Telitacicept as a BLyS/APRIL dual inhibitor for autoimmune disease

Efficacy and safety of telitacicept in IgA nephropathy: a real-world study

BACKGROUND

IgA nephropathy (IgAN) is the most common primary glomerular disease in the world, and specific therapeutic methods for IgAN are limited. Telitacicept is a humanized fusion protein composed of a transmembrane activator and calcium-modulating cyclophilin ligand interactor receptor and human IgG.

AIM

To evaluate the efficacy and safety of telitacicept in adult patients with IgAN in a real-world study.

METHODS

Biopsy-proven IgAN patients with 24-hour proteinuria greater than 0.5 g/d who received 240 mg telitacicept weekly were recruited for this study and 1:1:1 matched with patients who received supportive treatment only or immunosuppressive treatment by propensity score matching. The primary outcome was the change from baseline in 24-hour proteinuria over the 3-month follow-up.

RESULTS

Twenty-one patients in each group were enrolled. Telitacicept reduced median proteinuria by 0.72 g/d (54.6%) from baseline, compared with a reduction of 0.18 g/d (20%) in the supportive treatment group and 1.12 g/d (72.1%) in the immunosuppressive treatment group. Preserved eGFR levels were observed in the telitacicept group, whereas eGFR levels decreased in the other two groups. No serious adverse events were observed in the telitacicept treatment group.

CONCLUSION

Telitacicept may be an effective treatment for IgAN patients by reducing proteinuria and preserving eGFR, and showed a favorable safety profile.

Efficacy and safety of telitacicept in patients with class III-V lupus nephritis: A real-world retrospective cohort study

OBJECTIVES

This retrospective cohort study evaluated the efficacy and safety of telitacicept combined with standard therapy in class III-V lupus nephritis (LN).

METHODS

We enrolled 146 patients with lupus nephritis confirmed by renal biopsy. Among them, 73 patients received treatment with telitacicept in combination with the standard therapy regimen, while the remainder were treated with the standard therapy alone. This analysis included class III/IV ± V or class V LN. Efficacy endpoints included cumulative complete renal response (CRR, 24hUTP < 0.5 g with stable renal function) and partial renal response (PRR, 50 % reduction in 24hUTP from baseline) at 6 months, 1 year, and the end of follow-up. Multivariate regression was used to assess baseline predictors of CRR. Safety was also evaluated.

RESULTS

Compared with the control group, telitacicept showed remarkable efficacy in improving disease activity indicators such as serum albumin (ALB), complement levels, and 24-h urinary total protein (24hUTP), with a significant reduction in antibody positivity rates and immunoglobulin levels, alongside an improvement in anemia. By 6 months, the CRR rate in the telitacicept group reached 64.4 % (64.4 % vs 45.2 %, P = 0.020). At 1 year, the cumulative CRR was significantly higher in the telitacicept group compared to the control group (80.8 % vs 61.6 %; P = 0.010). During follow-up, the time to achieve CRR was significantly earlier in the telitacicept group (median 4.0 months, 95 %CI, 2.71-5.29) than in the control group (median 9.0 months, 95 %CI, 5.25-12.75) (LogRank P = 0.006). Moreover, subgroup analyses indicated better efficacy of telitacicept in patients with positive dsDNA antibodies (OR, 1.70, 95 %CI, 1.20-2.40, P for interaction = 0.031). Telitacicept dose reduction did not increase disease activity. Multivariate analysis showed that the use of telitacicept was a favorable factor for achieving CRR, and other predictors included BMI, eGFR, and 24hUTP. Compared with the standard treatment group, the risk of adverse renal outcome events in the telitacicept group was reduced by 53 %. The incidence of adverse events was similar between the two groups.

CONCLUSIONS

This real-event study confirmed that the addition of telitacicept to standard therapy significantly boosted clinical remission rates and improved prognosis in patients with LN. It was also found that telitacicept may be more likely to achieve CRR in dsDNA antibody-positive patients. At baseline, the use of telitacicept, lower BMI and 24hUTP levels, and higher eGFR levels were associated with a greater likelihood of achieving CRR. In addition, for patients who achieve CRR and SLEDAI score ≤ 6, we advocate dose reduction of telitacicept after 6 months of treatment.

Effects of telitacicept in SLE patients with antiphospholipid antibody positivity: a retrospective self-controlled case series

OBJECTIVES

Antiphospholipid antibody (aPL) is closely related to the manifestation of antiphospholipid syndrome (APS) and an increased risk of thrombosis in systemic lupus erythematosus (SLE) patients. Telitacicept is a new dual B cell inhibitor which has been approved in China to treat SLE, but its application in APS or aPL-positive patients is still lacking. This study aimed to observe the effects of telitacicept in SLE patients with aPL positivity.

METHODS

It is a retrospective self-controlled case series study on SLE patients with aPL positivity who received telitacicept at a Chinese medical center during June 2021 to March 2023. Demographical information, clinical and immunological characteristics, and aPL profiles were gleaned from the electronic medical records system, and response of aPL profiles to telitacicept treatment was analyzed.

RESULTS

Sixteen SLE patients were included. Eight of them were definite APS, and the other eight patients were aPL carriers. After 6 months of telitacicept administration, significant improvements were observed in parameters representing SLE disease activity, including SLEDAI-2 K, anti-dsDNA antibody levels, and complement levels. Meanwhile, we observed significant decreases in aPL levels that had not been previously reported. LAC normalized ratios significantly decreased from baseline after telitacicept treatment for 6 months (dRVVT: 1.86 (1.24, 2.80) vs. 1.44 (1.11, 1.94), P = 007; SCT: 1.76 (1.28, 3.23) vs. 1.36 (1.06, 2.01), P = 0.010). The titer of aCL IgG decreased from 196.6 (54.58, 328.85) to 90.20 (15.6, 202.20) CU, and anti-β2GPI IgG decreased from 828.70 (51.60, 2490.80) to 211.10 (18.40, 422.50) CU after 6 months of telitacicept treatment (P-value 0.005 and 0.013, respectively). Interestingly, a rebound tendency in aPL titers was observed after telitacicept withdrawal. No thrombosis events or pregnancy morbidities occurred, and no serious adverse events or death happened during treatment.

CONCLUSIONS

Telitacicept may be an effective and safe option for patients with persistent aPL. Further well-designed prospective cohort studies are needed to confirm these findings. Key Points • Telitacicept is effective to lower aPL titers and promote aPL seroconversion, which may provide potential for the application of telitacicept in APS by reducing aPL-related events. • No thrombosis events and serious adverse events happened in aPL-positive patients during telitacicept treatment.

The Fusion Protein MuSK-Fc Functions as a Decoy to Block the Binding of Anti-MuSK Antibodies to MuSK

Muscle-specific tyrosine kinase antibody-positive myasthenia gravis (MuSKMG) is a rare subtype of MG that is often more refractory to immune treatment than acetylcholine receptor (AChR) antibody-positive MG. Therefore, novel therapeutic strategies are needed. We previously developed AChR-Fc, an Fc fusion protein that neutralises pathogenic autoantibodies and suppresses pathogenic B cells while preserving normal immunity, as a potential treatment for AChR antibody-positive MG. Subsequently, we conducted preliminary experiments on MuSK-Fc, a fusion protein targeting MuSKMG, using patient serum samples. This study examined whether MuSK-Fc binds to MuSK antibodies and inhibits MuSK antibody binding to MuSK. We found that MuSK-Fc specifically binds to MuSK antibodies and prevents their interaction with MuSK. These findings indicate that MuSK-Fc may neutralise pathogenic antibodies and suppress disease activity in MuSKMG.

Therapeutic progress in the targeting of B cells in lupus nephritis: pathogenesis to clinical research

Lupus nephritis (LN) is a common complication in patients with systemic lupus erythematosus (SLE), where the key mechanism is the deposition of immune complexes in the kidneys, leading to renal damage. B lymphocytes play a crucial role in the pathogenesis of lupus nephritis through several pathways. These include the production of autoantibodies, which contribute to the deposition of immune complexes in the kidneys, activation of the complement system, and promotion of local inflammatory responses. Additionally, B cells act as antigen-presenting cells, facilitating T cell activation, and secrete proinflammatory cytokines that further exacerbate inflammation. Moreover, an imbalance in B cell subpopulations can worsen autoimmune damage, highlighting the complex role of B cells in the progression of LN. Targeting B cells has emerged as a promising therapeutic strategy, particularly for patients with relapsed or refractory LN. Recent advances in B cell-targeted therapies have shown significant clinical potential, offering new hope for better disease management. This review highlights the latest progress in B cell-targeted approaches for LN treatment and explores their potential to revolutionize care for this challenging condition.

