Placebo-Controlled Trial of an Oral BTK Inhibitor in Multiple Sclerosis

Bruton's tyrosine kinase - A new target for immune mediated inflammatory diseases?

Bruton's tyrosine kinase (BTK) is a cytoplasmic protein that plays a key role in signalling pathways downstream of diverse surface receptors in B-cells and myeloid cells. These include the B-cell receptor itself, Fc receptors including FcεRI, toll-like receptors and chemokine receptors. Congenital deficiency of BTK causes X-linked agammaglobulinaemia because of B-cell developmental block, and BTK inhibitors (BTKi) are approved for the treatment of certain B-cell malignancies. They have also been studied in a variety of autoimmune and inflammatory diseases. In rheumatic conditions, results have been disappointing in rheumatoid arthritis (RA) and systemic lupus erythematosus but with some evidence for efficacy in Sjogren's syndrome. Data are more positive in multiple sclerosis, as well as in the cutaneous disease chronic spontaneous urticaria and possibly pemphigus vulgaris. BTKi may also find a role in severe allergic disease such as food allergy. First generation BTKi had a safety profile that included cardiotoxicity, hypertension, haemorrhage and rash. Second generation inhibitors have a more acceptable safety profile although dose-limiting toxicity is still observed in some conditions, including RA. Pharmacokinetic factors aside, the variable efficacy in different diseases is not fully explained but is likely to reflect disease dependence on different pathways in B-cells and myeloid cells and their relative sensitivity to BTKi.

Evobrutinib mitigates neuroinflammation after ischemic stroke by targeting M1 microglial polarization via the TLR4/Myd88/NF-κB pathway

BACKGROUND

Evobrutinib, a third-generation Bruton's tyrosine kinase (BTK) inhibitor, shows great promise for treating neuroinflammatory diseases due to its small molecular size, ease of absorption, and ability to cross the blood-brain barrier. Although previous studies have confirmed significant BTK expression in microglia, the potential of Evobrutinib to treat ischemic stroke by modulating microglial function and its underlying mechanisms remain to be elucidated.

METHODS

Male C57BL/6 mice with cerebral ischemia was established to evaluate the effects of oral Evobrutinib treatment. Assessments included TTC staining, behavioral experiments, and pathological examinations were used to evaluate cerebral ischemic injury. Western Blot, flow cytometry, and qPCR were employed to monitor changes in BTK and pBTK expression in microglia and the impact of Evobrutinib on neuroinflammation following the stroke. In vitro, primary microglia were generated to determine the effects of Evobrutinib on the TLR4/ Myd88/NF-κB pathway and on the polarization of microglial subtypes.

RESULTS

The expression of BTK and pBTK is upregulated in microglia under conditions of cerebral ischemia and oxygen-glucose deprivation (OGD). Evobrutinib treatment not only reduced infarct volume in mice but also ameliorated pathological damage and facilitated neurological function recovery. Flow cytometry revealed that Evobrutinib decreased inflammatory cell infiltration and promoted M2 microglia polarization post-stroke. In vitro studies demonstrated that Evobrutinib downregulated the proportion of pro-inflammatory microglia and curtailed the secretion of inflammatory factors under OGD conditions. Mechanistically, Evobrutinib attenuated the OGD-induced upregulation of TLR4/Myd88/NF-κB expression, an effect that was further enhanced by the addition of the TLR4 pathway inhibitor TAK242.

CONCLUSIONS

Evobrutinib inhibits the expression and activation of BTK in microglia, reducing M1 microglia-mediated neuroinflammation and alleviating ischemic injury following stroke. This effect is mechanistically linked to the inhibition of TLR4/Myd88/NF-κB-mediated M1 polarization of microglia.

Impact of High-Efficacy Therapies for Multiple Sclerosis on B Cells

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative autoimmune disorder of the central nervous system characterized by demyelination and neurodegeneration. Traditionally considered a T-cell-mediated disease, the crucial role of B lymphocytes in its pathogenesis, through different mechanisms contributing to inflammation and autoreactivity, is increasingly recognized. The risk of long-term disability in MS patients can be reduced by an early treatment initiation, in particular with high-efficacy therapies. The aim of this review is to provide an overview of the mechanisms of action of high-efficacy therapies for MS, with a focus on their impact on B cells and how this contributes to the drugs' efficacy and safety profiles. Anti-CD20 monoclonal antibodies, Alemtuzumab, Cladribine and sequestering therapies encompassing Natalizumab and S1P receptors modulators will be discussed and emerging therapies, including Bruton's Tyrosine Kinase inhibitors, will be presented.

BTK and YKL-40 Levels and Their Association with Acute AQP4-IgG-Positive Neuromyelitis Optica Spectrum Disorder

This study investigated the potential correlation between BTK/YKL-40 levels and the severity of AQP4-IgG + NMOSD, aiming to identify biomarkers for disease monitoring and treatment assessment. Plasma YKL-40 expression was measured in 135 AQP4-IgG + NMOSD patients using ELISA. Patients were categorized into pre- and post-IVMP treatment acute phases, as well as during remission, with a healthy control group included. BTK and NF-κB mRNA levels in PBMCs were detected via q-PCR, and BTK/P-BTK protein expression was assessed using Western blotting. Disability was evaluated using the EDSS score, and clinical characteristics were evaluated alongside laboratory tests. Acute-phase NMOSD patients receiving pre-IVMP therapy presented significantly elevated plasma YKL-40 concentrations compared with those of post-treatment patients, patients in remission, and healthy controls. Additionally, these patients presented significantly higher levels of PBMC BTK mRNA, NF-κB mRNA, BTK, and P-BTK protein expression than remission patients and healthy controls. Plasma YKL-40 levels and PBMC BTK/P-BTK protein levels were positively correlated with EDSS scores. The plasma YKL-40 concentration significantly contributes to disease severity and serves as an independent risk factor for acute NMOSD. Elevated BTK, P-BTK, NF-κB, and YKL-40 levels were observed in acute-phase AQP4-IgG + NMOSD patients. These biomarkers are related to disease activity and may predict treatment efficacy. There is a connection among YKL-40, BTK, and P-BTK levels and disease severity, suggesting their potential involvement in the pathogenic mechanism of AQP4-IgG + NMOSD.

Caspase-12 exhibits non-redundant functions in response to endoplasmic reticulum stress to promote GSDMD-mediated NETosis, leading to thoracic aortic dissection

BACKGROUND

Thoracic aortic dissection (TAD) is a highly lethal condition that is characterized by inflammatory cell infiltration. Recent evidence has indicated that Gasdermin D (GSDMD) plays an important role in vascular inflammation and degeneration. However, its effects on neutrophil extracellular trap formation and release (NETosis) during TAD remain unknown.

METHODS

A TAD mouse model was generated using four-week-old male neutrophil-specific GSDMD-knockout mice (GSDMDF/F; ElaneCre) and dimethyl fumarate (DMF)-treated C57BL/6J mice by administering β-aminopropionitrile monofumarate (BAPN; 1 g/kg/day) in their drinking water for 4 weeks. Immunoprecipitation and immunofluorescence assays were performed to examine the role of the endoplasmic reticulum (ER) and its associated protein, caspase-12, in GSDMD-induced NETosis.

RESULTS

GSDMD was elevated and co-localized primarily in neutrophils in the aortic tissues of patients with TAD and mice with BAPN-induced TAD. This was accompanied by increased NETosis. Neutrophil-specific GSDMD knockout and the NETosis inhibitor, GSK484, mitigated TAD development in mice. However, GSK484 did not provide additional therapeutic effects against TAD in the neutrophil-specific, GSDMD knockout mice. Mechanistically, ER stress promoted GSDMD cleavage by caspase-4/11, thereby inducing NETosis. Furthermore, caspase-12 exhibited non-redundant functions in the cleavage of GSDMD by caspase-4/11. The GSDMD inhibitor, DMF, partially prevented TAD development.

CONCLUSIONS

The ER stress/GSDMD/NETosis signaling pathway provides a potential therapeutic target for the prevention and treatment of TAD.

Optimizing Drug Selection in Children with Multiple Sclerosis: What Do We Know and What Remains Unanswered?

Pediatric-onset multiple sclerosis (POMS) refers to multiple sclerosis with onset before 18 years of age. It is characterized by a more inflammatory course, more frequent clinical relapses, and a greater number of magnetic resonance imaging (MRI) lesions compared with adult-onset MS (AOMS), leading to significant impacts on both disability progression and cognitive outcomes in affected individuals. Managing POMS presents distinct challenges due to the unique needs of pediatric patients and the limited number of disease-modifying therapies (DMTs) approved for pediatric use. Notably, only one therapy (fingolimod) is approved by the United States (US) Food and Drug Administration (FDA) and three (fingolimod, teriflunomide, and dimethyl fumarate) by the European Medicines Agency (EMA) for use in youth with MS. However, observational evidence identifies use of almost all agents off-label in this population. This review provides a comprehensive overview of literature supporting the use of DMTs for POMS, including evidence from observational studies. In this paper, we highlight the shift in clinical practice, which has led to increased use of high-efficacy therapies (HETs) at or near disease onset. We review emerging evidence indicating better cognitive and motor outcomes in this population with early initiation of therapy. Finally, in this paper, we provide a suggested treatment algorithm for managing POMS. We underscore the need for personalized approaches in POMS management. We identify special considerations unique to pediatric care, including attention to family dynamics, and strategies to improve medication adherence and a smooth transition to adult care. Further research on DMTs in POMS is essential to optimize outcomes and improve long-term prognosis.

