dysfunction. The formation of tertiary lymphoid tissues (TLTs) in affected organs is crucial for understanding IgG4-RD, as T follicular helper (Tfh) 2 cells within TLTs drive IgG4+B cell differentiation, contributing to mass formation. Key cytokines IL-4 and IL-10, produced by Tfh2 cells, are essential for this process. Additionally, cytotoxic T cells and M2 macrophages significantly contribute to inflammation and fibrosis in the lesions. These insights into IgG4-RD have led to the development of innovative targeted therapies. While glucocorticoids are effective in many cases, they often cause disease flares during tapering and rarely result in long-term, treatment-free remissions. Long-term glucocorticoid use poses significant challenges owing to potential side effects, particularly in older patients who may already have complications such as diabetes and atherosclerotic diseases. In contrast, targeted therapies offer a promising alternative, potentially providing more effective disease control with fewer side effects. Current research is exploring several exciting approaches, including B-cell depletion, targeted immunomodulation of B cells, Bruton's tyrosine kinase inhibition, disruption of co-stimulation pathways, targeting the SLAMF7 cytokine or its receptor blockade (BAFF, IL-4, or IL-6), and JAK-STAT signaling pathway inhibition. These emerging strategies hold the promise of improving patient outcomes and advancing the management of IgG4-RD.

Update on Autoimmune Pancreatitis and IgG4-Related Disease

Autoimmune pancreatitis is an increasingly recognized inflammatory type of subacute pancreatitis; two subtypes of autoimmune pancreatitis have been identified so far: the "lymphoplasmacytic" type 1 variant and the "neutrophilic" type 2 variant. Type 1 autoimmune pancreatitis represents the most common manifestation of IgG4-related disease, a fibro-inflammatory disorder characterized by elevated IgG4 levels in the serum and affected tissues. Type 2 autoimmune pancreatitis is a pancreas-specific disorder that frequently occurs in the context of inflammatory bowel diseases. Due to the complexity of both diseases, a comprehensive work up with imaging, laboratory, and histological studies is required to achieve a diagnosis and rule out malignancies. Glucocorticoids represent the cornerstone of the treatment, often supported by other immunosuppressive drugs in case of steroid intolerance or aggressive disease. Maintenance treatment is often employed in type 1 autoimmune pancreatitis because of the higher relapse rate compared with type 2 autoimmune pancreatitis. In this review, we summarize the key concept of autoimmune pancreatitis, delve into the differential diagnosis between the two subtypes, and cover the recent relevant research findings and pressing unmet needs.

The Differential Complement, Fc and Chemokine Receptor Expression of B Cells in IgG4-Related Pancreatobiliary Disease and Primary Sclerosing Cholangitis and Its Relevance for Targeting B Cell Pathways in Disease

Background: Immune-mediated liver and biliary conditions, such as IgG4-related pancreatobiliary disease (IgG4-PB) and a subset of primary sclerosing cholangitis (PSC- high(h)IgG4), exhibit increased IgG4 levels in the blood. The relative expression of IgG4+ and IgG1+ B cells in the blood and the expression of complement and Fc receptors on these IgG1+ and IgG4+ B cells in IgG4-PB and PSC have not been previously described. We hypothesised that the patterns of expression of these cells and their receptors would differ, are relevant to disease pathogenesis and may represent therapeutic targets. Methods: CD19+ B cells were sorted from blood collected from patients with IgG4-PB, PSC-high(h)IgG4 and healthy volunteers. Cells were stained with fluorescent labelled antibodies specific to IgG1, IgG4, complement receptors (CR1 and CR2), Fc receptors (FcεRII and FcγRIIb) and chemokine receptors (CXCR3, CXCR4, CXCR5) and were analysed by flow cytometry. Findings: IgG4-PB, compared to healthy volunteers, showed decreased CR2 expression on IgG1+ B cells (MFI 416 (275-552) vs. 865 (515-3631), p = 0.04) and IgG4+ B cells (MFI 337 (231-353) vs. 571 (398-2521), p = 0.03). IgG4-PB, compared to healthy volunteers, showed increased FcεRII expression on IgG4+ B cells (MFI 296 (225-617) vs. 100 (92-138), p = 0.0145) and decreased FcγRIIb expression on IgG1+ B cells (134 (72-161) vs. 234 (175-291), p = 0.0262). FcγRIIb expression was also decreased in IgG1+ B cells in patients with PSC-hIgG4 compared to healthy volunteers. Conclusions: This exploratory study indicates that in IgG4-PB, B cells have decreased CR2 and FcγRIIb expression and increased FcεRII expression, suggesting altered sensitivity to complement, IgG-mediated inhibition and sensitisation by IgE, which may promote the relative expansion of IgG4+ B cells in this disease.