Telitacicept for systemic lupus erythematosus with post‑surgical papillary thyroid carcinoma: A case report

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a complex etiology primarily linked to abnormalities in B lymphocytes within the human body, resulting in the production of numerous pathogenic autoantibodies. Telitacicept is a relatively novel humanized, recombinant transmembrane activator, calcium modulator and cyclophilin ligand interactor fused with the Fc portion (TACI-Fc). It works by competitively inhibiting the TACI site, neutralizing the activity of B-cell lymphocyte stimulator and A proliferation-inducing ligand. This, in turn, inhibits the development and survival of plasma cells and mature B cells. A 28-year-old female was admitted to the Department of Rheumatology and Immunology (People's Hospital of Longhua; Shenzhen, China) in June 2021 due to systemic edema for more than a month and hair loss lasting for a week. After comprehensive examination, the patient was diagnosed with SLE with hematological system involvement, serositis, lupus nephritis and secondary antiphospholipid syndrome. After receiving medications including glucocorticoids, mycophenolate mofetil and cyclosporine, the patient's white blood cells, platelets, hemoglobin, urinary protein and multiple serositis returned to normal. However, the levels of complement 3 (C3) and C4 did not significantly improve. Subsequently, the patient underwent thyroid ultrasound examination, which suggested thyroid nodules. After thyroid puncture biopsy, the patient was diagnosed with papillary thyroid carcinoma (PTC). After surgical resection, the patient was confirmed to have PTC by pathological biopsy, with no lymph node metastasis. At two months after surgery, the patient was treated with telitacicept, and the complement levels not only returned to normal but also remained stable for a long time. The present case was the first to report the use of telitacicept for the successful treatment of a patient with SLE with post-surgical PTC, providing a potential therapeutic option for SLE with a prior history of carcinoma. The role of telitacept in this field requires further research and attention.

Myasthenia gravis in 2025: five new things and four hopes for the future

The last 10 years has brought transformative developments in the effective treatment of myasthenia gravis (MG). Beginning with the randomized trial of thymectomy in myasthenia gravis that demonstrated efficacy of thymectomy in nonthymomatous MG, several new treatment approaches have completed successful clinical trials and regulatory launch. These modalities, including B cell depletion, complement inhibition, and blockade of the neonatal Fc receptor, are now in use, offering prospects of sustained remission and neuromuscular protection in what is a long-term disease. In this review, we update our clinico-immunological review of 2016 with these important advances, examine their role in treatment algorithms, and focus attention on key issues of biomarkers for prognostication and the growing cohort of older patients, both those with long-term disease, and late-onset MG ('LOMG'). We close by expressing our four hopes for the next 5-10 years: improvements in laboratory medicine to facilitate rapid diagnosis, effective strategies for neuromuscular protection, more research into and better understanding of pathophysiology and treatment response in older individuals, and the potentially transformative role of therapies aimed at delivering a durable response such as chimeric antigen receptor (CAR) T cells. Our postscript summarizes some emerging themes in the field of serological and online biomarkers, which may develop greater stature in the next epoch.

Successful sequential therapy with rituximab and telitacicept in refractory Anti-NMDA receptor encephalitis and MOG-associated demyelination: a case report and literature review

Clinical management of the rare and complex overlapping syndrome of MOG-antibody disease and anti-NMDAR encephalitis (MNOS), which has an uncertain pathogenesis and a high risk of recurrence, is highly challenging. We describe the case of a 19 years-old female patient, who first complained of headache, fever, and irritability. After that, she experienced frequent seizures and mood disorders. The diagnosis of MNOS was verified through antibody tests and imaging. For the patient, intravenous immunoglobulin and high-dose methylprednisolone were effective as first-line immunotherapy. Long-term immunotherapy with oral prednisone and mycophenolate mofetil was used to prevent relapses. However, over six years, the patient had five relapses when the mycophenolate mofetil dosage was reduced. The patient's condition stabilized after taking rituximab as second-line immunotherapy, with less than 1% of total lymphocytes being CD19+ cells. Eleven months later, the plasmablast ratio increased, and patients experienced new symptoms such as bilateral optic neuritis. After that, the patient got telitacicept injections regularly for 13 months, during which time her symptoms subsided, and there were no adverse effects or relapses. This case suggests that telitacicept may be a viable adjunct or sequential therapy option for the depletion of B cells in MNOS.

Telitacicept for refractory cystitis associated with severe systemic lupus erythematosus: A case report

BACKGROUND

Lupus cystitis, a severe complication of systemic lupus erythematosus (SLE), presents considerable treatment challenges.

PURPOSE

This case report describes the use of telitacicept in treating severe SLE with lupus cystitis.

RESEARCH DESIGN

A single patient with lupus cystitis.

STUDY SAMPLE

A patient with symptoms including frequent urination, urgency, and acute urinary retention.

DATA COLLECTION AND ANALYSIS

Initial treatments included corticosteroid pulse therapy, immunoglobulin, and cyclophosphamide, which improved laboratory indicators but failed to alleviate symptoms of urinary retention. The patient was then treated with telitacicept.

RESULTS

Significant alleviation of urinary retention was observed shortly after incorporating telitacicept into the treatment regimen. The patient's condition remained stable with no relapse during the subsequent 10 months of follow-up.

CONCLUSIONS

This case highlights the therapeutic potential of telitacicept for SLE patients who are unresponsive to conventional therapies, particularly those with severe manifestations such as lupus cystitis.

Organ-based characterization of B cells in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic, inflammatory, and progressive autoimmune disease. The unclear pathogenesis, high heterogeneity, and prolonged course of the disease present significant challenges for effective clinical management of lupus patients. Dysregulation of the immune system and disruption of immune tolerance, particularly through the abnormal activation of B lymphocytes and the production of excessive autoantibodies, lead to widespread inflammation and tissue damage, resulting in multi-organ impairment. Currently, there is no systematic review that examines the specificity of B cell characteristics and pathogenic mechanisms across various organs. This paper reviews current research on B cells in lupus patients and summarizes the distinct characteristics of B cells in different organs. By integrating clinical manifestations of organ damage in patients with a focus on the organ-specific features of B cells, we provide a new perspective on enhancing the efficacy of lupus-targeted B cell therapy strategies.

Comparative efficacy and safety of different recommended doses of telitacicept in patients with systemic lupus erythematosus in China: a systematic review and meta-analysis

Background

Telitacicept, a new biological agent, was approved in China for treating systemic lupus erythematosus (SLE) in 2021. Its optimal dosing for treating SLE remains unclear. Therefore, the aim of this meta-analysis is to evaluate the efficacy and safety of various telitacicept doses in SLE treatment.

Methods

PubMed, EMBASE, Cochrane libraries, Web of science, China National Knowledge Infrastructure (CNKI), VIP, Wanfang, and Sinomed were searched for the controlled trials that studied the efficacy and safety of telitacicept on SLE patients from their initiation to April 30, 2024. The analysis included three randomized controlled trials (RCT) with 606 participants. We used fixed-effects models for meta-analyses and the risk ratios (RRs) and corresponding 95% confidence intervals (CIs) to evaluate the effectiveness and safety. Heterogeneity was assessed and quantified using I2.

