Cladribine: An Investigational Immunomodulatory Agent for Multiple Sclerosis

Real-world experience of cladribine treatment in relapsing-remitting multiple sclerosis: A Danish nationwide study

BACKGROUND

Cladribine is a nucleoside analogue interfering with synthesis and repair of DNA. Treatment with cladribine leads to a preferential reduction in lymphocytes, resulting in profound depletion of B-cells with a rapid recovery of naïve B-cells, while T-cell show a lesser but long-lasting depletion It is approved for treatment of relapsing multiple sclerosis (MS). Cladribine tablets 3.5 mg/kg bodyweight are administered in two yearly treatment courses, each including two treatment series lasting 4 or 5 days, one at the start of the first month and the other at the start of the second month.

OBJECTIVE

To describe treatment patterns of cladribine in a real-world setting.

METHODS

Registry based observational cohort study with prospectively enrolled cases from December 2017 through June 2021. The data source is The Danish Multiple Sclerosis Registry, which is a near complete nationwide population-based registry. Outcomes were length of the treatment, preceding and following treatments, treatment response, and safety data.

RESULTS

In total 268 patients had started therapy with cladribine tablets, 89 men and 179 women, with a median age of 40 years (interquartile range (IQR) 32-48. The disease course was relapsing-remitting MS in 97.8% of the patients, and at treatment start the median time from disease onset was 8.1 years (IQR 4.2-14.5) and EDSS 2.5 (IQR 1.5-3.5). Thirty-four patients (12.7%) were treatment naïve while 56 (20.9%) had received one previous disease-modifying therapy (DMT), 67 (25.0%) two, and 111 (41.4%) three or more previous DMTs. In total, 214 (80.0%) patients had completed the full treatment of two courses of cladribine, while 54 (20.0%) had received only one course of cladribine tablets. The median follow-up time after cladribine initiation was 34.7 months (IQR 23.3-43.7). Compared with an annualized relapse rate (ARR) of 0.67 (95% CI [0.56, 0.79]) in the year prior to start of cladribine, ARR was reduced to 0.11 (95% CI [0.08, 0.15]) in year 0-2 after 3-month re-baseline with cladribine (84.8% reduction). Adverse events, reported in 44 (16.4%) of the patients, were mild or moderate, and herpes zoster was only reported in 2 patients. In total, 30 (11.2%) patients discontinued cladribine treatment, of whom 7 (2.6%) discontinued because of adverse effects and 12 (4.5%) discontinued because of disease activity.

CONCLUSION

In this nationwide review of all Danish patients starting therapy with cladribine tablets in a real-world setting, cladribine treatment was safe, and the therapeutic response was as expected from previous clinical trials. A prolonged observation period is necessary to assess the long-term benefit and risk of cladribine.

Lymphocyte Counts and Multiple Sclerosis Therapeutics: Between Mechanisms of Action and Treatment-Limiting Side Effects

Although the detailed pathogenesis of multiple sclerosis (MS) is not completely understood, a broad range of disease-modifying therapies (DMTs) are available. A common side effect of nearly every MS therapeutic agent is lymphopenia, which can be both beneficial and, in some cases, treatment-limiting. A sound knowledge of the underlying mechanism of action of the selected agent is required in order to understand treatment-associated changes in white blood cell counts, as well as monitoring consequences. This review is a comprehensive summary of the currently available DMTs with regard to their effects on lymphocyte count. In the first part, we describe important general information about the role of lymphocytes in the course of MS and the essentials of lymphopenic states. In the second part, we introduce the different DMTs according to their underlying mechanism of action, summarizing recommendations for lymphocyte monitoring and definitions of lymphocyte thresholds for different therapeutic regimens.

Treatment of multiple sclerosis - success from bench to bedside

The modern era of multiple sclerosis (MS) treatment began 25 years ago, with the approval of IFNβ and glatiramer acetate for the treatment of relapsing-remitting MS. Ten years later, the first monoclonal antibody, natalizumab, was approved, followed by a third important landmark with the introduction of oral medications, initially fingolimod and then teriflunomide, dimethyl fumarate and cladribine. Concomitantly, new monoclonal antibodies (alemtuzumab and ocrelizumab) have been developed and approved. The modern era of MS therapy reached primary progressive MS in 2018, with the approval of ocrelizumab. We have also learned the importance of starting treatment early and the importance of clinical and MRI monitoring to assess treatment response and safety. Treatment decisions should account for disease phenotype, prognostic factors, comorbidities, the desire for pregnancy and the patient's preferences in terms of acceptable risk. The development of treatment for MS during the past 25 years is a fantastic success of translational medicine.

