Anti-CD20 monoclonal antibodies in Systemic Lupus Erythematosus

Disrupting B and T-cell collaboration in autoimmune disease: T-cell engagers versus CAR T-cell therapy?

B and T cells collaborate to drive autoimmune disease (AID). Historically, B- and T-cell (B-T cell) co-interaction was targeted through different pathways such as alemtuzumab, abatacept, and dapirolizumab with variable impact on B-cell depletion (BCD), whereas the majority of patients with AID including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and organ transplantation benefit from targeted BCD with anti-CD20 monoclonal antibodies such as rituximab, ocrelizumab, or ofatumumab. Refractory AID is a significant problem for patients with incomplete BCD with a greater frequency of IgD-CD27+ switched memory B cells, CD19+CD20- B cells, and plasma cells that are not directly targeted by anti-CD20 antibodies, whereas most lymphoid tissue plasma cells express CD19. Furthermore, B-T-cell collaboration is predominant in lymphoid tissues and at sites of inflammation such as the joint and kidney, where BCD may be inefficient, due to limited access to key effector cells. In the treatment of cancer, chimeric antigen receptor (CAR) T-cell therapy and T-cell engagers (TCE) that recruit T cells to induce B-cell cytotoxicity have delivered promising results for anti-CD19 CAR T-cell therapies, the CD19 TCE blinatumomab and CD20 TCE such as mosunetuzumab, glofitamab, or epcoritamab. Limited evidence suggests that anti-CD19 CAR T-cell therapy may be effective in managing refractory AID whereas we await evaluation of TCE for use in non-oncological indications. Therefore, here, we discuss the potential mechanistic advantages of novel therapies that rely on T cells as effector cells to disrupt B-T-cell collaboration toward overcoming rituximab-resistant AID.

Risk of Infections Secondary to the Use of Targeted Therapies in Hematological Malignancies

Concurrent infections in hematological malignancies (HM) are major contributors to adverse clinical outcomes, including prolonged hospitalization and reduced life expectancy. Individuals diagnosed with HM are particularly susceptible to infectious pathogens due to immunosuppression, which can either be inherent to the hematological disorder or induced by specific therapeutic strategies. Over the years, the treatment paradigm for HM has witnessed a tremendous shift, from broad-spectrum treatment approaches to more specific targeted therapies. At present, the therapeutic landscape of HM is constantly evolving due to the advent of novel targeted therapies and the enhanced utilization of these agents for treatment purposes. By initiating unique molecular pathways, these agents hinder the proliferation of malignant cells, consequently affecting innate and adaptive immunity, which increases the risk of infectious complications. Due to the complexity of novel targeted therapies and their associated risks of infection, it often becomes a daunting task for physicians to maintain updated knowledge in their clinical practice. The situation is further aggravated by the fact that most of the initial clinical trials on targeted therapies provide inadequate information to determine the associated risk of infection. In such a scenario, a cumulative body of evidence is paramount in guiding clinicians regarding the infectious complications that can arise following targeted therapies. In this review, I summarize the recent knowledge on infectious complications arising in the context of targeted therapies for HM.

The efficacy and safety of telitacicept for the treatment of systemic lupus erythematosus: a real life observational study

OBJECTIVE

To investigate the efficacy and safety of telitacicept treatment in a Chinese SLE cohort, with real-life settings.

METHODS

All patients with SLE who were receiving telitacicept treatment at least 4 weeks were included, and were followed up. Patients received subcutaneous injection of telitacicept weekly based on the standard treatment. SLE responder index-4 (SRI-4) was assessed before the first administration and at least 4 weeks after the first administration. Disease flares during the follow-up period were defined as an increase in disease activity and the number or dose of immunosuppressive drugs.

RESULTS

After 4-45 weeks' administration of telitacicept, 80% (n = 16) reached SRI-4 response. The prednisolone dosage declined from a mean of 30.25 mg/d (95% CI 21.99-38.51) before treatment to 13.25 mg/d (95% CI 9.92-16.58) after treatment. The proportion of patients without receiving an immunosuppressive drug increased from 15% to 43% at the endpoint. 19 cases showed various reduction of IgM after treatment (p < 0.05) and C3 and C4 showed either stable or an upward trend. The 24 h urinary protein median value of the 14 cases (baseline 24 h urinary protein >0.5 g/d) showed significant reduction, and 7 of them turned negative. Adverse events were mild to moderate and controllable.

CONCLUSION

Telitacicept is a potential treatment option for patients with SLE, especially in lupus nephritis, with significantly increased SRI-4 response rate and reduced the glucocorticoid and immunosuppressive drugs.

B cell depletion and inhibition in systemic lupus erythematosus

INTRODUCTION

Systemic lupus erythematosus (SLE) is characterized by autoantibody expression and aberrant autoreactive B cells contribute to disease progression; therefore, B cell inhibition has been an attractive target for novel therapies. However, after more than two decades of research and over 40 randomized clinical trials, only one such therapy, belimumab, has been approved for use in SLE.

