Assessment of the anti-CD40 antibody iscalimab in patients with primary Sjögren's syndrome: a multicentre, randomised, double-blind, placebo-controlled, proof-of-concept study

CD40 ligand antagonist dazodalibep in Sjögren's disease: a randomized, double-blinded, placebo-controlled, phase 2 trial

Sjögren's disease (SjD) is a chronic, systemic autoimmune disease with no approved disease-modifying therapies. Dazodalibep (DAZ), a novel nonantibody fusion protein, is a CD40 ligand antagonist that blocks costimulatory signals between T and B cells and antigen-presenting cells, and therefore may suppress the wide spectrum of cellular and humoral responses that drive autoimmunity in SjD. This study was a phase 2, randomized, double-blinded, placebo (PBO)-controlled trial of DAZ with a crossover stage in two distinct populations of participants with SjD. Population 1 had moderate-to-severe systemic disease activity and population 2 had an unacceptable symptom burden and limited systemic organ involvement. All participants had a diagnosis of SjD, with 21.6% and 10.1% having an associated connective tissue disease (rheumatoid arthritis or systemic lupus erythematosus) in populations 1 and 2, respectively. The remaining participants would be considered as having primary Sjögren's syndrome. The primary endpoint for population 1 (n = 74) was the change from baseline in the European League Against Rheumatism Sjögren's Syndrome Disease Activity Index at day 169. The primary endpoint for population 2 (n = 109) was the change from baseline in the European League Against Rheumatism Sjögren's Syndrome Patient Reported Index at day 169. The primary endpoints (least squares mean ± standard error) were achieved with statistical significance for both population 1 (DAZ, -6.3 ± 0.6; PBO, -4.1 ± 0.6; P = 0.0167) and population 2 (DAZ, -1.8 ± 0.2; PBO, -0.5 ± 0.2; P = 0.0002). DAZ was generally safe and well tolerated. Among the most frequently reported adverse events were COVID-19, diarrhea, headache, nasopharyngitis, upper respiratory tract infection, arthralgia, constipation and urinary tract infection. In summary, DAZ appears to be a potential new therapy for SjD and its efficacy implies an important role for the CD40/CD40 ligand pathway in its pathogenesis. ClinicalTrials.gov identifier: NCT04129164 .

Sequential immunotherapy: towards cures for autoimmunity

Despite major progress in the treatment of autoimmune diseases in the past two decades, most therapies do not cure disease and can be associated with increased risk of infection through broad suppression of the immune system. However, advances in understanding the causes of autoimmune disease and clinical data from novel therapeutic modalities such as chimeric antigen receptor T cell therapies provide evidence that it may be possible to re-establish immune homeostasis and, potentially, prolong remission or even cure autoimmune diseases. Here, we propose a 'sequential immunotherapy' framework for immune system modulation to help achieve this ambitious goal. This framework encompasses three steps: controlling inflammation; resetting the immune system through elimination of pathogenic immune memory cells; and promoting and maintaining immune homeostasis via immune regulatory agents and tissue repair. We discuss existing drugs and those in development for each of the three steps. We also highlight the importance of causal human biology in identifying and prioritizing novel immunotherapeutic strategies as well as informing their application in specific patient subsets, enabling precision medicine approaches that have the potential to transform clinical care.

Pulmonary Manifestations of Sjögren's Disease

Sjögren's disease (SjD) is a chronic, progressive autoimmune condition of exocrine and extraglandular tissues. It can present with isolated disease characterized by lymphocytic infiltration of salivary or lacrimal glands, but in approximately one-third of the patients, lymphocytic infiltration extends beyond exocrine glands to involve extraglandular organs such as the lungs. Pulmonary complications have been reported to occur between 9 and 27% of patients with SjD across studies. Respiratory manifestations occur on a spectrum of severity and include airways disease, interstitial lung disease, cystic lung disease, and lymphoma. Lung involvement can greatly affect patients' quality of life, has a major impact on the overall prognosis, and frequently leads to alteration in the treatment plans, highlighting the importance of maintaining a high index of clinical suspicion and taking appropriate steps to facilitate early recognition and intervention.

Elevated unphosphorylated STAT1 and IRF9 in T and B cells of primary sjögren's syndrome: Novel biomarkers for disease activity and subsets

OBJECTIVES

Autoreactive B cells and interferon (IFN) signature are hallmarks of primary sjögren's syndrome (pSS), but how IFN signaling pathways influence autoantibody production and clinical manifestations remain unclear. More detailed studies hold promise for improved diagnostic methodologies and personalized treatment.

METHODS

We analyzed peripheral blood T and B cell subsets from 34 pSS patients and 38 healthy donors (HDs) at baseline and upon stimulation regarding their expression levels of type I and II IFN signaling molecules (STAT1/2, IRF1, IRF9). Additionally, we investigated how the levels of these molecules correlated with serological and clinical characteristics and performed ROC analysis.

RESULTS

Patients showed elevated IFN pathway molecules, including STAT1, STAT2 and IRF9 among most T and B cell subsets. We found a reduced ratio of phosphorylated STAT1 and STAT2 in patients in comparison to HDs, although B cells from patients were highly responsive by increased phosphorylation upon IFN stimulation. Correlation matrices showed further interrelations between STAT1, IRF1 and IRF9 in pSS. Levels of STAT1 and IRF9 in T and B cells correlated with the IFN type I marker Siglec-1 (CD169) on monocytes. High levels of STAT1 and IRF9 within pSS B cells were significantly associated with hypergammaglobulinemia as well as anti-SSA/anti-SSB autoantibodies. Elevated STAT1 levels were found in patients with extraglandular disease and could serve as a biomarker for this subgroup (p < 0.01). Notably, IRF9 levels in T and B cells correlated with EULAR Sjögren's syndrome disease activity index (ESSDAI).

CONCLUSION

Here, we provide evidence that in active pSS patients, enhanced IFN signaling incl. unphosphorylated STAT1 and STAT2 with IRFs entertain chronic T and B cell activation. Furthermore, increased STAT1 levels candidate as biomarker of extraglandular disease, while IRF9 levels can serve as biomarker for disease activity.

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.

New molecular targets in the treatment of rheumatoid arthritis

PURPOSE OF REVIEW

This review will discuss selected emerging molecular targets and associated potential therapeutic agents for rheumatoid arthritis (RA)-directed treatment.

RECENT FINDINGS

Agents in active development for RA treatment include those targeted to CD40 and CD40 ligand, programmed death protein 1 (PD-1), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Several other molecules with a strong theoretical role in RA pathogenesis and/or demonstrated efficacy in other autoimmune diseases are also being evaluated as potential drug targets in preclinical or translational studies in RA. These targets include interleukin 1 receptor associated kinases 1 and 4 (IRAK1, IRAK4), tyrosine kinase 2 (Tyk2), bradykinin receptor 1 (B1R), OX40 and OX40 ligand.

SUMMARY

Identification of molecular targets for RA treatment remains an active area of investigation, with multiple therapeutic agents in clinical and preclinical development.

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.

British Society for Rheumatology guideline on management of adult and juvenile onset Sjögren disease

Sjögren disease (SD) is a chronic, autoimmune disease of unknown aetiology with significant impact on quality of life. Although dryness (sicca) of the eyes and mouth are the classically described features, dryness of other mucosal surfaces and systemic manifestations are common. The key management aim should be to empower the individual to manage their condition-conserving, replacing and stimulating secretions; and preventing damage and suppressing systemic disease activity. This guideline builds on and widens the recommendations developed for the first guideline published in 2017. We have included advice on the management of children and adolescents where appropriate to provide a comprehensive guideline for UK-based rheumatology teams.