A review of bioanalytical methods for chronic lymphocytic leukemia drugs and metabolites in biological matrices

Quantitation of drugs used for the treatment of chronic lymphocytic leukemia in various biological matrices during both pre-clinical and clinical developments is very important, often in routine therapeutic drug monitoring. The first developed methods for quantitation were traditionally done on LC in combination with either UV or fluorescence detection. However, the emergence of LC with mass spectrometry in tandem in early 1990s has revolutionized the quantitation as it has provided better sensitivity and selectivity within a shorter run time; therefore it has become the choice of method for the analysis of various drugs. In this article, an overview of various bioanalytical methods (HPLC or LC-MS/MS) for the quantification of drugs for the treatment of chronic lymphocytic leukemia, along with applicability of these methods, is given.

Pulsed immune reconstitution therapy in multiple sclerosis

Whereas drugs used for maintenance/escalation therapy do not maintain their beneficial effect after cessation of therapy, some new highly effective therapies can show prolonged treatment effects after a short treatment course. Such therapies have been named pulsed immune reconstitution therapies or pulsed immunosuppressive therapies, and typical representatives are alemtuzumab and cladribine. Autologous haematopoietic stem cell transplantation could be considered as the strongest immune reconstitution therapy. Both alemtuzumab and cladribine induce depletion of lymphocytes, and a common mechanism of action is preferential depletion of class-switched and unswitched memory B-cells. Whereas CD-19+ B-lymphocytes repopulate within 6 months, CD4+ T-cells repopulate at a slower rate, taking 1–2 years to reach the lower level of normal. In general, the depletion of lymphocytes is more profound and the repletion of T-cells is slower after alemtuzumab than after cladribine treatment. Both drugs have a strong effect on relapses and magnetic resonance imaging (MRI) activity, and reduce disability worsening. The therapeutic effect is maintained beyond the period of active treatment in a large proportion of patients, which is best documented for alemtuzumab. Adverse effects include reactivation of latent infections such as tuberculosis and risk of herpes zoster. The main disadvantage in alemtuzumab-treated patients is the risk of secondary immune-mediated disorders. Pulsed immune reconstitution therapy is an option as initial therapy in relapsing-remitting multiple sclerosis patients with high disease activity and in patients on treatment with another disease-modifying therapy with significant relapse and/or MRI activity.

Novel immunomodulatory approaches for the management of multiple sclerosis

We provide a focused review of novel immunomodulatory approaches for the treatment of multiple sclerosis, the most common acquired inflammatory demyelinating disease of humans. The requirement for such a review was stimulated by the emerging application of novel oral medications and the need for the practicing physician to place these within the treatment paradigm. We provide a conceptual diagram of our current view of the pathogenesis of demyelination and remyelination in this disorder. In addition, we include a working template on how to use a tier 1 and tier 2 approach to medications as the disease worsens in the individual. We emphasize the approach of treatment based on "individualized medicine," tailored to the specific needs of each patient. In the future, we envision new drugs to enhance remyelination and protect neurons and axons from death in order to promote central nervous system regeneration and repair.

Impact of cladribine therapy on changes in circulating dendritic cell subsets, T cells and B cells in patients with multiple sclerosis

BACKGROUND

Cladribine causes sustained reduction in peripheral T and B cell populations while sparing other immune cells. We determined two populations of dendritic cells (DCs): namely CD1c(+)/CD19(-) (myeloid DCs) and CD303(+)/CD123(+) (plasmacytoid DCs), CD19(+) B lymphocytes, CD3(+) T lymphocytes and CD4(+) or CD8(+) subpopulations in patients with multiple sclerosis after cladribine therapy.

METHODS

We examined 50 patients with secondary progressive multiple sclerosis (SP MS) according to McDonalds et al.'s criteria, 2001 [15]. Blood samples were collected before the initiation of cladribine therapy and after 1st, 2nd, 3th, 4th and 5th courses of treatment. DC subsets, T and B cells were analyzed by flow cytometry.

RESULTS

During cladribine treatment the myeloid DCs CD1c(+)/CD19(-) did not change (p=0.73175), and the plasmacytoid DCs CD303(+)/CD123(+) significantly increased (p=0.00034) which resulted in significant changes in the ratio of myeloid DCs to plasmacytoid DCs (p=0.00273). During therapy, B lymphocyte CD19(+) significantly decreased (p=0.00005) and significant changes in CD4(+) cells (p=0.00191), changes in CD8(+) cells (p=0.05760) and significant changes in CD3(+) (p=0.01822) were found.

CONCLUSIONS

We noticed significant trend to increase the CD303(+) circulating the dendritic cells. This population produces large amounts of IFN-alfa. We found significant and rapid decrease in B cells and CD4(+) Th cells. Our results suggest two possible ways of beneficial cladribine influence on immune system in MS. Induction of IFN-alfa producing cells and their predominance over BDCA-1(+) DCs, which are associated with cytotoxic response. Additionally, cladribine could influence two populations of lymphocytes: B cells and Th lymphocytes responsible for induction of immune response against myelin antigens.