Dynamic Expansion and Contraction of Multiple Sclerosis T2-Weighted Hyperintense Lesions Are Present below the Threshold of Visual Perception

BACKGROUND AND PURPOSE

The study of T2-weighted hyperintense lesions resulting from autoimmune inflammatory injury and associated volumes within the CNS remains fundamental to the diagnosis and disease surveillance of MS. We investigated the dynamic changes of individual T2-weighted hyperintense MS lesions on MRI and hypothesized that variations may be present below the threshold of visual perception when evaluating longitudinal data.

MATERIALS AND METHODS

A retrospective study was performed of people with MS, incorporating data from 3 consecutive MRI time points acquired within a single academic center. All included MRI studies lacked formal imaging interpretations of newly enlarging or contracting T2-weighted hyperintensities. Well-defined, noncoalescing, individual T2-weighted hyperintense lesions were targeted. A total of 8-12 lesions were randomly selected in a blinded fashion at MRI time point 1 and 3D lesion volumes were followed over MRI time points 2 and 3. The impact of treatment on lesion expansion and relationship to brain MRI advancement, patient-reported progression of disease, and physician-identified progression was also studied.

RESULTS

The study cohort comprised 115 people (81 (70.4%) women; mean disease duration of 9.36 years [standard deviation: 7.72 years]) who were primarily White (79.1%). A total of 1426 focal T2-weighted hyperintense MS lesions were identified on MRI time point 1 and longitudinally followed over MRI time points 2 and 3. In the evaluation of raw changes in individual T2-weighted hyperintense lesion volumes from MRI time point 1 to MRI time point 2, a similar number of individuals were observed with predominantly expanding (49/115; 42.6%) or contracting (51/115; 44.3%) lesions. However, most lesions expanded in volume (48/115; 41.7%) versus those that contracted (45/115; 39.1%) when evaluating MRI time point 3 to time point 1. Those individuals not on active treatment had a 67.15% reduction in the odds of more individual lesions predominantly contracting in volume relative to those on low-efficacy disease modifying therapy treatment (95% CI = [-83.89% to -33.01%], P = .0008) and 74.02% reduction relative to high-efficacy treatment individuals (95% CI = [-87.37% to -46.56%], P < .0001).

CONCLUSIONS

Dynamic changes in T2-weighted hyperintense lesions are abundant, occurring below the threshold of visual perception and are present more frequently in untreated individuals.

Exploring the Pathophysiology, Diagnosis, and Treatment Options of Multiple Sclerosis

The complicated neurological syndrome known as multiple sclerosis (MS) is typified by demyelination, inflammation, and neurodegeneration in the central nervous system (CNS). Managing this crippling illness requires an understanding of the complex interactions between neurophysiological systems, diagnostic techniques, and therapeutic methods. A complex series of processes, including immunological dysregulation, inflammation, and neurodegeneration, are involved in the pathogenesis of MS. Gene predisposition, autoreactive T cells, B cells, and cytokines are essential participants in the development of the disease. Demyelination interferes with the ability of the CNS to transmit signals, which can cause a variety of neurological symptoms, including impaired motor function, sensory deficiencies, and cognitive decline. Developing tailored therapeutics requires understanding the underlying processes guiding the course of the disease. Neuroimaging, laboratory testing, and clinical examination are all necessary for an accurate MS diagnosis. Evoked potentials and cerebrospinal fluid studies assist in verifying the diagnosis, but magnetic resonance imaging (MRI) is essential for identifying distinctive lesions in the CNS. Novel biomarkers have the potential to increase diagnostic precision and forecast prognosis. The goals of MS treatment options are to control symptoms, lower disease activity, and enhance quality of life. To stop relapses and reduce the course of the disease, disease-modifying treatments (DMTs) target several components of the immune response. DMTs that are now on the market include interferons, glatiramer acetate, monoclonal antibodies, and oral immunomodulators; each has a unique mode of action and safety profile. Symptomatic treatments improve patients' general well-being by addressing specific symptoms, including pain, sphincter disorders, fatigue, and spasticity. Novel treatment targets, neuroprotective tactics, and personalized medicine techniques will be the main focus of MS research in the future. Improving long-term outcomes for MS patients and optimizing disease treatment may be possible by utilizing immunology, genetics, and neuroimaging developments. This study concludes by highlighting the complexity of multiple MS, including its changing therapeutic landscape, diagnostic problems, and neurophysiological foundations. A thorough grasp of these elements is essential to improving our capacity to identify, manage, and eventually overcome this intricate neurological condition.

Effect of Different Treatments on Retinal Thickness Changes in Patients With Multiple Sclerosis: A Review

BACKGROUND

Multiple sclerosis (MS) is an autoimmune disorder affecting the central nervous system, with varying clinical manifestations such as optic neuritis, sensory disturbances, and brainstem syndromes. Disease progression is monitored through methods like MRI scans, disability scales, and optical coherence tomography (OCT), which can detect retinal thinning, even in the absence of optic neuritis. MS progression involves neurodegeneration, particularly trans-synaptic degeneration, which extends beyond the initial injury site. This review focuses on the impact of different MS treatments on retinal thickness as assessed by OCT.

RESULTS

Injectable drugs, such as interferon beta and glatiramer acetate (GA), have a relatively modest impact on retinal atrophy. Oral medications like Fingolimod, Teriflunomide, and Dimethyl fumarate also have different impacts on retinal thickness. Fingolimod has been shown to protect against retinal thinning but may lead to macular edema. DMF-treated patients had less ganglion cell-inner plexiform layer thinning than GA-treated patients but more thinning compared to natalizumab-treated patients and healthy controls. Teriflunomide's impact on retinal layers remains unexplored in human studies. Monoclonal antibodies, including Alemtuzumab, Rituximab, Ocrelizumab, and Natalizumab, had protective effects on retinal layer atrophy. Alemtuzumab-treated patients showed significantly less atrophy compared to interferon- and GA-treated patients. Rituximab initially increased atrophy rates in the first months but subsequently demonstrated potential neuroprotective effects. Ocrelizumab slowed the rate of inner nuclear layer thinning in progressive forms of the disease. Natalizumab is considered the most effective in reducing retinal layer atrophy, particularly the peripapillary retinal nerve fiber layer.

CONCLUSIONS

It's important to note that the effectiveness of these treatments may vary depending on MS subtype and individual factors. Future research should explore the long-term effects of these treatments on retinal layers and their correlations with overall disease progression and disability in MS patients.

Positive effect of evobrutinib in CNS remyelination models and lack of synergy with clemastine-A dose response study

Background

To recover normal functions, remyelination in multiple sclerosis is crucial. Although endogenous remyelination occurs, it is often insufficient, and finding molecules promoting repair of demyelinated lesions is needed.

Objectives

To compare the remyelination potential of evobrutinib, an inhibitor of Bruton's tyrosine kinase and clemastine, an antagonist of M1 muscarinic acetylcholine receptor.

Methods

Remyelination was investigated in lysolecithin demyelinated organotypic mouse cerebellar slices and a transgenic Xenopus model of inducible-demyelination.

Results

Evobrutinib (100 nM) and clemastine (200 nM) potentiated remyelination of mouse cerebellar slices by a factor of 2.9 and 1.76, respectively. In conditionally demyelinated Xenopus, evobrutinib and clemastine increased remyelination by a factor of 1.61 and 1.92, respectively. Evobrutinib targets Bruton's tyrosine kinase expressed by microglia, and we showed that the increase in number of myeloid cells following demyelination is due to an extravasation from nearby vessels of macrophages migrating toward the optic nerve. In contrast, clemastine is expected to antagonize muscarinic receptor 1 expressing cells of the oligodendroglial lineage. We investigated a possible synergistic effect on remyelination by adding simultaneously both molecules. In both experimental models tested no significative improvement on remyelination of co-treatment with evobrutinib plus clemastine was observed.

Discussion

While evobrutinib increased 1.59 fold the number of microglia/macrophages, in the presence of clemastine the number of innate immune cells was decreased by 0.39 fold, therefore counteracting the beneficial effect of microglia/macrophages on remyelination.

