Trial of Anti-BDCA2 Antibody Litifilimab for Systemic Lupus Erythematosus

Cutaneous lupus features specialized stromal niches and altered retroelement expression

Cutaneous Lupus is an inflammatory skin disease causing highly morbid inflamed skin and hair loss. In order to investigate the pathophysiology of cutaneous lupus, we performed single-cell RNA and spatial sequencing of lesional and non-lesional cutaneous lupus skin compared to healthy controls. Pathway enrichment analyses of lesional keratinocytes revealed elevated responses to type I interferon, type II interferon, tumor necrosis factor, and apoptotic signaling. Detailed clustering demonstrated unique fibroblasts specific to lupus skin with likely roles in inflammatory cell recruitment and fibrosis. We also evaluated the association of retroelement expression with type I interferons in the skin. We observed increased retroelement expression which correlated with interferon-stimulated genes across multiple cell types. Moreover, we saw elevated expression of genes involved in RIG-I and cGAS-STING pathways, which transduce elevated nucleic acid signals. Treatment of active cutaneous lupus with Anifrolumab reduced RIG-I and cGAS-STING pathways in addition to the most abundant retroelement family, L2b. Our studies better define type I interferon-mediated immunopathology in cutaneous lupus and identify an association between retroelement expression and interferon signatures in cutaneous lupus.

An Integrative Mechanistic Model of Type 1 IFN-Mediated Inflammation in Systemic Lupus Erythematosus

Type I interferon (IFN1) pathway-targeting therapies represent a highly promising class of remedies for the treatment of systemic lupus erythematosus. However, the overall clinical benefit of these compounds is afflicted by marked variability. In this study, we developed a quantitative systems pharmacology model of type I IFN-mediated inflammation and applied it for an indirect comparison of anifrolumab, sifalimumab, daxdilimab, and litifilimab pharmacodynamic response, represented in the model by the change in IFN1 gene signature (IFNGS). The model consists of 20 ordinary differential equations and 68 parameters, among which four systemic parameters (including one random effect) were estimated using patient-level data from Phase IIb anifrolumab clinical trial. Within-target and within-pathway validation was performed using study-level pharmacokinetics, IFNα, and/or IFNGS data from five anifrolumab, four sifalimumab, one daxdilimab, and one litifilimab trials. The model successfully captured overall trends in IFNGS at clinically relevant doses of these compounds and discriminated IFNGS response between patients with low (< 2.75) and high (≥ 2.75) baseline IFNGS. Overprediction of treatment benefit was observed for the low range of anifrolumab doses (100-150 mg every 4 weeks). In contrast, IFNGS response under 150 mg of daxdilimab was underpredicted, despite the accurate description of plasmacytoid dendritic cells and IFNα biomarkers. Results of the global sensitivity analysis revealed baseline IFNGS, IFNα, and IFNα fraction as key factors affecting treatment benefit the most. In terms of maximum IFNGS reduction, anifrolumab showed superior potential compared to sifalimumab, daxdilimab, and litifilimab (ΔIFNGS~25%), which was further enhanced in patients with high baseline IFNGS or IFNα (ΔIFNGS~50%-60%).

Immune mediated inflammatory diseases: moving from targeted biologic therapy, stem cell therapy to targeted cell therapy

Despite the advancements in targeted biologic therapy for immune-mediated inflammatory diseases (IMIDs), significant challenges persist, including challenges in drug maintenance, primary and secondary non-responses, and adverse effects. Recent data have strengthened the evidence supporting stem cell therapy as an experimental salvage therapy into a standard treatment option. Recent preclinical and clinical studies suggested that chimeric antigen receptor T cell (CAR-T) therapy, which depleting tissue and bone marrow B cells, may lead to improvement, even inducing long-lasting remissions for patients with IMIDs. In this review, we address the unmet needs of targeted biologic therapy, delineate the critical differences between stem cell transplantation and CAR-T therapy, evaluate the current status of CAR-T therapy for IMIDs and explore its potential and existing limitations.

Systemic lupus erythematosus: updated insights on the pathogenesis, diagnosis, prevention and therapeutics

Systemic lupus erythematosus (SLE) is a chronic inflammatory illness with heterogeneous clinical manifestations covering multiple organs. Diversified types of medications have been shown effective for alleviating SLE syndromes, ranging from cytokines, antibodies, hormones, molecular inhibitors or antagonists, to cell transfusion. Drugs developed for treating other diseases may benefit SLE patients, and agents established as SLE therapeutics may be SLE-inductive. Complexities regarding SLE therapeutics render it essential and urgent to identify the mechanisms-of-action and pivotal signaling axis driving SLE pathogenesis, and to establish innovative SLE-targeting approaches with desirable therapeutic outcome and safety. After introducing the research history of SLE and its epidemiology, we categorized primary determinants driving SLE pathogenesis by their mechanisms; combed through current knowledge on SLE diagnosis and grouped them by disease onset, activity and comorbidity; introduced the genetic, epigenetic, hormonal and environmental factors predisposing SLE; and comprehensively categorized preventive strategies and available SLE therapeutics according to their functioning mechanisms. In summary, we proposed three mechanisms with determinant roles on SLE initiation and progression, i.e., attenuating the immune system, restoring the cytokine microenvironment homeostasis, and rescuing the impaired debris clearance machinery; and provided updated insights on current understandings of SLE regarding its pathogenesis, diagnosis, prevention and therapeutics, which may open an innovative avenue in the fields of SLE management.

The Expanding Therapeutic Potential of Deucravacitinib Beyond Psoriasis: A Narrative Review

Deucravacitinib is an allosteric, selective tyrosine kinase 2 (TYK2) inhibitor that has demonstrated significant efficacy in the treatment of psoriasis. TYK2, a member of the Janus kinase (JAK) family, plays a critical role in intracellular signaling pathways for pro-inflammatory cytokines. Unlike traditional JAK inhibitors, which target active domains, deucravacitinib selectively binds to the pseudokinase domain of TYK2. This binding induces a conformational change that locks the enzyme in an inactive state, ensuring superior selectivity for TYK2 over JAK 1/2/3. This unique mechanism specifically inhibits key pro-inflammatory cytokines, including IL-12, IL-23, and type I interferons, critical in the pathogenesis of psoriasis and other immune-mediated diseases. As a result, deucravacitinib represents a promising option for targeted therapy in immune-mediated diseases and may reduce adverse events commonly associated with broader immunosuppressive treatments. Furthermore, its oral administration offers a convenient alternative to injectable biologics, potentially improving patient adherence and treatment satisfaction. This review highlights recent studies suggesting that deucravacitinib may also have therapeutic benefits in psoriatic arthritis, palmoplantar pustulosis, systemic lupus erythematosus, Sjogren's disease, and inflammatory bowel disease. Given its expanding therapeutic potential, deucravacitinib may provide a safer and more effective alternative to current therapies, offering a tailored approach to treatment.

Mechanosensing regulates pDC activation in the skin through NRF2 activation

Plasmacytoid DCs (pDCs) infiltrate the skin, chronically produce type I interferon (IFN-I), and promote skin lesions and fibrosis in autoimmune patients. However, what controls their activation in the skin is unknown. Here, we report that increased stiffness inhibits the production of IFN-I by pDCs. Mechanistically, mechanosensing activates stress pathways including NRF2, which induces the pentose phosphate pathway and reduces pyruvate levels, a product necessary for pDC responses. Modulating NRF2 activity in vivo controlled the pDC response, leading to resolution or chronic induction of IFN-I in the skin. In systemic sclerosis (SSc) patients, although NRF2 was induced in skin-infiltrating pDCs, as compared with blood pDCs, the IFN response was maintained. We observed that CXCL4, a profibrotic chemokine elevated in fibrotic skin, was able to overcome stiffness-mediated IFN-I inhibition, allowing chronic IFN-I responses by pDCs in the skin. Hence, these data identify a novel regulatory mechanism exerted by the skin microenvironment and identify points of dysregulation of this mechanism in patients with skin inflammation and fibrosis.