Results

All telitacicept dosages (80 mg, 160 mg, 240 mg) significantly improved SLE Responder Index 4 (SRI4) responses compared to the control group (RR = 2.20, 95%CI:1.50-3.21, p < 0.0001; RR = 2.18, 95%CI: 1.82-2.62, p < 0.00001; RR = 2.44, 95%CI: 1.67-3.56, p < 0.00001, respectively). The 80 mg, 160 mg, and 240 mg groups also showed better improvement on SELENA-SLE Disease Activity Index (SELENA-SLEDAI) scores (RR = 1.63, 95%CI: 1.23-2.17, p = 0.0008; RR = 1.72, 95%CI: 1.45-2.04, p < 0.00001; RR = 1.73, 95%CI: 1.30-2.30, p = 0.0002, respectively) and Physician Global Assessment (PGA) scores (RR = 1.25, 95%CI: 1.09-1.44, p = 0.002; RR = 1.39, 95%CI: 1.25-1.55, p < 0.00001; RR = 1.24, 95%CI: 1.09-1.42, p = 0.002, respectively). Furthermore, 160 mg group exhibited higher British Isles Lupus Assessment Group (BILAG) score than the control group (RR = 1.11, 95%CI: 1.01-1.22, p = 0.03). As for security, 160 mg telitacicept group had higher incidence of adverse events (AEs) than the control group (RR = 1.10, 95%CI: 1.03-1.18, p = 0.007).

Conclusion

Telitacicept combined with standard therapy presents potential benefits but there are certain safety concerns with certain dosages of telitacicept, warranting further investigation for optimal dosing strategies in SLE management.

Systematic review registration

INPLASY.COM, identifier INPLASY202440101.

The efficacy of rituximab plus belimumab or telitacicept in refractory lupus nephritis

OBJECTIVE

Lupus nephritis is a severe and common complication of systemic lupus erythematosus (SLE). The pathogenesis of lupus nephritis is characterized by B-cell activation and autoantibody formation. Rituximab and belimumab, as well as telitacicept, target B cells through different mechanisms, potentially exerting a synergistic effect in the treatment of lupus nephritis. This study aims to investigate the efficacy and safety of treatment with rituximab followed by belimumab or telitacicept in the management of refractory lupus nephritis.

METHODS

We conducted a single-center, open-label, retrospective study, including 25 patients with refractory lupus nephritis. All patients received combination therapy with rituximab in individualized dosages to achieve peripheral B-cell depletion, and then followed by belimumab or telitacicept. The follow-up period was at least 12 months, and the primary end point was renal remission rate at the last follow-up.

RESULTS

During a median follow-up of 19 (13, 29) months, 20 of 25 (80%) patients achieved objective remission (OR), including 19 (76%) patients achieved complete renal response (CRR). After rituximab (712 ± 416mg in average), 18 patients received belimumab and seven patients received telitacicept. In the rituximab plus telitacicept group, all patients achieved CRR; while in the rituximab plus belimumab group, 12 (66.7%) patients achieved CRR and 13 (72.2%) patients achieved OR. The mean SLEDAI-2K score decreased from 15 ± 6 to 6 ± 6, representing an average reduction of 60%. At the last follow-up, 18/25 (72%) had prednisone ≤ 5 mg/d or even discontinued prednisone use. Adverse effects were mainly immunoglobulin deficiency, respiratory tract infection, urinary tract infections, and rash. No death occurred.

CONCLUSIONS

Rituximab followed by belimumab or telitacicept may be effective in inducing remission in refractory lupus nephritis, with tolerable adverse effects.

Effectiveness and safety of Belimumab and Telitacicept in systemic lupus erythematosus: a real-world, retrospective, observational study

OBJECTIVE

To examine the effectiveness and safety of two different B cell activating factor/proliferation-inducing ligand inhibitors, telitacicept and belimumab, in treating patients with active systemic lupus erythematosus (SLE).

METHODS

Patients with active SLE who received belimumab (n = 100) or telitacicept (n = 101) from 2019 to 2023 at multiple centers in China were retrospectively collected, and the effectiveness and safety of telitacicept and belimumab was evaluated. The subgroups of lupus nephritis and hematologic abnormalities were analyzed to explore if there were any differences in the efficacy of the two biologics on improving kidney and blood systems. Propensity score-based inverse probability of treatment weighting (IPTW) was used to reduce selection bias.

RESULTS

No significant between-group differences in patient characteristics were observed after adjustment by IPTW. The proportion of SLE Responder Index 4 at 24 weeks was significantly higher in the telitacicept group (p = 0.031), but no significant difference was observed in 52 weeks follow-up data. More significant improvements were observed in telitacicept group for C4 and a larger decrease was observed in telitacicept group for IgA and IgM levels at 4 weeks. A better improvement of hemoglobin in anemia patients from the telitacicept group at 24 weeks was observed. There were no significant differences in kidney effectiveness and treatment-related adverse events differences between the two groups.

CONCLUSIONS

Patients receiving telitacicept showed a higher SRI-4 rate compared to those receiving belimumab at 24 weeks. Due to the real-world nature of this study and the limitation of IPTW application, further extensive investigations in larger cohorts and head-to-head clinical trials are required to validate these findings. Key Points • The telitacicept group displayed a higher SRI-4 rate at 24 weeks and a more substantial improvement in serological indices at 4 weeks. • No differences were observed in the effectiveness in lupus nephritis patients between belimumab and telitacicept groups. • A better improvement of hemoglobin in anemia patients at 24 weeks was observed in telitacicept group.

Recent status and trends of innate immunity and the gut-kidney aixs in IgAN: A systematic review and bibliometric analysis

BACKGROUND

There is a significant global demand for precise diagnosis and effective treatment of IgA nephropathy (IgAN), with innate immunity, particularly the complement system, exerting a profound influence on its pathogenesis. Additionally, the gut-kidney axis pathway is vital in the emergence and development of IgAN.

METHODS

We conducted a comprehensive search in the Web of Science database, spanning from January 1, 2000 to December 18, 2023. The gathered literature underwent a visual examination through CiteSpace, VOSviewer, and Scimago Graphica to delve into authors, nations, organizations, key terms, and other pertinent elements.

RESULT

Between 2000 and 2023, a total of 720 publications were identified, out of which 436 publications underwent screening for highly relevant literature analysis. The average annual number of articles focusing on IgAN, innate immunity, and the gut-kidney axis is approximately 31, with an upward trend observed. In terms of research impact encompassing publication count and authorship, the United States emerged as the leading contributor. Prominent keywords included "complement", "activation", "microbe", "gut-kidney axis", "C4d deposition", "alternative pathway" and "B cells" along with other prospective hot topics.

CONCLUSION

The correlation between IgAN and innate immunity is a focal point in current scientific research. Recent literature underscores the significance of the gut-kidney axis, where intestinal microorganisms and metabolites may influence IgAN. The complement system, a key component of innate immunity, also has a crucial function.Advancements in prevention, diagnosis, and treatment hinge on unraveling this intricate relationship.

Advances in B Cell Targeting for Treating Muscle-Specific Tyrosine Kinase-Associated Myasthenia Gravis

Myasthenia gravis (MG) is a typical autoimmune disease of the nervous system. It is characterized by skeletal muscle weakness and fatigue due to impaired neuromuscular junction transmission mediated by IgG autoantibodies. Muscle-specific receptor tyrosine kinase-associated MG (MuSK-MG), a rare and severe subtype of MG, is distinguished by the presence of anti-MuSK antibodies; it responds poorly to traditional therapies. Recent research on MuSK-MG treatment has focused on specific targeted therapies. Since B cells play a critical pathogenic role in producing autoantibodies and inflammatory mediators, they are often considered the preferred target for treating MuSK-MG. Currently, various B cell-targeted drugs have been developed to treat MuSK-MG; they have shown good therapeutic effects. This review explores the evolving landscape of B cell-targeted therapies in MuSK-MG, focusing on their mechanisms, efficacy, and safety, and the current limitations associated with their use. We discuss current B cell-targeted therapies aimed at depleting or modulating B cells via both direct and indirect approaches. Furthermore, we focus on novel and promising strategies such as Chimeric Autoantibody Receptor T cell therapy, which explicitly targets MuSK-specific B cells without compromising general humoral immunity. Finally, this review provides an outlook on the potential benefits and limitations of B cell-targeted therapy in developing new therapies for MuSK-MG. We conclude by discussing future research efforts needed to optimize these therapies, expand treatment options, and improve long-term outcomes in MuSK-MG management.

The Latest Progress in the Application of Telitacicept in Autoimmune Diseases

Introduction

Humoral immunity plays a key role in the pathogenesis of autoimmune diseases, and B-lymphocyte activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are essential for the maintenance of B-lymphocyte reservoirs and humoral immunity. In March 2021, telitacicept, the world's first dual target three-channel biologic, was approved in China for the treatment of SLE and is currently in clinical trials exploring multiple indications for other autoimmune diseases.