Switching from rituximab originator to GP2013 or CT-P10 biosimilars in autoimmune rheumatic diseases: drug retention rate and safety data from a multicentric retrospective cohort

Background

Real-world evidence supporting a safe and effective transition from rituximab originator (RTX-O) to its biosimilars (RTX-B) in autoimmune rheumatic diseases (ARDs) is still limited.

Objectives

The primary aims of this study were to evaluate the long-term persistence of RTX-B after the non-medical switch (NMS) from RTX-O in ARD patients, and to explore the RTX-B safety profile. The secondary aims were to evaluate the impact of different factors on RTX-B drug retention rate (DRR) and to identify any factors associated with RTX-B discontinuation.

Design

Retrospective observational study.

Methods

We included consecutive ARD patients undergoing NMS from RTX-O to GP2013 or CT-P10 from January 2018 to December 2020. RTX-B DRR was estimated by Kaplan-Meier plot analysis and compared according to different factors by the Log-rank test; the Cox proportional hazard model was used to detect factors associated with RTX-B discontinuation in the first 36 months.

Results

We enrolled 181 patients switching to RTX-B: GP2013 in 143 (79.0%) cases and CT-P10 in 38 (21.0%). The estimated DRR for RTX-B was 81.5% at 12 months, 80.6% at 24 months, and 77.4% at 36 months. The incidence of adverse events with RTX-B was 12.6/100 patients/year. In the Log-rank test, no statistically significant differences were observed in the RTX-B DRR according to sex (p = 0.171), ARD diagnosis (p = 0.281), and concomitant immunosuppressive therapy (p = 0.054); on the contrary, patients on GP2013 showed a higher DRR than those on CT-P10 (p < 0.001). In the Cox proportional hazard analysis, the switch to CT-P10 was associated with a higher probability of stopping treatment (hazard ratio, 1.83 (confidence interval, 1.10-3.04), p = 0.02).

Conclusion

NMS to RTX-B is associated with a high chance of retaining the drug for up to 36 months, irrespective of the diagnosis. GP2013 showed a higher retention rate than CT-P10.

Efficacy of Rituximab in Autoimmune-Mediated IgG4 Pancreaticobiliary Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

IgG4 pancreaticobilliary disease (IgG4-PBD) typically shows a rapid improvement with glucocorticoid treatment, yet most patients experience a recurrence. Rituximab (RTX) has emerged as a hopeful approach to prevent relapses in IgG4-PBD. Nevertheless, there is a lack of data on the efficacy and safety of RTX in IgG4-PBD. In this study, we aim to perform a systematic review and meta-analysis to study the pooled efficacy of RTX in this patient population.

METHODS

Multiple databases, including MEDLINE, SCOPUS, and Embase, were searched (in March 2024) using specific terms for studies evaluating the efficacy and safety of RTX in IgG4 pancreatic biliary disease. Outcomes of interest were relapse, remission, partial remission rates, and adverse events. Standard meta-analysis methods were used using the random-effects model. I2% heterogeneity was used to assess the heterogeneity.

RESULTS

Twelve studies were included in the study (257 patients). The pooled rate of complete remission was 68% (54% to 80%), I2 =53%, respectively. The pooled relapse rate was 23% (13% to 36%), I2=64%. The pooled rate of total adverse events was 21% (12% to 35%), I2=52%. The pooled partial remission rate is 16% (7% to 32%), I2=25%. The pooled rate of complete and partial remission was 81% (66% to 90%), I2=75%. The pooled infusion reaction and infection were 12% (7% to 18%), I2=0% and 14% (8% to 22%), I2=16%, respectively.

