Combination therapies in multiple sclerosis

Interleukin-7 is required for CD4(+) T cell activation and autoimmune neuroinflammation

IL-7 is known to be vital for T cell homeostasis but has previously been presumed to be dispensable for TCR-induced activation. Here, we show that IL-7 is critical for the initial activation of CD4(+) T cells in that it provides some of the necessary early signaling components, such as activated STAT5 and Akt. Accordingly, short-term in vivo IL-7Rα blockade inhibited the activation and expansion of autoantigen-specific CD4(+) T cells and, when used to treat experimental autoimmune encephalomyelitis (EAE), prevented and ameliorated disease. Our studies demonstrate that IL-7 signaling is a prerequisite for optimal CD4(+) T cell activation and that IL-7R antagonism may be effective in treating CD4(+) T cell-mediated neuroinflammation and other autoimmune inflammatory conditions.

Depression and disease progression in amyotrophic lateral sclerosis: A comprehensive meta-regression analysis

Depression in people with amyotrophic lateral sclerosis, a fatal and progressive neurodegenerative disorder, is a serious issue with important clinical consequences. However, physical impairment may confound the diagnosis when using generic questionnaires. We conducted a comprehensive review of literature. Mean scores from depression questionnaires were meta-regressed on study-level mean time since onset of symptoms. Data from 103 studies (3190 subjects) indicate that the Beck Depression Inventory and, to a lesser degree, the Hospital Anxiety and Depression Scale are influenced by the time since symptom onset, strongly related to physical impairment. Our results suggest that widely used depression scales overestimate depression due to confounding with physical symptoms.

Neuroprotective dimethyl fumarate synergizes with immunomodulatory interferon beta to provide enhanced axon protection in autoimmune neuroinflammation

INTRODUCTION

Despite recent advances in development of treatments for multiple sclerosis, there is still an unmet need for more effective and also safe therapies. Based on the modes of action of interferon-beta (IFN-β) and dimethyl fumarate (DMF), we hypothesized that anti-inflammatory and neuroprotective effects may synergize in experimental autoimmune encephalomyelitis (EAE).

METHODS

EAE was induced in C57BL/6 mice by immunization with MOG35-55-peptide. Murine IFN-β was injected s.c. every other day at 10.000IU, and DMF was provided at 15mg/kg by oral gavage twice daily. Control mice received PBS injections and were treated by oral gavage with the vehicle methylcellulose. Mice were scored daily by blinded observers and histological, FACS and cytokine studies were performed to further elucidate the underlying mechanism of action.

RESULTS

Combination therapy significantly ameliorated EAE disease course in comparison to controls and monotherapy with IFN-β. Histological analyses showed a significant effect on axon preservation with almost twice as much axons present in inflamed lesions as compared to control. Remarkably, the effect on axonal preservation was more pronounced under combination therapy than with both monotherapies. Neither monotherapy nor combination therapy demonstrated modulation of cytokines and frequency of antigen presenting cells.

DISCUSSION

Combination of IFN-β and DMF resulted in greater beneficial effects with improved tissue protection as compared to the respective monotherapies. Further combination studies of these safe therapies in human disease are warranted.

Risk-benefit considerations in the treatment of relapsing-remitting multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system and mainly affects young adults. Its natural history has changed in recent years with the advent of disease-modifying drugs, which have been available since the early 1990s. The increasing number of first-line and second-line treatment options, together with the variable course of the disease and patient lifestyles and expectations, makes the therapeutic decision a real challenge. The aim of this review is to give a comprehensive overview of the main present and some future drugs for relapsing-remitting MS, including risk-benefit considerations, to enable readers to draw their own conclusions regarding the risk-benefit assessment of personalized treatment strategies, taking into account not only treatment-related but also disease-related risks. We performed a Medline literature search to identify studies on the treatment of MS with risk stratification and risk-benefit considerations. We focused our attention on studies of disease-modifying, immunomodulating, and immunosuppressive drugs, including monoclonal antibodies. Here we offer personal considerations, stemming from long-term experience in the treatment of MS and thorough discussions with other neurologists closely involved in the care of patients with the disease. MS specialists need to know not only the specific risks and benefits of single drugs, but also about drug interactions, either in simultaneous or serial combination therapy, and patient comorbidities, preferences, and fears. This has to be put into perspective, considering also the risks of untreated disease in patients with different clinical and radiological characteristics. There is no single best treatment strategy, but therapy has to be tailored to the patient. This is a time-consuming task, rich in complexity, and influenced by the attitude towards risk on the parts of both the patient and the clinical team. The broader the MS drug market becomes, the harder it will be for the clinician to help the patient decide which therapeutic strategy to opt for.