Sequelae of B-Cell Depleting Therapy: An Immunologist's Perspective

B-cell depleting therapy (BCDT) has revolutionised the treatment of B-cell malignancies and autoimmune diseases by targeting specific B-cell surface antigens, receptors, ligands, and signalling pathways. This narrative review explores the mechanisms, applications, and complications of BCDT, focusing on the therapeutic advancements since the introduction of rituximab in 1997. Various monoclonal antibodies and kinase inhibitors are examined for their roles in depleting B cells through antibody-dependent and independent mechanisms. The off-target effects, such as hypogammaglobulinemia, infections, and cytokine release syndrome, are discussed, emphasising the need for immunologists to identify and help manage these complications. The increasing prevalence of BCDT has necessitated the involvement of clinical immunologists in addressing treatment-associated immunological abnormalities, including persistent hypogammaglobulinemia and neutropenia. We highlight the importance of considering underlying inborn errors of immunity (IEI) in patients presenting with these complications. Furthermore, we discuss the impact of BCDT on other immune cell populations and the challenges in predicting and managing long-term immunological sequelae. The potential for novel BCDT agents targeting the BAFF/APRIL-TACI/BCMA axis and B-cell receptor signalling pathways to treat autoimmune disorders is also explored, underscoring the rapidly evolving landscape of B-cell targeted therapies.

Targeting Oligodendrocyte Dynamics and Remyelination: Emerging Therapies and Personalized Approaches in Multiple Sclerosis Management

Multiple sclerosis (MS) is a progressive autoimmune condition that primarily affects young people and is characterized by demyelination and neurodegeneration of the central nervous system (CNS). This in-depth review explores the complex involvement of oligodendrocytes, the primary myelin- producing cells in the CNS, in the pathophysiology of MS. It discusses the biochemical processes and signalling pathways required for oligodendrocytes to function and remain alive, as well as how they might fail and cause demyelination to occur. We investigate developing therapeutic options that target remyelination, a fundamental component of MS treatment. Remyelination approaches promote the survival and differentiation of oligodendrocyte precursor cells (OPCs), restoring myelin sheaths. This improves nerve fibre function and may prevent MS from worsening. We examine crucial parameters influencing remyelination success, such as OPC density, ageing, and signalling pathway regulation (e.g., Retinoid X receptor, LINGO-1, Notch). The review also examines existing neuroprotective and antiinflammatory medications being studied to see if they can assist oligodendrocytes in surviving and reducing the severity of MS symptoms. The review focuses on medicines that target the myelin metabolism in oligodendrocytes. Altering oligodendrocyte metabolism has been linked to reversing demyelination and improving MS patient outcomes through various mechanisms. We also explore potential breakthroughs, including innovative antisense technologies, deep brain stimulation, and the impact of gut health and exercise on MS development. The article discusses the possibility of personalized medicine in MS therapy, emphasizing the importance of specific medicines based on individual molecular profiles. The study emphasizes the need for reliable biomarkers and improved imaging tools for monitoring disease progression and therapy response. Finally, this review focuses on the importance of oligodendrocytes in MS and the potential for remyelination therapy. It also underlines the importance of continued research to develop more effective treatment regimens, taking into account the complexities of MS pathology and the different factors that influence disease progression and treatment.

An updated systematic review and meta-analysis exploring the efficacy and safety of dimethyl fumarate (DMF) for patients with multiple sclerosis (MS)

Background

Dimethyl fumarate (DMF) is increasingly used in treating multiple sclerosis (MS) with controversial results of the safety and efficacy of different DMF doses. We aimed to systematically review the literature to examine the safety and efficacy of DMF for MS patients.

Methods

We searched PubMed Medline, Cochrane, Web of Science, Scopus databases and clinicaltrials.gov up to June 2023 for the published trials evaluating the use of DMF for MS in adults. All included studies were screened and abstracted independently by two authors. Efficacy and safety outcome measures were extracted. The meta-analysis was conducted using Review Manager 5.4.

Results

10 studies including eight randomised controlled trials, one open-label and one single-arm before-after study with a total population size of 4278 patients were included. DMF group showed a statistically significant reduction in the proportion of relapses compared with the control group, (OR: 0.47, 95% CI: [0.41, 0.55], p<0.00001) with no statistical differences between 240 mg two times per day and three times a day doses. Furthermore, the DMF group had a significant reduction in Gd-enhanced lesions compared with control (MD=-1.53, 95% CI: [-1.91 to -1.41], p<0.00001). Our results showed a non-significant difference in adverse events that led to discontinuation of the study with an OR of 1.29 (95% CI: [0.98, 1.71], p value=0.07).

Discussion

DMF had significant efficacy and safety compared with the control, with no difference between the DMF doses. More studies with large sample sizes and longer follow-ups are needed to detect long-term safety and efficacy.

The essential roles of memory B cells in the pathogenesis of systemic lupus erythematosus

Emerging evidence indicates that memory B cells are dysfunctional in systemic lupus erythematosus (SLE). They are hyporesponsive to signalling through the B cell receptor (BCR) but retain responsiveness to Toll-like receptor (TLR) and type I interferon signalling, as well as to T cell-mediated activation via CD40-CD154. Chronic exposure to immune complexes of ribonucleoprotein (RNP)-specific autoantibodies and TLR-engaging or BCR-engaging cargo is likely to contribute to this partially anergic phenotype. TLR7 or TLR8 signalling and the resulting production of type I interferon, as well as the sustained activation by bystander T cells, fuel a positive feedforward loop in memory B cells that can evade negative selection and permit preferential expansion of anti-RNP autoantibodies. Clinical trials of autologous stem cell transplantation or of B cell-targeted monoclonal antibodies and chimeric antigen receptor (CAR) T cells have correlated replenishment of the memory B cell population with relapse of SLE. Moreover, the BCR hyporesponsiveness of memory B cells might explain the failure of non-depleting B cell-targeting approaches in SLE, including BTK inhibitors and anti-CD22 monoclonal antibodies. Thus, targeting of dysfunctional memory B cells might prove effective in SLE, while also avoiding the adverse events of broad-spectrum targeting of B cell and plasma cell subsets that are not directly involved in disease pathogenesis.

Safety, pharmacokinetics, and pharmacodynamics of sofnobrutinib, a novel non-covalent BTK inhibitor, in healthy subjects: First-in-human phase I study

Bruton's tyrosine kinase (BTK) is a potential therapeutic target for allergic and autoimmune diseases. This first-in-human phase I study evaluated safety, pharmacokinetic, and pharmacodynamic profiles of sofnobrutinib (formerly AS-0871), a highly selective, orally available, non-covalent BTK inhibitor, in healthy adult subjects. Single ascending doses (SAD; 5-900 mg) and multiple ascending doses (MAD; 50-300 mg twice daily [b.i.d.] for 14 days [morning dose only on Day 14]) of sofnobrutinib were tested. In the entire study, all adverse events (AEs) were mild or moderate, and no apparent dose-proportional trend in severity or frequency was observed. No serious treatment-emergent AEs, cardiac arrythmias, or bleeding-related AEs were reported. In the SAD part, sofnobrutinib exhibited approximately dose-dependent systemic exposures up to 900 mg with rapid absorption (median time to maximum concentration of 2.50-4.00 h) and gradual decline (mean half-lives of 3.7-9.0 h). In the MAD part, sofnobrutinib showed low accumulation after multiple dosing (mean accumulation ratios of ≤1.54) and reached a steady state on ≤Day 7. Single dosing of sofnobrutinib rapidly and dose-dependently suppressed basophil and B-cell activations in ex vivo whole blood assays. Multiple dosing of sofnobrutinib achieved 50.8%-79.4%, 67.6%-93.6%, and 90.1%-98.0% inhibition of basophil activation during the dosing interval of 50, 150, and 300 mg b.i.d., respectively. Based on pharmacokinetic-pharmacodynamic analysis, half-maximal inhibitory concentration (IC50) of sofnobrutinib for basophil activation was 54.06 and 57.01 ng/mL in the SAD and MAD parts, respectively. Similarly, IC50 for B-cell activation was 187.21 ng/mL. These data support further investigation of sofnobrutinib in allergic and autoimmune diseases.

Safety and efficacy of evobrutinib in relapsing multiple sclerosis (evolutionRMS1 and evolutionRMS2): two multicentre, randomised, double-blind, active-controlled, phase 3 trials

BACKGROUND

Evobrutinib, a Bruton's tyrosine kinase (BTK) inhibitor, has shown preliminary efficacy in people with relapsing multiple sclerosis in a phase 2 trial. Here, we aimed to compare the safety and efficacy of evobrutinib with the active comparator teriflunomide in people with relapsing multiple sclerosis.

METHODS

EvolutionRMS1 and evolutionRMS2 were two multicentre, randomised, double-blind, double-dummy, active-controlled, phase 3 trials conducted at 701 multiple sclerosis centres and neurology clinics in 52 countries. Adults aged 18-55 years with relapsing multiple sclerosis (Expanded Disability Status Scale [EDSS] score of 0·0-5·5) were included. Participants were randomly assigned (1:1) using a central interactive web response system to receive either evobrutinib (45 mg twice per day with placebo once per day) or teriflunomide (14 mg once per day with placebo twice per day), all taken orally and in an unfasted state, with randomisation stratified by geographical region and baseline EDSS. All study staff and participants were masked to the study interventions. The primary endpoint for each study was annualised relapse rate based on adjudicated qualified relapses up to 156 weeks, assessed in the full analysis set (defined as all randomly assigned participants) with a negative binomial model. These studies are registered with ClinicalTrials.gov (NCT04338022 for evolutionRMS1 and NCT04338061 for evolutionRMS2, both are terminated).

