Natalizumab Therapy for Multiple Sclerosis

The treatment of relapsing remitting multiple sclerosis has witnessed major progress since the first effective disease modifying treatment, ß-interferon, became available in 1993. One of the most remarkable new treatments has been natalizumab. This review describes the evolution of this humanized anti-α4ß1 monoclonal antibody, from preclinical experimental research through proof-of-concept (phase 1/2) and pivotal (phase 3) clinical trials to the now extensive experience of its use in clinical practice. The future potential and challenges of natalizumab and oral therapies with a similar mechanism of action are also discussed.     

Alemtuzumab Therapy for Multiple Sclerosis

Alemtuzumab is a humanized monoclonal antibody that is administered daily for 5 days, and then no further therapy is required for 12 months. It causes rapid and prolonged lymphocyte depletion; the consequent homeostatic reconstitution leads to a radically reformed lymphocyte pool with a relative increase in regulatory T cells and expansion of autoreactive T cells. Although previously licensed for the treatment of B-cell chronic lymphocytic leukemia, it is now been considered for licensing in the treatment of multiple sclerosis (MS). From a disappointing experience with alemtuzumab in progressive MS, Alastair Compston and I argued that immunotherapies should be given early in the course of the disease. In a unique program of drug development in MS, alemtuzumab has been compared in 1 phase 2 trial and 2 phase 3 trials with the active comparator interferon beta-1a. In all trials, alemtuzumab was more effective in suppressing relapses than interferon beta-1a. In one phase 2 and one phase 3 trial, alemtuzumab also reduced the risk of accumulating disability compared with interferon beta-1a. Indeed, alemtuzumab treatment led to an improvement in disability and a reduction in cerebral atrophy. The safety issues are infusion-associated reactions largely controlled by methylprednisolone, antihistamines, and antipyretics; mild-to-moderate infections (with 3 opportunistic infections from the open-label experience: 1 case each of spirochaetal gingivitis, pyogenic granuloma, and Listeria meningitis); and autoimmunity. Usually autoimmunity is directed against the thyroid gland, but causes (1 %) immune thrombocytopenia, and in a few cases antiglomerular basement membrane syndrome. Alemtuzumab is an effective therapy for early relapsing-remitting MS, offering disability improvement at least to 5 years after treatment. Its use requires careful monitoring so that potentially serious side effects can be treated early and effectively.     

Daclizumab Therapy for Multiple Sclerosis

Daclizumab is a humanized monoclonal antibody of IgG1 subtype that binds to the Tac epitope on the interleukin-2 (IL-2) receptor α-chain (CD25), thus, effectively blocking the formation of the high-affinity IL-2 receptor. Because the high-affinity IL-2 receptor signaling promotes expansion of activated T cells in vitro, daclizumab was designed as a therapy that selectively inhibits T-cell activation. Assuming the previous statement, daclizumab received regulatory approval as add-on therapy to standard immunosuppressive regimen for the prevention of acute allograft rejection in renal transplantation. Based on its putative mechanism of action (MOA), daclizumab represented an ideal therapy for T-cell-mediated autoimmune diseases and was subsequently tested in inflammatory uveitis and multiple sclerosis (MS). In both of these diseases, daclizumab therapy significantly inhibited target organ inflammation. Mechanistic studies in MS demonstrated that the MOA of daclizumab is surprisingly broad and that the drug exerts unexpected effects on multiple components of the innate immune system. Specifically, daclizumab dramatically expands and activates immunoregulatory CD56^bright NK cells, which gain access to the intrathecal compartment in MS and can kill autologous activated T cells. Daclizumab also blocks trans-presentation of IL-2 by mature dendritic cells to primed T cells, resulting in profound inhibition of antigen-specific T cells. Finally, daclizumab modulates the development of innate lymphoid cells. In conclusion, daclizumab therapy, which is currently in phase III testing for inflammatory MS, has a unique MOA that does not limit migration of immune cells into the intrathecal compartment, but rather provides multifactorial immunomodulatory effects with resultant inhibition of MS-related inflammation.     

Remyelination Therapy for Multiple Sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system characterized by infiltration of immune cells and progressive damage to myelin and axons. All therapeutics used to treat MS have been developed to target an overactive immune response, with aims to reduce disease activity. Chronic demyelinated axons are further prone to irreversible damage and death, and it is imperative that new therapies address this critical issue. Remyelination, the generation of new myelin in the adult nervous system, is an endogenous repair mechanism that restores function of denuded axons and delays their deterioration. Although remyelination can be extensive in some patients, the majority of cases limit repair only to the acute phase of disease. A significant current drive in new MS therapeutics is to identify targets that can promote remyelination by boosting endogenous oligodendrocyte precursor cells to form new myelin. Also, a number of inhibitory pathways have been identified in chronic MS lesions that prevent oligodendrocyte precursor cells from being properly recruited to demyelinated lesions or interfere with their differentiation to myelin-forming oligodendrocytes. In this review, we introduce the phenomenon of remyelination from the view of experimental models and studies in MS patients, describe a potential role in remyelination for currently available MS mediations, and discuss many avenues that are being actively studied to promote remyelination. The next frontier in MS therapeutics will supplement immunomodulation with agents that directly foster myelin repair, with aims to delay disease progression and recover lost neurological functions.     