CONCLUSION

RTX therapy appears effective in inducing and maintaining remission of pancreaticobiliary disease with a low rate of side effects. RTX presents as a promising treatment option for patients grappling with recurrent or unresponsive IgG4-related ailments. In addition, RTX emerges as an attractive alternative for individuals intolerant to steroids or experiencing IgG4-related disease relapses. Future studies comparing RTX with other immunomodulators will offer deeper insights into relapse factors and elucidate the appropriateness of utilizing this maintenance treatment following the initial flare.

Efficacy and safety of rituximab induction therapy and effect of rituximab maintenance for IgG4-related disease: a systematic review and meta-analysis

BACKGROUND

Previous studies have reported that rituximab (RTX) therapy might be beneficial in reducing relapse rates in patients with IgG4-related disease (IgG4-RD). Therefore, we aimed to systematically assess the efficacy and safety of RTX induction treatment and the effect of RTX maintenance in patients with IgG4-RD.

METHODS

The protocol was registered in the PROSPERO (CRD42023427352). PubMed, Embase, the Cochrane database, Scopus, and the Web of Science were interrogated to identify studies that evaluated the impact of RTX on prognosis in IgG4-RD. We explored the impact of various subgroups of factors on relapse outcomes and focused on the possible role of maintenance therapy in reducing relapse rates. The pooled incidence of adverse events of RTX therapy and the influencing factors have also been evaluated.

RESULTS

Eighteen studies comprising 374 patients (mean age 56.0 ± 8.7 years; male 73.7 %) with a mean follow-up duration of 23.4 ± 16.3 months were included. The pooled estimate of the response rate, complete remission rate, overall relapse rate, adverse event rate, and serious adverse event rate of RTX induction therapy were 97.3 % (95 % CI, 94.7 %-99.1 %), 55.8 % (95 % CI, 39.6 %-71.3 %), 16.9 % (95 % CI, 8.7 %-27.1 %), 31.6 % (95 % CI, 16.7 %-48.9 %) and 3.9 % (95 % CI, 0.8 %-8.9 %), respectively. In subgroup analysis, the pooled relapse rate was significantly lower in studies with maintenance than without maintenance (2.8% vs 21.5 %, p < 0.01). Pooled Kaplan-Meier relapse curves also demonstrated that RTX maintenance therapy provided a better prognosis.

CONCLUSIONS

RTX induction therapy appears to have satisfactory efficacy in the induction of remission in IgG4-RD. In addition, prophylactic RTX maintenance therapy after induction may be beneficial in preventing relapse of IgG4-RD.

Fibrotic phenotype of IgG4-related disease

A prompt response to glucocorticoids is a clinical hallmark of IgG4-related disease. However, manifestations characterised by prominent tissue fibrosis on histological examination can be less responsive to glucocorticoid therapy than other types of IgG4-related disease. These manifestations include retroperitoneal fibrosis, fibrosing mediastinitis, Riedel thyroiditis, orbital pseudotumor, and hypertrophic pachymeningitis, among others. To explain this discrepancy, a preliminary distinction into proliferative and fibrotic phenotypes of IgG4-related disease has been proposed on the basis of clinical presentation, pathological features, and response to immunosuppressive therapy. Implications of this classification for patient management remain an important area of investigation. In this Series paper, we aim to dissect the pathophysiology of tissue fibrosis in IgG4-related disease and discuss how clinicians should approach the management of fibrotic manifestations of IgG4-related disease based on the most recent diagnostic and therapeutic developments.

Rituximab and pericardiectomy with waffle procedure in constrictive pericarditis due to IgG4-related disease: A case report

We should consider IgG4-related disease (IGRD) as one of the potential causes of constrictive pericarditis. In patients with constrictive pericarditis due to IGRD, the combination of surgical treatment and immunosuppressive therapy may be an effective strategy.

Assessment of patient-reported symptoms and distress in IgG4-related disease (IgG4-RD): Development, clinical validation, and content validation of the IgG4-RD Symptom Severity Index

OBJECTIVE

IgG4-related disease (IgG4-RD), a multi-organ autoimmune disease, causes diverse manifestations that can lead to symptoms and distress. We developed and validated the Symptom Severity Index (SSI) to assess symptom burden.