AREAS COVERED

In this review, we discuss the evidence for B cell-targeted therapies in SLE and lupus nephritis. Belimumab has been successful in several large clinical trials and is approved in several countries for use in SLE and lupus nephritis. Despite a lack of supporting phase III evidence, rituximab is used off-label in SLE. Several other B cell-targeted therapies have failed to meet their end points in late-stage clinical trials. Successful phase II trials have recently been reported for obinutuzumab and telitacicept with larger confirmatory trials currently underway.

EXPERT OPINION

Refinements in pharmaceutical mechanisms of action, trial design, and patient selection have resulted in recent preliminary successes, offering renewed optimism for B-cell targeted therapeutics in SLE management.

Safety and efficacy of telitacicept in refractory childhood-onset systemic lupus erythematosus: A self-controlled before–after trial

Objective

To observe the efficacy and safety of telitacicept in refractory childhood-onset systemic lupus erythematosus (cSLE).

Methods

A self-controlled before–after trial. Children with active SLE, aged 5–18 years, who cannot tolerate side effects of glucocorticoid, were enrolled in our study. Patients received subcutaneous injection of telitacicept weekly based on the standard treatment. SLE responder index-4 (SRI-4) was assessed before the first administration and at least 4 weeks after the first administration.

Results

Among the 15 cases of refractory cSLE, three were males (20%) and 12 were females (80%). The median age and weight were 13 years old and 52 kg, respectively. The median duration of disease was 30 months. 5–26 weeks (80 or 160 mg per week) after administration of telitacicept, 66.7% ( n=10) reached SRI-4 response. 12 cases reduced their glucocorticoid intake from 40 mg/d to 17.5 mg/d. The urinary protein after treatment declined in 8 cases whose 24-h proteinuria was >0.5 g at baseline. The urinary protein in two of the eight cases turned negative and plasma albumin in five of the eight cases rose to normal. In addition, three of these eight cases demonstrated varying degrees of improvement in renal impairment, whose estimated glomerular filtration rate (eGFR, ml/min·1.73 m2) rose from 17.4 to 26.6, 40.7 to 48.2, and 63.2 to 146.0, respectively. There were mild to moderate adverse events after treatment.

Conclusion

Telitacicept combined with the standard treatment may significantly increase the SRI-4 response rate and reduce the glucocorticoid dosage in refractory cSLE, and also shown efficacy on lupus nephritis. The related adverse drug events were controllable.

Preclinical Analysis of Candidate Anti-Human CD79 Therapeutic Antibodies Using a Humanized CD79 Mouse Model

The BCR comprises a membrane-bound Ig that is noncovalently associated with a heterodimer of CD79A and CD79B. While the BCR Ig component functions to sense extracellular Ag, CD79 subunits contain cytoplasmic ITAMs that mediate intracellular propagation of BCR signals critical for B cell development, survival, and Ag-induced activation. CD79 is therefore an attractive target for Ab and chimeric Ag receptor T cell therapies for autoimmunity and B cell neoplasia. Although the mouse is an attractive model for preclinical testing, due to its well-defined immune system, an obstacle is the lack of cross-reactivity of candidate therapeutic anti-human mAbs with mouse CD79. To overcome this problem, we generated knockin mice in which the extracellular Ig-like domains of CD79A and CD79B were replaced with human equivalents. In this study, we describe the generation and characterization of mice expressing chimeric CD79 and report studies that demonstrate their utility in preclinical analysis of anti-human CD79 therapy. We demonstrate that human and mouse CD79 extracellular domains are functionally interchangeable, and that anti-human CD79 lacking Fc region effector function does not cause significant B cell depletion, but induces 1) decreased expression of plasma membrane-associated IgM and IgD, 2) uncoupling of BCR-induced tyrosine phosphorylation and calcium mobilization, and 3) increased expression of PTEN, consistent with the levels observed in anergic B cells. Finally, anti-human CD79 treatment prevents disease development in two mouse models of autoimmunity. We also present evidence that anti-human CD79 treatment may inhibit Ab secretion by terminally differentiated plasmablasts and plasma cells in vitro.