Cell Therapy for Multiple Sclerosis

The spontaneous recovery observed in the early stages of multiple sclerosis (MS) is substituted with a later progressive course and failure of endogenous processes of repair and remyelination. Although this is the basic rationale for cell therapy, it is not clear yet to what degree the MS brain is amenable for repair and whether cell therapy has an advantage in comparison to other strategies to enhance endogenous remyelination. Central to the promise of stem cell therapy is the therapeutic plasticity, by which neural precursors can replace damaged oligodendrocytes and myelin, and also effectively attenuate the autoimmune process in a local, nonsystemic manner to protect brain cells from further injury, as well as facilitate the intrinsic capacity of the brain for recovery. These fundamental immunomodulatory and neurotrophic properties are shared by stem cells of different sources. By using different routes of delivery, cells may target both affected white matter tracts and the perivascular niche where the trafficking of immune cells occur. It is unclear yet whether the therapeutic properties of transplanted cells are maintained with the duration of time. The application of neural stem cell therapy (derived from fetal brain or from human embryonic stem cells) will be realized once their purification, mass generation, and safety are guaranteed. However, previous clinical experience with bone marrow stromal (mesenchymal) stem cells and the relative easy expansion of autologous cells have opened the way to their experimental application in MS. An initial clinical trial has established the probable safety of their intravenous and intrathecal delivery. Short-term follow-up observed immunomodulatory effects and clinical benefit justifying further clinical trials.     

Hyperbaric Oxygen Therapy for Multiple Sclerosis

Multiple sclerosis (MS) is a chronic, inflammatory, and degenerative neurological illness with no cure. It has been suggested that Hyperbaric Oxygen Therapy (HBO₂T) may slow or reverse the progress of the disease. This article summarizes the clinical evidence for the use of HBO₂T in the treatment of MS. We conducted a literature review focused on the interaction of hyperbaric oxygenation and MS. In particular, we appraised the clinical data regarding treatment and performed a meta‐analysis of the randomized evidence using the methodology of the Cochrane Collaboration. We found 12 randomized studies in the area, all of which were performed between 1983 and 1987. A meta‐analysis of this evidence suggests there is no clinically significant benefit from the administration of HBO₂T. The great majority of randomized trials investigated a course of 20 treatments at pressures between 1.75ATA and 2.5ATA daily for 60–120 min over 4 weeks against a placebo regimen. None have tested the efficacy of HBO₂T against alternative current best practice. No plausible benefit of HBO₂T on the clinical course of MS was identified in this review. It remains possible that HBO₂T is effective in a subgroup of individuals not clearly identified in the trials to date, but any benefit is unlikely to be of great clinical significance. There is some case for further human trials in selected subgroups and for prolonged courses of HBO₂T at modest pressures, but the case is not strong. At this time, the routine treatment of MS with HBO₂T is not recommended.     

Disease-Modifying Therapy of Pediatric Multiple Sclerosis

Multiple sclerosis (MS) is increasingly recognized in children and adolescents. Improved awareness, access to care, and subspecialty training in pediatric MS has allowed for better access to treatment. Children with MS present with an overwhelmingly relapsing form of the disease and have more frequent relapses than their adult counterparts during the early phases of disease. Cognitive deficits are prominent in pediatric MS, as opposed to locomotor disability. Beta interferons and glatiramer acetate are frequently used off-label drugs. Additional second-line therapies have occasionally been used in treatment failures. No randomized clinical trials have been performed to date in pediatric MS; however, recent legislation necessitates pediatric studies for new agents, which will allow for better defined pharmacokinetic, dosing, and efficacy data to guide the treating neurologist.     