METHODS

A pilot SSI was tested in n = 5; several gaps were identified. Twenty semi-structured qualitative interviews were performed to expand the item set and identify missing symptoms. Subsequent changes resulted in the current SSI; it was administered with quality of life (QOL) measures to n = 136. We assessed symptom burden and the construct validity of the SSI. A distress score for each symptom is calculated by multiplying symptom frequency ("Never" [0 points] to "Every Day" [3 points]) by associated distress ("None" [0 points] to "Very Much" [4 points]). Each distress score is summed to calculate a total SSI score.

RESULTS

The SSI assesses the frequency and distress of 24 symptoms. Among n = 136 with ≥ 1 SSI, 90% experienced ≥ 1 symptom and 88% had distress. The median SSI score was 6.5 (IQR 3.0, 18.0). Fear of more severe disease was observed in 49%. The SSI inversely correlated with the SF-36 (r= - 0.51, p<0.001), the feeling thermometer (r= - 0.28, p<0.001), and the EQ-5D (r= - 0.28, p<0.001). The median SSI score was higher during active vs non-active disease among n = 52 who completed >1 SSI (15 [6, 26] vs. 3 [2, 14], p = 0.008).

CONCLUSIONS

Symptoms and distress are common in IgG4-RD and associated with worse health-related QOL. The SSI has face, content, and construct validity; it corresponds with QOL measures.

Efficacy and Safety of Inebilizumab in IgG4-Related Disease: Protocol for a Randomized Controlled Trial

INTRODUCTION

Immunoglobulin G4-related disease (IgG4-RD) is a debilitating multiorgan disease characterized by recurring flares leading to organ dysfunction, decreased quality of life, and mortality. Glucocorticoids, the standard of care for IgG4-RD, are associated with substantial treatment-related toxicity. Inebilizumab, an antibody directed against CD19, mediates the rapid and durable depletion of CD19+ B cells thought to be involved in IgG4-RD pathogenesis. We describe the first international, prospective, double-blind, placebo-controlled trial to evaluate the safety and efficacy of B-cell depletion for flare prevention in IgG4-RD (MITIGATE).

METHODS

The study was designed by an international panel of physicians with expertise in IgG4-RD. Critical trial design decisions included the selection of participants, definition of clinically meaningful primary and secondary endpoints, accommodation of standard of care, and development of flare diagnostic criteria. The study is approved for conduct in 22 countries.

PLANNED OUTCOMES

The primary efficacy endpoint is time from randomization to the occurrence of the first centrally adjudicated and investigator-treated disease flare during the 1-year randomized controlled period. A set of novel, organ-specific flare diagnostic criteria were developed specifically for this trial, incorporating symptoms and signs, laboratory findings, imaging study results, and pathology data. MITIGATE aims to accrue 39 flares for the primary endpoint, which provides sufficient power to detect a relative risk reduction of 65% in the inebilizumab group. It is anticipated that enrollment of 160 participants will achieve this goal. Additional endpoints include safety, annualized flare rate, flare-free complete remission, quality-of-life measures, and cumulative glucocorticoid use. MITIGATE represents the first randomized, double-blind, placebo-controlled trial of any treatment strategy conducted in IgG4-RD. Data from this study will provide insights into the natural history and pathophysiology of IgG4-RD and the efficacy and safety of B-cell depletion as a therapeutic avenue.

TRIAL REGISTRATION

NCT04540497.

The spectrum of B cells in the pathogenesis, diagnosis and therapeutic applications of immunoglobulin G4-related disease

Immunoglobulin G4 (IgG4)-related disease is a chronic fibroinflammatory disease mediated by immune disorders. Given the challenging clinical diagnosis and treatment, knowledge of the pathogenesis of IgG4-related disease is important. The typical elevation of serum IgG4 concentrations and infiltration of IgG4-positive plasma cells in the involved tissues indicate the involvement of B lymphocytes in the pathogenesis of IgG4-related disease. Mass production of autoantibodies reflects abnormal activation of B cells, which causes tissue damage. Circulating plasmablasts are recently discovered markers that correlate with serum IgG4 concentration, the extent of organ involvement and disease activity. B-cell depletion therapy is an emerging curative strategy that can significantly alleviate clinical manifestations and achieve remission in patients with IgG4-related disease. These findings highlight the potential role of B cells in IgG4-related disease. In this review, we discuss the pathogenic impact of B lymphocytes on IgG4-related disease and describe novel therapies targeting B cells.