Identification of outcome domains in primary Sjögren's disease: A scoping review by the OMERACT Sjögren disease working group

OBJECTIVES

Sjögren's disease (SjD) is a heterogenous disease with a wide range of manifestations, ranging from symptoms of dryness, fatigue, and pain, to systemic involvement. Considerable advances have been made to evaluate systemic activity or patient-reported outcomes, but most of the instruments were not able to assess all domains of this multifaceted disease. The aim of this scoping review was to generate domains that have been assessed in randomized controlled trials, as the first phase of the Outcome Measures in Rheumatology (OMERACT) process of core domain set development.

METHODS

We systematically searched Medline (Pubmed) and EMBASE between 2002 and March 2023 to identify all randomized controlled trials assessing relevant domains, using both a manual approach and an artificial intelligence software (BIBOT) that applies natural language processing to automatically identify relevant abstracts. Domains were mapped to core areas, as suggested by the OMERACT 2.1 Filter.

RESULTS

Among the 5,420 references, we included 60 randomized controlled trials, focusing either on overall disease manifestations (53%) or on a single organ/symptom: dry eyes (17%), xerostomia (15%), fatigue (12%), or pulmonary function (3%). The most frequently assessed domains were perceived dryness (52% for overall dryness), fatigue (57%), pain (52%), systemic disease activity (45%), lacrimal gland function (47%) and salivary function (55%), B-cell activation (60%), and health-related quality of life (40%).

CONCLUSION

Our scoping review highlighted the heterogeneity of SjD, in the study designs and domains. This will inform the OMERACT SjD working group to select the most appropriate core domains to be used in SjD clinical trials and to guide the future agenda for outcome measure research in SjD.

Bridging the gender gap in autoimmunity with T-cell-targeted biomaterials

Autoimmune diseases are caused by malfunctions of the immune system and generally impact women at twice the frequency of men. Many of the most serious autoimmune diseases are accompanied by a dysregulation of T-cell phenotype, both regarding the ratio of CD4+ to CD8+ T-cells and proinflammatory versus regulatory phenotypes. Biomaterials, in the form of particles and hydrogels, have shown promise in ameliorating this dysregulation both in vivo and ex vivo. In this review, we explore the role of T-cells in autoimmune diseases, particularly those with high incidence rates in women, and evaluate the promise and efficacy of innovative biomaterial-based approaches for targeting T-cells.

Novel and potential future therapeutic options in systemic autoimmune diseases

Autoimmune inflammation is caused by the loss of tolerance to specific self-antigens and can result in organ-specific or systemic disorders. Systemic autoimmune diseases affect a significant portion of the population with an increasing rate of incidence, which means that is essential to have effective therapies to control these chronic disorders. Unfortunately, several patients with systemic autoimmune diseases do not respond at all or just partially respond to available conventional synthetic disease-modifying antirheumatic drugs and targeted therapies. However, during the past few years, some new medications have been approved and can be used in real-life clinical settings. Meanwhile, several new candidates appeared and can offer promising novel treatment options in the future. Here, we summarize the newly available medications and the most encouraging drug candidates in the treatment of systemic lupus erythematosus, rheumatoid arthritis, Sjögren's disease, systemic sclerosis, systemic vasculitis, and autoimmune myositis.

Manifestations and management of Sjögren's disease

Sjögren's disease is a heterogeneous autoimmune disorder that may be associated with systemic manifestations such as pulmonary or articular involvement. Systemic complications have prognostic implications and need to be identified and managed in a timely manner. Treatment should be tailored to the type and severity of organ involvement, ideally based on multidisciplinary evaluation.

B Cells Dynamic in Aging and the Implications of Nutritional Regulation

Aging negatively affects B cell production, resulting in a decrease in B-1 and B-2 cells and impaired antibody responses. Age-related B cell subsets contribute to inflammation. Investigating age-related alterations in the B-cell pool and developing targeted therapies are crucial for combating autoimmune diseases in the elderly. Additionally, optimal nutrition, including carbohydrates, amino acids, vitamins, and especially lipids, play a vital role in supporting immune function and mitigating the age-related decline in B cell activity. Research on the influence of lipids on B cells shows promise for improving autoimmune diseases. Understanding the aging B-cell pool and considering nutritional interventions can inform strategies for promoting healthy aging and reducing the age-related disease burden.

Estimated prevalence, incidence and healthcare costs of Sjögren's syndrome in France: a national claims-based study

OBJECTIVES

To estimate prevalence, incidence and mortality rates, and annual healthcare costs of primary Sjögren's syndrome (pSS) and SS associated with other autoimmune disorders (SS+AID) in France.

METHODS

French national healthcare claims-based study within the prospective Système National des Données de Santé database that includes the majority of the French population. An algorithm was developed to identify patients with SS and SS-related healthcare claims were analysed between 2011 and 2018.

RESULTS

Overall, 23 848 patients with pSS and 14 809 with SS+AID were identified. From 2011 to 2018, the prevalence rate increased slightly for pSS (23-32 per 100000) and SS+AID (16-20 per 100 000), with females comprising 90%-91% and 92%-93% of cases, respectively. The incidence rate of SS per 100 000 persons decreased from 2012 (pSS: 4.3; SS+AID: 2.0) to 2017 (pSS: 0.7; SS+AID: 0.3). Mortality rates per 100 000 persons increased from 2012 to 2018 in patients with pSS (0.2-0.8) or SS+AID (0.1-0.5); mean age of death also increased. Artificial tears and hydroxychloroquine were the most common drug reimbursements. Less than half of patients received annual specialist care from a dentist or ophthalmologist. Healthcare costs associated with SS increased from 2011 to 2018 and exceeded the national estimate of expected costs for chronic diseases.

CONCLUSION

In this large French population database study, the low prevalence of pSS confirms that it is an orphan disease. SS is clinically and economically burdensome; these findings may help clinicians better understand routine healthcare received by patients.

Evaluation and management of dry mouth and its complications in rheumatology practice

INTRODUCTION

The symptom of dry mouth has multiple potential etiologies and can be a diagnostic clue to the presence of common systemic diseases encountered in rheumatology practice. The presence of decreased saliva flow (i.e. salivary hypofunction) defines a subset of dry mouth patients in whom there may be reversible drug effects, an iatrogenic insult such as head and neck irradiation, or a disease that directly involves the salivary glands (e.g. Sjögren's disease). The assessment of salivary hypofunction includes sialometry, salivary gland imaging, salivary gland biopsy, and an assessment for relevant systemic diseases. Optimal management of dry mouth requires accurate definition of its cause, followed by general measures that serve to alleviate its symptoms and prevent its complications.

AREAS COVERED

Through a literature search on xerostomia and salivary hypofunction, we provide an overview of the causes of dry mouth, highlight the potential impact of salivary hypofunction on oral and systemic health, detail routine evaluation methods and treatment strategies, and emphasize the importance of collaboration with oral health care providers.

EXPERT OPINION

Our Expert Opinion is provided on unmet needs in the management of dry mouth and relevant research progress in the field.

Efficacy and safety of iscalimab, a novel anti-CD40 monoclonal antibody, in moderate-to-severe myasthenia gravis: A phase 2 randomized study

BACKGROUND

Increased morbidity in many patients with myasthenia gravis (MG) on long-term immunosuppression highlights the need for improved treatments. The aim of this study is to investigate the safety and efficacy of iscalimab (CFZ533), a fully human anti-CD40 monoclonal antibody, in patients with moderate-to-severe MG receiving standard-of-care (SoC) therapies.