Areas Covered

This article summarizes the mechanism of action, pharmacokinetics, and clinical efficacy of telitacicept for the treatment of multiple autoimmune diseases.

Expert Opinion

So far, the efficacy and safety of telitacicept in autoimmune diseases have been fully demonstrated in clinical practice. There are still many unresolved issues regarding the timing of initiation and discontinuation, still needs to be evaluated in future studies.

The emerging role of BLyS/APRIL in autoimmune diseases: Biological characteristics, functions, and therapeutic potential

Autoimmune diseases (AIDs) are common diseases in the world. Some cases are difficult to cure and can only delay the progression of the diseases. The B lymphocyte stimulator (BLyS)/a proliferation-inducing ligand (APRIL) plays an important role in B cell homeostasis, regulation of both innate and adaptive immune responses. After binding to their receptors, BLyS/APRIL primarily affects the survival and development of marginal, transitional, and mature B cells. Of note, elevated BLyS/APRIL is seen in many AIDs, such as systemic lupus erythematosus, rheumatoid arthritis, immunoglobulin A nephropathy, etc. Moreover, there is evidence that blocking these two cytokines can control the number of serum autoantibodies, promote the depletion of B lymphocytes, inhibit the activation of T cells and dendritic lymphocytes, and reduce inflammatory stress. Currently, some clinical studies are underway targeting BLyS/APRIL inhibitors for the treatment of AIDs. However, due to the scattered knowledge on the relationship between BLyS/APRIL and AIDs, it is necessary to sort out the existing data. Therefore, in this review, we describe the basic biological characteristics and functions of BLyS/APRIL in AIDs, summarize the potential clinical applications of related inhibitors, especially monoclonal antibodies and recombinant fusion proteins targeting BLyS/APRIL in AIDs, and also outline promising research directions.

Novel approaches to primary membranous nephropathy: Beyond the KDIGO guidelines

Primary membranous nephropathy (PMN) is an immune-mediated glomerular disease. Rituximab (RTX) is recommended as a first-line immunosuppressive therapy and shows high clinical efficacy, but the optimal doses remain controversial. Approximately 20%-40% of PMN patients experience RTX resistance and failure. Reduced bioavailability, RTX internalization and attack, anti-RTX antibody production, autoreactive B-cell reservoirs and chronic and irreversible renal damage may contribute to this problem. Therefore, new treatment modalities are needed to compensate for this deficit. New interventions and new dose combinations are being proposed. Multiple drug combination therapies show comparable clinical efficacy to conventional treatments by blocking the production of disease-causing antibodies in multiple directions, and can reduce single-agent doses without increasing adverse effects. New therapies that directly target B cells, plasma cells, and antibody production have shown encouraging results. In addition, new techniques for sweeping antibodies and chimeric antigen receptor T-cell therapy also may be promising strategies for PMN. Immunoadsorption could be used as an auxiliary choice for severe cases. This article explores new treatments for PMN and highlights possible mechanisms for potential new technologies that offer new ideas for treatment.

Single-dose telitacicept therapy for refractory idiopathic membranous nephropathy: A case series

Key Clinical Message

We report three cases of IMN from our center, where patients received a single dose of telitacicept after showing no response to conventional treatments. Although one case did not respond, the other two cases achieved complete or partial remission of proteinuria. These cases illustrates the telitacicept may offer new hope for the treatment of IMN.

Abstract

Despite the variety of treatment options available, effective therapies for refractory membranous nephropathy remain lacking. Recently, some reports have suggested that telitacicept is a new therapeutic option. However, only a few published studies have documented the use of telitacicept for treating idiopathic membranous nephropathy (IMN). We present three cases of IMN from our center, where patients received a single dose of telitacicept after showing no response to conventional treatments, including glucocorticoids, tacrolimus, mycophenolate mofetil, cyclophosphamide, cyclosporine, and rituximab. Although one case did not respond, the other two cases achieved complete or partial remission of proteinuria. Thus, telitacicept may offer new hope for the treatment of refractory membranous nephropathy.

Efficacy and safety of telitacicept, a BLyS/APRIL dual inhibitor, in the treatment of IgA nephropathy: a retrospective case-control study

Background

Telitacicept, a B lymphocyte stimulator/A proliferation-inducing ligand dual-target fusion protein, has recently been used in autoimmune diseases. We assessed the efficacy and safety of telitacicept in immunoglobulin A nephropathy (IgAN) patients.

Methods

This study included 42 IgAN patients who received telitacicept treatment, forming the 'whole telitacicept group'. Among them, 20 patients who had not previously received corticosteroid (CS) therapy or immunosuppressive (IS) agents were categorized as the 'newly treated telitacicept subgroup'. Additionally, 28 patients who were selected to match historical controls received conventional IS therapy (CS therapy with/without IS agents) and were classified as the 'conventional IS group'. Telitacicept was partially used in combination with conventional IS therapy, including initial CS in different doses. Various indicators were compared at 4-week intervals up to 24 weeks among the three groups.

Results

After 24 weeks of treatment, the 24-hour proteinuria decreased from 1.70 g [interquartile range (IQR) 1.05-2.58] to 0.21 g (IQR 0.39-0.13) (P = .043) in the newly treated telitacicept subgroup, from 1.78 g (IQR 0.97-2.82) to 0.44 g (IQR 1.48-0.16) (P = .001) in the conventional IS group and from 1.07 g (IQR 0.66-1.99) to 0.26 g (IQR 0.59-0.17) (P = .028) in the whole telitacicept group. The estimated glomerular filtration rate (eGFR) increased from 76.58 ± 30.26 ml/min/1.73 m2 to 80.30 ± 26.76 ml/min/1.73 m2 (P = .016) in the newly treated telitacicept subgroup, from 72.73 ± 33.41 ml/min/1.73 m2 to 84.08 ± 26.81 ml/min/1.73 m2 (P = .011) in the conventional IS group and from 70.10 ± 32.88 ml/min/1.73 m2 to 71.21 ± 31.49 ml/min/1.73 m2 (P = .065) in the whole telitacicept group. During follow-up periods, the efficacy rates of the three groups did not show statistically significant differences and no serious adverse events were observed.

Conclusions

Telitacicept may be a safe and effective treatment for IgAN, offering reductions in proteinuria and increases in eGFR similar to conventional IS therapy. After a 24-week follow-up, the incidence of adverse events was lower for telitacicept than for conventional IS therapy.

Efficacy and safety of telitacicept in patients with lupus nephritis

Although telitacicept is a promising drug for treating systemic lupus erythematosus, there are limited studies on its efficacy and safety in patients with lupus nephritis in China. This lack of research data restricts its potential for broader application and acceptance on a global scale. The present study aimed to determine the efficacy and safety of telitacicept in patients with lupus nephritis (LN) in China. Using a self-controlled before-after comparison method, patients with LN were recruited at Lishui Central Hospital between February 2022 and April 2023, who received telitacicept weekly as part of the standard treatment. Data on the systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K), glucocorticoid dosing and the quantity of immunosuppressive medicines prescribed was collected. Additionally, serum complements, erythrocyte sedimentation rate (ESR), urinary protein levels, immunoglobulin concentrations, serum creatinine levels, plasma albumin concentrations, platelet counts and renal function parameters were documented throughout the study. A total of 13 patients were enrolled in the trial, comprising 11 women and two men. Following 12-48 weeks of treatment with telitacicept (80 or 160 mg per week), 84.6% (n=11) of all patients experienced symptom relief and their SLEDAI-2K score was reduced by more than four points. By the observation endpoint, the median glucocorticoid dosage of the 13 patients was decreased from 15 to 2.5 mg/d, and six patients discontinued their glucocorticoids. Furthermore, 46.1% of patients (n=6) reduced their dose and number of immunosuppressive medicines, while 15.4% (n=2) stopped their immunosuppressive medicines. Minimal changes were observed in serum creatinine, platelet count, C3 levels and C4 levels among patients. Immunoglobulin levels (IgG, IgA and IgM) remained stable or showed an upward trend. Plasma albumin levels remained within the normal range in three patients and increased in ten patients. It increased to the normal range in three of these ten patients. At the endpoint, ESR levels decreased in all patients. Additionally, three patients displayed varying degrees of renal function improvement, and their estimated glomerular filtration rate (ml/min/l.73 m2) increased from 127.8 to 134.2, 95.1 to 123.1 and 61.5 to 67.3, respectively. Urinary protein levels decreased in all patients. It decreased >0.5 g/l in seven patients and reached the normal levels in three patients. The adverse events of telitacicept were manageable. Among the patients infected with COVID-19, three patients had fever, 10 patients remained asymptomatic and none of them exhibited severe respiratory syndromes. In this study, telitacicept effectively stabilized LN activity and alleviated the clinical symptoms of most patients. Furthermore, it reduced the dose of glucocorticoid and immunosuppressive medicines. Therefore, telitacicept may be a promising treatment option for individuals with lupus nephritis.