FINDINGS

The primary analysis was done using data for 2290 randomly assigned participants collected from June 12, 2020, to Oct 2, 2023. 1124 participants were included in the full analysis set in evolutionRMS1 (560 in the evobrutinib group and 564 in the teriflunomide group) and 1166 in evolutionRMS2 (583 in each group). 751 (66·8%) participants were female and 373 (33·1%) were male in evolutionRMS1, whereas 783 (67·2%) were female and 383 (32·8%) were male in evolutionRMS2. Annualised relapse rate was 0·15 (95% CI 0·12-0·18 with evobrutinib vs 0·14 [0·11-0·18] with teriflunomide (adjusted RR 1·02 [0·75-1·39]; p=0·55) in evolutionRMS1 and 0·11 (0·09-0·13 vs 0·11 [0·09-0·13]; adjusted RR 1·00 [0·74-1·35]; p=0·51) in evolutionRMS2. The pooled proportion of participants with any treatment-emergent adverse event (TEAE) was similar between treatment groups (976 [85·6%] of 1140 with evobrutinib vs 999 [87·2%] of 1146 with teriflunomide). The most frequently reported TEAEs were COVID-19 (223 [19·6%] with evobrutinib vs 223 [19·5%] with teriflunomide), alanine aminotransferase increased (173 [15·2%] vs 204 [17·8%]), aspartate aminotransferase increased (110 [9·6%] vs 131 [11·4%]), and headache (175 [15·4%] vs 176 [15·4%]). Serious TEAE incidence rates were higher with evobrutinib than teriflunomide (86 [7·5%] vs 64 [5·6%]). Liver enzyme elevations at least 5 × upper limit of normal were more common with evobrutinib than with teriflunomide, particularly in the first 12 weeks (55 [5·0%] vs nine [<1%]). Three people who received evobrutinib and one who received teriflunomide met the biochemical definition of Hy's law; all cases resolved after discontinuation of treatment. There were two deaths (one in each group), neither related to study treatment.

INTERPRETATION

The efficacy of evobrutinib was not superior to that of teriflunomide. Together, efficacy and liver-related safety findings do not support the use of evobrutinib in people with relapsing multiple sclerosis.

FUNDING

Merck.

Cortical Lesions as an Early Hallmark of Multiple Sclerosis: Visualization by 7 T MRI

OBJECTIVES

Compelling evidence indicates a significant involvement of cortical lesions in the progressive phase of multiple sclerosis (MS), significantly contributing to late-stage disability. Despite the promise of ultra-high-field magnetic resonance imaging (MRI) in detecting cortical lesions, current evidence falls short in providing insights into the existence of such lesions during the early stages of MS or their underlying cause. This study delineated, at the early stage of MS, (1) the prevalence and spatial distribution of cortical lesions identified by 7 T MRI, (2) their relationship with white matter lesions, and (3) their clinical implications.

MATERIALS AND METHODS

Twenty individuals with early-stage relapsing-remitting MS (disease duration <1 year) underwent a 7 T MRI session involving T1-weighted MP2RAGE, T2*-weighted multiGRE, and T2-weighted FLAIR sequences for cortical and white matter segmentation. Disability assessments included the Expanded Disability Status Scale, the Multiple Sclerosis Functional Composite, and an extensive evaluation of cognitive function.

RESULTS

Cortical lesions were detected in 15 of 20 patients (75%). MP2RAGE revealed a total of 190 intracortical lesions (median, 4 lesions/case [range, 0-44]) and 216 leukocortical lesions (median, 2 lesions/case [range, 0-75]). Although the number of white matter lesions correlated with the total number of leukocortical lesions ( r = 0.91, P < 0.001), no correlation was observed between the number of white matter or leukocortical lesions and the number of intracortical lesions. Furthermore, the number of leukocortical lesions but not intracortical or white-matter lesions was significantly correlated with cognitive impairment ( r = 0.63, P = 0.04, corrected for multiple comparisons).

CONCLUSIONS

This study highlights the notable prevalence of cortical lesions at the early stage of MS identified by 7 T MRI. There may be a potential divergence in the underlying pathophysiological mechanisms driving distinct lesion types, notably between intracortical lesions and white matter/leukocortical lesions. Moreover, during the early disease phase, leukocortical lesions more effectively accounted for cognitive deficits.

The Immunomodulatory Mechanisms of BTK Inhibition in CLL and Beyond

Bruton's tyrosine kinase (BTK), a cytoplasmic tyrosine kinase, plays a pivotal role in B cell biology and function. As an essential component of the B cell receptor (BCR) signaling pathway, BTK is expressed not only in B cells but also in myeloid cells, including monocytes/macrophages, dendritic cells, neutrophils, and mast cells. BTK inhibitors (BTKis) have revolutionized the treatment of chronic lymphocytic leukemia (CLL) and other B cell malignancies. Besides their well-characterized role in inhibiting BCR signaling, BTKis also exert significant immunological influences outside the tumor cell that extend their therapeutic potential and impact on the immune system in different ways. This work elucidates the immunomodulatory mechanisms associated with BTK inhibition, focusing on CLL and other clinical contexts. We discuss how BTK inhibition affects various immune cells, including B cells, T cells, and macrophages. The effects of BTKis on the profiles of cytokines, also fundamental parts of the tumor microenvironment (TME), are summarized here as well. This review also appraises the implications of these immunomodulatory actions in the management of autoimmune diseases and infections. Summarizing the dual role of BTK inhibition in modulating malignant lymphocyte and immune cell functions, this paper highlights the broader potential clinical use of compounds targeting BTK.

B-cell depletion in autoimmune diseases

B cells have a pivotal function in the pathogenesis of autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis and systemic lupus erythematosus. In autoimmune disease, B cells orchestrate antigen presentation, cytokine production and autoantibody production, the latter via their differentiation into antibody-secreting plasmablasts and plasma cells. This article addresses the current therapeutic strategies to deplete B cells in order to ameliorate or potentially even cure autoimmune disease. It addresses the main target antigens in the B-cell lineage that are used for therapeutic approaches. Furthermore, it summarises the current evidence for successful treatment of autoimmune disease with monoclonal antibodies targeting B cells and the limitations and challenges of these approaches. Finally, the concept of deep B-cell depletion and immunological reset by chimeric antigen receptor T cells is discussed, as well as the lessons from this approach for better understanding the role of B cells in autoimmune disease.

Bruton's tyrosine kinase inhibition suppresses pathological retinal angiogenesis

BACKGROUND AND PURPOSE

Pathological retinal angiogenesis is a typical manifestation of vision-threatening ocular diseases. Many patients exhibit poor response or resistance to anti-vascular endothelial growth factor (VEGF) agents. Bruton's tyrosine kinase (BTK) controls the proliferation and function of immune cells. Therefore, we examined the anti-inflammatory and anti-angiogenic effects of BTK inhibition on retinal angiogenesis.

EXPERIMENTAL APPROACH

Retinal neovascularisation and vascular leakage in oxygen-induced retinopathy in C57/BL6J mice were assessed by whole-mount retinal immunofluorescence. PLX5622 was used to deplete microglia and Rag1-knockout mice were used to test the contribution of lymphocytes to the effects of BTK inhibition. The cytokines, activation markers, inflammatory and immune-regulatory activities of retinal microglia/macrophages were detected using qRT-PCR and immunofluorescence. NLRP3 was detected by western blotting, and the effects of BTK inhibition on the co-culture of microglia and human retinal microvascular endothelial cells (HRMECs) were examined.

KEY RESULTS

BTK inhibition suppressed pathological angiogenesis and vascular leakage, and significantly reduced retinal inflammation, which involved microglia/macrophages but not lymphocytes. BTK inhibition increased anti-inflammatory factors and reduced pro-inflammatory cytokines that resulted from NLRP3 inflammasome activation. BTK inhibition suppressed the inflammatory activity of microglia/macrophages, and acted synergistically with anti-VEGF without retinal toxicity. Moreover, the supernatant of microglia incubated with BTK-inhibitor reduced the proliferation, tube formation and sprouting of HRMECs.

CONCLUSION AND IMPLICATIONS

BTK inhibition suppressed retinal neovascularisation and vascular leakage by modulating the inflammatory activity of microglia and macrophages. Our study suggests BTK inhibition as a novel and promising approach for alleviating pathological retinal angiogenesis.

Lymphocytes in autoimmune encephalitis: Pathogenesis and therapeutic target

Autoimmune encephalitis (AE) is an inflammatory disease of the central nervous system characterized by the production of various autoimmune antibodies targeting neuronal proteins. The pathogenesis of AE remains elusive. Accumulating evidence suggests that lymphocytes, particularly B and T lymphocytes, play an integral role in the development of AE. In the last two decades, autoimmune neural antibodies have taken center stage in diagnosing AE. Recently, increasing evidence has highlighted the importance of T lymphocytes in the onset of AE. CD4+ T cells are thought to influence disease progression by secreting associated cytokines, whereas CD8+ T cells exert a cytotoxic role, causing irreversible damage to neurons mainly in patients with paraneoplastic AE. Conventionally, the first-line treatments for AE include intravenous steroids, intravenous immunoglobulin, and plasma exchange to remove pathogenic autoantibodies. However, a minority of patients are insensitive to conventional first-line treatment protocols and suffer from disease relapse, a condition referred to as refractory AE. In recent years, new treatments, such as rituximab or CAAR-T, which target pathogenic lymphocytes in patients with AE, have offered new therapeutic options for refractory AE. This review aims to describe the current knowledge about the function of B and T lymphocytes in the pathophysiology of AE and to summarize and update the immunotherapy options for treating this disease.