METHODS

In this double-blind, placebo-controlled phase 2 study, symptomatic patients (n = 44) despite SoC were randomized 1:1 to receive intravenous iscalimab (10 mg/kg; n = 22) or placebo (n = 22) every 4 weeks for 6 doses in total. Patients were followed up for 6 months after the last dose. The total duration of the study was 52 weeks.

RESULTS

In total, 34 of 44 patients (77.3 %) completed the study. The primary endpoint, Quantitative MG score, did not change significantly between baseline and week 25 for iscalimab (median [90 % CI], -4.07 [-5.67, -2.47]) versus placebo (-2.93 [-4.53, -1.33]); however, non-thymectomized patients (n = 29) showed more favorable results (iscalimab, -4.35 [-6.07, -2.64] vs placebo, -2.26 [-4.16, -0.36]). A statistically significant difference between iscalimab and placebo groups was observed in MG Composite score (adjusted mean change: -4.19 [-6.67, -1.72]; p = 0.007) at week 13, and MG-Activities of Daily Living score (-1.93 [-3.24, -0.62]; p = 0.018) at week 21. Adverse events were comparable between the iscalimab (91 %) and placebo (96 %) groups.

CONCLUSION

Iscalimab showed favorable safety and improvements compared with placebo in non-thymectomized patients with moderate-to-severe MG. It did not show any protective effect in patients with moderate-to-severe MG.

Expert Perspective: Challenges in Sjögren's Disease

The management of Sjögren's disease is challenging because of several factors. Indeed, the clinical presentations are heterogeneous, and one must be able to identify prognostic markers to adapt the follow-up. In addition, there is no validated treatment. Nevertheless, international experts have been working for several years to establish recommendations to guide management. Since research in this field is extremely active, we anticipate the development of effective treatments for our patients in the near future.

First-in-Human Phase 1 Randomized Trial with the Anti-CD40 Monoclonal Antibody KPL-404: Safety, Tolerability, Receptor Occupancy, and Suppression of T-Cell-Dependent Antibody Response

Blockade of the cluster of differentiation 40 (CD40)-CD40L interaction has potential for treating autoimmune diseases and preventing graft rejection. This first-in-human, randomized, double-blind, placebo-controlled study (NCT04497662) evaluated safety, pharmacokinetics, receptor occupancy, and pharmacodynamics of the humanized anti-CD40 monoclonal antibody KPL-404. Healthy volunteers were randomized to one of two single-ascending-dose groups: single intravenous KPL-404 dose 0.03, 0.3, 1, 3, or 10 mg/kg or single subcutaneous KPL-404 dose 1 or 5 mg/kg. There were no dose-limiting or dose-related safety findings. Nonlinear dose-dependent changes in various pharmacokinetic parameters were identified following the range of intravenous doses. At the 10 mg/kg intravenous dose level, the t1/2 was approximately 7 days, and full receptor occupancy was observed through Day 71, with complete suppression of T-cell-dependent antibody response (TDAR) to keyhole limpet hemocyanin (KLH) challenge on Day 1 and rechallenge on Day 29 through Day 57. With KPL-404 5 mg/kg subcutaneously, full receptor occupancy was observed through Day 43, with complete suppression of TDAR through at least Day 29. Antidrug antibodies to KPL-404 were suppressed for 57 days with 10 mg/kg intravenously and for 50 days with 5 mg/kg subcutaneously, further confirming prolonged target engagement and pharmacodynamics. These findings support continued investigation of KPL-404 intravenous and subcutaneous administration in a broad range of indications. SIGNIFICANCE STATEMENT: This first-in-human clinical trial of KPL-404, a fully humanized IgG4 monoclonal antibody, was designed with two independent (by route of administration) placebo-controlled single-ascending-dose-level groups, one with four intravenous single-dose cohorts and another with two subcutaneous single-dose cohorts. The pharmacokinetic profile, duration of full CD40 receptor occupancy, and magnitude and duration of memory immune response suppression observed confirm pharmacodynamic activity regardless of administration route. These data provide evidence that chronic KPL-404 dosing regimens (intravenous or subcutaneous) could be practical.

A randomized, double-blind, placebo-controlled, parallel group study on the effects of a cathepsin S inhibitor in primary Sjögren's syndrome

OBJECTIVES

Primary SS (pSS) is a chronic autoimmune disorder characterized by mucosal dryness and systemic symptoms. We tested the effects of inhibition of cathepsin S using the potent and selective inhibitor RO5459072 on disease activity and symptoms of pSS.

METHODS

This was a randomized, double-blind, placebo-controlled, parallel-group, Phase IIA study to investigate the effects of RO5459072 (100 mg twice daily; 200 mg per day). Seventy-five patients with pSS were randomized 1:1 to receive either RO5459072 or placebo for 12 weeks. The primary outcome was the proportion of patients with a ≥3 point reduction from baseline in EULAR SS Disease Activity Index (ESSDAI) score. We also investigated the effects of RO5459072 on quality of life, exocrine gland function, biomarkers related to SS, and safety and tolerability.

RESULTS

The proportion of patients showing an improvement in ESSDAI score was not significantly different between the RO5459072 and placebo arms. No clinically meaningful treatment effects were observed in favour of RO5459072 for all secondary outcomes. Analysis of soluble biomarkers indicated target engagement between RO5459072 and cathepsin S. There were modest decreases in the number of circulating B cells and T cells in the RO5459072 group, although these did not reach significance. RO5459072 was safe and well-tolerated.

CONCLUSIONS

There was no clinically relevant improvement in ESSDAI score (primary endpoint), and no apparent benefit in favour of RO5459072 in any of the secondary clinical endpoints. Further work is needed in order to understand the mechanisms of MHC-II-mediated immune stimulation in pSS.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT02701985.

Rheumatic complications of checkpoint inhibitors: Lessons from autoimmunity

Immune checkpoint inhibitors are now an established treatment in the management of a range of cancers. Their success means that their use is likely to increase in future in terms of the numbers of patients treated, the indications and the range of immune checkpoints targeted. They function by counteracting immune evasion by the tumor but, as a consequence, can breach self-tolerance at other sites leading to a range of immune-related adverse events. Included among these complications are a range of rheumatologic complications, including inflammatory arthritis and keratoconjunctivitis sicca. These superficially resemble immune-mediated rheumatic diseases (IMRDs) such as rheumatoid arthritis and Sjogren's disease but preliminary studies suggest they are clinically and immunologically distinct entities. However, there appear to be common processes that predispose to the development of both that may inform preventative interventions and predictive tools. Both groups of conditions highlight the centrality of immune checkpoints in controlling tolerance and how it can be restored. Here we will discuss some of these commonalities and differences between rheumatic irAEs and IMRDs.

French national diagnostic and care protocol for Sjögren's disease

Sjögren's disease (SD), also known as Sjögren's syndrome (SS) or Gougerot-Sjögren's syndrome in France, is a rare systemic autoimmune disease in its primary form and is characterised by tropism for the exocrine glandular epithelia, particularly the salivary and lacrimal glands. The lymphocytic infiltration of these epithelia will clinically translate into a dry syndrome which, associated with fatigue and pain, constitutes the symptom triad of the disease. In about one third of patients, SD is associated with systemic complications that can affect the joints, skin, lungs, kidneys, central or peripheral nervous system, and lymphoid organs with an increased risk of B-cell lymphoma. SD affects women more frequently than men (9/1). The peak frequency is around the age of 50. However, the disease can occur at any age, with paediatric forms occurring even though they remain rare. SD can occur alone or in association with other systemic autoimmune diseases. In its isolated or primary form, the prevalence of SD is estimated to be between 1 per 1000 and 1 per 10,000 inhabitants. The most recent classification criteria were developed in 2016 by EULAR and ACR. The course and prognosis of the disease are highly variable and depend on the presence of systemic involvement and the severity of the dryness of the eyes and mouth. The current approach is therefore to identify at an early stage those patients most at risk of systemic complications or lymphoma, who require close follow-up. On the other hand, regular monitoring of the ophthalmological damage and of the dental status should be ensured to reduce the consequences.