Efficacy and Safety of Telitacicept in IgA Nephropathy: A Retrospective, Multicenter Study

INTRODUCTION

The efficacy of telitacicept treatment in reducing proteinuria in patients with IgA nephropathy (IgAN) was indicated in a phase II clinical trial with small sample size. In this study, we conducted a large multicenter retrospective study to explore the efficacy and safety of telitacicept in patients with IgAN.

METHODS

This study recruited patients with IgAN from 19 sites from China who were treated with telitacicept and had been followed up at least once or with side effect reported, since April 1, 2021, to April 1, 2023. The primary outcomes of the study were the changing in proteinuria and eGFR over time.

RESULTS

A cohort of 97 patients with IgAN who were treated with telitacicept were recruited, with a median follow-up duration of 3 months. The median baseline proteinuria was 2.3 [1.3, 3.9] g/day and eGFR was 45.0 [26.8, 73.7] mL/min/1.73 m2. There was a significant reduction of proteinuria at 2, 4, 6 months when compared with baseline (2.3 [1.5, 4.1] vs. 1.5 [0.8, 2.3] g/day; 2.3 [1.1, 3.7] vs. 1.1 [0.6, 1.9] g/day; 2.1 [1.0, 2.7] vs. 0.9 [0.5, 1.7] g/day, all p values <0.01). The level of eGFR were comparable between at the baseline and 2, 4, 6 months of follow-up time (41.5 [29.7, 72.0] vs. 42.5 [28.8, 73.3] mL/min/1.73 m2; 41.0 [26.8, 67.7] vs. 44.7 [31.0, 67.8] mL/min/1.73 m2; 33.7 [24.0, 58.5] vs. 32.6 [27.8, 57.5] mL/min/1.73 m2, all p values >0.26). Telitacicept was well tolerated in the patients.

CONCLUSIONS

This study indicates that telitacicept alone or on top of steroids therapy can significantly and safely reduce proteinuria in patients with IgAN. The long-term kidney protection still needs to be confirmed in large phase III trial.

Telitacicept: A novel horizon in targeting autoimmunity and rheumatic diseases

BLyS and APRIL have the capability to bind to B cells within the body, allowing these cells to evade elimination when they should naturally be removed. While BLyS primarily plays a role in B cell development and maturation, APRIL is linked to B cell activation and the secretion of antibodies. Thus, in theory, inhibiting BLyS or APRIL could diminish the population of aberrant B cells that contribute to SLE and reduce disease activity in patients. Telitacicept functions by binding to and neutralizing the activities of both BLyS and APRIL, thus hindering the maturation and survival of plasma cells and fully developed B cells. The design of telitacicept is distinctive; it is not a monoclonal antibody but a TACI-Fc fusion protein generated through recombinant DNA technology. This fusion involves merging gene segments of the TACI protein, which can target BLyS/APRIL simultaneously, with the Fc gene segment of the human IgG protein. The TACI-Fc fusion protein exhibits the combined characteristics of both proteins. Currently utilized for autoimmune disease treatment, telitacicept is undergoing clinical investigations globally to assess its efficacy in managing various autoimmune conditions. This review consolidates information on the mechanistic actions, dosing regimens, pharmacokinetics, efficacy, and safety profile of telitacicept-a dual-targeted biological agent. It integrates findings from prior experiments and pharmacokinetic analyses in the treatment of RA and SLE, striving to offer a comprehensive overview of telitacicept's research advancements.

Efficacy and safety of telitacicept in patients with lupus nephritis: a single-center, real-world retrospective study

BACKGROUND

Telitacicept, an innovative drug used for the treatment of systemic lupus erythematosus (SLE), can effectively control disease progression and achieve favorable outcomes. While case reports have mentioned the use of Telitacicept in lupus nephritis (LN) treatment, its safety and efficacy in treating patients with LN have not been explored. Therefore, in this study, we aimed to evaluate the safety and efficacy of Telitacicept in managing patients with LN.

METHODS

In a single-center, real-world retrospective study, 30 LN patients with poor response or adverse reactions to conventional glucocorticoids at our Hospital were enrolled to receive Telitacicept. Patients were administered 160 mg of Telitacicept subcutaneously once a week for at least 24 weeks in addition to standard treatment. We assessed the SLE responder index-4 (SRI-4) at the beginning and the end of the treatment period, measured laboratory test indicators at 3, 6, and 9 months, and observed the occurrence of adverse events in these patients.

RESULTS

The SRI-4 response rate was 86.67% (n = 26), with a significantly lower systemic lupus erythematosus disease activity index (SLEDAI) score compared to the baseline. Post Telitacicept treatment, glucocorticoid intake of patients with LN significantly reduced from 50 (IQR:40, 51.25) at baseline to 10 (IQR:5,10) at the endpoint (Z = - 6.547, p < 0.001). Patients with LN showed significantly improved urine occult blood levels after Telitacicept therapy. While the complement (C3 and C4) contents increased, immunoglobulins (IgG, IgA and IgM) reduced markedly (p < 0.001). The negative rate of dsDNA reached 26.67% and adverse events were alleviated post treatment. Only two cases of LN-related adverse reactions were reported, including herpes and infectious fever, respectively. Telitacicept primarily serves as an agent for the induction of remission therapy, with an attainment of complete remission rate standing at a commendable 73.3%.

CONCLUSIONS

Telitacicept treatment reduced disease severity in patients with LN. The initial clinical trial provided supportive evidence for the effectiveness and safety of Telitacicept as a viable treatment option for LN, allowing a reduction in the daily glucocorticoid intake while maintaining a good safety profile, and improving hypocomplementation in LN management.

A multicenter, randomized, open-label, phase 2 clinical study of telitacicept in adult patients with generalized myasthenia gravis

BACKGROUND AND PURPOSE

This study aimed to investigate the clinical efficacy and safety of telitacicept in patients with generalized myasthenia gravis (gMG) who tested positive for acetylcholine receptor antibodies or muscle-specific kinase antibodies and were receiving standard-of-care therapy.

METHODS

Patients meeting the eligibility criteria were randomly assigned to receive telitacicept subcutaneously once a week for 24 weeks in addition to standard-of-care treatment. The primary efficacy endpoint was the mean change in the quantitative myasthenia gravis (QMG) score from baseline to week 24. Secondary efficacy endpoints included mean change in QMG score from baseline to week 12 and gMG clinical absolute score from baseline to week 24. Additionally, safety, tolerability and pharmacodynamics were assessed.

RESULTS

Twenty-nine of the 41 patients screened were randomly selected and enrolled. The mean (± standard deviation [SD]) reduction in QMG score from baseline to week 24 was 7.7 (± 5.34) and 9.6 (± 4.29) in the 160 mg and 240 mg groups, respectively. At week 12, mean reductions in QMG scores for these two groups were 5.8 (± 5.85) and 9.5 (± 5.03), respectively, indicating rapid clinical improvement. Safety analysis revealed no adverse events leading to discontinuation or mortalities. All patients showed consistent reductions in serum immunoglobulin (Ig) A, IgG and IgM levels throughout the study.

CONCLUSION

Telitacicept demonstrated safety, good tolerability and reduced clinical severity throughout the study period. Further validation of the clinical efficacy of telitacicept in gMG will be conducted in an upcoming phase 3 clinical trial.

