Interferon targeted therapies in systemic lupus erythematosus

Interferon Inhibition in SLE: From Bench to Bedside

Despite advances in the management of systemic lupus erythematosus (SLE), it remains a chronic disease with frequent flares, requiring constant medical care, laboratory exams, hospitalisations, and the use of immunosuppressive drugs and corticosteroids, increasing the morbidity and mortality of these patients. The past decade of research has brought to light multiple observations on the role of interferons (IFNs) in the pathogenesis of SLE, which paved the way for the development of potential novel therapies targeting the interferon pathway. Following two phase III trials, anifrolumab, a monoclonal antibody which binds to the type I IFN receptor, blocking the activity of type I IFNs, was approved for active SLE. This review summarises the latest research on the role and mechanisms of type I IFNs in SLE and the development and advances on new therapeutic drugs based on IFN inhibition for SLE.

Safety, Tolerability, Pharmacokinetics, and Immunogenicity of the Anti-IFNAR1 Monoclonal Antibody QX006N: A First-in-Human Single Ascending Dose Study in Healthy Chinese Volunteers

BACKGROUND AND OBJECTIVE

QX006N is a novel, humanized, IgG4κ monoclonal antibody targeting IFNAR1, developed for the treatment of systemic lupus erythematosus. This study aims to investigate the pharmacokinetics, safety, tolerability, and immunogenicity of QX006N when administered intravenously to healthy Chinese individuals.

METHODS

A double-blind, randomized, placebo-controlled, single-ascending-dose, phase I clinical trial was conducted comprising five cohorts (n = 10 per cohort, except n = 5 for the first cohort). Subjects in each cohort were randomly assigned in a 4:1 ratio to receive a single intravenous infusion of QX006N (0.3 mg/kg, 1.0 mg/kg, 3.0 mg/kg, 6.0 mg/kg, or 10.0 mg/kg) or placebo for 30 minutes. Tolerability assessments included adverse events, vital signs, 12-lead electrocardiogram, physical examination, and clinical laboratory tests. The serum concentration of QX006N was measured using the enzyme-linked immunosorbent assay method, and the anti-drug antibodies were detected using the electrochemiluminescence assay method.

RESULTS

QX006N demonstrated a favorable safety and tolerability profile throughout the study. All treatment-emergent adverse events were of Grade 1-2 (CTCAE Version 5.0), and no serious adverse events, deaths, or drug discontinuations because of treatment-emergent adverse events were observed. All drug-related treatment-emergent adverse events showed no clear dose-related trends. Following an intravenous infusion of QX006N at doses that ranged from 0.3 mg/kg to 10 mg/kg, the half-life increased from 24.7 to 208 hours in a dose-dependent manner, while clearance decreased from 0.0828 to 0.0065 L/h. The maximum concentration exhibited nearly dose-proportional increases, and the area under the curve displayed a more than dose-proportional increment with non-linear pharmacokinetic characteristics. The incidence of anti-drug antibodies was observed to increase over time for doses that ranged from 1.0 mg/kg to 10.0 mg/kg of QX006N, reaching its peak at day 57 (range 62.50-87.50%). Conversely, the incidence of anti-drug antibodies in the QX006N 0.3-mg/kg and placebo cohorts remained low.

CONCLUSIONS

QX006N demonstrated acceptable safety, tolerability, and pharmacokinetic characteristics in healthy subjects when administered as a single intravenous infusion at doses that ranged from 0.3 mg/kg to 10.0 mg/kg. Based on the pharmacokinetic and safety outcomes, a recommended effective dose of 300 mg is proposed for future phase Ib studies.

CLINICAL TRIAL REGISTRATION

This study has been registered at http://www.chinadrugtrials.org.cn/ under identifier CTR20212834.

