Efficacy and Safety of Masitinib in Progressive Forms of Multiple Sclerosis: A Randomized, Phase 3, Clinical Trial

Disease-modifying strategies: Targeting protein kinases in multiple sclerosis and other autoimmune disorders

A wide variety of immunomodulatory therapies are already available for the treatment of multiple sclerosis (MS). Through fundamental insights from basic research with a gain of knowledge in the pathological processes underlying MS, the exploration of additional medical compounds within clinical trials has been ignited. Emerging novel medications with innovative mechanisms of action are being introduced. Those mechanisms of action include a broad therapeutic spectrum of substances targeting various protein kinases, some of which could also be used for the treatment of other autoimmune-mediated diseases. The advancement of new compounds could therefore enable a more personalized approach in treating MS, taking into consideration patients' co-existing autoimmune-mediated diseases. In this review, we discuss potential compounds targeting protein kinases, currently under investigation in clinical trials for various autoimmune diseases that could become viable treatment options for MS and comorbid autoimmune conditions in the future.

Neurodegeneration and demyelination in multiple sclerosis

Progressive multiple sclerosis (PMS) is an immune-initiated neurodegenerative condition that lacks effective therapies. Although peripheral immune infiltration is a hallmark of relapsing-remitting MS (RRMS), PMS is associated with chronic, tissue-restricted inflammation and disease-associated reactive glial states. The effector functions of disease-associated microglia, astrocytes, and oligodendrocyte lineage cells are beginning to be defined, and recent studies have made significant progress in uncovering their pathologic implications. In this review, we discuss the immune-glia interactions that underlie demyelination, failed remyelination, and neurodegeneration with a focus on PMS. We highlight the common and divergent immune mechanisms by which glial cells acquire disease-associated phenotypes. Finally, we discuss recent advances that have revealed promising novel therapeutic targets for the treatment of PMS and other neurodegenerative diseases.

c-KIT inhibitors reduce pathology and improve behavior in the Tg(SwDI) model of Alzheimer's disease

Treatments for Alzheimer's disease have primarily focused on removing brain amyloid plaques to improve cognitive outcomes in patients. We developed small compounds, known as BK40143 and BK40197, and we hypothesize that these drugs alleviate microglial-mediated neuroinflammation and induce autophagic clearance of neurotoxic proteins to improve behavior in models of neurodegeneration. Specificity binding assays of BK40143 and BK40197 showed primary binding to c-KIT/Platelet Derived Growth Factor Receptors (PDGFR)α/β, whereas BK40197 also differentially binds to FYVE finger-containing phosphoinositide kinase (PIKFYVE). Both compounds penetrate the CNS, and treatment with these drugs inhibited the maturation of peripheral mast cells in transgenic mice, correlating with cognitive improvements on measures of memory and anxiety. In the brain, microglial activation was profoundly attenuated and amyloid-beta and tau were reduced via autophagy. Multi-kinase inhibition, including c-KIT, exerts multifunctional effects to reduce neurodegenerative pathology via autophagy and microglial activity and may represent a potential therapeutic option for neurodegeneration.

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.

Taming the storm: potential anti-inflammatory compounds targeting SARS-CoV-2 MPro

In severe COVID-19 cases, an exacerbated inflammatory response triggers a cytokine storm that can worsen the prognosis. Compounds with both antiviral and anti-inflammatory activities show promise as candidates for COVID-19 therapy, as they potentially act against the SARS-CoV-2 infection regardless of the disease stage. One of the most attractive drug targets among coronaviruses is the main protease (MPro). This enzyme is crucial for cleaving polyproteins into non-structural proteins required for viral replication. The aim of this review was to identify SARS-CoV-2 MPro inhibitors with both antiviral and anti-inflammatory properties. The interactions of the compounds within the SARS-CoV-2 MPro binding site were analyzed through molecular docking when data from crystallographic structures were unavailable. 18 compounds were selected and classified into five different superclasses. Five of them exhibit high potency against MPro: GC-376, baicalein, naringenin, heparin, and carmofur, with IC50 values below 0.2 μM. The MPro inhibitors selected have the potential to alleviate lung edema and decrease cytokine release. These molecules mainly target three critical inflammatory pathways: NF-κB, JAK/STAT, and MAPK, all previously associated with COVID-19 pathogenesis. The structures of the compounds occupy the S1/S2 substrate binding subsite of the MPro. They interact with residues from the catalytic dyad (His41 and Cys145) and/or with the oxyanion hole (Gly143, Ser144, and Cys145), which are pivotal for substrate recognition. The MPro SARS-CoV-2 inhibitors with potential anti-inflammatory activities present here could be optimized for maximum efficacy and safety and be explored as potential treatment of both mild and severe COVID-19.

Safety of masitinib in patients with neurodegenerative diseases: a meta-analysis of randomized controlled trials

OBJECTIVES

This meta-analysis aimed to examine the safety of masitinib in patients with neurodegenerative diseases.

METHODS

We considered randomized controlled trials (RCTs) comparing different doses of masitinib versus placebo. We performed our analysis using the R (v.4.3.0) programming language and the incidence of adverse events was pooled using risk ratio (RR) and 95% confidence interval (CI).

RESULTS

We included five RCTs, focusing on multiple sclerosis (MS), Alzheimer's disease (AD), and amyotrophic lateral sclerosis. The meta-analysis revealed a significantly higher incidence of adverse events in the masitinib group compared to the control group, regardless of adverse event grade and masitinib dose (RR = 1.12, 95% CI [1.07 to 1.17], P < 0.01). Adverse events categorized as severe, non-fatal serious, leading to dose reduction, and leading to permanent discontinuation also showed a higher incidence in the masitinib group (P ≤ 0.01). Subgroup analysis for AD and MS supported these findings. The pooled incidence of adverse events, regardless of their grade, was higher in the masitinib group for both the 3 mg/kg/d dose (RR = 1.13, P = 0.01) and the 4.5 mg/kg/d dose (RR = 1.11, P < 0.01). However, there was no significant difference between masitinib 3 mg/kg/d dose and placebo regarding severe and non-fatal serious adverse events for the.