Chimeric antigen receptor-modified T-cell therapy: Recent updates and challenges in autoimmune diseases

Chimeric antigen receptor (CAR) T-cell therapy (CAR-T) has revolutionized the treatment of hematologic malignancies, demonstrating significant clinical efficacy and leading to US Food and Drug Administration approval of several CAR T-cell-based products. This success has prompted exploration of CAR-T in other disease areas, including autoimmune diseases (AIDs). CAR-T targeting B cells has been shown to provide clinical and biological improvements in patients with refractory AIDs. The aim of this review is to discuss promising strategies involving CAR-T in AIDs, such as those targeting B cells and T cells, and to explore new approaches targeting fibroblasts or plasmacytoid dendritic cells. Despite these advances, the application of CAR-T in AIDs faces several unique challenges. The quality and functionality of T cells in patients with AIDs may be compromised as a result of previous treatments and the underlying inflammatory state, affecting the generation and efficacy of CAR-T. In addition, achieving adequate tissue biodistribution and persistence of CAR T cells in affected tissues remains a major challenge. Finally, the high costs associated with T-cell production pose economic problems, particularly in the context of chronic diseases, which are far more numerous than the hematologic diseases for which CAR-Ts have been granted marketing authorization to date. If the indications for CAR-T increase significantly, production costs will have to drop drastically in order to obtain reliable economic models.

A focused report on IFN-1 targeted therapies for lupus erythematosus

INTRODUCTION

Patients with Systemic Lupus Erythematosus (SLE) experience varied manifestations and unpredictable flares, complicating treatment and drug development. Despite these challenges, anifrolumab, voclosporin, and belimumab were approved by FDA. These treatments complement, but don't replace, traditional therapies like NSAIDs, corticosteroids, antimalarials, and immunosuppressives. Therefore, there remains an unmet need for more effective medications targeting excessive proinflammatory cytokines in SLE patients.

AREAS COVERED

This review summarizes the clinical trial outcomes of four upcoming medications targeting cytokine activity: Litifilimab showed a 7-point reduction in CLASI-A in its phase II trial. Daxdilimab was unsuccessful in its phase II trial. Anifrolumab reduced SLE activity in both phase II and III trials. Deucravacitinib decreased disease activity by multiple measures in its phase II trial.

EXPERT OPINION

High levels of IFN-I (type 1 interferon) are present in most SLE patients, making this pathway an attractive target for drug development. Litifilimab downregulates IFN-I by targeting BDCA2, while dexadilimab targets ILT7 to recruit effector cells, reducing IFN-I production by killing PDCs. Anifrolumab binds to the IFN-I receptor, blocking the activity of all IFN-Is, and deucravacitinib reduces IFN-I by inhibiting TYK2, thereby interfering with downstream signaling. Therapies that target IFN-I represents a promising class of medications for SLE patients.

Deucravacitinib shows superior efficacy and safety in cutaneous lupus erythematosus compared to various biologics and small molecules - A systematic review and meta-analysis

BACKGROUND

Novel therapies for cutaneous lupus erythematosus (CLE) and systemic lupus erythematosus (SLE) demonstrated efficacy and safety in previous trials. However, data on the comparison of these treatments is still lacking, limiting their integration into clinical practice. Therefore, our aim is to perform a systematic review and network meta-analysis to compare the efficacy and safety of novel systemic therapies in CLE.

METHODS

A systematic search was performed across PubMed, Embase, and CENTRAL on November 25, 2023, to identify studies involving patients with CLE or SLE with active skin involvement treated with novel systemic therapies. The primary outcomes assessed were the proportion of patients achieving the Cutaneous Lupus Erythematosus Disease Area and Severity Index-50 (CLASI-50), the change in CLASI-A, the occurrence of adverse events (AEs), and serious adverse events (SAEs).

RESULTS

18,280 records were retrieved, of which 53 met the inclusion criteria. Deucravacitinib showed significantly greater efficacy in achieving the CLASI50 compared to placebo (OR: 8.28, 95 % CI: 2.22-30.91). Both litifilimab (OR: 2.54, 95 % CI: 1.20-5.40) and anifrolumab (OR: 2.25, 95 % CI: 1.23-4.14) were also significantly more effective than placebo. No significant differences were observed in the occurrence of AEs and SAEs between these therapeutics and placebo.

CONCLUSION

Anifrolumab and litifilimab are effective and safe treatment options in CLE. However, deucravacitinib demonstrated superior efficacy and safety with fewer adverse events compared to anifrolumab. CLE patients who have shown an inadequate response to first- and second-line treatments may benefit from the incorporation of deucravacitinib into their treatment regimens.

Sequential activation of conventional and plasmacytoid dendritic cells in autoimmune pancreatitis and systemic lupus erythematosus: similarities and dissimilarities

Type 1 autoimmune pancreatitis (AIP) and systemic lupus erythematosus (SLE) are caused by type I IFNs secreted by plasmacytoid dendritic cells (pDCs). Our understanding of the immune consequences before and after pDC activation in SLE is expanding, whereas knowledge on those in AIP are insufficient. In this article, we summarize the similarities and dissimilarities in pDC activation between AIP and SLE. In SLE, neutrophil extracellular traps containing self-DNA, anti-microbial peptides, and endogenous alarmins form anti-DNA antibody complexes, promoting type I IFN production by pDCs. Type I IFNs produced by pDCs function as initiators rather than effectors in SLE, as evidenced by the fact that these cytokines induce the maturation of conventional DCs (cDCs) leading to the expansion of autoreactive T cells and B cells. Notably, type I IFNs produced by pDCs were observed at the maturation phase but not at the induction phase in experimental AIP. Mechanistically, cDCs producing type I IFNs, C-X-C motif chemokine ligand 9 (CXCL9), and CXCL10 are initiator cells of AIP, and C-X-C chemokine receptor 3 (CXCR3)+T helper type 1(Th1) cells migrate to the pancreas in response to CXCL9 and CXCL10. CXCR3+Th1 cells produce C-C chemokine ligand 25 (CCL25) to attract C-C chemokine receptor 9 (CCR9)+pDCs to the pancreas. Pancreatic pDCs producing type I IFNs, CXCL9, CXCL10, and CXCR3+Th1 cells producing CCL25 form a positive feedback loop in which the sensing of intestinal dysbiosis induces large amounts of type I IFNs by pDCs.

Monoclonal antibodies for the management of cutaneous lupus erythematosus: an update on the current treatment landscape

Cutaneous lupus erythematosus (CLE) is a complex autoimmune disease often characterized by a multitude of skin findings. CLE is generally classified into three main categories: acute CLE, subacute CLE and chronic CLE. The current therapeutic guidelines for CLE include counselling patients on general measures and medication regimens. Treatment options include optimized photoprotection, avoidance of environmental triggers, corticosteroids, topical and systemic immunomodulators, and antimalarials. To date, no biologic medications (i.e. monoclonal antibodies, mAbs) are approved for CLE. The first mAb for the treatment of both systemic lupus erythematosus (SLE) and active lupus nephritis was belimumab, and was approved for these diseases in 2011 and 2020, respectively. Belimumab is a specific inhibitor of B-lymphocyte stimulator. Anifrolumab, a type I interferon receptor antagonist, was approved in 2021 for SLE. Other mAbs with different targets, including a novel biologic that inhibits blood dendritic cell antigen 2, are currently under investigation for CLE. This review will describe the general treatment landscape for CLE. Selected studies related to these various mAbs will be discussed, as well as their safety profiles and efficacies demonstrated in clinical trials. Biologic medications can potentially augment the number of treatment options for patients living with CLE.