Outline of Salivary Gland Pathogenesis of Sjögren's Syndrome and Current Therapeutic Approaches

Sjögren's syndrome (SS) is an autoimmune disease characterized by the involvement of exocrine glands such as the salivary and lacrimal glands. The minor salivary glands, from which tissue samples may be obtained, are important for the diagnosis, evaluation of therapeutic efficacy, and genetic analyses of SS. In the onset of SS, autoantigens derived from the salivary glands are recognized by antigen-presenting dendritic cells, leading to the activation of T and B cells, cytokine production, autoantibody production by plasma cells, the formation of ectopic germinal centers, and the destruction of salivary gland epithelial cells. A recent therapeutic approach with immune checkpoint inhibitors for malignant tumors enhances the anti-tumor activity of cytotoxic effector T cells, but also induces SS-like autoimmune disease as an adverse event. In the treatment of xerostomia, muscarinic agonists and salivary gland duct cleansing procedure, as well as sialendoscopy, are expected to ameliorate symptoms. Clinical trials on biological therapy to attenuate the hyperresponsiveness of B cells in SS patients with systemic organ involvement have progressed. The efficacy of treatment with mesenchymal stem cells and chimeric antigen receptor T cells for SS has also been investigated. In this review, we will provide an overview of the pathogenesis of salivary gland lesions and recent trends in therapeutic approaches for SS.

Why do drug treatments fail in Sjögren's disease? Considerations for treatment, trial design and interpretation of clinical efficacy

INTRODUCTION

Despite ongoing efforts to develop effective therapeutics, no disease-modifying drugs have been officially licensed for the indication of Sjögren's disease (SjD). This is partly due to heterogeneity in disease manifestations, which complicates drug target selection, trial design and interpretation of clinical efficacy in SjD.

AREAS COVERED

Here, we summarize developments and comment on challenges in 1) identifying the right target for treatment, 2) selection of the primary study endpoint for trials and definition of clinically relevant response to treatment, 3) inclusion criteria and patient stratification, 4) distinguishing between disease activity and damage and 5) establishing the effect of treatment considering measurement error, natural variation, and placebo or nocebo responses.

EXPERT OPINION

Targets that are involved in both the immune cell response and dysregulation of glandular epithelial cells (e.g. B-lymphocytes, type-I interferon) are of particular interest to treat both glandular and extra-glandular manifestations of SjD. The recent development of composite study endpoints (CRESS and STAR) may be a crucial step forward in the search for clinically effective systemic treatment of patients with SjD. Important additional areas for future research are symptom-based and/or molecular pathway-based patient stratification, prevention of irreversible damage, and establishing the effect of treatment.

Primary-Sjögren's-Syndrome-Related Interstitial Lung Disease: A Clinical Review Discussing Current Controversies

Lung involvement, especially interstitial lung disease, is a potentially severe extra-glandular manifestation of Primary Sjogren's Syndrome (pSS-ILD). ILD can manifest either as a late complication of pSS or anticipate sicca symptoms, likely reflecting two different patho-physiological entities. Presence of lung involvement in pSS subjects can remain subclinical for a long time; therefore, patients should be actively screened, and lung ultrasound is currently being investigated as a potential low cost, radiation-free, easily repeatable screening tool for detection of ILD. In contrast, rheumatologic evaluation, serology testing, and minor salivary gland biopsy are crucial for the recognition of pSS in apparently idiopathic ILD patients. Whether the HRCT pattern influences prognosis and treatment response in pSS-ILD is not clear; a UIP pattern associated with a worse prognosis in some studies, but not in others. Many aspects of pSS-ILD, including its actual prevalence, association with specific clinical-serological characteristics, and prognosis, are still debated by the current literature, likely due to poor phenotypic stratification of patients in clinical studies. In the present review, we critically discuss these and other clinically relevant "hot topics" in pSS-ILD. More specifically, after a focused discussion, we compiled a list of questions regarding pSS-ILD that, in our opinion, are not easily answered by the available literature. We subsequently tried to formulate adequate answers on the basis of an extensive literature search and our clinical experience. At the same, we highlighted different issues that require further investigation.

Emerging treatment for Sjögren's disease: a review of recent phase II and III trials

INTRODUCTION

Sjögren's Disease, SjD, is a systemic autoimmune disorder characterized by reduced function of the salivary and lacrimal glands. Patients suffer from dryness, fatigue, and pain and may present with or without extra-glandular organ involvement. Symptoms limit SjD patients' quality of life and are the most difficult to improve with therapy. SjD patients are heterogeneous and clustering them into biologically similar subgroups might improve the efficacy of therapies. The need for therapies that address both the symptoms and extra glandular organ involvement of SjD presents an unmet opportunity that has recently attracted a growing interest in the pharmaceutical industry.

AREAS COVERED

The goal of this report is to review recent phase II/III studies in SjD. To accomplish our goal, we performed a literature search for phase II/III studies and abstracts recently presented at conferences.

EXPERT OPINION

This review allows updates the reader on the multitude of recent phase II/III clinical trials. We speculate on how subtypes of SjD will drive future therapeutic targeting and inform pathogenesis.

Genetics and epigenetics of primary Sjögren syndrome: implications for future therapies

In primary Sjögren syndrome (pSS), chronic inflammation of exocrine glands results in tissue destruction and sicca symptoms, primarily of the mouth and eyes. Fatigue, arthralgia and myalgia are also common symptoms, whereas extraglandular manifestations that involve the respiratory, nervous and vascular systems occur in a subset of patients. The disease predominantly affects women, with an estimated female to male ratio of 14 to 1. The aetiology of pSS, however, remains incompletely understood, and effective treatment is lacking. Large-scale genetic and epigenetic investigations have revealed associations between pSS and genes in both innate and adaptive immune pathways. The genetic variants mediate context-dependent effects, and both sex and environmental factors can influence the outcome. As such, genetic and epigenetic studies can provide insight into the dysregulated molecular mechanisms, which in turn might reveal new therapeutic possibilities. This Review discusses the genetic and epigenetic features that have been robustly connected with pSS, putting them into the context of cellular function, carrier sex and environmental challenges. In all, the observations point to several novel opportunities for early detection, treatment development and the pathway towards personalized medicine.

Involvement of aquaporin 5 in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disease with the pathological hallmark of lymphoplasmacytic infiltration of exocrine glands - more specifically salivary and lacrimal glands - resulting in a diminished production of tears and saliva (sicca syndrome). The pathophysiology underscoring the mechanisms of the sicca symptoms in SS has still yet to be unraveled but recent advances have identified a cardinal role of aquaporin-5 (AQP5) as a key player in saliva secretion as well as salivary gland epithelial cell dysregulation. AQP5 expression and localization are significantly altered in salivary glands from patients and mice models of the disease, shedding light on a putative mechanism accounting for diminished salivary flow. Furthermore, aberrant expression and localization of AQP5 protein partners, such as prolactin-inducible protein and ezrin, may account for altered AQP5 localization in salivary glands from patients suffering from SS and are considered as new players in SS development. This review provides an overview of the role of AQP5 in SS salivary gland epithelial cell dysregulation, focusing on its trafficking and protein-protein interactions.