CONCLUSION

Masitinib use in neurodegenerative diseases presents safety concerns that may impact patients' quality of life and require management. Further research is recommended to determine the optimal dose with minimal safety concerns in this patient population.

Drug repurposing for neurodegenerative diseases

Neurodegenerative diseases (NDDs) are neuronal problems that include the brain and spinal cord and result in loss of sensory and motor dysfunction. Common NDDs include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Multiple Sclerosis (MS), and Amyotrophic Lateral Sclerosis (ALS) etc. The occurrence of these diseases increases with age and is one of the challenging problems among elderly people. Though, several scientific research has demonstrated the key pathologies associated with NDDs still the underlying mechanisms and molecular details are not well understood and need to be explored and this poses a lack of effective treatments for NDDs. Several lines of evidence have shown that NDDs have a high prevalence and affect more than a billion individuals globally but still, researchers need to work forward in identifying the best therapeutic target for NDDs. Thus, several researchers are working in the directions to find potential therapeutic targets to alter the disease pathology and treat the diseases. Several steps have been taken to identify the early detection of the disease and drug repurposing for effective treatment of NDDs. Moreover, it is logical that current medications are being evaluated for their efficacy in treating such disorders; therefore, drug repurposing would be an efficient, safe, and cost-effective way in finding out better medication. In the current manuscript we discussed the utilization of drugs that have been repurposed for the treatment of AD, PD, HD, MS, and ALS.

Recent advances in the treatment of primary and secondary progressive Multiple Sclerosis

BACKGROUND

The article highlights upcoming potential treatments, which target different phases of inflammation and offer remyelinating strategies as well as direct and indirect neuroprotective and oligodendrocyte protective effects, providing a hopeful outlook for patients with primary and secondary progressive multiple sclerosis (PPMS and SPMS).

OBJECTIVES

The review aims to identify potential treatments and ongoing clinical trials for PPMS and SPMS, and compare their mechanisms of action, efficacy, and side effects with current treatments.

METHODS

We reviewed ongoing clinical trials for PPMS and SPMS on the NIH website, as well as articles from PubMed, Embase, and clinicaltrails.gov since 2010.

RESULTS

BTKIs like, tolebrutinib, and fenebrutinib are being explored as potential PMS treatments. Vidofludimus calcium, an orally available treatment, has shown a reduction of active and new MRI lesions. Other treatments like simvastatin, N-acetylcysteine (NAC), and alpha-lipoic acid are being explored for their antioxidant properties. AHSCT and mesenchymal stem cell therapy are experimental options for younger patients with high inflammatory activity.

CONCLUSIONS

SPMS and PPMS are being studied for new treatments and future trials should consider combination therapies targeting inflammation, demyelination, and neuronal death, as the pathogenesis of PMS involves complex factors.

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.

Masitinib as a neuroprotective agent: a scoping review of preclinical and clinical evidence

OBJECTIVES

Masitinib, originally developed as a tyrosine kinase inhibitor for cancer treatment, has shown potential neuroprotective effects in various neurological disorders by modulating key pathways implicated in neurodegeneration. This scoping review aimed to summarize the current evidence of masitinib's neuroprotective activities from preclinical to clinical studies.

METHODS

This scoping review was conducted following the guidelines described by Arksey and O'Malley and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria covered all original studies reporting on the neuroprotective effects of masitinib, including clinical studies, animal studies, and in vitro studies.

RESULTS

A total of 16 studies met the inclusion criteria and were included in the review. These comprised five randomized controlled trials (RCTs), one post-hoc analysis study, one case report, and nine animal studies. The RCTs focused on Alzheimer's disease (two studies), multiple sclerosis (two studies), and amyotrophic lateral sclerosis (one study). Across all included studies, masitinib consistently demonstrated neuroprotective properties. However, the majority of RCTs reported concerns regarding the safety profile of masitinib. Preclinical studies revealed the neuroprotective mechanisms of masitinib, which include inhibition of certain kinases interfering with cell proliferation and survival, reduction of neuroinflammation, and exhibition of antioxidant activity.

CONCLUSION

The current evidence suggests a promising therapeutic benefit of masitinib in neurodegenerative diseases. However, further research is necessary to validate and expand upon these findings, particularly regarding the precise mechanisms through which masitinib exerts its therapeutic effects. Future studies should also focus on addressing the safety concerns associated with masitinib use.

Fyn, Blk, and Lyn kinase inhibitors: A mini-review on medicinal attributes, research progress, and future insights

Fyn, Blk, and Lyn are part of a group of proteins called Src family kinases. They are crucial in controlling cell communication and their response to the growth, changes, and immune system. Blocking these proteins with inhibitors can be a way to treat diseases where these proteins are too active. The primary mode of action of these inhibitors is to inhibit the phosphorylation of Fyn, Blk, and Lyn receptors, which in turn affects how signals pass within the cells. This review shows the structural and functional aspects of Fyn, Blk, and Lyn kinases, highlighting the significance of their dysregulation in diseases such as cancer and autoimmune disorders. The discussion encompasses the design strategies, SAR analysis, and chemical characteristics of effective inhibitors, shedding light on their specificity and potency. Furthermore, it explores the progress of clinical trials of these inhibitors, emphasizing their potential therapeutic applications.