Advances in Targeted Therapy for Systemic Lupus Erythematosus: Current Treatments and Novel Approaches

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with diverse clinical manifestations that can lead to severe organ damage. The complex pathophysiology of SLE makes treatment selection difficult. This review examines the current evidence for biological therapies in SLE, including the anti-B cell activating factor antibody belimumab; the type I interferon receptor antagonist anifrolumab; the novel calcineurin inhibitor voclosporin; and rituximab, which targets CD20 on B cells. We also describe emerging therapies, including novel agents in development and CD19-directed chimeric antigen receptor (CAR) T cell therapy, which has shown promise in early clinical experience. Recent advances in biomarker research, including interferon signatures and transcriptomic profiles, may facilitate patient stratification and treatment selection. This review offers insights into current and future treatment strategies for patients with SLE by analyzing clinical trial results and recent immunological findings.

Innovations in Cutaneous Lupus

Cutaneous lupus erythematosus (CLE) is an autoimmune-mediated skin disease under the family of lupus erythematosus. Systemic immunosuppressants and topical treatments have been used to manage CLE; however, these treatments tend to be moderately efficacious and leave patients with unmet therapeutic needs. There is a need for medications that target pruritus, scarring, dyspigmentation, and other symptoms of chronic CLE that contribute to decreased quality of life. The introduction of new biologics and other systemic medications has expanded dermatologists' and rheumatologists' ability to manage CLE. This article discusses new pharmaceuticals and guidelines providing an updated overview of the clinical management of CLE.

Subtype and Racial Erythema Variation for Cutaneous Lupus Trials

Importance

Regulatory guidance and standardization of disease outcome measures are essential to improve cutaneous lupus erythematosus (CLE) trial design and enhance the diversity of trial participants.

Objective

To assess variability in erythema presentation across CLE subtypes and among race and ethnicity groups to determine whether these potential differences affect patient eligibility for erythema trials.

Design, Setting, and Participants

This cross-sectional study included 377 patients with CLE enrolled in the University of Pennsylvania Cutaneous Lupus Erythematosus Database from January 2007 to December 2023. Data analyses were performed from December 2023 to February 2024.

Exposure

Race and CLE subtype.

Main Outcomes and Measures

Mean erythema calculated per the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI)-Activity total score divided by areas affected; then, the result was categorized as pink (1.00-1.49) or red (≥1.50) as surrogate estimates of scores per the Cutaneous Lupus Activity Investigator Global Assessment (CLA-IGA).

Results

The total study cohort included 377 adult patients with CLE (mean [SD; range] age, 45.2 [14.8; 18.4-88.8] years; 305 females [80.9%] and 72 males [19.1%]; 115 Black [30.5%], 228 White [60.5%], 34 patients of other races [9.0%; Asian, multiple races, Native American/Pacific Islander, or unknown], and 11 of Hispanic/Latino ethnicity [2.9%]). The most common CLE subtype was chronic CLE (CCLE), affecting 243 patients (64.5%), followed by subacute CLE (SCLE) in 103 patients (27.3%) and acute CLE (ACLE) in 31 patients (8.2%). Significant differences were observed in average erythema across subtypes, with mean (SD) SCLE of 1.62 (0.39) and hypertrophic CCLE of 1.78 (0.25) as the only subtypes routinely classified as red. Significant differences were also observed by race and ethnicity: mean (SD) erythema score in White patients was red (1.58 [0.45]) more frequently than in Black patients (1.36 [0.40]) and patients of other races (1.30 [0.39]), in whom, on average, it was scored as pink. Importantly, among patients who would meet typical CLASI entry criteria (score ≥8) for clinical trials, erythema in more Black patients than in White patients was classified as pink (42% [96 patients] vs 24% [28 patients]), which suggests exclusion from trial participation when a baseline of red lesions is required.

Conclusions and Relevance

The findings of this cross-sectional study suggest that using average erythema scores per the CLA-IGA scale imposes substantial limitations on trial eligibility, specifically by race and subtype. Given the critical need to standardize CLE trial outcome measures and increase diverse representation in clinical trials, our findings support the use of the CLASI as the primary scoring tool to determine erythema trial eligibility.

Targeting the Type I Interferon Pathway in Glomerular Kidney Disease: Rationale and Therapeutic Opportunities

Type I interferons (IFNs) are immunostimulatory molecules that can activate the innate and adaptive immune systems. In cases of immune dysfunction, prolonged activation of the type I IFN pathway has been correlated with kidney tissue damage in a wide range of kidney disorders, such as lupus nephritis (LN) and focal segmental glomerulosclerosis (FSGS). Genetic mutations, such as APOL1 risk variants in conjunction with elevated type I IFN expression, are also associated with higher rates of chronic kidney disease in patients with LN and collapsing FSGS. Long-term activation of the type I IFN pathway can result in chronic inflammation, leading to kidney tissue damage, cell death, and decline in organ function. Thus, therapeutic strategies targeting type I IFN could provide clinical benefits to patients with immune dysregulation who are at risk of developing impaired kidney function. Here, we present a critical review of type I IFN signaling, the consequences of chronically elevated type I IFN expression, and therapeutic strategies targeting type I IFN signaling in the context of kidney disease.

The Dectin-1 and Dectin-2 clusters: C-type lectin receptors with fundamental roles in immunity

The ability of myeloid cells to recognize and differentiate endogenous or exogenous ligands rely on the presence of different transmembrane protein receptors. C-type lectin receptors (CLRs), defined by the presence of a conserved structural motif called C-type lectin-like domain (CTLD), are a crucial family of receptors involved in this process, being able to recognize a diverse range of ligands from glycans to proteins or lipids and capable of initiating an immune response. The Dectin-1 and Dectin-2 clusters involve two groups of CLRs, with genes genomically linked within the natural killer cluster of genes in both humans and mice, and all characterized by the presence of a single extracellular CTLD. Fundamental immune cell functions such as antimicrobial effector mechanisms as well as internalization and presentation of antigens are induced and/or regulated through activatory, or inhibitory signalling pathways triggered by these receptors after ligand binding. In this review, we will discuss the most recent concepts regarding expression, ligands, signaling pathways and functions of each member of the Dectin clusters of CLRs, highlighting the importance and diversity of their functions.

Evolving Treatment Strategies for Systemic Lupus Erythematosus in Clinical Practice: A Narrative Review

Systemic lupus erythematosus (SLE) is an autoimmune disease that more commonly affects African American people, although it is seen in people of all racial backgrounds. This condition is characterized by a dysregulated immune response resulting in widespread inflammation. Clinical manifestations caused by this inflammation include arthritis, anemia, cutaneous rashes, pleuritis, and nephritis. Treatment for SLE aims to reduce disease activity and maintain a state of low inflammation. In this regard, numerous treatments are used, such as hydroxychloroquine, glucocorticoids, and non-glucocorticoid immunosuppressants such as methotrexate. Related to these drugs resulting in significant adverse effects and being ineffective in controlling SLE symptoms in some patients, new biologic agents have been created in hopes of better treating SLE. This includes belimumab and anifrolumab, monoclonal antibodies directed against the cytokine, and type 1 interferon receptor, respectively. These agents are indicated in patients with SLE whose symptoms are inadequately controlled by standard therapy alone. Clinical trials have shown that these agents effectively reduce SLE symptoms as judged using standardized metrics of disease activity. These biological agents have also been shown to have generally mild side effects when taken by patients with SLE, making them safe for use. In addition to the above medications, new treatments are being developed for SLE patients, such as cenerimod, litifilimab, chimeric antigen receptor T cells, and DS-7011a (anti-toll-like receptor 7 monoclonal antibody). These new treatments have shown promise in clinical trials. However, more information regarding their safety and efficacy is needed before they are available for the treatment of SLE.

Cell damage shifts the microRNA content of small extracellular vesicles into a Toll-like receptor 7-activating cargo capable to propagate inflammation and immunity

BACKGROUND

The physiological relevance of cell-to-cell communication mediated by small extracellular vesicle-encapsulated microRNAs (sEV-miRNAs) remains debated because of the limiting representativity of specific miRNAs within the extracellular pool. We hypothesize that sEV-miRNA non-canonical function consisting of the stimulation of Toll-like receptor 7 (TLR7) may rely on a global shift of the sEV cargo rather than on the induction of one or few specific miRNAs. Psoriasis represents an ideal model to test such hypothesis as it is driven by overt activation of TLR7-expressing plasmacytoid dendritic cells (pDCs) following keratinocyte damage.

