A DNA vaccine for multiple sclerosis

Knowledge mapping of disease-modifying therapy (DMT) in multiple sclerosis (MS): A bibliometrics analysis

Background

Multiple sclerosis (MS) is a heterogeneous autoimmune disease, with a rapidly evolving body of literature on disease-modifying therapy (DMT) that urgently needs to be synthesized and regularized.

Methods

The original material used for the analysis was obtained from the Web of Science Core Collection (WoSCC) in the Science Citation Index Expanded Edition (SCI-E). The data material was accessed through VOSviewer, Citespace, R package "Bibliometrix", and Scimago Graphica for data analysis and visualization. Among them, the clustering algorithm based on the Largest Likelihood Ratio (LLR) and the burst citation algorithm is the key.

Results

As of November 6th, 2022, 4142 publications related to emerging disease-modifying therapies (e-DMT) for MS, 6521 publications related to traditional disease-modifying therapies (t-DMT) for MS, and 1793 publications in cross-cutting disease-modifying therapies (I-DMT) for MS were included in the analysis, respectively. Publications related to DMT in MS were analyzed descriptively (for three subjects: country, institution, and author) and predictively (for two subjects: keywords and references) separately according to three sections: e-DMT, t-DMT, and I-DMT. Topics that still have relevant reference output as of 2022 include the safety of Coronavirus disease 2019 (COVID-19) mRNA vaccination, therapeutic inertia (TI), cladribine tablets, autologous hematopoietic stem cell transplantation (aHSCT), progressive multiple sclerosis, and pediatric multiple sclerosis.

Conclusion

The future research focus for MS DMT is the combination trial or cross-trial of various treatment methods to improve the development of individualized treatment plans for MS patients. The exact contents of the research frontiers are included but not limited to ocrelizumab, fingolimod and other monoclonal antibodies, fumaric acid ester, cladribine tablet, aHSCT, and other interventions of randomized controlled trials (RCTs); the impact of mRNA COVID-19 vaccination on MS patients; TI, patient adherence, and other medical management issues; and continued exploration of biomarkers for more accurate disease classification based on the existing clinical indication classification.

Further understanding of the immunopathology of multiple sclerosis: impact on future treatments

INTRODUCTION

The understanding of the immunopathogenesis of multiple sclerosis (MS) has expanded with more research into T-cell subtypes, cytokine contributors, B-cell participation, mitochondrial dysfunction, and more. Treatment options have rapidly expanded with three relatively recent oral therapy alternatives entering the arena.

AREAS COVERED

In the following review, we discuss current mechanisms of immune dysregulation in MS, how they relate to current treatments, and the impact these findings will have on the future of therapy. Expert commentary: The efficacy of these medications and understanding their mechanisms of actions validates the immunopathogenic mechanisms thought to underlie MS. Further research has exposed new targets, while new promising therapies have shed light on new aspects into the pathophysiology of MS.

Emerging immunopharmacological targets in multiple sclerosis

Inflammatory demyelination of the central nervous system (CNS) is the hallmark of multiple sclerosis (MS), a chronic debilitating disease that affects more than 2.5 million individuals worldwide. It has been widely accepted, although not proven, that the major pathogenic mechanism of MS involves myelin-reactive T cell activation in the periphery and migration into the CNS, which subsequently triggers an inflammatory cascade that leads to demyelination and axonal damage. Virtually all MS medications now in use target the immune system and prevent tissue damage by modulating neuroinflammatory processes. Although current therapies such as commonly prescribed disease-modifying medications decrease the relapse rate in relapsing-remitting MS (RRMS), the prevention of long-term accumulation of deficits remains a challenge. Medications used for progressive forms of MS also have limited efficacy. The need for therapies that are effective against disease progression continues to drive the search for novel pharmacological targets. In recent years, due to a better understanding of MS immunopathogenesis, new approaches have been introduced that more specifically target autoreactive immune cells and their products, thus increasing specificity and efficacy, while reducing potential side effects such as global immunosuppression. In this review we describe several immunopharmacological targets that are currently being explored for MS therapy.

Tovaxin for multiple sclerosis

INTRODUCTION

A potential therapeutic possibility for multiple sclerosis (MS) is provided by Tovaxin, a personalized autologous T-cell immunotherapy utilizing myelin-reactive lymphocytes from peripheral blood.

AREAS COVERED

This review covers the production of the vaccine, which follows a series of steps after the acquisition of T-cells. This includes identification of the subsets that are myelin reactive, expansion ex vivo and, also extrinsically, inactivation of their replication capacity by cellular irradiation. Once attenuated, the modified cells are reintroduced into the donor. This process appears to induce a vigorous immune response towards specific populations of autoreactive T-cells determined to attack the myelin and its derivatives by trafficking from the vascular space into the CNS in MS. Historical aspects of the T-cell vaccination with Tovaxin, the process to obtain reactive T-cells and their attenuation techniques ex vivo are described. The clinical results obtained from clinical trials are also discussed.

EXPERT OPINION

The process of T-cell vaccination is complicated and presents some limitations. Further studies are required to provide scientific support and clinical evidence of the efficacy of Tovaxin in MS.

Genetic vaccination for re-establishing T-cell tolerance in type 1 diabetes

Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease resulting in the destruction of the insulin-secreting β cells. Currently, there is no established clinical approach to effectively suppress long-term the diabetogenic response. Genetic-based vaccination offers a general strategy to reestablish β-cell specific tolerance within the T-cell compartment. The transfer of genes encoding β-cell autoantigens, anti-inflammatory cytokines and/or immunomodulatory proteins has proven to be effective at preventing and suppressing the diabetogenic response in animal models of T1D. The current review will discuss genetic approaches to prevent and treat T1D with an emphasis on plasmid DNA- and adeno-associated virus-based vaccines.

DNA vaccines for autoimmune diseases

Autoimmune diseases represent a group of disorders in which there exists a large unmet medical need for effective treatments, but also where there exists a tremendous responsibility among physicians and drug developers to maintain adequate and acceptable patient safety. Several drugs have been approved and many others are about to be approved for the treatment of autoimmune diseases, but in pushing the envelope of therapeutic efficacy, concerns have been raised about the long-term safety of these new therapies. DNA vaccines provide a method of treating autoimmune diseases in a highly specific manner, and could therefore overcome these safety concerns while still maintaining comparable efficacy. The numerous reports of DNA vaccines in animal models of autoimmune diseases and results from three recent human trials of DNA vaccines in autoimmune diseases are reviewed here.

Immune-directed gene therapeutic development for Alzheimer's, prion, and Parkinson's diseases

The development of novel immune-based therapeutics for neurodegenerative diseases is an area of intense focus. Neurodegenerative diseases represent a particular challenge since in many cases the onset of symptoms occurs after considerable degeneration has ensued. Based on human genetic and histopathological evidence from patients with neurodegenerative diseases, animal models that recapitulate specific pathologic features have been developed. Utilizing these animal models in combination with viral vector-based gene therapeutics, specific epochs of disease can be targeted. One common feature of several neurodegenerative diseases is misfolded proteins. The mechanism by which these altered protein conformers lead to neurodegeneration is not completely understood but much effort has been put forward to either degrade aberrant protein or prevent the formation of misfolded conformers. In this review, we will summarize work that employs viral vector gene therapeutics to modulate the brain's response to misfolded proteins with a specific focus on neurodegeneration.