Identification of Covariates Modulating B-Cell Repopulation Kinetics in Subjects Receiving Rituximab Treatment

OBJECTIVE

B-cell depletion using the anti-CD20 monoclonal antibody rituximab is a cornerstone in the therapeutic concept of multiple autoimmune diseases. B-cell depletion is associated with a higher risk for severe infections, and the time span of B-cell repopulation differs greatly between individuals. Data on factors influencing B-cell repopulation kinetics are limited. This study aims to identify patient-specific and therapy-associated covariates that modulate B-cell repopulation.

METHODS

This single-center retrospective observational study presents data of 839 subjects receiving 2,017 courses of rituximab for autoimmune diseases. Assessed covariates are patient-specific factors (sex, age, kidney function, and underlying disease) and co-immunosuppression with common agents (azathioprine, cyclosporine A, cyclophosphamide, hydroxychloroquine, methotrexate, mycophenolate mofetil, tacrolimus, and corticosteroids). The primary end point is the time to B-cell repopulation (≥5/μl). The secondary end point is the time to B-cell reconstitution (≥50/μl). Multivariate time-to-event analysis and logistic regression models were applied to estimate the influence of covariates.

RESULTS

Age over 60 years (hazard ratio [HR] 0.71 for repopulation, P = 0.008), impaired kidney function (HR 0.72, P = 0.001), antineutrophil cytoplasmic antibody-associated vasculitis (HR 0.61, P < 0.001), solid organ transplantation (HR 0.4, P < 0.001), and co-immunosuppression with corticosteroids (HR 0.64, P < 0.001) or azathioprine (HR 0.49, P < 0.001) were associated with impaired B-cell repopulation and reconstitution. Effects of corticosteroids (P = 0.043) and azathioprine (P = 0.025) were dose dependent.

CONCLUSION

Prolonged rituximab dosing intervals may be effective to achieve B-cell depletion and reduce risk of infection in advanced age or patients with impaired kidney function. Co-medication with corticosteroids or azathioprine prolongs B-cell recovery, which may increase therapeutic effects but also the rate of adverse events.

IgG4-related digestive diseases: diagnosis and treatment

IgG4-related digestive diseases encompass a group of chronic inflammatory disorders characterized by autoimmune reactions and fibrosis affecting multiple digestive organs. These diseases are identified by elevated serum levels of IgG4 and the presence of IgG4-positive plasma cell infiltration in the affected sites, along with storiform fibrosis, obliterative phlebitis, and eosinophilic infiltration. Although extensive research has been conducted, a comprehensive understanding of these conditions remains elusive. Current clinical diagnosis often relies on the application of integrated diagnostic criteria for IgG4-related diseases, combined with specific organ involvement criteria. Distinguishing them from malignancies poses considerable challenges. Moreover, further investigations are required to elucidate the underlying pathogenic mechanisms and explore potential therapeutic interventions. This review provides a systematic classification of IgG4-related digestive diseases while discussing their diagnostic strategies, clinical presentations, and treatment modalities. The comprehensive insights shared herein aim to guide clinicians in their practice and contribute to the advancement of knowledge in this field.

B-Cell depletion therapy in IgG4-related disease: State of the art and future perspectives

IgG4-related disease (IgG4-RD) is an increasingly recognized immune-mediated fibroinflammatory disorder that promptly responds to glucocorticoids but commonly relapses during steroid tapering or after discontinuation. In the last few years, B-cell depletion therapy with rituximab (RTX) proved to be effective in the induction of remission and maintenance treatment of IgG4-RD, providing a new powerful tool in the management of this emerging condition. In this review, we outline the pathogenetic rationale for using B-cell depleting agents in IgG4-RD, we summarize available clinical experience with RTX in this disease, and we describe future possible therapies targeting B-lymphocytes that are now in the pipeline.