METHODS

To mimic the onset of psoriasis, keratinocytes were treated with a cocktail of psoriatic cytokines or UV-irradiated. SmallRNA sequencing was performed on sEVs released by healthy and UV-treated keratinocytes. sEV-miRNAs were analyzed for nucleotide composition as well as for the presence of putative TLR7-binding triplets. Primary human pDCs where stimulated with sEVs +/- inhibitors of TLR7 (Enpatoran), of sEV release (GW4869 + manumycin) and of TLR7-mediated pDC activation (anti-BDCA-2 antibody). Secretion of type I IFNs and activation of CD8+T cells were used as readouts. qPCR on psoriatic and healthy skin biopsies was conducted to identify induced miRNAs.

RESULTS

sEV-miRNAs released by damaged keratinocytes revealed a significantly higher content of TLR7-activating sequences than healthy cells. As expected, differential expression analysis confirmed the presence of miRNAs upregulated in psoriatic skin, including miR203a. More importantly, 76.5% of induced miRNAs possessed TLR7-binding features and among these we could detect several previously demonstrated TLR7 ligands. In accordance with this in silico analysis, sEVs from damaged keratinocytes recapitulated key events of psoriatic pathogenesis by triggering pDCs to release type I interferon and activate cytotoxic CD8+T cells in a TLR7- and sEV-dependent manner.

DISCUSSION

Our results demonstrate that miR203a is just one paradigmatic TLR7-activating miRNA among the hundreds released by UV-irradiated keratinocytes, which altogether trigger pDC activation in psoriatic conditions. This represents the first evidence that cell damage shifts the miRNA content of sEVs towards a TLR7-activating cargo capable to propagate inflammation and immunity, offering strong support to the physiological role of systemic miRNA-based cell-to-cell communication.

Severity Scores for Cutaneous Lupus Erythematosus

Despite the significant disease burden of cutaneous lupus erythematosus (CLE), there have been no United States Food and Drug Administration-approved therapies for 65 years. To facilitate advancement of therapies, severity scores are needed to evaluate QOL, how patients feel, activity of disease, and organ-specific damage to assess response to therapies and disease progression. In this paper, we delineate the development process of provider- and patient-reported severity scores for CLE. Cutaneous Lupus Disease Area and Severity Index (CLASI), a provider-reported measure that distinguishes between activity and damage, has undergone rigorous validation and reliability testing for over 20 years. Its performance has been tested in clinical trials as a primary or secondary endpoint and tool to stratify patients. As an objective disease measure that captures a provider's perspective of disease activity and damage, the CLASI inherently does not assess disease impact on patients' QOL. Cutaneous Lupus Erythematosus Quality of Life (CLEQoL), a patient-reported measure, captures features elucidated through focus groups, including symptoms, emotions, functioning, body image, and photosensitivity. It has undergone psychometric property testing to ensure reliability and validity. Together, CLASI and CLEQoL are simple and reliable CLE-specific severity scores capturing disease activity, damage, and QOL from provider and patient perspectives.

ANA-associated arthritis: clinical and biomarker characterization of a population for basket trials

OBJECTIVES

ANA-associated rheumatic and musculoskeletal (MSK) diseases (RMDs) [SLE, primary SS (pSS), scleroderma, inflammatory myositis, MCTD and UCTD] make up a disease spectrum with overlapping clinical and immunological features. MSK inflammation is common and impactful across ANA-associated RMDs. The objectives of this study were to evaluate MSK inflammation (ANA-associated arthritis) prevalence in a multidisease ANA-associated RMD study, assess its clinical impact across ANA-associated RMD diagnoses, propose new basket groupings of patients, and evaluate immunological profiles in legacy and new basket contexts.

METHODS

An observational study enrolled patients with ANA-associated RMDs. Demographic variables, comorbidities, therapies, disease activity instruments [BILAG, SLEDAI, the EULAR SS disease activity index (ESSDAI), physician visual analogue scale (VAS)], patient-reported outcomes [SF36, FACIT-Fatigue, EQ5D, ICECAP-A, Work Productivity and Activity impairment (WPAI), patient VAS] and the biomarker profile (six-gene expression scores, flow cytometry, autoantibody profile) were analysed. Reclustering utilized Gaussian mixture modelling (GMM). The clinical and immune features of new and legacy clusters were compared.

RESULTS

Inflammatory MSK symptoms were prevalent across ANA-associated RMDs, in 213/294 patients. In ANA-associated arthritis patients, most variables did not differ between diagnoses, with the exception of the EQ5D-5L index and mobility domains (lower in MCTD/pSS, both P < 0.05). FM and OA prevalence were similar across diagnoses. Therapy use differed significantly, the use of biologics being greatest in SLE (P < 0.05). GMM yielded two multidisease clusters: High MSK disease activity (n = 89) and low MSK disease activity (n = 124). The high MSK disease activity cluster included all patients with active joint swelling, and they had significantly higher prednisolone usage, physician global assessment (PGA), Sm/RNP/SmRNP/chromatin positivity, Tetherin mean fluorescence intensity (MFI), and IFN Score-A activity, along with numerically lower FM and OA prevalence.

CONCLUSION

We defined ANA-associated arthritis, a more clinically and immunologically homogeneous population than existing RMD populations for trials, and a more prevalent population for therapies in the clinic.

Immunopathogenesis of systemic lupus erythematosus: An update

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease characterized by dysregulated immune responses leading to widespread inflammation and damage in various organs. Environmental factors such as infections, hormonal influences and exposure to ultraviolet light can trigger the disease in genetically predisposed individuals. Genome-wide association studies have identified over 100 susceptibility loci linked to immune regulation, interferon (IFN) signaling and antigen presentation in SLE. In addition, rare cases of monogenic lupus have been instrumental in understanding critical underlying disease mechanisms. Several immunological abnormalities contribute to the loss of self-tolerance and the perpetuation of autoimmune responses in SLE. In particular, defective clearance of apoptotic cells due to defective phagocytosis and complement activation leads to accumulation of self-antigens. Dysregulated innate immune responses activate the adaptive immune system, amplifying the inflammatory response with an important role for type I IFNs. Abnormalities in B cell development and activation lead to the production of autoreactive antibodies, forming immune complexes that cause tissue damage. Similarly, disturbances in T-cell compartments, altered regulatory T-cell functions and altered cytokine production, particularly IFN-α, contribute to tissue damage. Understanding of the immunopathogenesis of SLE is evolving rapidly, with ongoing research identifying new molecular pathways and potential therapeutic targets. Future classifications of SLE are likely to be based on underlying biological pathways rather than clinical and serological signs alone. This review aims to provide a detailed update on the most recent findings regarding the immunopathogenesis of SLE, focusing on the variability of biological pathways and the implications for future therapeutic strategies, in particular chimeric antigen receptor T (CAR T) cells.

Biologics in Systemic Lupus Erythematosus: Recent Evolutions and Benefits

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multifaceted autoimmune disorder characterized by significant autoantibodies, particularly targeting nuclear antigens. SLE pathogenesis involves genetic, environmental, and hormonal factors. The disease course includes flares and remission and involves various organs. Recent therapeutic progresses, including biologics, have improved management and prognosis, though the long-term impact of novel therapies remains to be determined. Biologics in SLE: Rituximab, the earliest B-cell-oriented biologic, binds CD20 and depletes CD20+ B cells, leading to remission in some SLE patients. Belimumab is a B-cell-activating factor (BAFF) inhibitor with a recent additional indication for lupus nephritis. The CALIBRATE and BLISS-BELIEVE studies investigated combinations of these drugs with conventional therapies, showing varied efficacy. Ocrelizumab and obinutuzumab, newer CD20-oriented SLE therapies, together with ofatumumab and veltuzumab, are also promising. The latest trials highlight their efficacy and safety. Anifrolumab, targeting type-I interferon receptors, was evaluated in the TULIP 1/2 trials. The ongoing TULIP LTE trial supports the long-term safety and efficacy of anifrolumab. Additionally, the IRIS Phase III trial is exploring anifrolumab for lupus nephritis, showing favorable renal responses. Tocilizumab and secukinumab are being assessed for SLE, with mixed outcomes. Several biologics targeting the C5 complement protein, together with immunomodulators and immunotherapeutics, are also under investigation for potential benefits in SLE.