Targeting Bruton's tyrosine kinase (BTK) as a signaling pathway in immune-mediated diseases: from molecular mechanisms to leading treatments

Bruton's tyrosine kinase (BTK), a nonreceptor tyrosine kinase, plays a remarkable role in the transmission and amplification of extracellular signals to intracellular signaling pathways. Various types of cells use the BTK pathway to communicate, including hematopoietic cells particularly B cells and T cells. The BTK pathway plays a role in controlling the proliferation, survival, and functions of B cells as well as other myeloid cells. First, second, and third-generation BTK inhibitors are currently being evaluated for the treatment of immune-mediated diseases in addition to B cell malignancies. In this article, the available evidence on the action mechanisms of BTK inhibitors is reviewed. Then, the most recent data obtained from preclinical studies and ongoing clinical trials for the treatment of autoimmune diseases, such as pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid, systemic lupus erythematosus, Sjögren's disease, rheumatoid arthritis, systemic sclerosis, multiple sclerosis, myasthenia gravis, and inflammatory diseases such as psoriasis, chronic spontaneous urticaria, atopic dermatitis, and asthma are discussed. In addition, adverse effects and complications associated with BTK inhibitors as well as factors predisposing patients to BTK inhibitors complications are discussed.

Tyrosine kinases: multifaceted receptors at the intersection of several neurodegenerative disease-associated processes

Tyrosine kinases (TKs) are catalytic enzymes activated by auto-phosphorylation that function by phosphorylating tyrosine residues on downstream substrates. Tyrosine kinase inhibitors (TKIs) have been heavily exploited as cancer therapeutics, primarily due to their role in autophagy, blood vessel remodeling and inflammation. This suggests tyrosine kinase inhibition as an appealing therapeutic target for exploiting convergent mechanisms across several neurodegenerative disease (NDD) pathologies. The overlapping mechanisms of action between neurodegeneration and cancer suggest that TKIs may play a pivotal role in attenuating neurodegenerative processes, including degradation of misfolded or toxic proteins, reduction of inflammation and prevention of fibrotic events of blood vessels in the brain. In this review, we will discuss the distinct roles that select TKs have been shown to play in various disease-associated processes, as well as identify TKs that have been explored as targets for therapeutic intervention and associated pharmacological agents being investigated as treatments for NDDs.

Therapeutic Approach to Autoimmune Neurologic Disorders

OBJECTIVE

Autoimmune neurologic disorders encompass a broad category of diseases characterized by immune system attack of the central, peripheral, or autonomic nervous systems. This article provides information on both acute and maintenance immunotherapy used to treat autoimmune neurologic disorders as well as a review of symptomatic management and special considerations when caring for patients with these diseases.

LATEST DEVELOPMENTS

Over the past 20 years, more than 50 antibodies have been identified and associated with autoimmune neurologic disorders. Although advances in diagnostic testing have allowed for more rapid diagnosis, the therapeutic approach to these disorders has largely continued to rely on expert opinion, case series, and case reports. With US Food and Drug Administration (FDA) approval of biologic agents to treat neuromyelitis optica spectrum disorder (NMOSD) and myasthenia gravis as well as ongoing clinical trials for the treatment of autoimmune encephalitis, the landscape of immunotherapy options continues to expand. Consideration of the unique pathogenesis of individual autoimmune neurologic disorders as well as the mechanism of action of the diverse range of treatment options can help guide treatment decisions today while evidence from clinical trials informs new therapeutics in the future.

ESSENTIAL POINTS

Recognizing patients who have a clinical history and examination findings concerning for autoimmune neurologic disorders and conducting a thorough and directed imaging and laboratory evaluation aimed at ruling out mimics, identifying specific autoimmune syndromes, and screening for factors that may have an impact on immunotherapy choices early in the clinical course are essential to providing optimal care for these patients. Providers must consider immunotherapy, symptomatic treatment, and a multidisciplinary approach that addresses each patient's unique needs when treating patients with autoimmune neurologic disorders.

Bruton tyrosine kinase inhibitor-related atrial fibrillation and its implications in the treatment of B-cell lymphoma

Adverse events of atrial fibrillation (AF) have been commonly reported in lymphoma patients in treating Bruton's tyrosine kinase inhibitors (BTKi). The incidence rate of AF can vary depending on the specific types of BTKi and the patient population. Totally 45 published studies have revealed that the overall incidence rate of AF is 5% (95% CI 4%-7%). By performing a subtype single-rate analysis, the second-generation BTKi shows a lower AF incidence rate and lower cardiovascular toxicity. In the subtype single-rate analysis, we conclude the different AF incidence rates of Ibrutinib (10%, 95% CI 7%-13%), Acalabrutinib (4%, 95% CI 1%-6%), Orelabrutinib (0%, 95% CI 0%-1%), and Zanubrutinib (0%, 95% CI 0%-1%). The comprehensive analysis of AF inspires us to better predict and manage AF and other cardiovascular events in treating lymphoma. Meticulous evaluation, collaboration between cardiologists and hematologists, and discovery of new biomarkers are essential for its management.

Novel and Emerging Treatments to Target Pathophysiological Mechanisms in Various Phenotypes of Multiple Sclerosis

The objective is to comprehensively review novel pharmacotherapies used in multiple sclerosis (MS) and the possibilities they may carry for therapeutic improvement. Specifically, we discuss pathophysiological mechanisms worth targeting in MS, ranging from well known targets, such as autoinflammation and demyelination, to more novel and advanced targets, such as neuroaxonal damage and repair. To set the stage, a brief overview of clinical MS phenotypes is provided, followed by a comprehensive recapitulation of both clinical and paraclinical outcomes available to assess the effectiveness of treatments in achieving these targets. Finally, we discuss various promising novel and emerging treatments, including their respective hypothesized modes of action and currently available evidence from clinical trials. SIGNIFICANCE STATEMENT: This comprehensive review discusses pathophysiological mechanisms worth targeting in multiple sclerosis. Various promising novel and emerging treatments, including their respective hypothesized modes of action and currently available evidence from clinical trials, are reviewed.

Cancer and multiple sclerosis: 2023 recommendations from the French Multiple Sclerosis Society

BACKGROUND

Epidemiological data reveal that 45% of persons with multiple sclerosis (PwMS) in France are more than 50 years. This population more than 50 is more susceptible to cancer, and this risk may be increased by frequent use of immunosuppressive drugs. Consequently, concerns have arisen about the potential increased risk of cancer in PwMS and how patients should be screened and managed in terms of cancer risk.

OBJECTIVE

To develop evidence-based recommendations to manage the coexistence of cancer and multiple sclerosis (MS).

METHODS

The French Group for Recommendations in MS collected articles from PubMed and university databases covering the period January 1975 through June 2022. The RAND/UCLA method was employed to achieve formal consensus. MS experts comprehensively reviewed the full-text articles and developed the initial recommendations. A group of multidisciplinary health care specialists then validated the final proposal.

RESULTS

Five key questions were addressed, encompassing various topics such as cancer screening before or after initiating a disease-modifying therapy (DMT), appropriate management of MS in the context of cancer, recommended follow-up for cancer in patients receiving a DMT, and the potential reintroduction of a DMT after initial cancer treatment. A strong consensus was reached for all 31 recommendations.

CONCLUSION

These recommendations propose a strategic approach to managing cancer risk in PwMS.

Nanoparticle-neutrophils interactions for autoimmune regulation

Neutrophils play an essential role as 'first responders' in the immune response, necessitating many immune-modulating capabilities. Chronic, unresolved inflammation is heavily implicated in the progression and tissue-degrading effects of autoimmune disease. Neutrophils modulate disease pathogenesis by interacting with the inflammatory and autoreactive cells through effector functions, including signaling, degranulation, and neutrophil extracellular traps (NETs) release. Since the current gold standard systemic glucocorticoid administration has many drawbacks and side effects, targeting neutrophils in autoimmunity provides a new approach to developing therapeutics. Nanoparticles enable targeting of specific cell types and controlled release of a loaded drug cargo. Thus, leveraging nanoparticle properties and interactions with neutrophils provides an exciting new direction toward novel therapies for autoimmune diseases. Additionally, recent work has utilized neutrophil properties to design novel targeted particles for delivery into previously inaccessible areas. Here, we outline nanoparticle-based strategies to modulate neutrophil activity in autoimmunity, including various nanoparticle formulations and neutrophil-derived targeting.