Biology of neurofibrosis with focus on multiple sclerosis

Tissue damage elicits a wound healing response of inflammation and remodeling aimed at restoring homeostasis. Dysregulation of wound healing leads to accumulation of effector cells and extracellular matrix (ECM) components, collectively termed fibrosis, which impairs organ functions. Fibrosis of the central nervous system, neurofibrosis, is a major contributor to the lack of neural regeneration and it involves fibroblasts, microglia/macrophages and astrocytes, and their deposited ECM. Neurofibrosis occurs commonly across neurological conditions. This review describes processes of wound healing and fibrosis in tissues in general, and in multiple sclerosis in particular, and considers approaches to ameliorate neurofibrosis to enhance neural recovery.

Clinical trials for progressive multiple sclerosis: progress, new lessons learned, and remaining challenges

Despite the success of disease-modifying treatments in relapsing multiple sclerosis, for many individuals living with multiple sclerosis, progressive disability continues to accrue. How to interrupt the complex pathological processes underlying progression remains a daunting and ongoing challenge. Since 2014, several immunomodulatory approaches that have modest but clinically meaningful effects have been approved for the management of progressive multiple sclerosis, primarily for people who have active inflammatory disease. The approval of these drugs required large phase 3 trials that were sufficiently powered to detect meaningful effects on disability. New classes of drug, such as Bruton tyrosine-kinase inhibitors, are coming to the end of their trial stages, several candidate neuroprotective compounds have been successful in phase 2 trials, and innovative approaches to remyelination are now also being explored in clinical trials. Work continues to define intermediate outcomes that can provide results in phase 2 trials more quickly than disability measures, and more efficient trial designs, such as multi-arm multi-stage and futility approaches, are increasingly being used. Collaborations between patient organisations, pharmaceutical companies, and academic researchers will be crucial to ensure that future trials maintain this momentum and generate results that are relevant for people living with progressive multiple sclerosis.

Neuregulin-1 and ALS19 (ERBB4): at the crossroads of amyotrophic lateral sclerosis and cancer

BACKGROUND

Neuregulin-1 (NRG1) is implicated in both cancer and neurologic diseases such as amyotrophic lateral sclerosis (ALS); however, to date, there has been little cross-field discussion between neurology and oncology in regard to these genes and their functions.

MAIN BODY

Approximately 0.15-0.5% of cancers harbor NRG1 fusions that upregulate NRG1 activity and hence that of the cognate ERBB3/ERBB4 (HER3/HER4) receptors; abrogating this activity with small molecule inhibitors/antibodies shows preliminary tissue-agnostic anti-cancer activity. Notably, ERBB/HER pharmacologic suppression is devoid of neurologic toxicity. Even so, in ALS, attenuated ERBB4/HER4 receptor activity (due to loss-of-function germline mutations or other mechanisms in sporadic disease) is implicated; indeed, ERBB4/HER4 is designated ALS19. Further, secreted-type NRG1 isoforms may be upregulated (perhaps via a feedback loop) and could contribute to ALS pathogenesis through aberrant glial cell stimulation via enhanced activity of other (e.g., ERBB1-3/HER1-3) receptors and downstream pathways. Hence, pan-ERBB inhibitors, already in use for cancer, may be agents worthy of testing in ALS.

CONCLUSION

Common signaling cascades between cancer and ALS may represent novel therapeutic targets for both diseases.

Pathophysiology, Diagnosis, Treatment and Emerging Neurotherapeutic Targets for Progressive Multiple Sclerosis: The Age of PIRA

More than one million individuals are impacted by progressive forms of multiple sclerosis. The literature examining the management of MS has focused primarily on relapsing forms of disease, and effective therapies targeting progressive mechanisms in MS remains a significant unmet need. Despite this, there are several encouraging potential therapeutics on the horizon. Improved understanding of mechanisms underlying MS progression, identification and validation of biomarkers, identification of novel therapeutic targets, and improved trial design are needed to further propel progress in the management of individuals with progressive forms of MS.

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.

Treatment Patterns and Unmet Need for Patients with Progressive Multiple Sclerosis in the United States: Survey Results from 2016 to 2021

INTRODUCTION

Much of the current literature on treatment patterns and disability progression in multiple sclerosis (MS) does not distinguish between the relapsing-remitting and progressive subtypes (including primary [PPMS] and secondary progressive MS [SPMS]), or between active/nonactive disease. Current treatment options for progressive MS are limited, with only one approved product for PPMS and none specifically for nonactive SPMS. Here we report treatment patterns, disability progression, and unmet needs among patients with active and nonactive PPMS and SPMS.

METHODS

The annual, cross-sectional survey from the Adelphi Disease Specific Program was used to collect physician-reported data on US adult patients with PPMS and SPMS, including active and nonactive disease. Treatment patterns (including the proportion of patients who were untreated with a disease-modifying therapy [DMT]), disability progression, and unmet need are described from 2016 to 2021.

RESULTS

Data were collected for 2067 patients with progressive MS (PPMS, 1583; SPMS, 484). A substantial proportion of patients were untreated across all groups, and this was highest for nonactive PPMS (~ 43%). The proportion of untreated patients generally declined over time but remained high in 2018-2021 (~ 10-38%). Among treated patients, the proportion receiving infusions increased over time to ~ 34-46%, largely driven by ocrelizumab use after approval. Disability progression was reported for most patients (> 50%), including many who were receiving a DMT. Across all disease subtypes, when physicians were asked about the greatest unmet need with current DMTs, they most frequently cited effectiveness (~ 63-87%), and specifically slowing disease progression (~ 32-59%).

CONCLUSIONS

This analysis of physician-reported data reveals that patients with progressive MS, particularly those with nonactive disease, frequently remain untreated or continue to decline despite treatment with available DMTs. Thus there is an enduring need for safe and effective treatments for this underserved population.

Cancer drugs with high repositioning potential for Alzheimer's disease

INTRODUCTION

Despite the recent full FDA approval of lecanemab, there is currently no disease modifying therapy (DMT) that can efficiently slow down the progression of Alzheimer's disease (AD) in the general population. This statement emphasizes the need to identify novel DMTs in the shortest time possible to prevent a global epidemic of AD cases as the world population experiences an increase in lifespan.