DISCUSSION

Biologics in SLE target specific immune components, aiming to improve disease control and reduce the side effects of conventional therapy. However, trial outcomes vary due to factors like inclusion criteria and trial design.

CONCLUSIONS

Biotechnology progress enables targeted biologic therapies for SLE, reducing disease activity and improving patients' quality of life.

The role of plasmacytoid dendritic cells (pDCs) in immunity during viral infections and beyond

Type I and III interferons (IFNs) are essential for antiviral immunity and act through two different but complimentary pathways. First, IFNs activate intracellular antimicrobial programs by triggering the upregulation of a broad repertoire of viral restriction factors. Second, IFNs activate innate and adaptive immunity. Dysregulation of IFN production can lead to severe immune system dysfunction. It is thus crucial to identify and characterize the cellular sources of IFNs, their effects, and their regulation to promote their beneficial effects and limit their detrimental effects, which can depend on the nature of the infected or diseased tissues, as we will discuss. Plasmacytoid dendritic cells (pDCs) can produce large amounts of all IFN subtypes during viral infection. pDCs are resistant to infection by many different viruses, thus inhibiting the immune evasion mechanisms of viruses that target IFN production or their downstream responses. Therefore, pDCs are considered essential for the control of viral infections and the establishment of protective immunity. A thorough bibliographical survey showed that, in most viral infections, despite being major IFN producers, pDCs are actually dispensable for host resistance, which is achieved by multiple IFN sources depending on the tissue. Moreover, primary innate and adaptive antiviral immune responses are only transiently affected in the absence of pDCs. More surprisingly, pDCs and their IFNs can be detrimental in some viral infections or autoimmune diseases. This makes the conservation of pDCs during vertebrate evolution an enigma and thus raises outstanding questions about their role not only in viral infections but also in other diseases and under physiological conditions.

Monoclonal antibodies targeting interleukins for systemic lupus erythematosus: updates in early clinical drug development

INTRODUCTION

The advent of biological therapies has already revolutionized treatment strategies and disease course of several rheumatologic conditions, and monoclonal antibodies (mAbs) targeting cytokines and interleukins represent a considerable portion of this family of drugs. In systemic lupus erythematosus (SLE) dysregulation of different cytokine and interleukin-related pathways have been linked to disease development and perpetration, offering palatable therapeutic targets addressable via such mAbs.

AREAS COVERED

In this review, we provide an overview of the different biological therapies under development targeting cytokines and interleukins, with a focus on mAbs, while providing the rationale behind their choice as therapeutic targets and analyzing the scientific evidence linking them to SLE pathogenesis.

EXPERT OPINION

An unprecedented number of clinical trials on biological drugs targeting different immunological pathways are ongoing in SLE. Their success might allow us to tackle present challenges of SLE management, including the overuse of glucocorticoids in daily clinical practice, as well as SLE heterogenicity in treatment response among different individuals, hopefully paving the way toward precision medicine.

Plasmacytoid dendritic cells at the forefront of anti-cancer immunity: rewiring strategies for tumor microenvironment remodeling

Plasmacytoid dendritic cells (pDCs) are multifaceted immune cells executing various innate immunological functions. Their first line of defence consists in type I interferons (I-IFN) production upon nucleic acids sensing through endosomal Toll-like receptor (TLR) 7- and 9-dependent signalling pathways. Type I IFNs are a class of proinflammatory cytokines that have context-dependent functions on cancer immunosurveillance and immunoediting. In the last few years, different studies have reported that pDCs are also able to sense cytosolic DNA through cGAS-STING (stimulator of interferon genes) pathway eliciting a potent I-IFN production independently of TLR7/9. Human pDCs are also endowed with direct effector functions via the upregulation of TRAIL and production of granzyme B, the latter modulated by cytokines abundant in cancer tissues. pDCs have been detected in a wide variety of human malignant neoplasms, including virus-associated cancers, recruited by chemotactic stimuli. Although the role of pDCs in cancer immune surveillance is still uncompletely understood, their spontaneous activation has been rarely documented; moreover, their presence in the tumor microenvironment (TME) has been associated with a tolerogenic phenotype induced by immunosuppressive cytokines or oncometabolites. Currently tested treatment options can lead to pDCs activation and disruption of the immunosuppressive TME, providing a relevant clinical benefit. On the contrary, the antibody-drug conjugates targeting BDCA-2 on immunosuppressive tumor-associated pDCs (TA-pDCs) could be proposed as novel immunomodulatory therapies to achieve disease control in patients with advance stage hematologic malignancies or solid tumors. This Review integrate recent evidence on the biology of pDCs and their pharmacological modulation, suggesting their relevant role at the forefront of cancer immunity.

Mitochondrial Dysfunction in Systemic Lupus Erythematosus with a Focus on Lupus Nephritis

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting mostly women of child-bearing age. Immune dysfunction in SLE results from disrupted apoptosis which lead to an unregulated interferon (IFN) stimulation and the production of autoantibodies, leading to immune complex formation, complement activation, and organ damage. Lupus nephritis (LN) is a common and severe complication of SLE, impacting approximately 30% to 40% of SLE patients. Recent studies have demonstrated an alteration in mitochondrial homeostasis in SLE patients. Mitochondrial dysfunction contributes significantly to SLE pathogenesis by enhancing type 1 IFN production through various pathways involving neutrophils, platelets, and T cells. Defective mitophagy, the process of clearing damaged mitochondria, exacerbates this cycle, leading to increased immune dysregulation. In this review, we aim to detail the physiopathological link between mitochondrial dysfunction and disease activity in SLE. Additionally, we will explore the potential role of mitochondria as biomarkers and therapeutic targets in SLE, with a specific focus on LN. In LN, mitochondrial abnormalities are observed in renal cells, correlating with disease progression and renal fibrosis. Studies exploring cell-free mitochondrial DNA as a biomarker in SLE and LN have shown promising but preliminary results, necessitating further validation and standardization. Therapeutically targeting mitochondrial dysfunction in SLE, using drugs like metformin or mTOR inhibitors, shows potential in modulating immune responses and improving clinical outcomes. The interplay between mitochondria, immune dysregulation, and renal involvement in SLE and LN underscores the need for comprehensive research and innovative therapeutic strategies. Understanding mitochondrial dynamics and their impact on immune responses offers promising avenues for developing personalized treatments and non-invasive biomarkers, ultimately improving outcomes for LN patients.

Targeting Interferon Signalling in Systemic Lupus Erythematosus: Lessons Learned

The development of new medicines for systemic lupus erythematosus (SLE) has not addressed unmet clinical need, with only three drugs receiving regulatory approval for SLE in the last 60 years, one of which was specifically licensed for lupus nephritis. In the last 20 years it has become clear that activation of type 1 interferons (IFN) is reproducibly detected in the majority of SLE patients, and the actions of IFN in the immune system and on target tissues is consistent with a pathogenic role in SLE. These findings led to considerable drug discovery activity, first with agents directly targeting IFN family cytokines, with results that were encouraging but underwhelming. In contrast, targeting the type I IFN receptor with the monoclonal antibody anifrolumab, thereby blocking all IFN family members, was effective in a phase II clinical trial. This led to a pair of phase III trials, one of which was negative and the other positive, reflecting the difficulty of obtaining outcomes from trials in this complex disease. Nonetheless, the balance of evidence resulted in approval of anifrolumab in multiple jurisdictions from 2021 onwards. Multiple approaches to targeting the type 1 IFN pathway have subsequently had positive phase II clinical trials, including antibodies targeting cells that produce IFN, and small molecules targeting the receptor kinase TYK2, required for IFN signalling. Despite multiple hurdles, it is clear that IFN targeting in SLE is here to stay. The story of IFN-targeting therapy in SLE has lessons for drug development overall in this disease.