Bruton tyrosine kinase inhibitors in multiple sclerosis: evidence and expectations

PURPOSE OF REVIEW

Despite availability of high-efficacy therapies for multiple sclerosis (MS), many patients experience significant disability worsening due to limited effects of currently available drugs on central nervous system (CNS)-compartmentalized inflammation. Bruton tyrosine kinase (BTK) is an intracellular signaling molecule involved in regulation of maturation, survival, migration, and activation of B cells and microglia, which are central players in the immunopathogenesis of progressive MS. Therefore, CNS-penetrant BTK inhibitors may better prevent disease progression by targeting immune cells on both sides of the blood-brain barrier. This review gives an overview on the preliminary results of clinical trials.

RECENT FINDINGS

Currently, the efficacy and safety of six BTK inhibitors are being evaluated in clinical trials in patients with relapsing and progressive MS. Evobrutinib, tolebrutinib and fenebrutinib have shown efficacy and safety in relapsing MS in phase 2 studies, and evobrutinib and tolebrutinib in their extension studies up to 3-5 years. However, evobrutinib failed to distinguish itself from the comparator drug teriflunomide in reduction of relapse rate (primary end point) in two phase 3 studies in relapsing MS.

SUMMARY

Inhibition of BTK has emerged as a promising therapeutic approach to target the CNS-compartmentalized inflammation. Results from phase 3 clinical trials will shed light on differences in efficacy and safety of BTK inhibitors and its potential role in the future MS landscape.

From progression to progress: The future of multiple sclerosis

Significant advances have been made in the diagnosis and treatment of multiple sclerosis in recent years yet challenges remain. The current classification of MS phenotypes according to disease activity and progression, for example, does not adequately reflect the underlying pathophysiological mechanisms that may be acting in an individual with MS at different time points. Thus, there is a need for clinicians to transition to a management approach based on the underlying pathophysiological mechanisms that drive disability in MS. A Canadian expert panel convened in January 2023 to discuss priorities for clinical discovery and scientific exploration that would help advance the field. Five key areas of focus included: identifying a mechanism-based disease classification system; developing biomarkers (imaging, fluid, digital) to identify pathologic processes; implementing a data-driven approach to integrate genetic/environmental risk factors, clinical findings, imaging and biomarker data, and patient-reported outcomes to better characterize the many factors associated with disability progression; utilizing precision-based treatment strategies to target different disease processes; and potentially preventing disease through Epstein-Barr virus (EBV) vaccination, counselling about environmental risk factors (e.g. obesity, exercise, vitamin D/sun exposure, smoking) and other measures. Many of the tools needed to meet these needs are currently available. Further work is required to validate emerging biomarkers and tailor treatment strategies to the needs of individual patients. The hope is that a more complete view of the individual's pathobiology will enable clinicians to usher in an era of truly personalized medicine, in which more informed treatment decisions throughout the disease course achieve better long-term outcomes.

Oxidative phosphorylation regulates B cell effector cytokines and promotes inflammation in multiple sclerosis

Dysregulated B cell cytokine production contributes to pathogenesis of immune-mediated diseases including multiple sclerosis (MS); however, the underlying mechanisms are poorly understood. In this study we investigated how cytokine secretion by pro-inflammatory (GM-CSF-expressing) and anti-inflammatory (IL-10-expressing) B cells is regulated. Pro-inflammatory human B cells required increased oxidative phosphorylation (OXPHOS) compared with anti-inflammatory B cells. OXPHOS reciprocally modulated pro- and anti-inflammatory B cell cytokines through regulation of adenosine triphosphate (ATP) signaling. Partial inhibition of OXPHOS or ATP-signaling including with BTK inhibition resulted in an anti-inflammatory B cell cytokine shift, reversed the B cell cytokine imbalance in patients with MS, and ameliorated neuroinflammation in a myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalitis mouse model. Our study identifies how pro- and anti-inflammatory cytokines are metabolically regulated in B cells and identifies ATP and its metabolites as a "fourth signal" that shapes B cell responses and is a potential target for restoring the B cell cytokine balance in autoimmune diseases.

Inhibitors of Bruton's tyrosine kinase as emerging therapeutic strategy in autoimmune diseases

Bruton's tyrosine kinase (BTK) is a cytoplasmic, non-receptor signal transducer, initially identified as an essential signaling molecule for B cells, with genetic mutations resulting in a disorder characterized by disturbed B cell and antibody development. Subsequent research revealed the critical role of BTK in the functionality of monocytes, macrophages and neutrophils. Various immune cells, among which B cells and neutrophils, rely on BTK activity for diverse signaling pathways downstream of multiple receptors, which makes this kinase an ideal target to treat hematological malignancies and autoimmune diseases. First-generation BTK inhibitors are already on the market to treat hematological disorders. It has been demonstrated that B cells and myeloid cells play a significant role in the pathogenesis of different autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus and primary Sjögren's syndrome. Consequently, second-generation BTK inhibitors are currently being developed to treat these disorders. Despite the acknowledged involvement of BTK in various cell types, the focus on B cells often overshadows its impact on innate immune cells. Among these cell types, neutrophils are often underestimated in the pathogenesis of autoimmune diseases. In this narrative review, the function of BTK in different immune cell subsets is discussed, after which an overview is provided of different upcoming BTK inhibitors tested for treatment of autoimmune diseases. Special attention is paid to BTK inhibition and its effect on neutrophil biology.

A review of Bruton's tyrosine kinase inhibitors in multiple sclerosis

Bruton's tyrosine kinase (BTK) inhibitors are an emerging class of therapeutics in multiple sclerosis (MS). BTK is expressed in B-cells and myeloid cells, key progenitors of which include dendritic cells, microglia and macrophages, integral effectors of MS pathogenesis, along with mast cells, establishing the relevance of BTK inhibitors to diverse autoimmune conditions. First-generation BTK inhibitors are currently utilized in the treatment of B-cell malignancies and show efficacy in B-cell modulation. B-cell depleting therapies have shown success as disease-modifying treatments (DMTs) in MS, highlighting the potential of BTK inhibitors for this indication; however, first-generation BTK inhibitors exhibit a challenging safety profile that is unsuitable for chronic use, as required for MS DMTs. A second generation of highly selective BTK inhibitors has shown efficacy in modulating MS-relevant mechanisms of pathogenesis in preclinical as well as clinical studies. Six of these BTK inhibitors are undergoing clinical development for MS, three of which are also under investigation for chronic spontaneous urticaria (CSU), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Phase II trials of selected BTK inhibitors for MS showed reductions in new gadolinium-enhancing lesions on magnetic resonance imaging scans; however, the safety profile is yet to be ascertained in chronic use. Understanding of the safety profile is developing by combining safety insights from the ongoing phase II and III trials of second-generation BTK inhibitors for MS, CSU, RA and SLE. This narrative review investigates the potential of BTK inhibitors as an MS DMT, the improved selectivity of second-generation inhibitors, comparative safety insights established thus far through clinical development programmes and proposed implications in female reproductive health and in long-term administration.

Managing multiple sclerosis in individuals aged 55 and above: a comprehensive review

Multiple Sclerosis (MS) management in individuals aged 55 and above presents unique challenges due to the complex interaction between aging, comorbidities, immunosenescence, and MS pathophysiology. This comprehensive review explores the evolving landscape of MS in older adults, including the increased incidence and prevalence of MS in this age group, the shift in disease phenotypes from relapsing-remitting to progressive forms, and the presence of multimorbidity and polypharmacy. We aim to provide an updated review of the available evidence of disease-modifying treatments (DMTs) in older patients, including the efficacy and safety of existing therapies, emerging treatments such as Bruton tyrosine kinase (BTKs) inhibitors and those targeting remyelination and neuroprotection, and the critical decisions surrounding the initiation, de-escalation, and discontinuation of DMTs. Non-pharmacologic approaches, including physical therapy, neuromodulation therapies, cognitive rehabilitation, and psychotherapy, are also examined for their role in holistic care. The importance of MS Care Units and advance care planning are explored as a cornerstone in providing patient-centric care, ensuring alignment with patient preferences in the disease trajectory. Finally, the review emphasizes the need for personalized management and continuous monitoring of MS patients, alongside advocating for inclusive study designs in clinical research to improve the management of this growing patient demographic.

Efficacy and safety results after >3.5 years of treatment with the Bruton's tyrosine kinase inhibitor evobrutinib in relapsing multiple sclerosis: Long-term follow-up of a Phase II randomised clinical trial with a cerebrospinal fluid sub-study

BACKGROUND

Evobrutinib - an oral, central nervous system (CNS)-penetrant, and highly selective Bruton's tyrosine kinase inhibitor - has shown efficacy in a 48-week, double-blind, Phase II trial in patients with relapsing MS.

OBJECTIVE

Report results of the Phase II open-label extension (OLE; up to week 192 from randomisation) and a cerebrospinal fluid (CSF) sub-study.

METHODS

In the 48-week double-blind period (DBP), patients received evobrutinib 25 mg once-daily, 75 mg once-daily, 75 mg twice-daily or placebo (switched to evobrutinib 25 mg once-daily after week 24). Patients could then enter the OLE, receiving evobrutinib 75 mg once-daily (mean (± standard deviation (SD)) duration = 50.6 weeks (±6.0)) before switching to 75 mg twice-daily.