Case report: Three cases of systemic lupus erythematosus presenting primarily with massive ascites and significantly elevated CA-125 levels and a review of pseudo-pseudo Meigs' syndrome in literature

This article presents three detailed case reports and a brief review of the literature on a rare manifestation of systemic lupus erythematosus (SLE) known as Pseudo-Pseudo Meigs' Syndrome (PPMS). The patients' condition was characterized by elevated CA-125 levels, massive ascites andpleural effusion which is typically associated with ovarian malignancies but can also present in various non-malignant conditions, including SLE. A thorough literature review was conducted, summarizing similar cases and their clinical outcomes to provide a broader understanding of this uncommon syndrome. The findings emphasize the need for heightened awareness and consideration of pseudo-pseudo Meigs' syndrome in patients with SLE presenting with unexplained ascites and pleural effusion.

Frequency and predictors for early-achieved lupus low disease activity state in systemic lupus erythematosus patients treated with telitacicept or belimumab: A real-life, single-center observational study

Objective

To collect real-world data regarding the attainment of the early-achieved lupus low disease activity state (LLDAS) in systemic lupus erythematosus (SLE) patients receiving telitacicept or belimumab treatment, and identify factors predictive of target achievement.

Methods

Eighty-seven SLE patients who received telitacicept (N=42) or belimumab (N=45) were retrospectively reviewed in this observational study. Clinical and laboratory data, disease activity assessment, and glucocorticoid dosage were collected for analysis. Achieving LLDAS at least once within 24 weeks post-treatment was considered as early-achieved LLDAS. Multivariate regression was used to assess baseline predictive variables for early-achieved LLDAS. Subgroup analysis and interaction tests were also performed to examine the robustness of the results across different sets of baseline characteristics. Prognostic stratification for early-achieved LLDAS was established based on the identified risk factors.

Results

During the 24-week follow-up period, LLDAS was achieved by at least one time in 49.43% (43/87) of the patients, with sustained achievement through week 24 observed in 36 out of these 43 patients (83.27%). Multivariate analysis revealed that early achievement of LLDAS was particularly observed in patients with higher baseline lymphocyte counts [HR=1.79, 95% CI (1.19-2.67), P=0.005]and serum albumin levels [HR=1.06, 95% CI (1.003-1.12), P=0.039]. Conversely, hematological involvement [HR=0.48, 95% CI (0.24-0.93), P=0.031] predicted lower attainment of early-achieved LLDAS. The use of telitacicept was associated with a reduced risk of failing to attain early achievement of LLDAS [HR=2.55, 95% CI (1.36-4.79), P=0.004]. Subgroup analyses and interaction tests showed a stable relationship between the telitacicept use and LLDAS achievement. The results remained consistent across all subgroup analyses. Significant differences (P<0.001) were observed in the Kaplan-Meier estimates for LLDAS among risk groups based on the number of identified risk factors.

Conclusion

The achievement of LLDAS is attainable in the management of SLE patients undergoing treatment with telitacicept or belimumab in real-life clinical practice. Baseline lymphocyte counts, serum albumin levels, hematological involvement and the use of telitacicept serve as robust predictors for early-achieved LLDAS, helping to identify patients who are likely to benefit on the treatment.

Advancements and prospects of novel biologicals for myasthenia gravis: toward personalized treatment based on autoantibody specificities

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease with a prevalence of 150-250 cases per million individuals. Autoantibodies include long-lived antibodies against the acetylcholine receptor (AChR), mainly of the IgG1 subclass, and IgG4, produced almost exclusively by short-lived plasmablasts, which are prevalent in muscle-specific tyrosine kinase (MuSK) myasthenia gravis. Numerous investigations have demonstrated that MG patients receiving conventional medication today still do not possess satisfactory symptom control, indicating a substantial disease burden. Subsequently, based on the type of the autoantibody and the pathogenesis, we synthesized the published material to date and reached a conclusion regarding the literature related to personalized targeted therapy for MG. Novel agents for AChR MG have shown their efficacy in clinical research, such as complement inhibitors, FcRn receptor antagonists, and B-cell activating factor (BAFF) inhibitors. Rituximab, a representative drug of anti-CD20 therapy, has demonstrated benefits in treatment of MuSK MG patients. Due to the existence of low-affinity antibodies or unidentified antibodies that are inaccessible by existing methods, the treatment for seronegative MG remains complicated; thus, special testing and therapy considerations are necessary. It may be advantageous to initiate the application of novel biologicals at an early stage of the disease. Currently, therapies can also be combined and individualized according to different types of antibodies. With such a wide range of drugs, how to tailor treatment strategies to patients with various conditions and find the most suitable solution for each MG profile are our necessary and urgent aims.

Emerging biologic frontiers for Sjogren's syndrome: Unveiling novel approaches with emphasis on extra glandular pathology

Primary Sjögren's Syndrome (pSS) is a complex autoimmune disorder characterized by exocrine gland dysfunction, leading to dry eyes and mouth. Despite growing interest in biologic therapies for pSS, FDA approval has proven challenging due to trial complications. This review addresses the absence of a molecular-target-based approach to biologic therapy development and highlights novel research on drug targets and clinical trials. A literature search identified potential pSS treatment targets and recent advances in molecular understanding. Overlooking extraglandular symptoms like fatigue and depression is a notable gap in trials. Emerging biologic agents targeting cytokines, signal pathways, and immune responses have proven efficacy. These novel therapies could complement existing methods for symptom alleviation. Improved grading systems accounting for extraglandular symptoms are needed. The future of pSS treatment may involve gene, stem-cell, and tissue-engineering therapies. This narrative review offers insights into advancing pSS management through innovative biologic interventions.

Case report: A highly active refractory myasthenia gravis with treatment of telitacicept combined with efgartigimod

There is always a lack of effective treatment for highly active refractory generalized myasthenia gravis (GMG). Recently, telitacicept combined with efgartigimod significantly reduces circulating B cells, plasma cells, and immunoglobulin G, which brings promising therapeutic strategies. We report a case of a 37-year-old female patient with refractory GMG, whose condition got significant improvement and control with this latest treatment after multiple unsuccessful therapies of immunosuppressants. The new combination deserves further attention in the therapeutic application of myasthenia gravis.

Anti-inflammatory role of APRIL by modulating regulatory B cells in antigen-induced arthritis

APRIL (A Proliferation-Inducing Ligand), a member of the TNF superfamily, was initially described for its ability to promote proliferation of tumor cells in vitro. Moreover, this cytokine has been related to the pathogenesis of different chronic inflammatory diseases, such as rheumatoid arthritis. This study aimed to evaluate the ability of APRIL in regulating B cell-mediated immune response in the antigen-induced arthritis (AIA) model in mice. AIA was induced in previously immunized APRIL-transgenic (Tg) mice and their littermates by administration of antigen (mBSA) into the knee joints. Different inflammatory cell populations in spleen and draining lymph nodes were analyzed using flow cytometry and the assay was performed in the acute and chronic phases of the disease, while cytokine levels were assessed by ELISA. In the acute AIA, APRIL-Tg mice developed a less severe condition and a smaller inflammatory infiltrate in articular tissues when compared with their littermates. We also observed that the total cellularity of draining lymph nodes was decreased in APRIL-Tg mice. Flow cytometry analysis revealed an increase of CD19+IgM+CD5+ cell population in draining lymph nodes and an increase of CD19+CD21hiCD23hi (B regulatory) cells in APRIL-Tg mice with arthritis as well as an increase of IL-10 and CXCL13 production in vitro.

Drugs in Development to Treat IgA Nephropathy

IgA nephropathy is a common glomerulonephritis consequent to the autoimmune response to aberrant glycosylated immunoglobulin (Ig) A antibodies. Although it has historically been considered a benign disease, it has since become clear that a substantial percentage of patients reach end-stage kidney failure over the years. Several therapeutic attempts have been proposed, with systemic steroids being the most prevalent, albeit burdened by possible serious adverse events. Thanks to the more in-depth knowledge of the pathogenesis of IgA nephropathy, new treatment targets have been identified and new drugs developed. In this narrative review, we summarise the molecules under clinical development for the treatment of IgA nephropathy. As a search strategy, we used PubMed, Google, ClinicalTrials.gov and abstracts from recent international congresses. TRF budesonide and sparsentan are the two molecules at a more advanced stage, just entering the market. Other promising agents are undergoing phase III clinical development. These include anti-APRIL and anti-BLyS/BAFF antibodies and some complement inhibitors. Other new possible strategies include spleen tyrosine kinase inhibitors, anti-CD40 ligands and anti-CD38 antibodies. In an era increasingly characterised by 'personalised medicine' and 'precision therapy' approaches and considering that the potential therapeutic armamentarium for IgA nephropathy will be very broad in the near future, the identification of biomarkers capable of helping the nephrologist to select the right drug for the right patient should be the focus of future studies.