New and emerging therapies for systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) and lupus nephritis treatment is still based on non-specific immune suppression despite the first biological therapy for the disease having been approved more than a decade ago. Intense basic and translational research has uncovered a multitude of pathways that are actively being evaluated as treatment targets in SLE and lupus nephritis, with two new medications receiving FDA approval in the last 3 years. Herein we provide an overview of targeted therapies for SLE including medications targeting the B lymphocyte compartment, intracellular signaling, co-stimulation, and finally the interferons and other cytokines.

Ontogeny and Function of Plasmacytoid Dendritic Cells

Plasmacytoid dendritic cells (pDCs) represent a unique cell type within the innate immune system. Their defining property is the recognition of pathogen-derived nucleic acids through endosomal Toll-like receptors and the ensuing production of type I interferon and other soluble mediators, which orchestrate innate and adaptive responses. We review several aspects of pDC biology that have recently come to the fore. We discuss emerging questions regarding the lineage affiliation and origin of pDCs and argue that these cells constitute an integral part of the dendritic cell lineage. We emphasize the specific function of pDCs as innate sentinels of virus infection, particularly their recognition of and distinct response to virus-infected cells. This essential evolutionary role of pDCs has been particularly important for the control of coronaviruses, as demonstrated by the recent COVID-19 pandemic. Finally, we highlight the key contribution of pDCs to systemic lupus erythematosus, in which therapeutic targeting of pDCs is currently underway.

Systemic lupus erythematosus therapeutic strategy: From immunotherapy to gut microbiota modulation

Systemic lupus erythematosus (SLE) is characterized by a systemic dysfunction of the innate and adaptive immune systems, leading to an attack on healthy tissues of the body. During the development of SLE, pathogenic features, such as the formation of autoantibodies to self-nuclear antigens, caused tissue damage including necrosis and fibrosis, with an increased expression of type Ⅰ interferon (IFN) regulated genes. Treatment of lupus with immunosuppressants and glucocorticoids, which are used as the standard therapy, is not effective enough and causes side effects. As an alternative, more effective immunotherapies have been developed, including monoclonal and bispecific antibodies that target B cells, T cells, co-stimulatory molecules, cytokines or their receptors, and signaling molecules. Encouraging results have been observed in clinical trials with some of these therapies. Furthermore, a chimeric antigen receptor T cells (CAR-T) therapy has emerged as the most effective, safe, and promising treatment option for SLE, as demonstrated by successful pilot studies. Additionally, emerging evidence suggests that gut microbiota dysbiosis may play a significant role in the severity of SLE, and the use of methods to normalize the gut microbiota, particularly fecal microbiota transplantation (FMT), opens up new opportunities for effective treatment of SLE.

Emerging biologic therapies for systemic lupus erythematosus

PURPOSE OF REVIEW

The approval of belimumab and anifrolumab has expanded the scope of treatment for systemic lupus erythematosus (SLE) patients. However, many patients remain refractory to currently available therapies and suffer from drug toxicities. This review will discuss approved and target-specific therapeutics in development that bring hope for better SLE treatments.

RECENT FINDINGS

Since the last review on this subject in the journal, the FDA has approved anifrolumab and belimumab for SLE and lupus nephritis (LN), respectively. A fully humanized anti-CD20, obinutuzumab, met the primary end point in a phase II trial in LN. A Tyk2 inhibitor, deucravacitinib, and an antibody targeting plasmacytoid dendritic cells, litifilimab, met the primary end point in phase II trials in SLE and cutaneous lupus erythematosus (CLE). Ustekinumab and baricitinib met the primary end point in phase II but not in phase III trials.

SUMMARY

While many drug candidates which met the end points in phase II trials have failed phase III trials, the number of target-specific therapies for SLE has continued to expand.

Vascular damage in systemic lupus erythematosus

Vascular disease is a major cause of morbidity and mortality in patients with systemic autoimmune diseases, particularly systemic lupus erythematosus (SLE). Although comorbid cardiovascular risk factors are frequently present in patients with SLE, they do not explain the high burden of premature vascular disease. Profound innate and adaptive immune dysregulation seems to be the primary driver of accelerated vascular damage in SLE. In particular, evidence suggests that dysregulation of type 1 interferon (IFN-I) and aberrant neutrophils have key roles in the pathogenesis of vascular damage. IFN-I promotes endothelial dysfunction directly via effects on endothelial cells and indirectly via priming of immune cells that contribute to vascular damage. SLE neutrophils are vasculopathic in part because of their increased ability to form immunostimulatory neutrophil extracellular traps. Despite improvements in clinical care, cardiovascular disease remains the leading cause of mortality among patients with SLE, and treatments that improve vascular outcomes are urgently needed. Improved understanding of the mechanisms of vascular injury in inflammatory conditions such as SLE could also have implications for common cardiovascular diseases, such as atherosclerosis and hypertension, and may ultimately lead to personalized therapeutic approaches to the prevention and treatment of this potentially fatal complication.

cGAS-STING pathway mediates activation of dendritic cell sensing of immunogenic tumors

Type I interferons (IFN-I) play pivotal roles in tumor therapy for three decades, underscoring the critical importance of maintaining the integrity of the IFN-1 signaling pathway in radiotherapy, chemotherapy, targeted therapy, and immunotherapy. However, the specific mechanism by which IFN-I contributes to these therapies, particularly in terms of activating dendritic cells (DCs), remains unclear. Based on recent studies, aberrant DNA in the cytoplasm activates the cyclic GMP-AMP synthase (cGAS)- stimulator of interferon genes (STING) signaling pathway, which in turn produces IFN-I, which is essential for antiviral and anticancer immunity. Notably, STING can also enhance anticancer immunity by promoting autophagy, inflammation, and glycolysis in an IFN-I-independent manner. These research advancements contribute to our comprehension of the distinctions between IFN-I drugs and STING agonists in the context of oncology therapy and shed light on the challenges involved in developing STING agonist drugs. Thus, we aimed to summarize the novel mechanisms underlying cGAS-STING-IFN-I signal activation in DC-mediated antigen presentation and its role in the cancer immune cycle in this review.

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.

Inhibitory receptors of plasmacytoid dendritic cells as possible targets for checkpoint blockade in cancer

Plasmacytoid dendritic cells (pDCs) are the major producers of type I interferons (IFNs), which are essential to mount antiviral and antitumoral immune responses. To avoid exaggerated levels of type I IFNs, which pave the way to immune dysregulation and autoimmunity, pDC activation is strictly regulated by a variety of inhibitory receptors (IRs). In tumors, pDCs display an exhausted phenotype and correlate with an unfavorable prognosis, which largely depends on the accumulation of immunosuppressive cytokines and oncometabolites. This review explores the hypothesis that tumor microenvironment may reduce the release of type I IFNs also by a more pDC-specific mechanism, namely the engagement of IRs. Literature shows that many cancer types express de novo, or overexpress, IR ligands (such as BST2, PCNA, CAECAM-1 and modified surface carbohydrates) which often represent a strong predictor of poor outcome and metastasis. In line with this, tumor cells expressing ligands engaging IRs such as BDCA-2, ILT7, TIM3 and CD44 block pDC activation, while this blocking is prevented when IR engagement or signaling is inhibited. Based on this evidence, we propose that the regulation of IFN secretion by IRs may be regarded as an "innate checkpoint", reminiscent of the function of "classical" adaptive immune checkpoints, like PD1 expressed in CD8+ T cells, which restrain autoimmunity and immunopathology but favor chronic infections and tumors. However, we also point out that further work is needed to fully unravel the biology of tumor-associated pDCs, the neat contribution of pDC exhaustion in tumor growth following the engagement of IRs, especially those expressed also by other leukocytes, and their therapeutic potential as targets of combined immune checkpoint blockade in cancer immunotherapy.