Pathogenesis and treatment of Sjogren's syndrome: Review and update

Sjogren's syndrome (SS) is a chronic autoimmune disease accompanied by multiple lesions. The main manifestations include dryness of the mouth and eyes, along with systemic complications (e.g., pulmonary disease, kidney injury, and lymphoma). In this review, we highlight that IFNs, Th17 cell-related cytokines (IL-17 and IL-23), and B cell-related cytokines (TNF and BAFF) are crucial for the pathogenesis of SS. We also summarize the advances in experimental treatment strategies, including targeting Treg/Th17, mesenchymal stem cell treatment, targeting BAFF, inhibiting JAK pathway, et al. Similar to that of SLE, RA, and MS, biotherapeutic strategies of SS consist of neutralizing antibodies and inflammation-related receptor blockers targeting proinflammatory signaling pathways. However, clinical research on SS therapy is comparatively rare. Moreover, the differences in the curative effects of immunotherapies among SS and other autoimmune diseases are not fully understood. We emphasize that targeted drugs, low-side-effect drugs, and combination therapies should be the focus of future research.

Abatacept ameliorates both glandular and extraglandular involvements in patients with Sjögren's syndrome associated with rheumatoid arthritis: Findings from an open-label, multicentre, 1-year, prospective study: The ROSE (Rheumatoid Arthritis with Orencia Trial Toward Sjögren's Syndrome Endocrinopathy) and ROSE II trials

OBJECTIVE

To clarify the efficacy and safety of intravenous abatacept for glandular and extraglandular involvements in Sjögren's syndrome (SS) associated with rheumatoid arthritis (RA).

MATERIALS AND METHODS

We performed an open-label, prospective, 1-year, observational multicenter study (ROSE and ROSE II trials). The primary endpoint was the remission rate as measured by SDAI at 52 weeks. The secondary endpoints included the changes in the Saxon's test, Schirmer's test, ESSDAI and ESSPRI. Adverse events and adherence rates were also analyzed.

RESULTS

68 patients (36 in ROSE and 32 in ROSE II, all women) were enrolled. SDAI decreased significantly from 23.6 ± 13.2 at baseline to 9.9 ± 9.5 at 52 weeks. Patients with SDAI remission increased from 0 (0 weeks) to 19 patients (27.9%) at 52 weeks. Saliva volume increased significantly at 24 weeks. Tear volume increased significantly at 52 weeks. Both ESSDAI and ESSPRI were significantly decreased at 12 weeks, and these responses were maintained up to 52 weeks. The rate of adherence to abatacept over the 52-week period was 83.8%. Twenty-two adverse events occurred in 15 patients.

CONCLUSION

Abatacept ameliorated both glandular and extraglandular involvements, as well as the systemic disease activities and patient-reported outcomes based on composite measures, in SS associated with RA.

Safety and efficacy of filgotinib, lanraplenib and tirabrutinib in Sjögren's syndrome: a randomized, phase 2, double-blind, placebo-controlled study

OBJECTIVE

The aim of this study was to characterize the safety and efficacy of filgotinib, lanraplenib and tirabrutinib in patients with active SS.

METHODS

This multicentre, double-blind study randomized patients with active primary or secondary SS [EULAR SS disease activity index (ESSDAI) ≥5) to receive filgotinib 200 mg (Janus kinase-1 inhibitor), lanraplenib 30 mg (spleen tyrosine kinase inhibitor), tirabrutinib 40 mg (Bruton's tyrosine kinase inhibitor), or placebo. The composite primary end point was the week-12 proportion of patients fulfilling protocol-specified improvement criteria (based on CRP and SS-related symptoms). The EULAR SS patient-reported index (ESSPRI) and the ESSDAI change from baseline (CFB) were secondary end points. Exploratory end points included disease-related biomarkers. Treatment-emergent adverse events (AEs) represented safety outcomes.

RESULTS

The mean of the baseline ESSDAI was 10.1, and of ESSPRI was 6.2 in the 150 patients who were treated; 125 completed the 24-week placebo-controlled treatment period. At week 12, 43.3% of the filgotinib group achieved the primary end point (P = 0.17 vs placebo) vs 42.3% (P = 0.16), 34.7% (P = 0.33), and 26.7% of lanraplenib, tirabrutinib, and placebo groups, respectively. Neither secondary end point was met. Biomarker reductions included immunoglobulins classically associated with SS disease activity. Filgotinib ESSDAI CFB appeared more pronounced in subgroups with baseline ESSDAI ≥14 or without DMARDs/CSs. Most AEs were Grade 1 or 2.

CONCLUSION

Three drugs with disparate mechanisms were tested, but no significant differences vs placebo in primary or secondary end points were observed. These results may be considered hypothesis-generating, given the drug tolerability, subgroup analysis, and biomarker findings.

TRIAL REGISTRATION

ClinicalTrials.gov, https://clinicaltrials.gov, NCT03100942.

Current and future treatment in primary Sjögren's syndrome - A still challenging development

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by sicca symptoms, systemic manifestations and constitutional symptoms substantially diminishing patient's quality of life. In this review, we summarize recent recommendations for management of pSS patients and current clinical studies in pSS addressing unmet medical needs. Expanding knowledge about disease pathogenesis and the introduction of validated outcome measures, such as capturing disease activity (ESSDAI) and patient-reported outcomes (ESSPRI) have shaped recent developments. In contrast, lack of evidence for current treatment options remarkably limits the management of pSS patients as reflected by the 2019 updated EULAR recommendations for management of Sjögren's syndrome. In this context, symptomatic treatment is usually appropriate for sicca symptoms, whereas systemic treatment is reserved for moderate to severe organ manifestations including care by a multidisciplinary team in centers of expertise. Most promising targets for new treatment modalities are based on immunopathological insights and include direct B cell targeting strategies, targeting co-stimulation by CD40/CD40L blocking, inhibition of key cytokine activity (BLyS/BAFF, type I interferon) and intracellular signaling pathways.

Sjögren's syndrome: shedding light on emerging and key drug targets

INTRODUCTION

Sjögren's syndrome (SS) is an immune-mediated inflammatory condition characterized by sicca syndrome, musculoskeletal pain, and fatigue. Extra-glandular manifestations are common and there is a markedly increased risk of lymphoma development. SS is associated with high health-economic burden driven largely by the symptom burden on patients. Currently, there is no approved disease-modifying treatment and management is based on empirical evidence. Progress in the understanding of SS pathogenesis has led to an expanding portfolio of more targeted therapies under development.

AREAS COVERED

This review summarizes the key development in targeted biological therapies in SS including emerging targets. It also highlights the challenges in therapeutic development in SS such as disease heterogeneity and defining appropriate disease assessment tools to evaluate therapeutic efficacy.

EXPERT OPINION

Early trials in SS failed to meet their primary outcomes which may in part due to the use of inappropriate or insensitive study endpoints. Recent trials targeting B-cells, B-T cell co-stimulation and IFN signaling have shown promising results. Development of composite endpoints including patient reported outcomes and objective disease measure may provide a more holistic approach to disease assessment. The impact of these new tools on therapeutic development that benefit patients remains to be fully evaluated.

Investigational drugs for the treatment of kidney transplant rejection

INTRODUCTION

Kidney transplant rejection remains an important clinical problem despite the development of effective immunosuppressive drug combination therapy. Two major types of rejection are recognized, namely T-cell-mediated rejection (TCMR) and antibody-mediated rejection (ABMR), which have a different pathophysiology and are treated differently. Unfortunately, long-term outcomes of both TCMR and ABMR remain unsatisfactory despite current therapy. Hence, alternative therapeutic drugs are urgently needed.