The interferon beta therapies for treatment of relapsing-remitting multiple sclerosis: are they equally efficacious? A comparative review of open-label studies evaluating the efficacy, safety, or dosing of different interferon beta formulations alone or in combination

Interferon beta preparations are the most widely used initial therapies prescribed for patients with relapsing-remitting multiple sclerosis. Phase III studies have demonstrated comparable efficacy on clinical measures of disease activity, variable benefits on radiological measures, and good overall tolerability. Subsequent clinical studies have attempted to compare directly the three available interferon beta preparations, reporting both safety and efficacy data. We review the literature on studies evaluating interferon beta therapy for patients with relapsing-remitting multiple sclerosis, discuss reasons for discrepant findings, and assess the utility of interferon beta-based combination regimens as the focus of future studies in the increasingly complex multiple sclerosis therapy landscape.

Escalating immunotherapy of multiple sclerosis

Basic disease-modifying treatment for relapsing forms of active multiple sclerosis (MS) is now available in many countries with high prevalence rates, for this chronic inflammatory disease of the central nervous system. Several lines of evidence support early immunomodulatory treatment with either recombinant interferon-beta or glatiramer acetate, and positive results from phase III trials encourage start of treatment even in patients with clinically isolated syndromes (CIS). However, currently available drugs for basic therapy are only partially effective and patients may still encounter relapses or disease progression. As treatment-refractory, clinically active MS can quickly lead to irreversible neurological disability there is an urgent need for effective escalating strategies. Patients with suboptimal treatment response to basic therapy have been treated with combination therapies, cytotoxic drugs (such as mitoxantrone and cyclophosphamide) or autologous hematopoietic stem cell transplantation. Recently, the monoclonal antibody, natalizumab, was added to this armamentarium. None of these strategies have been vigorously evaluated in large randomized, controlled phase III trials with patients who failed basic therapy. Therefore, the decision to escalate immunotherapy is still based on limited evidence. This article will review potential candidates for intensified immunosuppression and call for innovative study designs to better evaluate escalating immunotherapy in MS.

Immunomodulatory drug treatment in multiple sclerosis

The fundamental role of inflammatory immune processes in the pathology of multiple sclerosis (MS) provides the rationale for immunomodulatory therapies that attempt to shift the immune system from pro-inflammatory to anti-inflammatory pathways and induce regulatory mechanisms. Growing understanding of immune cellular and molecular mechanisms together with modern biotechnology engendered promising immunomodulatory treatment strategies, with novel mechanisms of actions and different levels of specificity. These include inhibitory molecules, monoclonal antibodies, cell therapies and agents that are administered orally or by infrequent infusions. Several of these treatments have demonstrated impressive efficacy in Phase II and III clinical trials by reducing disease activity and accumulation of disability. However, with the advent of potent therapies, rare but severe adverse effects, such as CNS infections and malignancies, have occurred. This article describes current and upcoming immunomodulatory strategies for MS therapy. The potential of immunomodulatory treatments to counteract the inflammatory characteristics of MS and support neuroprotective processes is discussed.

Chemotherapeutics in the treatment of multiple sclerosis

The likely pathogenic mechanisms of multiple sclerosis (MS) provide a sound rationale for investigating the efficacy of drugs possessing immunosuppressive or immunomodulatory properties. With proven efficacy, safety and tolerability, interferon beta formulations and glatiramer acetate have become the mainstay of initial treatment for patients with relapsing forms of MS. More recently, natalizumab, a humanized monoclonal antibody (mAb) against the cellular adhesion molecule α4-integrin, has been employed for patients with an inadequate response or lack of tolerability to an alternate MS therapy, or as initial therapy for patients with severe disease. Various agents initially developed for oncological indications, either as chemotherapeutics or mAbs, may also have current or future uses in MS treatment. Mitoxantrone is currently the only chemotherapeutic agent approved for treatment of MS in the United States, while in parts of Europe azathioprine is approved and widely used for MS treatment. Other chemotherapeutics that have been tested in MS to date include cyclophosphamide, methotrexate, cladribine, and the mAbs alemtuzumab and rituximab. While there has been varying evidence of efficacy for these compounds, each appears to be associated with serious risks that require careful consideration and management. Given the risks that have been demonstrated for available chemotherapeutic agents and while long-term postmarketing safety data are still not available for those agents in development, it seems prudent to carefully assess the possible use of chemotherapeutics in the treatment of MS. A thorough risk-benefit analysis is becoming increasingly important in the assessment of therapeutic options for this disabling disease.