Anti-ANX A1 Antibody Therapy in MRL/lpr Murine Model of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a severe autoimmune disease characterized by dysfunction of immune regulation, overproduction of inflammatory cytokines and attack on normal tissues by self-reactive cells and antibodies. The main role in the pathogenesis plays the autoreactive tandem of B-T cells, responsible for lupus progression and acceleration. Both activated B and T cells express a phospholipid binding protein Annexin A1 and abnormal levels of the protein were found in murine and human autoimmune syndromes, potentiating its role as a therapeutic target. Here, using anti-annexin A1 antibody we explore its property to modulate the autoimmune response in MRL/lpr mouse model of lupus. Anti-ANX A1 antibody was tested in vitro using spleen cells from MRL/lpr mice to determine the effect on lymphocyte activation, plasma cells differentiation, apoptosis and proliferation by flow cytometry and ELISpot assays. Subsequently, several groups of young (disease-free) and old (sick) MRL/lpr mice were treated with the antibody to determine the levels of panel auto-antibodies and cytokines, T cell arrest and migration. Treatment of splenocytes with anti-ANX A1 antibody inhibited T-cell activation and proliferation, suppressed anti-dsDNA antibody-producing plasma cells and affected B cell apoptosis. Administration of the antibody to MRL/lpr mice resulted to decreased autoantibody levels to various lupus antigens, suppressed T cell migration from lymph nodes and increased the levels of IL4 mRNA compared to the control group. Anti-ANX A1 antibody therapy suppresses B and T cell over-activation and down- modulates disease activity.

An Update on the Management of Childhood-Onset Systemic Lupus Erythematosus

Childhood-onset systemic lupus erythematosus (cSLE) is a prototype of a multisystemic, inflammatory, heterogeneous autoimmune condition. This disease is characterized by simultaneous or sequential organ and system involvement, with unpredictable flare and high levels of morbidity and mortality. Racial/ethnic background, socioeconomic status, cost of medications, difficulty accessing health care, and poor adherence seem to impact lupus outcomes and treatment response. In this article, the management of cSLE patients is updated. Regarding pathogenesis, a number of potential targets for drugs have been studied. However, most treatments in pediatric patients are off-label drugs with recommendations based on inadequately powered studies, therapeutic consensus guidelines, or case series. Management practices for cSLE patients include evaluations of disease activity and cumulative damage scores, routine non-live vaccinations, physical activity, and addressing mental health issues. Antimalarials and glucocorticoids are still the most common drugs used to treat cSLE, and hydroxychloroquine is recommended for nearly all cSLE patients. Disease-modifying antirheumatic drugs (DMARDs) should be standardized for each patient, based on disease flare and cSLE severity. Mycophenolate mofetil or intravenous cyclophosphamide is suggested as induction therapy for lupus nephritis classes III and IV. Calcineurin inhibitors (cyclosporine, tacrolimus, voclosporin) appear to be another good option for cSLE patients with lupus nephritis. Regarding B-cell-targeting biologic agents, rituximab may be used for refractory lupus nephritis patients in combination with another DMARD, and belimumab was recently approved by the US Food and Drug Administration for cSLE treatment in children aged > 5 years. New therapies targeting CD20, such as atacicept and telitacicept, seem to be promising drugs for SLE patients. Anti-interferon therapies (sifalimumab and anifrolumab) have shown beneficial results in phase II randomized control trials in adult SLE patients, as have some Janus kinase inhibitors, and these could be alternative treatments for pediatric patients with severe interferon-mediated inflammatory disease in the future. In addition, strict control of proteinuria and blood pressure is required in cSLE, especially with angiotensin-converting enzyme inhibitor and angiotensin receptor blocker use.

CD47 Potentiates Inflammatory Response in Systemic Lupus Erythematosus

Background: To investigate the role of CD47 in inflammatory responses in systemic lupus erythematosus (SLE). Methods: Expression of CD47 and signal regulatory protein alpha (SIRPα) by peripheral blood mononuclear cells (PBMCs) and changes in CD47 expression after exposure to SLE serum, healthy control (HC) serum, recombinant interferon (IFN)-α, or tumor necrosis factor (TNF)-α were examined. Human monocytes and THP1 cells were incubated with lipopolysaccharide (LPS), an anti-CD47 antibody, or both. TNF-α production was examined. Sera from SLE patients and HCs were screened to detect autoantibodies specific for CD47. Results: Twenty-five SLE patients and sixteen HCs were enrolled. CD47 expression by monocytes from SLE patients was higher than those from HCs (mean fluorescence intensity ± SD: 815.9 ± 269.4 vs. 511.5 ± 199.4, respectively; p < 0.001). CD47 expression by monocytes correlated with SLE disease activity (Spearman’s rho = 0.467, p = 0.019). IFN-α but not TNF-α, increased CD47 expression. Exposing monocytes to an anti-CD47 antibody plus LPS increased TNF-α production by 21.0 ± 10.9-fold (compared with 7.3 ± 5.5-fold for LPS alone). Finally, levels of autoantibodies against CD47 were higher in SLE patients than in HCs (21.4 ± 7.1 ng/mL vs. 16.1 ± 3.1 ng/mL, respectively; p = 0.02). Anti-CD47 antibody levels did not correlate with disease activity (Spearman’s rho = −0.11, p = 0.759) or CD47 expression on CD14 monocytes (Spearman’s rho = 0.079, p = 0.838) in patients. Conclusions: CD47 expression by monocytes is upregulated in SLE and correlates with disease activity. CD47 contributes to augmented inflammatory responses in SLE. Targeting CD47 might be a novel treatment for SLE.