AREAS COVERED

Here, we review several classes of anti-cancer drugs that have been or are being investigated in Phase II/III clinical trials for AD, including immunomodulatory drugs, RXR agonists, sex hormone therapies, tyrosine kinase inhibitors, and monoclonal antibodies.

EXPERT OPINION

Given the overall course of brain pathologies during the progression of AD, we express a great enthusiasm for the repositioning of anti-cancer drugs as possible AD DMTs. We anticipate an increasing number of combinatorial therapy strategies to tackle AD symptoms and their underlying pathologies. However, we strongly encourage improvements in clinical trial study designs to better assess target engagement and possible efficacy over sufficient periods of drug exposure.

Signaling pathways in macrophages: molecular mechanisms and therapeutic targets

Macrophages play diverse roles in development, homeostasis, and immunity. Accordingly, the dysfunction of macrophages is involved in the occurrence and progression of various diseases, such as coronavirus disease 2019 and atherosclerosis. The protective or pathogenic effect that macrophages exert in different conditions largely depends on their functional plasticity, which is regulated via signal transduction such as Janus kinase-signal transducer and activator of transcription, Wnt and Notch pathways, stimulated by environmental cues. Over the past few decades, the molecular mechanisms of signaling pathways in macrophages have been gradually elucidated, providing more alternative therapeutic targets for diseases treatment. Here, we provide an overview of the basic physiology of macrophages and expound the regulatory pathways within them. We also address the crucial role macrophages play in the pathogenesis of diseases, including autoimmune, neurodegenerative, metabolic, infectious diseases, and cancer, with a focus on advances in macrophage-targeted strategies exploring modulation of components and regulators of signaling pathways. Last, we discuss the challenges and possible solutions of macrophage-targeted therapy in clinical applications. We hope that this comprehensive review will provide directions for further research on therapeutic strategies targeting macrophage signaling pathways, which are promising to improve the efficacy of disease treatment.

Treatment of Alzheimer's Disease: Beyond Symptomatic Therapies

In an ever-increasing aged world, Alzheimer's disease (AD) represents the first cause of dementia and one of the first chronic diseases in elderly people. With 55 million people affected, the WHO considers AD to be a disease with public priority. Unfortunately, there are no final cures for this pathology. Treatment strategies are aimed to mitigate symptoms, i.e., acetylcholinesterase inhibitors (AChEI) and the N-Methyl-D-aspartate (NMDA) antagonist Memantine. At present, the best approaches for managing the disease seem to combine pharmacological and non-pharmacological therapies to stimulate cognitive reserve. Over the last twenty years, a number of drugs have been discovered acting on the well-established biological hallmarks of AD, deposition of β-amyloid aggregates and accumulation of hyperphosphorylated tau protein in cells. Although previous efforts disappointed expectations, a new era in treating AD has been working its way recently. The Food and Drug Administration (FDA) gave conditional approval of the first disease-modifying therapy (DMT) for the treatment of AD, aducanumab, a monoclonal antibody (mAb) designed against Aβ plaques and oligomers in 2021, and in January 2023, the FDA granted accelerated approval for a second monoclonal antibody, Lecanemab. This review describes ongoing clinical trials with DMTs and non-pharmacological therapies. We will also present a future scenario based on new biomarkers that can detect AD in preclinical or prodromal stages, identify people at risk of developing AD, and allow an early and curative treatment.

Multiple Sclerosis Pathogenesis and Updates in Targeted Therapeutic Approaches

PURPOSE OF REVIEW

In this review, we provide a comprehensive update on current scientific advances and emerging therapeutic approaches in the field of multiple sclerosis.

RECENT FINDINGS

Multiple sclerosis (MS) is a common disorder characterized by inflammation and degeneration within the central nervous system (CNS). MS is the leading cause of non-traumatic disability in the young adult population. Through ongoing research, an improved understanding of the disease underlying mechanisms and contributing factors has been achieved. As a result, therapeutic advancements and interventions have been developed specifically targeting the inflammatory components that influence disease outcome. Recently, a new type of immunomodulatory treatment, known as Bruton tyrosine kinase (BTK) inhibitors, has surfaced as a promising tool to combat disease outcomes. Additionally, there is a renewed interested in Epstein-Barr virus (EBV) as a major potentiator of MS. Current research efforts are focused on addressing the gaps in our understanding of the pathogenesis of MS, particularly with respect to non-inflammatory drivers. Significant and compelling evidence suggests that the pathogenesis of MS is complex and requires a comprehensive, multilevel intervention strategy. This review aims to provide an overview of MS pathophysiology and highlights the most recent advances in disease-modifying therapies and other therapeutic interventions.

Current and future therapeutic strategies for Alzheimer's disease: an overview of drug development bottlenecks

Alzheimer's disease (AD) is the most common chronic neurodegenerative disease worldwide. It causes cognitive dysfunction, such as aphasia and agnosia, and mental symptoms, such as behavioral abnormalities; all of which place a significant psychological and economic burden on the patients' families. No specific drugs are currently available for the treatment of AD, and the current drugs for AD only delay disease onset and progression. The pathophysiological basis of AD involves abnormal deposition of beta-amyloid protein (Aβ), abnormal tau protein phosphorylation, decreased activity of acetylcholine content, glutamate toxicity, autophagy, inflammatory reactions, mitochondria-targeting, and multi-targets. The US Food and Drug Administration (FDA) has approved five drugs for clinical use: tacrine, donepezil, carbalatine, galantamine, memantine, and lecanemab. We have focused on the newer drugs that have undergone clinical trials, most of which have not been successful as a result of excessive clinical side effects or poor efficacy. Although aducanumab received rapid approval from the FDA on 7 June 2021, its long-term safety and tolerability require further monitoring and confirmation. In this literature review, we aimed to explore the possible pathophysiological mechanisms underlying the occurrence and development of AD. We focused on anti-Aβ and anti-tau drugs, mitochondria-targeting and multi-targets, commercially available drugs, bottlenecks encountered in drug development, and the possible targets and therapeutic strategies for future drug development. We hope to present new concepts and methods for future drug therapies for AD.