RESULTS

Of 164 evobrutinib-treated patients who entered the OLE, 128 (78.0%) completed ⩾192 weeks of treatment. Patients receiving DBP evobrutinib 75 mg twice-daily: annualised relapse rate at week 48 (0.11 (95% confidence interval (CI) = 0.04-0.25)) was maintained with the OLE twice-daily dose up to week 192 (0.11 (0.05-0.22)); Expanded Disability Status Scale score remained stable; serum neurofilament light chain fell to levels like a non-MS population (Z-scores); T1 gadolinium-enhancing lesion numbers remained low. No new safety signals were identified. In the OLE, evobrutinib was detected in the CSF of all sub-study patients.

CONCLUSION

Long-term evobrutinib treatment was well tolerated and associated with a sustained low level of disease activity. Evobrutinib was present in CSF at concentrations similar to plasma.

Effect of Evobrutinib on Slowly Expanding Lesion Volume in Relapsing Multiple Sclerosis: A Post Hoc Analysis of a Phase 2 Trial

BACKGROUND AND OBJECTIVES

Chronic active lesions (CALs) are demyelinated multiple sclerosis (MS) lesions with ongoing microglia/macrophage activity, resulting in irreversible neuronal damage and axonal loss. Evobrutinib is a highly selective, covalent, CNS-penetrant, Bruton tyrosine kinase inhibitor. This post hoc analysis evaluated the effect of evobrutinib on slowly expanding lesion (SEL) volume, an MRI marker of CALs, assessed baseline-week 48 in a phase 2, double-blind, randomized trial (NCT02975349) in relapsing MS (RMS).

METHODS

In the 48-week, double-blind trial, adult patients received evobrutinib (25 mg once daily [QD], 75 mg QD, or 75 mg twice daily [BID]), placebo (switched to evobrutinib 25 mg QD after week 24), or open-label dimethyl fumarate (DMF) 240 mg BID. SELs were defined as slowly and consistently radially expanding areas of preexisting T2 lesions of ≥10 contiguous voxels (∼30 mm3) over time. SELs were identified by MRI and assessed by the Jacobian determinant of the nonlinear deformation from baseline to week 48. SEL volume analysis, stratified by baseline T2 lesion volume tertiles, was based on week 48/end-of-treatment status (completers/non-completers). Treatment effect was analyzed using the stratified Hodges-Lehmann estimate of shift in distribution and stratified Wilcoxon rank-sum test. Comparisons of evobrutinib and DMF vs placebo/evobrutinib 25 mg QD were made. Subgroup analyses used pooled treatment groups (evobrutinib high dose [75 mg QD/BID] vs low dose [placebo/evobrutinib 25 mg QD]).

RESULTS

The SEL analysis set included 223 patients (mean [SD] age: 42.4 [10.7] years; 69.3% female; 87.4% relapsing/remitting MS). Mean (SD) SEL volume was 2,099 (2,981.0) mm3 with evobrutinib 75 mg BID vs 2,681 (3,624.2) mm3 with placebo/evobrutinib 25 mg QD. Median number of SELs/patient ranged from 7 to 11 across treatments. SEL volume decreased with increasing evobrutinib dose vs placebo/evobrutinib 25 mg QD, and no difference with DMF vs placebo/evobrutinib 25 mg QD was noted. SEL volume significantly decreased with evobrutinib 75 mg BID vs placebo/evobrutinib 25 mg QD (-474.5 mm3 [-1,098.0 to -3.0], p = 0.047) and vs DMF (-711.6 [-1,290.0 to -149.0], p = 0.011). SEL volume was significantly reduced for evobrutinib high vs low dose within baseline Expanded Disability Status Scale ≥3.5 and longer disease duration (≥8.5 years) subgroups.

DISCUSSION

Evobrutinib reduced SEL volume in a dose-dependent manner in RMS, with a significant reduction with evobrutinib 75 mg BID. This is evident that evobrutinib affects brain lesions associated with chronic inflammation and tissue loss.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov number: NCT02975349. Submitted to ClinicalTrials.gov on November 29, 2016. First patient enrolled: March 7, 2017.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that evobrutinib reduces the volume of SELs assessed on MRI comparing baseline with week 48, in patients with RMS.

Dimethyl fumarate induces cardiac developmental toxicity in zebrafish via down-regulation of oxidative stress

Dimethyl fumarate (DMF) is an immunosuppressant commonly used to treat multiple sclerosis and other autoimmune diseases. Despite known side effects such as lymphopenia, the effect of DMF on cardiac development remains unclear. To assess this, we used zebrafish to evaluate the cardiac developmental toxicity of DMF. Our study showed that DMF reduced the survival rate of zebrafish embryos, with those exposed to 1, 1.3, and 1.6 mg/L exhibiting heart rate reduction, shortened body length, delayed yolk sac absorption, pericardial edema, increased distance from sinus venous to bulbus arteriosus, and separation of cardiomyocytes and endocardial cells at 72 hpf. Heart development-related genes showed disorder, apoptosis-related genes were up-regulated, and the oxidative stress response was down-regulated. Treatment with cysteamine ameliorated the heart development defects. Our study demonstrates that DMF induces cardiac developmental toxicity in zebrafish, possibly by down-regulating oxidative stress responses. This study provides a certain research basis for further study of DMF-induced cardiac developmental toxicity, and provides some experimental evidence for future clinical application and study of DMF.

Drugs Targeting CD20 in Multiple Sclerosis: Pharmacology, Efficacy, Safety, and Tolerability

Currently, there are four monoclonal antibodies (mAbs) that target the cluster of differentiation (CD) 20 receptor available to treat multiple sclerosis (MS): rituximab, ocrelizumab, ofatumumab, and ublituximab. B-cell depletion therapy has changed the therapeutic landscape of MS through robust efficacy on clinical manifestations and MRI lesion activity, and the currently available anti-CD20 mAb therapies for use in MS are a cornerstone of highly effective disease-modifying treatment. Ocrelizumab is currently the only therapy with regulatory approval for primary progressive MS. There are currently few data regarding the relative efficacy of these therapies, though several clinical trials are ongoing. Safety concerns applicable to this class of therapeutics relate primarily to immunogenicity and mechanism of action, and include infusion-related or injection-related reactions, development of hypogammaglobulinemia (leading to increased infection and malignancy risk), and decreased vaccine response. Exploration of alternative dose/dosing schedules might be an effective strategy for mitigating these risks. Future development of biosimilar medications might make these therapies more readily available. Although anti-CD20 mAb therapies have led to significant improvements in disease outcomes, CNS-penetrant therapies are still needed to more effectively address the compartmentalized inflammation thought to play an important role in disability progression.

Bruton's Tyrosine Kinase Inhibitors: Recent Updates

Bruton's tyrosine kinase (BTK) inhibitors have revolutionized the landscape for the treatment of hematological malignancies, solid tumors, and, recently, autoimmune disorders. The BTK receptor is expressed in several hematopoietic cells such as macrophages, neutrophils, mast cells, and osteoclasts. Similarly, the BTK receptor is involved in signaling pathways such as chemokine receptor signaling, Toll-like receptor signaling, and Fc receptor signaling. Due to their unique mechanism, these agents provide a diverse utility in a variety of disease states not limited to the field of malignant hematology and are generally well-tolerated.

Aberrant B cell receptor signaling in circulating naïve and IgA+ memory B cells from newly-diagnosed autoantibody-positive rheumatoid arthritis patients

OBJECTIVE

Altered B cell receptor (BCR) signaling has been implicated in the pathogenesis of rheumatoid arthritis (RA). Here we aimed to identify signaling aberrations in autoantibody-positive and autoantibody-negative RA patients by performing a comprehensive analysis of the BCR signaling cascade in different B cell subsets.

METHODS

We first optimized phosphoflow cytometry for an in-depth analysis of BCR signaling across immunoglobulin isotypes in healthy donors. Subsequently, we compared BCR signaling in circulating B cell subsets from treatment-naïve, newly-diagnosed autoantibody-positive RA and autoantibody-negative RA patients and healthy controls (HCs).

RESULTS

We observed subset-specific phosphorylation patterns of the BCR signalosome in circulating B cells from healthy donors. Compared with HCs, autoantibody-positive RA patients displayed enhanced responses to BCR stimulation for multiple signaling proteins, specifically in naïve and IgA+ memory B cells. Whereas in unstimulated healthy donor B cells, the phosphorylation status of individual signaling proteins showed only limited correlation, BCR stimulation enhanced the interconnectivity in phosphorylation within the BCR signalosome. However, this strong interconnectivity within the BCR signalosome in stimulated B cells from HCs was lost in RA, especially in autoantibody-positive RA patients. Finally, we observed strong correlations between SYK and BTK protein expression, and IgA and IgG anti-citrullinated protein antibody concentrations in serum from autoantibody-positive RA patients.