Exploring the depths of IgG4: insights into autoimmunity and novel treatments

IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.

Blockade of BLyS inhibits B-cell responses and antibody production for the prevention of chronic transplant rejection

BACKGROUND

Chronic rejection, closely related to the activation of B cells and donor-specific antibody (DSA) production, has unsatisfactory therapeutic outcomes. B lymphocyte stimulator (BLyS) is a major regulatory factor that controls the activation and differentiation of B cells. However, it remains unclear whether BLyS blockade can regulate B and plasma cells in the transplantation setting and affect chronic rejection. Here, we investigated the efficacy of the BLyS inhibitors belimumab and telitacicept in controlling B-cell response and preventing chronic rejection.

METHODS

The effects of belimumab and telitacicept on B-cell activation, differentiation, and antibody production in vitro were determined. A chronic rejection model in mouse was established by allogeneic cardiac transplantation with CTLA4-Ig treatment. Allograft survival, histology, DSA levels, and B-cell responses were analyzed to evaluate the chronic rejection-preventive effects of belimumab and telitacicept.

RESULTS

In vitro experiments confirmed that belimumab and telitacicept inhibited B-cell activation and differentiation and reduced antibody production. In vivo experiments indicated that they significantly prolonged allograft survival, attenuated chronic rejection through significant suppression of myocardial ischemic necrosis and interstitial fibrosis, and reduced DSA-IgG levels, C4d deposition, and inflammatory cell infiltration. Furthermore, the frequencies of B cells, plasma cells, and IgG-producing cells in the recipients' spleen, lymph nodes, bone marrow, and blood were decreased after BLyS inhibitors treatment.

CONCLUSIONS

This study demonstrated that belimumab and telitacicept inhibit B-cell responses and antibody production and alleviate chronic transplant rejection. Therefore, BLyS inhibitors are expected to be used for the prevention of chronic rejection in clinical practice.

Effect of Telitacicept on Circulating Gd-IgA1 and IgA-Containing Immune Complexes in IgA Nephropathy

Introduction

Telitacicept, a transmembrane activator and cyclophilin ligand interactor (TACI) fusion protein targeting B cell activating factor and a proliferation-inducing ligand (APRIL), has proven efficacy in treating Immunoglobulin A (IgA) nephropathy (IgAN). However, serum biomarkers that could predict the clinical response during the treatment remain unclear.

Methods

Plasma samples from 24 participants in the phase 2 clinical trial were collected at baseline and after 4, 12, and 24 weeks; with 8 participants in the placebo group, 9 in the 160 mg group, and 7 in the 240 mg group. We measured the levels of galactose-deficient-IgA1 (Gd-IgA1), IgA-containing immune complexes, C3a, C5a, and sC5b-9. The association between the changes in these markers and proteinuria reduction was analyzed.

Results

After 24 weeks of treatment, Gd-IgA1 decreased by 43.9% (95% confidence interval: 29.8%, 55.1%), IgG-IgA immune complex by 31.7% (14.4%, 45.5%), and poly-IgA immune complex by 41.3% (6.5%, 63.1%) in the 160 mg group; Gd-IgA1 decreased by 50.4% (38.6%, 59.9%), IgG-IgA immune complex decreased by 42.7% (29.5%, 53.4%), and poly-IgA immune complex decreased by 67.2% (48.5%,79.1%) in the 240 mg group. There were no significant changes in the circulatory C3a, C5a, or sC5b-9 levels during telitacicept treatment. Decreases in both plasma Gd-IgA1 and IgG-IgA or poly-IgA immune complexes were associated with proteinuria reduction. In turn, IgG-IgA or poly-IgA immune complexes showed a dose-dependent effect, consistent with proteinuria reduction during telitacicept treatment.

Conclusion

Telitacicept lowered both circulating Gd-IgA1 and IgA-containing immune complexes, whereas IgA immune complex levels were more consistent with decreased proteinuria.

Efficacy and safety of telitacicept in primary Sjögren's syndrome: a randomized, double-blind, placebo-controlled, phase 2 trial

OBJECTIVE

To evaluate the efficacy and safety of telitacicept in adult patients with primary SS (pSS) in a phase II randomized double-blind placebo-controlled trial.

METHODS

Patients with pSS with positive anti-SSA antibody and ESSDAI ≥ 5 were randomly assigned, in a 1:1:1 ratio, to receive weekly subcutaneous telitacicept 240 mg, 160 mg, or placebo for 24 weeks. The primary end point was the change from baseline in the ESSDAI at week 24. Safety was monitored.

RESULTS

A total of 42 patients were enrolled and randomized (n = 14 per group). Administration of telitacicept 160 mg resulted in a significant reduction in ESSDAI score from baseline to week 24 compared with placebo (P < 0.05). The placebo-adjusted least-squares mean change from baseline was -4.3 (95% CI -7.0, -1.6; P = 0.002). While, mean change of ESSDAI in telitacicept 240 mg was -2.7(-5.6-0.1) with no statistical difference when compared that in placebo group (P = 0.056). In addition, MFI-20 and serum immunoglobulins decreased significantly (P < 0.05) at week 24 in both telitacicept groups compared with placebo. No serious adverse events were observed in the telitacicept treating group.

CONCLUSION

Telitacicept showed clinical benefits and good tolerance and safety in the treatment of pSS.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT04078386.

New investigational drugs to treat Sjogren's syndrome: lessons learnt from immunology

INTRODUCTION

Sjögren's syndrome is a heterogeneous autoimmune condition that impairs quality of life because of dryness, fatigue, pain, and systemic involvements. Current treatment largely depends on empirical evidence, with no effective therapy approved. Clinical trials on targeted drugs often fail to report efficacy due to common factors.

AREAS COVERED

This review summarizes the pathogenesis and what caused the failure of new investigational drugs in clinical trials, highlighting solutions for more effective investigations, with greater consistency between research outcomes, clinical use, and patient needs.

EXPERT OPINION

Unlinked pathobiology with symptoms resulted in misidentified targets and disappointing trials. Useful stratification tools are necessary for the heterogeneous SS patients. Composite endpoints or improvements in ESSDAI scores are needed, considering the high placebo response, and the unbalance between symptom burden and disease activity. Compared to classic biologics, targeted cell therapy will be a more promising field of investigation in the coming years.

Efficacy of Telitacicept in a systemic lupus erythematosus patient with suboptimal response to Belimumab: A case report

As a therapeutic treatment for systemic lupus erythematosus (SLE), Belimumab reduces disease relapses and minimizes organ damage. Clinical practice, however, shows that the treatment is ineffective for a number of patients. Treatments for such cases are still lacking. As a biologic agent that targets both BLys and APRIL, Telitacicept inhibits both B cells and plasma cells. This case report describes a 35-year-old female with lupus nephritis (LN) who had previously undergone 10 cycles of Belimumab treatment but remained poorly controlled. Despite this, her condition improved significantly after switching to Telitacicept. This is the first report on the efficacy of Telitacicept in an SLE patient with suboptimal response to Belimumab. Telitacicept's role in this scenario needs more investigation and attention.