Do clinical trials prepare to fail by failing to prepare? An examination of MS trials and recommendations for patient-reported outcome measure selection

BACKGROUND

Many clinical trials use patient-reported outcome (PRO) measures, which can influence treatment decision-making, drug approval and label claims. Given that many PRO measure options exist, and there are conceptual and contextual complexities with PRO measurement, we aimed to evaluate how and why specific PRO measures have been selected for pivotal multiple sclerosis (MS) clinical trials. Specifically, we aimed to identify the reasons documented for PRO measure selection in contemporary phase III MS disease-modifying treatment (DMT) clinical trials.

METHODS

We searched for phase III clinical trials of MS DMTs published between 2015 and 2021 and evaluated trial protocols, or primary publications where available, for PRO measure selection information. Specifically, we examined study documents for their clarification of clinical concepts measured, definitions of concepts measured, explanations of which PRO measures were considered, why specific PRO measures were chosen, and trade-offs in PRO measure selection.

RESULTS

We identified 1705 abstracts containing 61 unique phase III MS DMT clinical trials. We obtained and examined 27/61 trial protocols. Six protocols were excluded: four contained no mention of PRO measures and two contained redacted sections preventing adequate assessment, leaving 21 protocols for assessment. For the remaining 34 trials (61-27), we retrieved 31 primary publications; 15 primary publications mentioned the use of a PRO measure. None of the 36 clinical trials that mentioned the use of PRO measures (21 protocols and 15 primary publications) documented clear PRO or clinical outcome assessment (COA) measurement strategies, provided clear justifications for PRO selection, or reasons why specific PRO measures were selected when alternatives existed.

CONCLUSION

PRO measure selection for clinical trials is not evidence-based or underpinned by structured systematic approaches. This represents a critical area for study design improvement as PRO measure results directly affect patient care, PRO measurement has conceptual and contextual complexities, and there is a wide range of options when selecting a PRO measure. We recommend trial designers use formal approaches for PRO measure selection to ensure PRO measurement-based decisions are optimised. We provide a simple, logical, five-stage approach for PRO measure selection in clinical trials.

Central nervous system demyelinating diseases: glial cells at the hub of pathology

Inflammatory demyelinating diseases (IDDs) are among the main causes of inflammatory and neurodegenerative injury of the central nervous system (CNS) in young adult patients. Of these, multiple sclerosis (MS) is the most frequent and studied, as it affects about a million people in the USA alone. The understanding of the mechanisms underlying their pathology has been advancing, although there are still no highly effective disease-modifying treatments for the progressive symptoms and disability in the late stages of disease. Among these mechanisms, the action of glial cells upon lesion and regeneration has become a prominent research topic, helped not only by the discovery of glia as targets of autoantibodies, but also by their role on CNS homeostasis and neuroinflammation. In the present article, we discuss the participation of glial cells in IDDs, as well as their association with demyelination and synaptic dysfunction throughout the course of the disease and in experimental models, with a focus on MS phenotypes. Further, we discuss the involvement of microglia and astrocytes in lesion formation and organization, remyelination, synaptic induction and pruning through different signaling pathways. We argue that evidence of the several glia-mediated mechanisms in the course of CNS demyelinating diseases supports glial cells as viable targets for therapy development.

Current Updates on the Diagnosis and Management of Multiple Sclerosis for the General Neurologist

Multiple sclerosis (MS) is an immune-driven disease that affects the central nervous system and is characterized by acute-on-chronic demyelination attacks. It is a major cause of global neurological disability, and its prevalence has increased in the United States. Conceptual understandings of MS have evolved over time, including the identification of B cells as key factors in its pathophysiology. The foundation of MS management involves preventing flares so as to avoid long-term functional decline. Treatments may be categorized into low-, middle-, and high-efficacy medications based on their efficacy in relapse prevention. With 24 FDA-approved treatments for MS, individual therapy is chosen based on distinct mechanisms and potential side effects. This review provides a detailed update on the epidemiology, diagnosis, treatment advances, and major ongoing research investigations in MS.

Masitinib: The promising actor in the next season of the Amyotrophic Lateral Sclerosis treatment series

Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease with high mortality and morbidity rate affecting both upper and lower motor neurons (MN). Muscle force reduction, behavioral change, pseudobulbar affect, and cognitive impairments are the most common clinical manifestations of ALS. The main physiopathology of ALS is still unclear, though several studies have identified that oxidative stress, proteinopathies, glutamate-related excitotoxicity, microglial activation, and neuroinflammation may be involved in the pathogenesis of ALS. From 1995 until October 2022, only Riluzole, Dextromethorphan Hydrobromide (DH) with Quinidine sulfate (Q), Edaravone, and Sodium phenylbutyrate with Taurursodiol (PB/TUDCO) have achieved FDA approval for ALS treatment. Despite the use of these four approved agents, the survival rate and quality of life of ALS patients are still low. Thus, finding novel treatments for ALS patients is an urgent requirement. Masitinib, a tyrosine kinase inhibitor, emphasizes the neuro-inflammatory activity of ALS by targeting macrophages, mast cells, and microglia cells. Masitinib downregulates the proinflammatory cytokines, indirectly reduces inflammation, and induces neuroprotection. Also, it was effective in phase 2/3 and 3 clinical trials (CTs) by increasing overall survival and delaying motor, bulbar, and respiratory function deterioration. This review describes the pathophysiology of ALS, focusing on Masitinib's mechanism of action and explaining why Masitinib could be a promising actor in the treatment of ALS patients. In addition, Masitinib CTs and other competitor drugs in phase 3 CTs have been discussed.