CONCLUSION

Collectively, the isotype-specific analysis of multiple key components of the BCR signalosome identified aberrant BCR signaling responses in treatment-naïve autoantibody-positive RA patients, particularly in naïve B cells and IgA+ memory B cells. Our findings support differential involvement of dysregulated BCR signaling in the pathogenesis of autoantibody-positive and autoantibody-negative RA.

Current knowledge on multiple sclerosis pathophysiology, disability progression assessment and treatment options, and the role of autologous hematopoietic stem cell transplantation

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that affects nearly 2.8 million people each year. MS distinguishes three main types: relapsing-remitting MS (RRMS), secondary progressive MS (SPMS) and primary progressive MS (PPMS). RRMS is the most common type, with the majority of patients eventually progressing to SPMS, in which neurological development is constant, whereas PPMS is characterized by a progressive course from disease onset. New or additional insights into the role of effector and regulatory cells of the immune and CNS systems, Epstein-Barr virus (EBV) infection, and the microbiome in the pathophysiology of MS have emerged, which may lead to the development of more targeted therapies that can halt or reverse neurodegeneration. Depending on the type and severity of the disease, various disease-modifying therapies (DMTs) are currently used for RRMS/SPMS and PPMS. As a last resort, and especially in highly active RRMS that does not respond to DMTs, autologous hematopoietic stem cell transplantation (AHSCT) is performed and has shown good results in reducing neuroinflammation. Nevertheless, the question of its potential role in preventing disability progression remains open. The aim of this review is to provide a comprehensive update on MS pathophysiology, assessment of MS disability progression and current treatments, and to examine the potential role of AHSCT in preventing disability progression.

Bruton's Tyrosine Kinase Inhibitors for Multiple Sclerosis Treatment: A New Frontier

Multiple sclerosis (MS) can cause significant disability to patients via relapse-associated worsening and progression independent of relapses. The causes of neuronal and myelin damage can include lymphocyte-mediated inflammation and microglial activation. Bruton's tyrosine kinase (BTK) is an enzyme that mediates B cell activation and the proinflammatory phenotype of microglia. Inhibiting BTK provides a novel therapeutic target for MS but also has a complicated pharmacology based on binding specificity, CNS penetration, half-life, and enzyme inhibition characteristics. Multiple agents are being studied in phase 3 trials, and each agent will have unique efficacy and safety profiles that must be considered individually.

Deciphering Drug Targets and Actions with Single-Cell and Spatial Resolution

Recent advances in chemical, molecular, and genetic approaches have provided us with an unprecedented capacity to identify drug-target interactions across the whole proteome and genome. Meanwhile, rapid developments of single-cell and spatial omics technologies are revolutionizing our understanding of the molecular architecture of biological systems. However, a significant gap remains in how we align our understanding of drug actions, traditionally based on molecular affinities, with the in vivo cellular and spatial tissue heterogeneity revealed by these newer techniques. Here, we review state-of-the-art methods for profiling drug-target interactions and emerging multiomics tools to delineate the tissue heterogeneity at single-cell resolution. Highlighting the recent technical advances enabling high-resolution, multiplexable in situ small-molecule drug imaging (clearing-assisted tissue click chemistry, or CATCH), we foresee the integration of single-cell and spatial omics platforms, data, and concepts into the future framework of defining and understanding in vivo drug-target interactions and mechanisms of actions.

Multiple sclerosis

Multiple sclerosis remains one of the most common causes of neurological disability in the young adult population (aged 18-40 years). Novel pathophysiological findings underline the importance of the interaction between genetics and environment. Improvements in diagnostic criteria, harmonised guidelines for MRI, and globalised treatment recommendations have led to more accurate diagnosis and an earlier start of effective immunomodulatory treatment than previously. Understanding and capturing the long prodromal multiple sclerosis period would further improve diagnostic abilities and thus treatment initiation, eventually improving long-term disease outcomes. The large portfolio of currently available medications paved the way for personalised therapeutic strategies that will balance safety and effectiveness. Incorporation of cognitive interventions, lifestyle recommendations, and management of non-neurological comorbidities could further improve quality of life and outcomes. Future challenges include the development of medications that successfully target the neurodegenerative aspect of the disease and creation of sensitive imaging and fluid biomarkers that can effectively predict and monitor disease changes.

The Plasticity of Immune Cell Response Complicates Dissecting the Underlying Pathology of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative autoimmune disease characterized by the destruction of the myelin sheath of the neuronal axon in the central nervous system. Many risk factors, including environmental, epigenetic, genetic, and lifestyle factors, are responsible for the development of MS. It has long been thought that only adaptive immune cells, especially autoreactive T cells, are responsible for the pathophysiology; however, recent evidence has indicated that innate immune cells are also highly involved in disease initiation and progression. Here, we compile the available data regarding the role immune cells play in MS, drawn from both human and animal research. While T and B lymphocytes, chiefly enhance MS pathology, regulatory T cells (Tregs) may serve a more protective role, as can B cells, depending on context and location. Cells chiefly involved in innate immunity, including macrophages, microglia, astrocytes, dendritic cells, natural killer (NK) cells, eosinophils, and mast cells, play varied roles. In addition, there is evidence regarding the involvement of innate-like immune cells, such as γδ T cells, NKT cells, MAIT cells, and innate-like B cells as crucial contributors to MS pathophysiology. It is unclear which of these cell subsets are involved in the onset or progression of disease or in protective mechanisms due to their plastic nature, which can change their properties and functions depending on microenvironmental exposure and the response of neural networks in damage control. This highlights the need for a multipronged approach, combining stringently designed clinical data with carefully controlled in vitro and in vivo research findings, to identify the underlying mechanisms so that more effective therapeutics can be developed.

Unraveling the Role of the Glycogen Synthase Kinase-3β, Bruton's Tyrosine Kinase, and Sphingosine 1 Phosphate Pathways in Multiple Sclerosis

Inflammation, demyelination, and neurodegeneration are symptoms of the central nervous system (CNS) condition known as Multiple sclerosis (MS). Due to its crucial function in controlling immune cell activation and inflammation, the glycogen synthase kinase-3β (GSK- 3β), Bruton's tyrosine kinase (BTK), and Sphingosine 1 phosphate (S1P) signaling pathway have become a viable target for the therapy of MS. The GSK-3β signaling system, which controls several biological target processes, including cell survival, proliferation, and inflammation, depends on the GSK-3β enzyme. In MS animal models and human studies, GSK-3β inhibition has been demonstrated to lessen demyelination and inflammation. Clinical research on MS has demonstrated that BTK inhibitors decrease inflammation and disease activity by preventing B cell activation and the subsequent release of cytokines. Clinical investigations for MS have demonstrated that S1P modulators, such as fingolimod, lower disease activity and inflammation by limiting immune cell migration to the central nervous system and preventing cytokine production. The GSK-3β /BTK/S1P signaling pathway in MS is the subject of this paper's summary and discussion of prospective treatment targets.

Disease Modifying Strategies in Multiple Sclerosis: New Rays of Hope to Combat Disability?

Multiple sclerosis (MS) is the most prevalent chronic autoimmune inflammatory- demyelinating disorder of the central nervous system (CNS). It usually begins in young adulthood, mainly between the second and fourth decades of life. Usually, the clinical course is characterized by the involvement of multiple CNS functional systems and by different, often overlapping phenotypes. In the last decades, remarkable results have been achieved in the treatment of MS, particularly in the relapsing- remitting (RRMS) form, thus improving the long-term outcome for many patients. As deeper knowledge of MS pathogenesis and respective molecular targets keeps growing, nowadays, several lines of disease-modifying treatments (DMT) are available, an impressive change compared to the relative poverty of options available in the past. Current MS management by DMTs is aimed at reducing relapse frequency, ameliorating symptoms, and preventing clinical disability and progression. Notwithstanding the relevant increase in pharmacological options for the management of RRMS, research is now increasingly pointing to identify new molecules with high efficacy, particularly in progressive forms. Hence, future efforts should be concentrated on achieving a more extensive, if not exhaustive, understanding of the pathogenetic mechanisms underlying this phase of the disease in order to characterize novel molecules for therapeutic intervention. The purpose of this review is to provide a compact overview of the numerous currently approved treatments and future innovative approaches, including neuroprotective treatments as anti-LINGO-1 monoclonal antibody and cell therapies, for effective and safe management of MS, potentially leading to a cure for this disease.

Inflammatory Demyelinating Diseases of the Central Nervous System

Over the past decades, a large number of immunomodulatory or immunosuppressive treatments have been approved to treat central nervous system (CNS) demyelinating disorders such as multiple sclerosis (MS). Owing to the heterogeneity of patients with CNS demyelinating diseases, there is no clinical treatment that can adequately control all disease subtypes. Although significant progress has been made for relapsing-remitting MS, effective management of the progressive phase of MS has not yet been achieved. This is at least in part caused by our incomplete understanding of the mechanisms driving disease progression, despite our increasing knowledge regarding the underlying cellular and molecular mechanisms. Here, we summarized our current knowledge regarding the mechanisms of CNS demyelinating disorders and their animal models to identify open questions and challenges for existing concepts. We also discussed potential strategies for the future design of immune therapies to treat CNS demyelinating disorders.