Effect of add-on hydroxychloroquine therapy on serum proinflammatory cytokine levels in patients with systemic lupus erythematosus

We investigated the effect of hydroxychloroquine (HCQ) as an add-on treatment to immunosuppressants on the expression of proinflammatory cytokines in patients with systemic lupus erythematosus. Serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-2, IL-6, IL-8, vascular endothelial growth factor (VEGF)-A, monocyte chemotactic protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), and interleukin 1 receptor antagonist (IL-1ra) were measured immediately before and 3 months after treatment with oral HCQ. Among the 51 patients enrolled in the study, HCQ treatment led to significantly reduced serum levels of TNF-α, IL-6, IL-8, VEGF-A, IL-1ra, and IL-2 (p < 0.0001; p = 0.0006; p = 0.0460, p = 0.0177; p < 0.0001; p = 0.0282, respectively) and to decreased (but not significantly) levels of MIP-1α (p = 0.0746). No significant changes were observed in the serum MCP-1 levels before and after HCQ administration (p = 0.1402). Our results suggest that an add-on HCQ treatment modulates the expression of proinflammatory cytokines even in systemic lupus erythematosus patients with low disease activity.

Dihydroartemisinin attenuated the symptoms of mice model of systemic lupus erythematosus by restoring the Treg/Th17 balance

The Treg/Th17 imbalance is associated with the development of systemic lupus erythematosus (SLE). Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, is isolated from the traditional Chinese herb Artemisia annua Artemisia annua L. This study aims to evaluate the effects of DHA alone or in combination with prednisone in immunodeficiency of SLE. In vivo, the therapeutical effect of DHA alone or in combination with prednisone was assessed in the pristane-induced SLE mouse model. Then, the level of serum antibodies, creatinine (Cre), blood urea nitrogen (BUN), urine protein, kidney histopathology, interleukin (IL)-17, IL-6, transforming growth factor (TGF)-β, the expression of RORγt and Foxp3, the percentages of Treg and Th17 in peripheral blood and spleen were assayed. In vitro, the mouse spleen lymphocytes were separated and treated with DHA alone or DHA in combination with prednisone. Then the percentages of Treg and Th17, the concentration of IL-17, IL-6, TGF-β, and the expression of RORγt and Foxp3 were assayed. It was shown that DHA alone or in combination with prednisone treatment significantly alleviated the manifestations of pristane-induced SLE mice, suppressed inflammation and restored the Treg/Th17 balance. DHA alone or in combination with prednisone significantly inhibited Th17 cell differentiation while induced Treg cell differentiation in vitro. DHA alone or in combination with prednisone also reduced the transcription of RORγt and increased Foxp3 in lymphocytes, as well as IL-17 and TGF-β levels. Our data indicated that DHA can produce synergistic effect with prednisone to attenuate the symptoms of SLE by restoring Treg/Th17 balance.

Can endolysosomal deacidification and inhibition of autophagy prevent severe COVID-19?

The possibility is examined that immunomodulatory pharmacotherapy may be clinically useful in managing the pandemic coronavirus disease 2019 (COVID-19), known to result from infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a positive-sense single-stranded RNA virus. The dominant route of cell entry of the coronavirus is via phagocytosis, with ensconcement in endosomes thereafter proceeding via the endosomal pathway, involving transfer from early (EEs) to late endosomes (LEs) and ultimately into lysosomes via endolysosomal fusion. EE to LE transportation is a rate-limiting step for coronaviruses. Hence inhibition or dysregulation of endosomal trafficking could potentially inhibit SARS-CoV-2 replication. Furthermore, the acidic luminal pH of the endolysosomal system is critical for the activity of numerous pH-sensitive hydrolytic enzymes. Golgi sub-compartments and Golgi-derived secretory vesicles also depend on being mildly acidic for optimal function and structure. Activation of endosomal toll-like receptors by viral RNA can upregulate inflammatory mediators and contribute to a systemic inflammatory cytokine storm, associated with a worsened clinical outcome in COVID-19. Such endosomal toll-like receptors could be inhibited by the use of pharmacological agents which increase endosomal pH, thereby reducing the activity of acid-dependent endosomal proteases required for their activity and/or assembly, leading to suppression of antigen-presenting cell activity, decreased autoantibody secretion, decreased nuclear factor-kappa B activity and decreased pro-inflammatory cytokine production. It is also noteworthy that SARS-CoV-2 inhibits autophagy, predisposing infected cells to apoptosis. It is therefore also suggested that further pharmacological inhibition of autophagy might encourage the apoptotic clearance of SARS-CoV-2-infected cells.