Treatment of autoimmunity: The impact of disease-modifying therapies in multiple sclerosis and comorbid autoimmune disorders

More than 10 disease-modifying therapies (DMT) are approved by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA) for the treatment of multiple sclerosis (MS) and new therapeutic options are on the horizon. Due to different underlying therapeutic mechanisms, a more individualized selection of DMTs in MS is possible, taking into account the patient's current situation. Therefore, concomitant treatment of various comorbid conditions, including autoimmune mediated disorders such as rheumatoid arthritis, should be considered in MS patients. Because the pathomechanisms of autoimmunity partially overlap, DMT could also treat concomitant inflammatory diseases and simplify the patient's treatment. In contrast, the exacerbation and even new occurrence of several autoimmune diseases have been reported as a result of immunomodulatory treatment of MS. To simplify treatment and avoid disease exacerbation, knowledge of the beneficial and adverse effects of DMT in other autoimmune disorders is critical. Therefore, we conducted a literature search and described the beneficial and adverse effects of approved and currently studied DMT in a large number of comorbid autoimmune diseases, including rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel diseases, cutaneous disorders including psoriasis, Sjögren´s syndrome, systemic lupus erythematosus, systemic vasculitis, autoimmune hepatitis, and ocular autoimmune disorders. Our review aims to facilitate the selection of an appropriate DMT in patients with MS and comorbid autoimmune diseases.

Masitinib for mild-to-moderate Alzheimer's disease: results from a randomized, placebo-controlled, phase 3, clinical trial

BACKGROUND

Masitinib is an orally administered tyrosine kinase inhibitor that targets activated cells of the neuroimmune system (mast cells and microglia). Study AB09004 evaluated masitinib as an adjunct to cholinesterase inhibitor and/or memantine in patients with mild-to-moderate dementia due to probable Alzheimer's disease (AD).

METHODS

Study AB09004 was a randomized, double-blind, two parallel-group (four-arm), placebo-controlled trial. Patients aged ≥50 years, with clinical diagnosis of mild-to-moderate probable AD and a Mini-Mental State Examination (MMSE) score of 12-25 were randomized (1:1) to receive masitinib 4.5 mg/kg/day (administered orally as two intakes) or placebo. A second, independent parallel group (distinct for statistical analysis and control arm), randomized patients (2:1) to masitinib at an initial dose of 4.5 mg/kg/day for 12 weeks that was then titrated to 6.0 mg/kg/day, or equivalent placebo. Multiple primary outcomes (each tested at a significance level of 2.5%) were least-squares mean change from baseline to week 24 in the Alzheimer's Disease Assessment Scale - cognitive subscale (ADAS-cog), or the Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory scale (ADCS-ADL). Safety for each masitinib dose level was compared against a pooled placebo population.

RESULTS

Masitinib (4.5 mg/kg/day) (n=182) showed significant benefit over placebo (n=176) according to the primary endpoint of ADAS-cog, -1.46 (95% CI [-2.46, -0.45]) (representing an overall improvement in cognition) versus 0.69 (95% CI [-0.36, 1.75]) (representing increased cognitive deterioration), respectively, with a significant between-group difference of -2.15 (97.5% CI [-3.48, -0.81]); p<0.001. For the ADCS-ADL primary endpoint, the between-group difference was 1.82 (97.5% CI [-0.15, 3.79]); p=0.038 (i.e., 1.01 (95% CI [-0.48, 2.50]) (representing an overall functional improvement) versus -0.81 (95% CI [-2.36, 0.74]) (representing increased functional deterioration), respectively). Safety was consistent with masitinib's known profile (maculo-papular rash, neutropenia, hypoalbuminemia). Efficacy results from the independent parallel group of titrated masitinib 6.0 mg/kg/day versus placebo (n=186 and 91 patients, respectively) were inconclusive and no new safety signal was observed.

CONCLUSIONS

Masitinib (4.5 mg/kg/day) may benefit people with mild-to-moderate AD. A confirmatory study has been initiated to substantiate these data.

TRIAL REGISTRATION

EudraCT: 2010-021218-50.

CLINICALTRIALS

gov : NCT01872598.

To Investigate Growth Factor Receptor Targets and Generate Cancer Targeting Inhibitors

Receptor tyrosine kinase (RTK) regulates multiple pathways, including Mitogenactivated protein kinases (MAPKs), PI3/AKT, JAK/STAT pathway, etc. which has a significant role in the progression and metastasis of tumor. As RTK activation regulates numerous essential bodily processes, including cell proliferation and division, RTK dysregulation has been identified in many types of cancers. Targeting RTK is a significant challenge in cancer due to the abnormal upregulation and downregulation of RTK receptors subfamily EGFR, FGFR, PDGFR, VEGFR, and HGFR in the progression of cancer, which is governed by multiple RTK receptor signalling pathways and impacts treatment response and disease progression. In this review, an extensive focus has been carried out on the normal and abnormal signalling pathways of EGFR, FGFR, PDGFR, VEGFR, and HGFR and their association with cancer initiation and progression. These are explored as potential therapeutic cancer targets and therefore, the inhibitors were evaluated alone and merged with additional therapies in clinical trials aimed at combating global cancer.