Type 1 interferons: A target for immune-mediated inflammatory diseases (IMIDs)

The improved understanding of the molecular basis of innate immunity have led to the identification of type I interferons (IFNs), particularly IFN-α, as central mediators in the pathogenesis of several Immune-mediated inflammatory diseases (IMIDs) such as systemic lupus erythematosus (SLE), systemic sclerosis, inflammatory myositis and Sjögren's syndrome. Here, we review the main data regarding the opportunity to target type I IFNs for the treatment of IMIDs. Type I IFNs and their downstream pathways can be targeted pharmacologically in several manners. One approach is to use monoclonal antibodies against IFNs or the IFN-receptors (IFNARs, such as with anifrolumab). The downstream signaling pathways of type I IFNs also contain several targets of interest in IMIDs, such as JAK1 and Tyk2. Of these, anifrolumab is licensed and JAK1/Tyk2 inhibitors are in phase III trials in SLE. Targeting IFN-Is for the treatment of SLE is already a reality and in the near future may prove useful in other IMIDs. IFN assays will find a role in routine clinical practice for the care of IMIDs as further validation work is completed and a greater range of targeted therapies becomes available.

Fragility of randomised controlled trials for systemic lupus erythematosus and lupus nephritis therapies

OBJECTIVE

We aimed to evaluate the robustness of phase III randomised controlled trials (RCTs) for SLE and lupus nephritis (LN) using the fragility index (FI), the reverse FI (RFI) and the fragility quotient (FQ).

METHODS

We searched for phase III RCTs that included patients with active SLE or LN. Data on primary endpoints, total participants and the number of events for each arm were obtained. We calculated the FI score for RCTs with statistically significant results (number of patients required to change from event to non-event to make the study lose statistical significance), the RFI for RCTs without statistically significant results (number of patients required to change from non-event to event to make study gain statistical significance) and the FQ score for both (FI or RFI score divided by the sample size).

RESULTS

We evaluated 20 RCTs (16 SLE, four LN). The mean FI/RFI score was 13.6 (SD 6.6). There were nine RCTs with statistically significant results (seven SLE, two LN), and the mean FI score was 10.2 (SD 6.2). The lowest FI was for the ILLUMINATE-2 trial (FI=2), and the highest FI was for the BLISS-52 trial (FI=17).Twelve studies had non-statistically significant results (10 SLE, two LN) with a mean RFI score of 15.6 (SD 6.1). The lowest RFI was for the ILLUMINATE-1 trial (RFI=4), and the highest RFI was for the TULIP-1 trial (RFI=27). The lowest FQ scores were found in the ILLUMINATE trials and the highest in the Rituximab trials (EXPLORER and LUNAR), meaning that the last ones were the most robust results after accounting for sample size.

CONCLUSIONS

The evidence of therapies for patients with SLE and LN is derived mostly from fragile RCTs. Clinicians and trialists must be aware of the fragility of these RCTs for clinical decision-making and designing trials for novel therapeutics.

An immunomodulatory antibody-drug conjugate targeting BDCA2 strongly suppresses plasmacytoid dendritic cell function and glucocorticoid responsive genes

OBJECTIVES

Blood dendritic cell antigen 2 (BDCA2) is exclusively expressed on plasmacytoid dendritic cells (pDCs) whose uncontrolled production of type I IFN (IFN-I) is crucial in pathogenesis of SLE and other autoimmune diseases. Although anti-BDCA2 antibody therapy reduced disease activity in SLE patients, its clinical efficacy needs further improvement. We developed a novel glucocorticoid receptor agonist and used it as a payload to conjugate with an anti-BDCA2 antibody to form an BDCA2 antibody-drug conjugate (BDCA2-ADC). The activation of BDCA2-ADC was evaluated in vitro.

METHODS

Inhibitory activity of BDCA2-ADC was evaluated in peripheral blood mononuclear cells or in purified pDCs under ex vivo toll-like receptor agonistic stimulation. The global gene regulation in purified pDCs was analysed by RNA-seq. The antigen-dependent payload delivery was measured by reporter assay.

RESULTS

The BDCA2-ADC molecule causes total suppression of IFNα production and broader inhibition of inflammatory cytokine production compared with the parental antibody in human pDCs. Global gene expression analysis confirmed that the payload and antibody acted synergistically to regulate both type I IFN signature genes and glucocorticoid responsive genes in pDCs.

CONCLUSION

Taken together, these data suggest dual mechanisms of BDCA2-ADC on pDCs and the potential for BDCA2-ADC to be the first ADC treatment for SLE in the world and a better treatment option than anti-BDCA2 antibody for SLE patients.

PANoptosis: Mechanisms, biology, and role in disease

Cell death can be executed through distinct subroutines. PANoptosis is a unique inflammatory cell death modality involving the interactions between pyroptosis, apoptosis, and necroptosis, which can be mediated by multifaceted PANoptosome complexes assembled via integrating components from other cell death modalities. There is growing interest in the process and function of PANoptosis. Accumulating evidence suggests that PANoptosis occurs under diverse stimuli, for example, viral or bacterial infection, cytokine storm, and cancer. Given the impact of PANoptosis across the disease spectrum, this review briefly describes the relationships between pyroptosis, apoptosis, and necroptosis, highlights the key molecules in PANoptosome formation and PANoptosis activation, and outlines the multifaceted roles of PANoptosis in diseases together with a potential for therapeutic targeting. We also discuss important concepts and pressing issues for future PANoptosis research. Improved understanding of PANoptosis and its mechanisms is crucial for identifying novel therapeutic targets and strategies.

Anifrolumab: first biologic approved in the EU not restricted to patients with a high degree of disease activity for the treatment of moderate to severe systemic lupus erythematosus

INTRODUCTION

Type 1 interferons (IFNs) play a crucial role in the pathogenesis of systemic lupus erythematosus (SLE) and various type I IFNs targeting therapeutic approaches have been developed. Anifrolumab, a monoclonal antibody that binds to the subunit 1 of the type I IFN receptor, has acquired considerable interest and has entered different clinical human trials willing to evaluate its efficacy and safety.

AREAS COVERED

This review summarizes the data obtained in phases 1, 2, and 3 clinical trials of anifrolumab for SLE patients. A focus is made on data of clinical efficacy and safety obtained in MUSE, TULIP-1 and TULIP-2 trials.

EXPERT OPINION/COMMENTARY

Anifrolumab is a promising therapeutic option for patients with SLE, currently authorized for moderate-to-severe SLE. Extensive real-world use is now going to generate data required to gain experience on the type of patients who benefit the most from the drug, and the exact positioning of anifrolumab in the therapeutic plan.

The development of litifilimab (BIIB 059) for cutaneous and systemic lupus erythematosus

This review describes the litifilimab (BIIB 059) development program to date for systemic lupus erythematosus (SLE) and cutaneous lupus erythematosus (CLE). Plasmacytoid dendritic cells (pDCs), major producers of type I interferons (IFN-I), play a key role in SLE pathogenesis. Litifilimab, a humanized monoclonal antibody, binds to BDCA2, a protein uniquely expressed on pDCs. The consequence of BDCA2 ligation is the inhibition of IFN-I as well as IFN-III, cytokine and chemokine production. Phase I and II LILAC trial parts A and B achieved primary end points in SLE and CLE patients, confirming the importance of pDCs and IFN-I in SLE and CLE. Litifilimab is currently being evaluated in phase III trials in both SLE and CLE.