多发性硬化的治疗进展

多发性硬化（MS）是一种常见的中枢神经系统自身免疫性炎性脱髓鞘疾病,自身抗原激活T细胞和B细胞介导的免疫机制异常在MS的致病过程中起重要作用。MS改良治疗（DMTs）可特异性作用于某个与致病机制相关的靶细胞或分子而发挥治疗作用,本文就近年口服药物和单克隆抗体治疗MS的新进展做一综述。     

Epigenetic Modifications and Therapy in Multiple Sclerosis

Breakthroughs in genetic studies, like whole human genome sequencing and genome-wide association studies (GWAS), have richened our knowledge of etiopathology of autoimmune diseases (AID) through discovery of genetic patterns. Nonetheless, the precise etiology of autoimmune diseases remains largely unknown. The lack of complete concordance of autoimmune disease in identical twins suggests that non-genetic factors also play a major role in determining disease susceptibility. Although there is no certain definition, epigenetics has been known as heritable alterations in gene function without changes in the nucleotide sequence. DNA methylation, histone modifications, and microRNA-associated gene expression suppression are the central mechanisms for epigenetic regulations. Multiple sclerosis (MS) is a disorder of the central nervous system (CNS), characterized by both inflammatory and neurodegenerative features. Although studies on epigenetic alterations in MS only began in the past decade, a mounting number of surveys suggest that epigenetic changes may be involved in the initiation and development of MS, probably through bridging the effects of environmental risk factors to genetics. Arming with clear understanding of epigenetic dysregulations underpins development of epigenetic therapies. Identifying agents inhibiting the enzymes controlling epigenetic modifications, particularly DNA methyltransferases and histone deacetylases, will be promising therapeutic tool toward MS. In the article underway, it is aimed to go through the recent progresses, attempting to disclose how epigenetics associates with the pathogenesis of MS and how can be used as therapeutic approach.     

多发性硬化的治疗进展

传统观点认为多发性硬化（MS）是一种中枢神经系统的自身免疫性炎性脱髓鞘疾病,常采用免疫抑制和抗炎治疗。随着对MS发病机制研究的深入,许多新的治疗策略被用于MS的治疗。MS疾病修正治疗已尝试进行MS发病的特异性靶点治疗,而对进展性MS则采用神经保护和神经修复治疗。与当前的治疗措施相比,新的治疗方案对控制MS复发更有效,但也带来一定的风险。目前仍在积极寻找进展性MS的有效治疗手段。     

Autologous Bone Marrow Transplantation for the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system and represents one of the leading causes of neurologic disability in young adults. Current treatments for MS have shown limited efficacy in patients with either a progressive or an aggressive disease course. Hematopoietic stem cell transplantation (HSCT) has been proposed to control or even cure refractory cases of MS. Indeed, HSCT is able to temporarily eradicate the autoreactive cells and to reset the aberrant immune response to self-antigens. In the last decade, owing to the growing experience in selecting the most appropriate patients to transplant and the recent advances in chemotherapeutic and support regimens, the transplant-related mortality of autologous HSCT in MS patients dropped down to 1,3 % and the progression-free survival ranges from 47 % to 100 %. Altogether, these data support autologous HSCT as a possible second-line therapy for refractory MS.     

High-Dose Cyclophosphamide in the Treatment of Multiple Sclerosis

High dose cyclophosphamide (HDC) has been successfully used for the treatment of a variety of autoimmune diseases. In this study, we sought to determine whether the use of high dose cyclophosphamide provided stabilization of relapsing remitting MS (RRMS), secondary progressive MS (SPMS), or primary progressive MS (PPMS). The parameters evaluated were EDSS scores, lesion load and brain volumes by MRI and frequency of relapses. Twenty-three patients underwent immunoablative therapy with HDC and were followed for 3.5 years. Nine were relapsing remitting (RRMS), 11 secondary progressive (SPMS), and 3 primary progressive (PPMS). Four of 9 RRMS have had no clinical progression up to 3.5 years following treatment. Three of 9 patients maintained a normal neurologic examination with improved EDSS scores. Seven of the nine RRMS patients had reduction in flare frequency which was maintained for 3.5 years following treatment or no immunomodulating agents. Subgroup analysis in the RRMS patients of lesion load and brain parenchymal volume revealed a favorable trend in these parameters which did not reach statistical significance. The treatment was generally ineffective for SPMS and failed in the 2 PPMS patients. HDC was well tolerated, demonstrated a good safety profile and had minimal adverse effects. These results along with previous reports suggest that early use of HDC therapy in RRMS is promising.     

Advances in and Algorithms for the Treatment of Relapsing-Remitting Multiple Sclerosis

Treatment options in relapsing-remitting multiple sclerosis have increased considerably in recent years; currently, a dozen different preparations of disease-modifying therapies are available and some more are expected to be marketed soon. For the treating neurologist this broad therapeutic repertoire not only greatly improves individualized management of the disease, but also makes choices more complex and difficult. A number of factors must be considered, including disease activity and severity, safety profile, and patient preference. We here discuss the currently existing options and suggest treatment algorithms for managing relapsing-remitting multiple sclerosis.