Aging and aging-related diseases: from molecular mechanisms to interventions and treatments

Aging is a gradual and irreversible pathophysiological process. It presents with declines in tissue and cell functions and significant increases in the risks of various aging-related diseases, including neurodegenerative diseases, cardiovascular diseases, metabolic diseases, musculoskeletal diseases, and immune system diseases. Although the development of modern medicine has promoted human health and greatly extended life expectancy, with the aging of society, a variety of chronic diseases have gradually become the most important causes of disability and death in elderly individuals. Current research on aging focuses on elucidating how various endogenous and exogenous stresses (such as genomic instability, telomere dysfunction, epigenetic alterations, loss of proteostasis, compromise of autophagy, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, deregulated nutrient sensing) participate in the regulation of aging. Furthermore, thorough research on the pathogenesis of aging to identify interventions that promote health and longevity (such as caloric restriction, microbiota transplantation, and nutritional intervention) and clinical treatment methods for aging-related diseases (depletion of senescent cells, stem cell therapy, antioxidative and anti-inflammatory treatments, and hormone replacement therapy) could decrease the incidence and development of aging-related diseases and in turn promote healthy aging and longevity.

Interaction of Masitinib with Organic Cation Transporters

Tyrosine kinase inhibitors (TKI) such as Masitinib were reported to be useful as therapeutic options in malignant disorders and nonmalignant diseases, like coronavirus disease 2019 (COVID-19). Most kinases must be translocated into targeted cells by the action of specific transport proteins, as they are hydrophilic and not able to cross cell membranes freely. Accordingly, the efficacy of TKI in target cells is closely dependent on the expression of their transporters. Specifically, Masitinib is an organic cation and is expected to interact with organic cation transporters (OCT and Multidrug and Toxin Extrusion proteins-MATE-). The aim of this work was to characterize the interaction of Masitinib with different OCTs. Human embryonic kidney 293 cells stably transfected with murine or human OCT were used for the experiments. The interaction of Masitinib with OCTs was investigated using quenching experiments. The intracellular accumulation of this drug was quantified using high performance liquid chromatography. Our results identified interactions of Masitinib with almost all investigated mouse (m) and human (h) OCTs and hMATE1 and indicated OCT1 and hOCT2 to be especially potent Masitinib translocators across cell membranes. Interestingly, some important differences were observed for the interaction with murine and human OCTs. In the future, investigations concerning further in vitro and in vivo properties of Masitinib and its efficacy related to transporter-related uptake mechanisms under pathophysiological conditions should be performed. Clinical trials in humans and other animals with Masitinib have already shown promising results. However, further research is necessary to understand the disease specific transport mechanisms of Masitinib to contribute to a successful and responsible therapy employment.

Bruton's Tyrosine Kinase Inhibitors: The Next Frontier of B-Cell-Targeted Therapies for Cancer, Autoimmune Disorders, and Multiple Sclerosis

Bruton's tyrosine kinase (BTK) is an important protein belonging to the tyrosine kinase family that plays a key role in the intracellular signaling and proliferation, migration, and survival of normal and malignant B-lymphocytes and myeloid cells. Understanding the role of BTK in the B-cell signaling pathway has led to the development of BTK inhibitors (BTKi) as effective therapies for malignancies of myeloid origin and exploration as a promising therapeutic option for other cancers. Given its central function in B-cell receptor signaling, inhibition of BTK is an attractive approach for the treatment of a wide variety of autoimmune diseases that involve aberrant B-cell function including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS). Here, we review the role of BTK in different cell signaling pathways, the development of BTKi in B-cell malignancies, and their emerging role in the treatment of MS and other autoimmune disorders.

Safety and efficacy of tyrosine kinase inhibitors for the treatment of multiple sclerosis: A systematic review and meta-analysis from randomized controlled trials

Background

Multiple sclerosis (MS), an autoimmune disease, is characterized by inflammatory demyelinating lesions in the white matter of the central nervous system. Drugs targeting tyrosine kinase, a critical component of immune cell receptor signaling, have been developed to treat MS. However, the exact efficacy and safety of tyrosine kinase inhibitors (TKIs) are still controversial, and comprehensive analysis with a high level of evidence is needed.

Methods

Medline, Embase, Cochrane Library, and Clinicaltrials.gov for randomized controlled trials (RCTs) evaluating TKIs versus placebo for MS were searched up to April 1st, 2022. The risk ratio (RR) and mean difference (MD) or standard mean difference (SMD) were analyzed using dichotomous outcomes and continuous outcomes, respectively, with a random effect model.

Results

A total of 1,043 patients derived from four clinical trials were included to investigate the efficacy and safety of TKI therapy for MS. According to our analysis, TKIs decreased the cumulative number of gadolinium-enhancing lesions on T1-weighted MRI with the application of high dose (SMD = −0.61, 95% CI: −0.93 to −0.30, P = 0.0001). Meanwhile, TKIs prevented the expanded disability status scale (EDSS) from rising (MD = −0.10, 95% CI: −0.19 to −0.00, P = 0.046). In terms of MS relapse, TKIs have not revealed an obvious statistical difference compared with placebo (RR = 0.96, 95% CI: 0.55–1.65, P = 0.8755). However, more adverse events seem to occur in the TKIs group, both for adverse events (RR = 1.12, 95% CI: 1.05–1.19, P = 0.0009) and serious adverse events (RR = 1.91, 95% CI: 1.30–2.81, P = 0.001).

Conclusion

Tyrosine kinase inhibitors have shown promise in treating MS. Generally, TKIs that attain the effective dose demonstrate definite efficacy and have tolerable side effects. More clinical trials and validation are needed, and we anticipate that TKIs will be a viable alternative for MS patients.

Does the use of the Bruton Tyrosine Kinase inhibitors and the c-kit inhibitor masitinib result in clinically significant outcomes among patients with various forms of multiple sclerosis?