Clinical efficacy issues in the treatment of multiple sclerosis: update of natalizumab

Multiple sclerosis is a frequent neurologic disease, which causes sensory impairment, fatigue, cognitive deficits, imbalance, loss of mobility, spasticity, and bladder and bowel dysfunction. Several new therapies have been introduced in the past decade, but additional drugs are needed to slow disease progression and reduce disability. Natalizumab (NA) is an α4 integrin antagonist, effective in decreasing the development of brain lesions in experimental models and in several studies of patients with MS. Six randomized controlled trials of NA in MS have been published in the last 10 years. Overall, 2,688 relapsing-remitting MS subjects have been enrolled in these studies. Hence, there are already sufficient data to draw some conclusions about the effectiveness of NA in the treatment of MS, although for definitive considerations it would be reasonable to wait for the observational phase IV studies of clinical practice to complete. Moreover, the medical community is concerned with the safety of NA, particularly with the risk of developing progressive multifocal leukoencephalopathy while on NA therapy. From the analyses of the six cases, it seems that the overall risk is around 1/1,000 and could increase with the number of NA infusions.

The future of multiple sclerosis treatment

Recent years have seen considerable evolution and increasing sophistication of our concepts of the pathophysiology of multiple sclerosis. These new notions include the increased recognition of the importance of extralesional pathology, of the interplay between inflammation and neurodegenerative changes, pathophysiological heterogeneity and additional immune cell populations contributing to disease. These advances have driven the development and evaluation of new therapeutic strategies and outcome measures for clinical trials. A sizeable number of new immunomodulatory and immunosuppressive agents are under development and attracting great attention. These may offer potential advantages over existing treatments in terms of convenience and efficacy, but certain agents may raise safety concerns. In addition, neuroprotective and repair strategies are beginning to be considered. Not all of these agents will eventually be marketed but they will all help us gain insight into the pathophysiology of multiple sclerosis and decipher the mechanisms that underlie its heterogeneity. The place that these therapies will come to occupy in future years will depend on their relative benefits and risks.

Immunosuppression in clinical practice: approaches to individualized therapy

Despite novel immunoactive agents, immunosuppressants still play a considerable role in the treatment of MS, especially in rapidly progressive cases. Given the limited tolerability and potentially severe side effects of most immunosuppressive drugs, identification of patients with a favorable benefit-risk profile is essential. A narrow therapeutic index, with sometimes high interindividual variability in terms of response and side effects may partially be explained by genetic factors affecting different metabolic pathways. Here, we will review practical aspects in the clinical use of immunosuppressants in MS and discuss approaches to individualized treatment schemes, including novel pharmacogenetic strategies.

The DNA cleavage reaction of topoisomerase II: wolf in sheep's clothing

Topoisomerase II is an essential enzyme that is required for virtually every process that requires movement of DNA within the nucleus or the opening of the double helix. This enzyme helps to regulate DNA under- and overwinding and removes knots and tangles from the genetic material. In order to carry out its critical physiological functions, topoisomerase II generates transient double-stranded breaks in DNA. Consequently, while necessary for cell survival, the enzyme also has the capacity to fragment the genome. The DNA cleavage/ligation reaction of topoisomerase II is the target for some of the most successful anticancer drugs currently in clinical use. However, this same reaction also is believed to trigger chromosomal translocations that are associated with specific types of leukemia. This article will familiarize the reader with the DNA cleavage/ligation reaction of topoisomerase II and other aspects of its catalytic cycle. In addition, it will discuss the interaction of the enzyme with anticancer drugs and the mechanisms by which these agents increase levels of topoisomerase II-generated DNA strand breaks. Finally, it will describe dietary and environmental agents that enhance DNA cleavage mediated by the enzyme.