Immunotherapeutic approaches for systemic lupus erythematosus: early overview and future potential

Systemic lupus erythematosus (SLE) is a complex autoimmune disease. Current SLE therapies include immunosuppressants, antimalarial drugs, non-steroidal anti-inflammatory drugs (NSAIDs), and corticosteroids, but these treatments can cause substantial toxicities to organs and may not be effective for all patients. In recent years, significant progress has been made in the treatment of SLE using immunotherapy, including Benlysta and Saphnelo. These advances in immunotherapy hold promise for SLE patients, providing new therapeutic options that may offer better clinical benefit and effectiveness. Simultaneously, several new biological therapies focusing on cytokines, peptides, targeted antibodies, and cell-based approaches are under clinical evaluation and have shown immense potential for the treatment of SLE. However, the complexity of SLE immunopathogenesis and disease heterogeneity present significant challenges in the development of effective immunological therapies. This review aims to discuss past experiences and understanding of diverse immunological targeting therapies for SLE and highlight future perspectives for the development of novel immunological therapies.

Emerging immunotherapeutic strategies for cutaneous lupus erythematosus: an overview of recent phase 2 and 3 clinical trials

INTRODUCTION

Cutaneous lupus erythematosus (CLE) is an autoimmune disease that is clinically heterogenous and may occur with or without the presence of systemic lupus erythematosus (SLE). While existing on a spectrum, CLE and SLE present differences in their underlying pathogenesis and therapeutic responses. No new therapies have been approved in recent decades by the U.S. Food and Drug Administration for CLE, although frequently refractory to conventional therapies. There is an unmet need to develop effective drugs for CLE as it significantly impacts patients' quality of life and may leave irreversible disfiguring damage.

AREAS COVERED

This review provides an update on the latest phase 2 and 3 clinical trials performed in CLE or SLE using skin-specific outcome measures. Emergent therapies are presented alongside their mechanism of action as recent translational studies have permitted identification of critical targets among immune cells and/or pathways involved in CLE.

EXPERT OPINION

While the recent literature has few trials for CLE, drugs targeting type I interferon, its downstream signaling and plasmacytoid dendritic cells have shown promising results. Further research is required to develop long-awaited effective therapies, and this review highlights the importance of implementing trials dedicated to CLE to fill the current gap in CLE therapeutics.

New and future therapies: Changes in the therapeutic armamentarium for SLE

Following better understanding of molecular pathways involved in the pathogenesis of Systemic lupus erythematosus (SLE), pharmaceutical companies have been investigating new targeted drugs for SLE. The purpose of this scoping review is to provide an updated view of the most promising targeted therapies currently in clinical development or recently approved for SLE treatment as well as of the most promising potential future therapeutic strategies in SLE. In the past several years, two new drugs have been developed for lupus treatment along with an extended indication for belimumab. Anifrolumab, the anti-interferon medication, to treat non-renal lupus; voclosporin, a calcineurin inhibitor, for the treatment of lupus nephritis; and belimumab for lupus nephritis. More than 90 investigational drugs are currently in clinical development for SLE treatment, with various targets including inflammatory cytokines and their receptors, intracellular signaling, B cells or plasma cells, co-stimulation molecules, complement fractions, T cells, plasmacytoid dendritic cells as well as various other immunological targets of interest. Researchers are also actively engaged in the development of new therapeutic strategies, including the use of monoclonal antibodies in combination with bispecific monoclonal antibodies, nanobodies and nanoparticles, therapeutic vaccines, utilizing siRNA interference techniques, autologous hematopoietic stem-cell transplantation and Chimeric Antigens Receptor (CAR)-T cells. The therapeutic management and prognosis of SLE have profoundly evolved with changes in the therapeutic armamentarium. With the broad pipeline of targeted treatments in clinical development and new treatment strategies in the future, current challenges are transitioning from the availability of new drugs to the selection of the most appropriate strategy at the patient level.

Advances in the management of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a severe multisystem autoimmune disease that can cause injury in almost every body system. While considered a classic example of autoimmunity, it is still relatively poorly understood. Treatment with immunosuppressive agents is challenging, as many agents are relatively non-specific, and the underlying disease is characterized by unpredictable flares and remissions. This State of The Art Review provides a comprehensive current summary of systemic lupus erythematosus based on recent literature. In basic and translational science, this summary includes the current state of genetics, epigenetics, differences by ancestry, and updates about the molecular and immunological pathogenesis of systemic lupus erythematosus. In clinical science, the summary includes updates in diagnosis and classification, clinical features and subphenotypes, and current guidelines and strategies for treatment. The paper also provides a comprehensive review of the large number of recent clinical trials in systemic lupus erythematosus. Current knowns and unknowns are presented, and potential directions for the future are suggested. Improved knowledge of immunological pathogenesis and the molecular differences that exist between patients should help to personalize treatment, minimize side effects, and achieve better outcomes in this difficult disease.

Type I Interferons in Autoimmunity: Implications in Clinical Phenotypes and Treatment Response

Type I interferon (IFN-I) is thought to play a role in many systemic autoimmune diseases. IFN-I pathway activation is associated with pathogenic features, including the presence of autoantibodies and clinical phenotypes such as more severe disease with increased disease activity and damage. We will review the role and potential drivers of IFN-I dysregulation in 5 prototypic autoimmune diseases: systemic lupus erythematosus, dermatomyositis, rheumatoid arthritis, primary Sjögren syndrome, and systemic sclerosis. We will also discuss current therapeutic strategies that directly or indirectly target the IFN-I system.

[Research progress in systemic lupus erythematosus from 2021 to 2022]

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects multiple organ systems, presenting a complex and diverse clinical manifestation. The heterogeneous treatment response and prognosis of SLE pose significant challenges to its diagnosis, classification, and homogeneous treatment. The emergence of new technologies and fields, such as synthetic biology, genomics, and proteomics, has contributed to a deeper exploration of the pathogenesis and biomarkers of SLE, facilitating precision diagnosis and treatment. This review summarizes the latest research data and achievements in SLE for the years 2021-2022, providing an overview and summary of relevant studies conducted in the past two years.

CSL362 potently and specifically depletes pDCs invitro and ablates SLE-immune complex-induced IFN responses

Systemic lupus erythematosus (SLE) is an autoimmune disease with significant morbidity and mortality. Type I interferon (IFN) drives SLE pathology and plasmacytoid dendritic cells (pDCs) are potent producers of IFN; however, the specific effects of pDC depletion have not been demonstrated. We show CD123 was highly expressed on pDCs and the anti-CD123 antibody CSL362 potently depleted pDCs in vitro. CSL362 pre-treatment abrogated the induction of IFNα and IFN-induced gene transcription following stimulation with SLE patient-derived serum or immune complexes. RNA transcripts induced in pDCs by ex vivo stimulation with TLR ligands were reflected in gene expression profiles of SLE blood, and correlated with disease severity. TLR ligand-induced protein production by SLE patient peripheral mononuclear cells was abrogated by CSL362 pre-treatment including proteins over expressed in SLE patient serum. These findings implicate pDCs as key drivers in the cellular activation and production of soluble factors seen in SLE.

Litifilimab (BIIB059), a promising investigational drug for cutaneous lupus erythematosus

INTRODUCTION

There are no U.S. Food and Drug Administration (FDA) approved therapies for cutaneous lupus erythematosus (CLE). Litifilimab is a monoclonal antibody against BDCA2, a plasmacytoid dendritic cell specific antigen, currently under investigation for systemic lupus erythematosus (SLE) and CLE. The LILAC study, published in the New England Journal of Medicine, is a phase II randomized controlled trial for CLE which demonstrated superiority of Litifilimab over placebo using a skin directed outcome measure.

AREAS COVERED

This review identifies challenges that have hindered the development of any approved treatments for CLE, recent SLE trials that include skin disease data, and the pharmacological properties of litifilimab. We review the clinical efficacy and safety of litifilimab for both SLE and CLE in the phase I and II clinical trials. This review aims to highlight the need for more CLE specific clinical trials and examine the potential of litifilimab as the first FDA approved therapy for CLE. (Clinical trial registration: www.clinicaltrials.gov identifier is NCT02847598.).

EXPERT OPINION

Litifilimab demonstrated efficacy in a randomized phase II clinical trial as a standalone CLE trial using validated skin specific outcome measures, making it the first successful clinical trial for a CLE targeted therapy. If approved, litifilimab will be a pivotal change in the landscape of CLE management especially for severe and refractory disease.