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system accompanied by chronic inflammation, axonal loss, and neurodegeneration. Traditionally, MS has been thought of as a T-cell mediated disease, but research over the past decade has demonstrated the importance of B cells in both acute demyelination and disease progression. The highly selective irreversible Bruton Tyrosine Kinase (BTK) inhibitors evobrutinib, tolebrutinib, and orelabrutinib, and the reversible BTK inhibitor fenebrutinib, all target B-cell activation and aspects of innate immunity, including macrophage and microglia biology. The c-KIT inhibitor masitinib mitigates neuroinflammation by controlling the survival, migration, and degranulation of mast cells, leading to the inhibition of proinflammatory and vasoactive molecular cascades that result from mast cell activation. This article will review and critically appraise the ongoing clinical trials of two classes of receptor tyrosine kinase inhibitors that are emerging as potential medical treatments for the varying subtypes of MS: BTK inhibitors and c-KIT inhibitors. Specifically, this review will attempt to answer whether BTK inhibitors have measurable positive clinical effects on patients with RRMS, SPMS with relapses, relapse-free SPMS, and PPMS through their effect on MRI T1 lesions; annualized relapse rate; EDSS scale; MSFC score; and time to onset of composite 12-week confirmed disability progression. Additionally, this review will examine the literature to determine if masitinib has positive clinical effects on patients with PPMS or relapse-free SPMS through its effect on EDSS or MSFC scores.

The SARS-CoV-2 main protease (Mpro): Structure, function, and emerging therapies for COVID-19

The main proteases (Mpro), also termed 3-chymotrypsin-like proteases (3CLpro), are a class of highly conserved cysteine hydrolases in β-coronaviruses. Increasing evidence has demonstrated that 3CLpros play an indispensable role in viral replication and have been recognized as key targets for preventing and treating coronavirus-caused infectious diseases, including COVID-19. This review is focused on the structural features and biological function of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease Mpro (also known as 3CLpro), as well as recent advances in discovering and developing SARS-CoV-2 3CLpro inhibitors. To better understand the characteristics of SARS-CoV-2 3CLpro inhibitors, the inhibition activities, inhibitory mechanisms, and key structural features of various 3CLpro inhibitors (including marketed drugs, peptidomimetic, and non-peptidomimetic synthetic compounds, as well as natural compounds and their derivatives) are summarized comprehensively. Meanwhile, the challenges in this field are highlighted, while future directions for designing and developing efficacious 3CLpro inhibitors as novel anti-coronavirus therapies are also proposed. Collectively, all information and knowledge presented here are very helpful for understanding the structural features and inhibitory mechanisms of SARS-CoV-2 3CLpro inhibitors, which offers new insights or inspiration to medicinal chemists for designing and developing more efficacious 3CLpro inhibitors as novel anti-coronavirus agents.

Emerging therapies to target CNS pathophysiology in multiple sclerosis

The rapidly evolving therapeutic landscape of multiple sclerosis (MS) has contributed to paradigm shifts in our understanding of the biological mechanisms that contribute to CNS injury and in treatment philosophies. Opportunities remain to further improve treatment of relapsing-remitting MS, but two major therapeutic gaps are the limiting of progressive disease mechanisms and the repair of CNS injury. In this Review, we provide an overview of selected emerging therapies that predominantly target processes within the CNS that are thought to be involved in limiting non-relapsing, progressive disease injury or promoting tissue repair. Among these, we consider agents that modulate adaptive and innate CNS-compartmentalized inflammation, which can be mediated by infiltrating immune cells and/or resident CNS cells, including microglia and astrocytes. We also discuss agents that target degenerative disease mechanisms, agents that might confer neuroprotection, and agents that create a more favourable environment for or actively contribute to oligodendrocyte precursor cell differentiation, remyelination and axonal regeneration. We focus on agents that are novel for MS, that are known to or are presumed to penetrate the CNS, and that have already entered early stages of development in MS clinical trials.

New drugs for multiple sclerosis: new treatment algorithms

PURPOSE OF REVIEW

To discuss recent changes in the multiple sclerosis (MS) treatment algorithm and to present therapies currently in MS clinical trials.

RECENT FINDINGS

High efficacy disease modifying therapies are optimally beneficial when used in the early, inflammatory phase of MS. Bruton's tyrosine kinase has emerged as an important therapeutic target for both relapsing and progressive forms of MS. Multiple therapies targeting remyelination failed to provide conclusive evidence of broad therapeutic benefit; however, more targeted approaches offer hope that myelin repair might be achieved resulting in specific clinical improvements. Strategies targeting chronic Epstein-Barr virus infection and dysbiosis of the gut microbiome are the first to link microbial risk factors for MS and therapeutic interventions.

SUMMARY

A striking number of diverse treatments under investigation bodes well for development of better and more effective therapies in MS.

Is the effect of drugs in progressive MS only due to an effect on inflammation? A subgroup meta-analysis of randomised trials

BACKGROUND

It is unclear whether drugs approved for the treatment of progressive multiple sclerosis (PMS) are effective in disability progression only because of their effect on the inflammatory component of the disease.

OBJECTIVE

This meta-analysis aimed to evaluate whether the benefits of PMS treatments are mediated by its effect on the active component of the disease.

METHODS

We conducted a systematic search to identify randomised, double-blind, placebo-controlled trials evaluating the efficacy of disease-modifying therapies on disability progression for primary or secondary PMS. The primary endpoint of the analysis was disability progression based on the expanded disability status scale. A subgroup meta-analysis evaluated the effects of treatment according to disease activity at baseline.

RESULTS

Twelve trials (a total of 8659 PMS cases) were selected. Analysis of the included trials demonstrated that treatment benefit appears to be mainly confined to the group with active disease (hazard ratio (HR) = 0.67; 95% confidence interval (CI): 0.58-0.79) as compared to the group with inactive disease (HR = 0.90; 95% CI: 0.79-1.02, interaction test: p = 0.005).

CONCLUSIONS

This study showed that the benefit of treating patients with PMS was mostly confined to those with the more active disease. Drugs targeting specific pathological processes leading to disability progression remain necessary.