Interchangeability and adverse events in originator-rituximab and its biosimilar (CT-P10) among rheumatic patients: a real-life experience

Biosimilars offer cost-effective and safe treatment options both for patients and healthcare systems. CT-P10 is the first biosimilar of rituximab approved in Europe for use in all indications of originator rituximab (oRTX). This study aimed to provide real-life data on treatment changes and adverse events in patients who received oRTX or CT-P10. We retrospectively reviewed treatment-related adverse events [infusion-related reactions (IRRs), infections, hypogammaglobulinemia] in patients treated with at least one dose of oRTX (MabThera^®) or CT-P10 (Truxima^®) between 2020 and 2021 and had at least 6 months follow-up after rituximab infusion in a rheumatology clinic. The switches between oRTX and CT-P10 were performed according to drug availability at the hospital pharmacy at the time of infusion according to the local hospital procedure. Physicians were not involved in the decision of biosimilar selection. A total of 128 patients (CT-P10, n = 64; oRTX, n = 64) were included. CT-P10 was switched in 52 (40.6%) patients who had previously used oRTX, and 48 (37.5%) patients remained on oRTX. We demonstrated no difference between patients treated with oRTX or CT-P10 in the rates of IRRs, in which all reactions were grade 1 and 2. Comparable rates of infections (p > 0.05) and the rate of hypogammaglobulinemia (p > 0.05) were found in both groups with no significant difference. CT-P10 provides a safe treatment alternative in patients who require rituximab therapy. The rational use of biosimilars can be supported by evolving evidence on interchangeability and switching in real-life settings, which will help clinicians in decision-making.

A Developer's Perspective on Clinical Evidence and Benefits for Rituximab Biosimilar Uptake, with a Focus on CT-P10

To date, four rituximab biosimilars have received regulatory approval from the European Medicines Agency and/or US Food and Drug Administration. CT-P10 was the first rituximab biosimilar to be approved by each agency, in 2017 and 2018, respectively. Regulatory approval of CT-P10 followed demonstration of pharmacokinetic equivalence to the reference product in a phase I study in patients with rheumatoid arthritis. Phase III pivotal studies of CT-P10 subsequently demonstrated equivalence or non-inferiority of pharmacokinetics and efficacy between CT-P10 and reference rituximab in patients with rheumatoid arthritis, advanced-stage follicular lymphoma, and low-tumour-burden follicular lymphoma. Almost 5 years after its initial regulatory approval, significant real-world experience has accumulated with CT-P10 use, particularly in diffuse large B-cell lymphoma, one of the indications approved by extrapolation. This article summarises the pivotal data underlying regulatory approval for the four licensed rituximab biosimilars, before focusing on real-world data gathered with CT-P10. These data provide further support for the safety and effectiveness of CT-P10 and should boost healthcare professional and patient confidence in its use. Pharmacoeconomic analyses support the potential healthcare system cost savings offered by rituximab biosimilar uptake, which could lead to improved patient access to biologic treatments. Opportunities arising from biosimilar uptake extend further, potentially enabling innovative investigator-led research and therapeutic advances.

Long-Term Outcomes of IgG4-Related Ophthalmic Disease in a Chinese IgG4-Related Disease Cohort

Purpose: To define the treatment response and long-term outcomes of a large IgG4-related ophthalmic disease (IgG4-ROD) cohort.

Methods: A total of 132 patients with a minimum follow-up of 1 year were included in this study. Demographic, clinical, and laboratory data were collected. Treatment response was assessed by the IgG4-RD responder index (IgG4-RD RI). Risk factors for relapse were analyzed with the multivariate Cox regression analysis.