AREAS COVERED

This review covers novel and investigational drugs for the pharmacological treatment of kidney transplant rejection. Potential therapeutic strategies and future directions are discussed.

EXPERT OPINION

The development of alternative pharmacologic treatment of rejection has focused mostly on ABMR, since this is the leading cause of kidney allograft loss and currently lacks an effective, evidence-based therapy. At present, there is insufficient high-quality evidence for any of the covered investigational drugs to support their use in ABMR. However, with the emergence of targeted therapies, this potential arises for individualized treatment strategies. In order to generate more high-quality evidence for such strategies and overcome the obstacles of classic, randomized, controlled trials, we advocate the implementation of adaptive trial designs and surrogate clinical endpoints. We believe such adaptive trial designs could help to understand the risks and benefits of promising drugs such as tocilizumab, clazakizumab, belimumab, and imlifidase.

Qualitative Research with Patients and Physicians to Assess Content Validity and Meaningful Change on ESSDAI and ESSPRI in Sjögren’s

Introduction

Methods

Results

Conclusions

European Alliance of Associations for Rheumatology (EULAR) Sjögren’s Syndrome Disease Activity Index (ESSDAI) is an assessment used by physicians to measure how active Sjögren’s is in individuals with the condition. EULAR Sjögren’s Syndrome Patient Reported Index (ESSPRI) is a questionnaire completed by individuals with Sjögren’s to assess the severity of their symptoms. It is important to show that ESSDAI and ESSPRI are considered appropriate by physicians and individuals with Sjögren’s, respectively, and that ESSPRI is well understood by individuals with Sjögren’s completing the questionnaire. Therefore, interviews were conducted with physicians who specialise in Sjögren’s to explore the appropriateness of ESSDAI, the level of improvement on the assessment that would be important to individuals with Sjögren’s, and the appropriateness of the ESSPRI recall period (i.e. whether it is acceptable to ask individuals to remember their symptoms over the past 2 weeks). Interviews were also conducted with individuals with Sjögren’s to explore their understanding and relevance of ESSPRI (including the 2-week recall period) and the level of improvement on the questionnaire that would be important to them. Most physicians and patients considered ESSDAI and ESSPRI appropriate, supporting their use in a range of settings including Sjögren’s clinical trials, clinical practice and other research settings. Most physicians reported that a 3-point improvement in ESSDAI total score would be meaningful to individuals with Sjögren’s. Individuals with Sjögren’s reported that a 1-to-2-point improvement in ESSPRI total score would be meaningful.

B cell-targeted therapies in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that primarily affects women of childbearing age. There is no disease more heterogeneous than SLE as patients experience a myriad of manifestations and unpredictable periods of heightened disease activity. This heterogeneity not only makes it difficult for treatment decisions and prognostication, but has made drug development quite challenging. Despite these challenges, belimumab, voclosporin, and anifromulab, approved by the United States Food and Drug Administration (FDA) to treat SLE or lupus nephritis (LN), enhanced our armamentarium of traditional therapies, such as hydroxychloroquine, corticosteroids, and immunosuppressives. However, there remains a dire need to develop therapies that offer greater efficacy and safety. Patients with SLE produce excessive amounts of autoantibodies and cytokines that result in inflammation and organ damage. While a considerable number of potential drug development targets exist, there has been much attention focused on B cells. Strategies have included direct B cell killing, modulation of B cell function, inhibition of molecules essential to B cell growth and survival, and acceleration of autoantibody clearance, to name just a few. In this article, we review SLE clinical trials evaluating experimental agents that target B cells or plasma cells.

Development and preliminary validation of the Sjögren's Tool for Assessing Response (STAR): a consensual composite score for assessing treatment effect in primary Sjögren's syndrome

OBJECTIVE

To develop a composite responder index in primary Sjögren's syndrome (pSS): the Sjögren's Tool for Assessing Response (STAR).

METHODS

To develop STAR, the NECESSITY (New clinical endpoints in primary Sjögren's syndrome: an interventional trial based on stratifying patients) consortium used data-driven methods based on nine randomised controlled trials (RCTs) and consensus techniques involving 78 experts and 20 patients. Based on reanalysis of rituximab trials and the literature, the Delphi panel identified a core set of domains with their respective outcome measures. STAR options combining these domains were proposed to the panel for selection and improvement. For each STAR option, sensitivity to change was estimated by the C-index in nine RCTs. Delphi rounds were run for selecting STAR. For the options remaining before the final vote, a meta-analysis of the RCTs was performed.

RESULTS

The Delphi panel identified five core domains (systemic activity, patient symptoms, lachrymal gland function, salivary gland function and biological parameters), and 227 STAR options combining these domains were selected to be tested for sensitivity to change. After two Delphi rounds, a meta-analysis of the 20 remaining options was performed. The candidate STAR was then selected by a final vote based on metrological properties and clinical relevance.

CONCLUSION

The candidate STAR is a composite responder index that includes all main disease features in a single tool and is designed for use as a primary endpoint in pSS RCTs. The rigorous and consensual development process ensures its face and content validity. The candidate STAR showed good sensitivity to change and will be prospectively validated by the NECESSITY consortium in a dedicated RCT.

Sjögren syndrome: looking forward to the future

Primary Sjögren’s syndrome (pSS) is a heterogeneous disease characterised by a wide spectrum of manifestations that vary according to the different stages of the disease and among different subsets of patients. The aim of this qualitative literature review is to summarise the recent advances that have been reported in pSS, ranging from the early phases to the established disease and its complications. We analysed the diagnostic, prognostic, and management aspects of pSS, with a look into future clinical and research developments. The early phases of pSS, usually antedating diagnosis, allow us to investigate the pathophysiology and risk factors of the overt disease, thus allowing better and timely patient stratification. Salivary gland ultrasound (SGUS) is emerging as a valid complementary, or even alternative, tool for histopathology in the diagnosis of pSS, due to a standardised scoring system with good agreement and performance. Other promising innovations include the application of artificial intelligence to SGUS, ultrasound-guided core needle biopsy, and a wide array of novel diagnostic and prognostic biomarkers. Stratifying pSS patients through the integration of clinical, laboratory, imaging, and histopathological data; differentiating between activity-related and damage-related manifestations; and identifying patients at higher risk of lymphoma development are essential steps for an optimal management and individualised treatment approach. As new treatment options are emerging for both glandular and systemic manifestations, there is a need for a more reliable treatment response evaluation. pSS is a complex and heterogeneous disease, and many distinct aspects should be considered in the different stages of the disease and subsets of patients. In recent years, efforts have been made to improve our understanding of the disease, and certainly in the coming years, some of these novelties will become part of our routine clinical practice, thus improving the management of pSS patients.

Sjögren's and non-Sjögren's sicca share a similar symptom burden but with a distinct symptom-associated proteomic signature

OBJECTIVES

Given the similarity in symptoms between primary Sjogren's syndrome (SjS) and non-SjS sicca syndrome (sicca), we sought to characterise clinical and proteomic predictors of symptoms in both groups in order to better understand disease mechanisms and help guide development of immunomodulatory treatments. These have not, to date, unequivocally improved symptoms in SjS clinical trials.

METHODS

Serum proteomics was performed using O-link inflammation and cardiovascular II panels. SjS (n=53) fulfilled 2016 ACR/European Alliance of Associations for Rheumatology (EULAR) criteria whereas sicca (n=60) were anti-Ro negative, displayed objective or subjective dryness, and either had a negative salivary gland biopsy or, in the absence of a biopsy, it was considered that a biopsy result would not change classification status. Linear regression analysis was performed to identify the key predictors of symptoms. Cluster analysis was completed using protein expression values.