The role of BAFF and APRIL in IgA nephropathy: pathogenic mechanisms and targeted therapies

Immunoglobulin A nephropathy (IgAN), characterized by mesangial deposition of galactose-deficient-IgA1 (Gd-IgA1), is the most common biopsy-proven primary glomerulonephritis worldwide. Recently, an improved understanding of its underlying pathogenesis and the substantial risk of progression to kidney failure has emerged. The "four-hit hypothesis" of IgAN pathogenesis outlines a process that begins with elevated circulating levels of Gd-IgA1 that trigger autoantibody production. This results in the formation and deposition of immune complexes in the mesangium, leading to inflammation and kidney injury. Key mediators of the production of Gd-IgA1 and its corresponding autoantibodies are B-cell activating factor (BAFF), and A proliferation-inducing ligand (APRIL), each playing essential roles in the survival and maintenance of B cells and humoral immunity. Elevated serum levels of both BAFF and APRIL are observed in patients with IgAN and correlate with disease severity. This review explores the complex pathogenesis of IgAN, highlighting the pivotal roles of BAFF and APRIL in the interplay between mucosal hyper-responsiveness, B-cell activation, and the consequent overproduction of Gd-IgA1 and its autoantibodies that are key features in this disease. Finally, the potential therapeutic benefits of inhibiting BAFF and APRIL in IgAN, and a summary of recent clinical trial data, will be discussed.

Telitacicept Treatment Refractory Lupus Nephritis: A Case Report

Introduction

Refractory lupus nephritis (LN) causes kidney disease progression and increases the risk of loss of renal function. Due to the high specificity and few side effects of biological agents, they are recommended for the treatment of systemic lupus erythematosus. There are few data on telitacicept for the treatment of refractory LN.

Case Presentation

Here, we report the efficacy and safety of telitacicept in the treatment of refractory LN in a 25-year-old female patient. This patient with refractory lupus developed Pneumocystis jirovecii pneumonia while using multitargeted therapy, and the patient's urine protein was rapidly relieved after telitacicept combination with low-dose mycophenolate mofetil (MMF).

Conclusion

This result suggests that telitacicept has a positive effect on refractory LN with no significant side effects. Further reports and a registry are necessary to confirm that telitacicept with low-dose MMF should be preferred in refractory LN.

Case Report: Telitacicept in severe myasthenia gravis: a case study with multiple autoantibodies

Multi-antibody-positive myasthenia gravis (MG) presentations are relatively rare, often found in older patients, and generally predict a poor prognosis. We report a case of a female patient with generalized MG, testing positive for Titin antibodies (Titin-Ab), ryanodine receptor antibodies (RyR-Ab), and acetylcholine receptor antibodies (AChR-Ab), and resistant to acetylcholinesterase inhibitors. Following unsuccessful traditional therapies, she received Telitacicept, leading to significant improvements. This case underscores Telitacicept's potential efficacy for similar patients and offers insights into the clinical characteristics of multi-antibody MG.

Combination treatment with telitacicept, cyclophosphamide and glucocorticoids for severe Granulomatous polyangiitis: a case report and literature review

Granulomatous polyangiitis (GPA) is a rare autoimmune disease that can involve multiple systems throughout the body, including the ear, nose, upper and lower respiratory tracts. It is classified as an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Telitacicept is a novel recombinant fusion protein targeting B-lymphocyte stimulator (BLyS). Telitacicept can inhibit the development and maturation of abnormal B cells by blocking BLyS, and inhibit the production of antibodies by abnormal plasma cells by blocking APRIL (A proliferation-inducing ligand), which is expected to become a new drug for the treatment of GPA. We report a 64-year-old man diagnosed at our hospital with GPA involving multiple systems including kidneys, lungs, nose and ears. Renal involvement was severe, with a clinical characteristic of rapidly progressive glomerulonephritis and a pathologic manifestation of crescentic nephritis with plasma cell infiltration. The patient was treated with hormones, immunoglobulins and cyclophosphamide (CYC) with the addition of telitacicept and a rapid reduction in hormone dosage. The patient's renal function improved significantly within a short period of time, and his hearing and lung lesions improved significantly. At the same time, he did not develop serious infections and other related complications. Our report suggests that short-term control of the patient's conditions is necessary in GPA patients with organ-threatening disease. Telitacicept combined with CYC and glucocorticoids may be an induction therapy with safety and feasibility. However, more clinical trials are needed to validate the efficacy and safety of the therapeutic regimen.

The contribution of a proliferation-inducing ligand (APRIL) and other TNF superfamily members in pathogenesis and progression of IgA nephropathy

Advances in our understanding of the pathogenesis of immunoglobulin A nephropathy (IgAN) have led to the identification of novel therapeutic targets and potential disease-specific treatments. Specifically, a proliferation-inducing ligand (APRIL) has been implicated in the pathogenesis of IgAN, mediating B-cell dysregulation and overproduction of pathogenic galactose-deficient IgA1 (Gd-IgA1). Animal and clinical studies support the involvement of APRIL in the pathogenesis and progression of IgAN. An elevated level of APRIL is found in IgAN when compared with controls, which correlates with the level of Gd-IgA1 and associates with more severe disease presentation and worse outcomes. Conversely, anti-APRIL therapy reduces pathogenic Gd-IgA1 and IgA immune complex formation and ameliorates the severity of kidney inflammation and injury. Genome-wide association studies in IgAN have identified TNFSF13 and TNFRSF13B, a cytokine ligand-receptor gene pair encoding APRIL and its receptor, respectively, as risk susceptibility loci in IgAN, further supporting the causal role of the APRIL signalling pathway in IgAN. Several novel experimental agents targeting APRIL, including atacicept, telitacicept, zigakibart and sibeprenlimab, are currently under investigation as potential therapies in IgAN. Preliminary results suggest that these agents are well-tolerated, and reduce levels of Gd-IgA1, with corresponding improvement in proteinuria. Further studies are ongoing to confirm the safety and efficacy of anti-APRIL approaches as an effective therapeutic strategy in IgAN.

Case Report: Telitacicept in treating a patient with NF155+ autoimmune nodopathy: a successful attempt to manage recurrent elevated sero-anti-NF155 antibodies

This report presents a case of a neurofascin-155 (NF155)+ autoimmune nodopathy (AN) patient who exhibited resistance to conventional treatments but responded positively to telitacicept therapy. Telitacicept, a dual inhibitor of B lymphocyte stimulator (BLyS) and A proliferation-inducing ligand (APRIL), suppressed the development and survival of plasma cells and mature B cells. The patient's unique clinical features were consistent with NF155+ AN, showing limited response to standard treatments like rituximab and a recurrent significant increase in anti-NF155 antibody titers. Administering telitacicept (160mg, ih) led to an improvement in clinical symptoms, inflammatory neuropathy cause and treatment (INCAT) scale and inflammatory Rasch-built overall disability scale (I-RODS), and stabilized anti-NF155 antibody levels without a rebound. This case demonstrates telitacicept as a potential novel therapy for NF155+ AN, particularly when conventional treatments fail. Further investigation into its safety, efficacy, dosage, and treatment cycle in NF155+ AN is warranted.

Case report: Successful treatment of refractory membranous nephropathy with telitacicept

Despite various treatment methods, the remission rate of membranous nephropathy remains limited. Refractory membranous nephropathy especially lacks effective treatment plans. Telitacicept achieves comprehensive inhibition of CD20-positive B cells, plasma cells, and T cells, thereby bringing new hope to the treatment of membranous nephropathy and refractory membranous nephropathy. Here, we report a case of a 46-year-old man with membranous nephropathy. Although the combined treatment with glucocorticoid, tacrolimus, mycophenolate mofetil, cyclophosphamide, and rituximab was not successful, the patient achieved complete remission of urinary protein after glucocorticoid combined with telitacicept. This is the first report on the application of telitacicept in the treatment of membranous nephropathy, especially refractory membranous nephropathy. The application of telitacicept in the treatment of membranous nephropathy deserves further attention.

B Cell Tolerance and Targeted Therapies in SLE

Systemic Lupus Erythematosus (SLE) is a chronic systemic autoimmune disease of high clinical and molecular heterogeneity, and a relapsing-remitting pattern. The disease is currently without cure and more prevalent in women. B cell tolerance and production of autoantibodies are critical mechanisms that drive SLE pathophysiology. However, how the balance of the immune system is broken and how the innate and adaptive immune systems are interacting during lupus-specific autoimmune responses are still largely unknown. Here, we review the latest knowledge on B cell development, maturation, and central versus peripheral tolerance in connection to SLE and treatment options. We also discuss the regulation of B cells by conventional T cells, granulocytes, and unconventional T cells, and how effector B cells exert their functions in SLE. We also discuss mechanisms of action of B cell-targeted therapies, as well as possible future directions based on current knowledge of B cell biology.