Results: The median follow-up time was 39 months. Lacrimal gland involvement was detected in 87.9% of cases. Extraocular muscles, the trigeminal nerve, and other soft tissue were affected in 25.8, 6.1, and 18.2% of patients. The relapse rate of watchful waiting, glucocorticoid monotherapy, immunosuppressant monotherapy, and combination therapy was 50.0, 51.7, 50.0, and 26.7% (p = 0.038), respectively. The combination therapy group exhibited shorter glucocorticoids therapy duration (36 vs. 48 months, p = 0.009) and maintenance period (24 vs. 42 months, p = 0.003). At the 6th month, the median IgG4-RD RI declined from 12 to 1 and 105 (79.5%) patients achieved complete response (CR). Relapse occurred in 49 (37.1%) patients. The multivariate Cox regression analysis exhibited that CR at the 6th month was an independent protective factor for relapse. Patients with multiple ocular lesions suffered from a higher risk of relapse. No patient had severe adverse reactions to the treatment in this study.

Conclusion: Relapse was common in patients with IgG4-ROD. Patients receiving combination therapy showed a lower relapse rate and a shorter glucocorticoids therapy period. The presence of multiple ocular lesions was associated with a higher risk of relapse. CR at the 6th month might be a predictor for a better prognosis in IgG4-ROD. Thus, a more aggressive regimen should be prescribed for patients with a poor initial response.

Efficacy and safety of rituximab for IgG4-related pancreato-biliary disease: A systematic review and meta-analysis

BACKGROUND

Type I autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC) belong to the IgG4-related disease (IgG4-RD) spectrum. Both entities respond to glucocorticoids, but iatrogenic toxicity associated with prolonged steroid therapy and relapse represent relevant clinical concerns in the long-term. Rituximab is increasingly used as an effective alternative strategy to induce remission but data regarding the safety and efficacy of B-cell depletion therapy for pancreato-biliary involvement of IgG4-RD are limited. We performed a systematic review and meta-analysis to estimate the rate of remission, flare, and adverse events (AEs) occurring in pancreato-biliary IgG4-RD following rituximab treatment.

METHODS

The MEDLINE, SCOPUS, and EMBASE databases were searched from inception to December 2020 to identify studies reporting the outcomes of IgG4-related pancreato-biliary disease after treatment with rituximab. Studies involving ≥2 patients were selected. In case of duplicated studies, the most recent or the one with the biggest N were chosen. The study was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled effects were calculated using a random-effect model and expressed in terms of pooled remission, relapse, and AEs rates.

RESULTS

Seven cohort studies met inclusion criteria and 101 patients were included. Reasons for rituximab administration were new disease onset (18.5%), disease flare after glucocorticoids (63.5%), and glucocorticoids intolerance (17.9%). The median follow-up time was 19 months. The pooled rate of complete response at 6 months was 88.9% (95%CI 80.5-93.9) with no heterogeneity (I2 = 0%). The pooled estimate of relapse rate was 21% (95%CI 10.5-40.3) with moderate heterogeneity (I2 = 51%). A higher rate of relapse (35.9%, 95%CI 17.3-60.1) was reported in studies including patients with multiorgan involvement (OOI). The median time to relapse was 10 months. The pooled estimate of rituximab-related AEs was 25% (95%CI 8.8-53) with substantial heterogeneity (I2 = 73.6%). No publication bias was observed.

CONCLUSION

Treatment of IgG4-related pancreato-biliary disease with rituximab is associated with high remission rate, a higher relapse rate in the presence of OOI, and limited AEs. Randomized controlled trials with adequate power are needed to confirm these findings.

B cell targeted therapy for immunoglobulin G4-related disease

Glucocorticoids are the first-line drug for the remission induction therapy of immunoglobulin (Ig) G4-related disease. Achieving drug-free remission using glucocorticoids alone is difficult, however, and many patients require maintenance therapy with glucocorticoids and immunosuppressants. Studies have recently found that the number of peripheral memory B cells and plasmablasts is increased in IgG4-related disease and have indicated the efficacy of rituximab, which, in remission induction therapy, rapidly reduces serum IgG4 levels and has the tapering effect of glucocorticoids. Rituximab has been shown to reduce the risk of relapse more than oral immunosuppressants such as azathioprine. However, maintaining drug-free remission is difficult with a single course of rituximab alone, and many cases require maintenance therapy with rituximab. This article outlines the potential of B-cell targeted therapy, focusing on the efficacy, and safety of rituximab for IgG4-related disease.