RESULTS

EULAR-Sjögren's-Syndrome-Patient-Reported-Index (ESSPRI), EuroQoL-5 Dimension utility values, and anxiety and depression did not differ between SjS and sicca. Correlations between body mass index (BMI) and ESSPRI were found in sicca and to a lesser extent in SjS. Twenty proteins positively associated with symptoms in sicca but none in SjS. We identified two proteomically defined subgroups in sicca and two in SjS that differed in symptom burden. Within hierarchical clustering of the SjS and sicca pool, the highest symptom burden groups were the least distinct. Levels of adrenomedullin (ADM), soluble CD40 (CD40) and spondin 2 (SPON2) together explained 51% of symptom variability in sicca. ADM was strongly correlated with ESSPRI (spearman's r=0.62; p<0.0001), even in a multivariate model corrected for BMI, age, objective dryness, depression and anxiety scores.

CONCLUSIONS

Obesity-related metabolic factors may regulate symptoms in sicca. Further work should explore non-inflammatory drivers of high symptom burden in SjS to improve clinical trial outcomes.

Tear miRNAs Identified in a Murine Model of Sjögren’s Syndrome as Potential Diagnostic Biomarkers and Indicators of Disease Mechanism

Objective

The tear miRNAome of the male NOD mouse, a model of ocular symptoms of Sjögren’s syndrome (SS), was analyzed to identify unique miRNAs.

Methods

Male NOD mice, aged 12-14 weeks, were used to identify tear miRNAs associated with development of autoimmune dacryoadenitis. Age- and sex-matched male BALB/c mice served as healthy controls while age-matched female NOD mice that do not develop the autoimmune dacryoadenitis characteristic of SS were used as additional controls. Total RNA was isolated from stimulated tears pooled from 5 mice per sample and tear miRNAs were sequenced and analyzed. Putative miRNA hits were validated in additional mouse cohorts as well as in tears of SS patients versus patients with another form of dry eye disease, meibomian gland disease (MGD) using qRT-PCR. The pathways influenced by the validated hits were identified using Ingenuity Pathway Analysis.

Results

In comparison to tears from both healthy (male BALB/c) and additional control (female NOD) mice, initial analy1sis identified 7 upregulated and 7 downregulated miRNAs in male NOD mouse tears. Of these, 8 were validated by RT-qPCR in tears from additional mouse cohorts. miRNAs previously implicated in SS pathology included mmu-miR-146a/b-5p, which were significantly downregulated, as well as mmu-miR-150-5p and mmu-miR-181a-5p, which were upregulated in male NOD mouse tears. All other validated hits including the upregulated miR-181b-5p and mmu-miR-203-3p, as well as the downregulated mmu-miR-322-5p and mmu-miR-503-5p, represent novel putative indicators of autoimmune dacryoadenitis in SS. When compared to tears from patients with MGD, miRNAs hsa-miR-203a-3p, hsa-miR-181a-5p and hsa-miR-181b-5p were also significantly increased in tears of SS patients.

Conclusions

A panel of differentially expressed miRNAs were identified in tears of male NOD mice, with some preliminary validation in SS patients, including some never previously linked to SS. These may have potential utility as indicators of ocular symptoms of SS; evaluation of the pathways influenced by these dysregulated miRNAs may also provide further insights into SS pathogenesis.

Targeted Immunotherapy for Autoimmune Disease

In the past few decades, biological drugs and small molecule inhibitors targeting inflammatory cytokines, immune cells, and intracellular kinases have become the standard-of-care to treat autoimmune diseases. Inhibition of TNF, IL-6, IL-17, and IL-23 has revolutionized the treatment of autoimmune diseases, such as rheumatoid arthritis, ankylosing spondylitis, and psoriasis. B cell depletion therapy using anti-CD20 mAbs has shown promising results in patients with neuroinflammatory diseases, and inhibition of B cell survival factors is approved for treatment of systemic lupus erythematosus. Targeting co-stimulatory molecules expressed on Ag-presenting cells and T cells is also expected to have therapeutic potential in autoimmune diseases by modulating T cell function. Recently, small molecule kinase inhibitors targeting the JAK family, which is responsible for signal transduction from multiple receptors, have garnered great interest in the field of autoimmune and hematologic diseases. However, there are still unmet medical needs in terms of therapeutic efficacy and safety profiles. Emerging therapies aim to induce immune tolerance without compromising immune function, using advanced molecular engineering techniques.

Current Topics of Relevance to the Xenotransplantation of Free Pig Islets

Pig islet xenotransplantation is a potential treatment for patients with type 1 diabetes. Current efforts are focused on identifying the optimal pig islet source and overcoming the immunological barrier. The optimal age of the pig donors remains controversial since both adult and neonatal pig islets have advantages. Isolation of adult islets using GMP grade collagenase has significantly improved the quantity and quality of adult islets, but neonatal islets can be isolated at a much lower cost. Certain culture media and coculture with mesenchymal stromal cells facilitate neonatal islet maturation and function. Genetic modification in pigs affords a promising strategy to prevent rejection. Deletion of expression of the three known carbohydrate xenoantigens (Gal, Neu5Gc, Sda) will certainly be beneficial in pig organ transplantation in humans, but this is not yet proven in islet transplantation, though the challenge of the '4th xenoantigen' may prove problematic in nonhuman primate models. Blockade of the CD40/CD154 costimulation pathway leads to long-term islet graft survival (of up to 965 days). Anti-CD40mAbs have already been applied in phase II clinical trials of islet allotransplantation. Fc region-modified anti-CD154mAbs successfully prevent the thrombotic complications reported previously. In this review, we discuss (I) the optimal age of the islet-source pig, (ii) progress in genetic modification of pigs, (iii) the immunosuppressive regimen for pig islet xenotransplantation, and (iv) the reduction in the instant blood-mediated inflammatory reaction.

New developments in Sjogren's syndrome

SS is a chronic, autoimmune condition characterized by lymphocytic infiltration of the exocrine glands and B-cell dysfunction. Current treatment strategies are largely empirical and offer only symptomatic relief for patients. There are no proven treatments that alter disease progression or treat the systemic manifestations of disease. B-cell depletion is used in patients with systemic disease but its overall clinical efficacy has not been demonstrated in two large randomized controlled trials. Studies are now focussing on alternative strategies to target B-cells, including co-stimulation targets, with promising data. It is increasingly clear that clinical trials in SS will require patient stratification and relevant and sensitive outcome measures to identify successful treatment modalities.

Cellular and molecular diversity in Sjogren's syndrome salivary glands: Towards a better definition of disease subsets

Primary Sjögren's syndrome (pSS) is a highly heterogeneous disease in terms of clinical presentation ranging from a mild disease localised to the salivary and lacrimal glands, to multiorgan complications of various degrees of severity, finishing with the evolution, in around 5% of pSS patients, to B cell lymphomas most commonly arising in the inflamed salivary glands. Currently, there are poor positive or negative predictors of disease evolution able to guide patient management and treatment at early stages of the diseases. Recent understanding of the pathogenic mechanisms driving immunopathology in pSS, particularly through histological and transcriptomic analysis of minor and parotid salivary gland (SG) biopsies, has highlighted a high degree of cellular and molecular heterogeneity of the inflammatory lesions but also allowed the identification of clusters of patients with similar underlying SG immunopathology. In particular, patients presenting with high degrees of B/T cell infiltration and the formation of ectopic lymphoid structures (ELS) in the SG have been associated, albeit with conflicting results, with higher degree of disease severity and enhanced risk of lymphoma evolution, suggesting that a dysregulated adaptive immune response plays a key role in driving disease manifestations in pSS. Recent data from randomised clinical trials with novel biological therapies in pSS have also highlighted the potential role of SG immunopathology and molecular pathology in stratifying patients for trial inclusion as well as assessing proof of mechanisms in longitudinal SG biopsies before and after treatment. Although significant progress has been made in the understanding of disease pathogenesis and heterogeneity through cellular and molecular SG pathology, further work is needed to validate their clinical utility in routine clinical settings and in randomised clinical trials.

Development and Application of the Placebo Response Model in Clinical Trials for Primary Sjögren's Syndrome

This study aimed to develop a placebo response model for pharmaceutical clinical trials of primary Sjogren's syndrome,and to quantitatively analyze the distribution and related factors influencing the placebo response to further optimize the design of clinical trials and evaluate the results of single-arm clinical trials. Public databases, including PubMed, Embase, and Cochrane Library were searched for reports on randomized placebo-controlled trials for Sjögren's syndrome which used the change from baseline in ESSDAI score as the primary outcome. The model-based meta-analysis method was used to evaluate the time course and the related influencing factors of the placebo response for ESSDAI in such clinical trials. A virtual placebo control group was constructed based on the final placebo response model to determine the treatment efficacy of belimumab and cyclosporine A for primary Sjögren's syndrome in a single-arm study. A total of 12 studies involving 450 subjects were included in the analysis. The established model described the time-course characteristics of the changes in ESSDAI score from the baseline in the 48 weeks placebo group. We found that the onset time of placebo response was approximately 12 weeks, and its efficacy plateaued at 48 weeks. The baseline ESSDAI score had a significant effect on the maximum value of the placebo response; the maximum value of the placebo response decreased by 0.552 for every 1 score rise in the baseline ESSDAI score. The efficacy of belimumab and cyclosporine A in the single-arm trial was comparable to that of the placebo response at the same baseline; no significant therapeutic advantage was observed. The placebo response model established in this study could provide a basis for designing clinical trials for primary Sjogren's syndrome in the future. It may also provide a reliable external efficacy control standard for single-arm clinical trials.

Targeted Therapy for Primary Sjögren's Syndrome: Where are We Now?

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by dryness symptoms. This review briefly describes recent advances in the targeted therapies for pSS. Biologics evaluated for pSS treatment mainly include B cell-depleting agents, inhibitors of B cell activation, and agents that target co-signaling molecules or proinflammatory cytokines. Small molecule inhibitors that target signaling pathways have also been evaluated. However, current evidence for the efficacy of targeted therapies in pSS is still sparse. Although ianalumab (an anti-B cell-activating factor [BAFF]-receptor antibody) and iscalimab (an anti-CD40 antibody) are promising biologics for pSS, their efficacy still needs to be evaluated in larger clinical trials. For other biologics, clinical trials have found no differences versus placebo in the change from baseline in European League Against Rheumatism Sjögren's Syndrome Disease Activity Index (ESSDAI) score and fatigue score. Possible causes of the disappointing outcomes mainly include the inefficacy of those evaluated biologics in treating pSS, the high heterogeneous nature of pSS, irreversible exocrine glandular failure at advanced disease stages, inappropriate recruitment strategy in clinical trials, and outcome measures. Early diagnosis and glandular function-centered outcome measures may help to improve the current situation in the systemic therapy of pSS.

Unique Aspects of Pediatric Sjögren Disease

Sjögren disease increasingly is recognized in pediatric patients. Clinical features, primarily parotitis and sicca symptoms, and results of diagnostic tests may be different from those in adult disease. Adult criteria fail to capture most pediatric patients. Pediatric-specific criteria are urgently needed to define the natural history of the disease, identify risk and prognostic factors, and evaluate the impact of therapeutics and other interventions on disease course in young patients.

Immune checkpoints and the multiple faces of B cells in systemic lupus erythematosus

PURPOSE OF REVIEW

B-lymphocytes are crucial in the pathogenesis of systemic lupus erythematosus (SLE), including autoantibody production, antigen presentation, co-stimulation, and cytokine secretion. Co-stimulatory and co-inhibitory molecules control interactions between B and T cells during an inflammatory response, which is essential for an appropriate host protection and maintenance of self-tolerance. Here, we review recent findings about checkpoint molecules and SLE B cells including their potential therapeutic implications and experiences from clinical trials.

RECENT FINDINGS

Most prominent checkpoint molecules involved in pathologic B and T cell interaction in SLE are CD40/CD40L and inducible co-stimulator/ICOSL, both also intimately involved in the formation of germinal centers and ectopic lymphoid tissue. Dysregulations of inhibitory checkpoint molecules, like programmed death-1/programmed death-ligand 1 and B- and T-lymphocyte attenuator have been suggested to impair B cell functions in SLE recently.

SUMMARY

Accumulating evidence indicates that dampening immune responses by either blocking co-activating signals or enhancing co-inhibitory signals in different cell types is a promising approach to treat autoimmune diseases to better control active disease but may also allow resolution of chronic autoimmunity.

Current and future therapies for primary Sjögren syndrome

Primary Sjögren syndrome (pSS) is a systemic autoimmune disease that is characterized by a triad of symptoms that affect all patients (dryness, pain and fatigue). In addition, systemic involvement can affect between one-third and one-half of patients. The management of patients with pSS has been negatively affected by a lack of effective treatments; however, knowledge of the epidemiology of pSS has increased, and advances in developing classification criteria, systemic disease activity scoring and patient-reported outcomes have been made during the past decade. Progress has also been made in understanding the mechanisms that underlie the pathogenesis of pSS, which has enabled a more targeted therapeutic approach to be taken. At present, therapeutic decisions rely on the evaluation of symptoms and systemic manifestations and are mostly formed on the basis of experience rather than evidence, and on similarities with other autoimmune diseases, although the 2019 management recommendations from EULAR are now being used to inform clinical management of pSS. This Review summarizes the available evidence for systemic treatments for pSS and includes discussions of advances in outcome assessment, the current evidence for DMARD use and an overview of promising future therapeutics.

What Therapeutic Regimen Will Be Optimal for Initial Clinical Trials of Pig Organ Transplantation?

We discuss what therapeutic regimen might be acceptable/successful in the first clinical trial of genetically engineered pig kidney or heart transplantation. As regimens based on a calcineurin inhibitor or CTLA4-Ig have proved unsuccessful, the regimen we administer to baboons is based on induction therapy with antithymocyte globulin, an anti-CD20 mAb (Rituximab), and cobra venom factor, with maintenance therapy based on blockade of the CD40/CD154 costimulation pathway (with an anti-CD40 mAb), with rapamycin, and a corticosteroid. An anti-inflammatory agent (etanercept) is administered for the first 2 wk, and adjuvant therapy includes prophylaxis against thrombotic complications, anemia, cytomegalovirus, and pneumocystis. Using this regimen, although antibody-mediated rejection certainly can occur, we have documented no definite evidence of an adaptive immune response to the pig xenograft. This regimen could also form the basis for the first clinical trial, except that cobra venom factor will be replaced by a clinically approved agent, for example, a C1-esterase inhibitor. However, none of the agents that block the CD40/CD154 pathway are yet approved for clinical use, and so this hurdle remains to be overcome. The role of anti-inflammatory agents remains unproven. The major difference between this suggested regimen and those used in allotransplantation is the replacement of a calcineurin inhibitor with a costimulation blockade agent, but this does not appear to increase the complications of the regimen.