Multiple sclerosis: new insights in pathogenesis and novel therapeutics

Concepts of multiple sclerosis (MS) have shifted from the traditional view of a T cell-mediated, demyelinating disease of the white matter to include a broad range of immunopathogenic mechanisms, axonal damage, and widespread gray matter pathology. The cause of MS remains unknown, but recent epidemiological work has focused on genetic factors; environmental factors such as vitamin D, sunlight, and Epstein-Barr virus; and the controversial theory of chronic cerebrospinal venous insufficiency. Revised criteria facilitate making the diagnosis of MS. Emerging therapies are rapidly expanding treatment options, including both parenterally administered and oral medications. Strategies to preserve tissue, promote repair, and restore function are under development, and it is anticipated that they will provide better options for patients with progressive disease.

Development of oral immunomodulatory agents in the management of multiple sclerosis

The emergence of oral disease-modifying therapies in multiple sclerosis (MS) will have a significant impact on the evolving scenario of immunomodulatory treatments in MS where current therapies are all injectable. Reducing relapses in trials translates for individuals with MS into a therapeutic aim of stopping future events. Thus the possible absence of any perceived benefits to the individual together with the long disease course, variable outcome, and a younger age group affected in MS makes side effects the major issue. The use of disease-modifying therapies as a whole needs to be placed in the context of a widening therapeutic indication where the use of these therapies is being justified at an increasingly early stage and in pre-MS syndromes such as clinically isolated and radiologically isolated syndromes where no fixed disability is likely to have accumulated. The five oral therapies discussed (cladribine, fingolimod, laquinimod, BG-12, and teriflunomide) have just completed Phase III studies and some have just been licensed. New oral drugs for MS need to be placed within this evolving marketplace where ease of delivery together with efficacy and side effects needs to be balanced against the known issues but also the known long-term safety of standard injectables.

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.

T-cell based immunotherapy in experimental autoimmune encephalomyelitis and multiple sclerosis

One of the reasons multiple sclerosis (MS) has been considered a T-cell mediated autoimmune disease is that a similar experimental disease can be induced in certain rodents and primates by immunization with myelin antigens, leading to T-cell-mediated inflammatory demyelination in the CNS. In addition, most if not all pharmacological treatments available for MS are biologically active on T cells. In this article we review the principles of T-cell-based immunotherapies and the specific actions of current and novel treatments on T-cell functions, when these are known. For both licensed and innovative agents, we also discuss biological actions on other immune cell types. Finally, we offer a brief perspective on expected changes in the use of MS immunotherapies in the near future.

Disease modifying agents for multiple sclerosis

Objective:

To summarize major clinical trials which evaluate the efficacy and safety data of approved disease modifying agents for the treatment of various types of multiple sclerosis.

Data Sources:

A MEDLINE (1966 to August 2008) search of clinical trials using the terms multiple sclerosis, interferon, glatiramer, mitoxantrone and natalizumab was performed. A manual bibliographic search was also conducted. English-language articles identified from the searches were evaluated. New agents under investigation in phase 3 clinical trials were identified using www.clinicaltrials.gov.

Study Selection & Data Extraction:

Relevant information was identified and selected based on clinical relevance and evidence-based strength. Prescribing information leaflets were used to provide usual dosage, contraindications, precautions, monitoring parameters and other relevant drug-specific information.

Data Synthesis:

Interferon beta products are more efficacious for the treatment of relapsing-remitting multiple sclerosis. Interferon beta 1-b also delayed the time to diagnosis of definite multiple sclerosis and reduced brain lesion burden in patients with clinical isolated syndrome. Glatiramer and natalizumab have both established efficacy in relapsing forms of multiple sclerosis; whereas mitoxantrone is more commonly used in patients with advanced disease. There are limited data the comparative efficacy among different disease modifying agents. New agents currently under investigation have showed promising results and may offer more treatment options in the future.

Conclusions:

MS is a complex and devastating disease with challenging treatment considerations and approaches. Interferon beta products continue to be the mainstay of therapy in many patients, however, other treatments are proving to be at least as effective in the management of various types of MS. Newer compounds are being developed and studied with much anticipation and promise for the clinical management of the disease.

Development of oral cladribine for the treatment of multiple sclerosis

Multiple sclerosis (MS) is a chronic immune-mediated disorder of the CNS in which autoreactive CD4+ and CD8+ T lymphocytes, B lymphocytes, antibodies, macrophages and cytokines synergize to attack myelin sheaths and injure underlying axons. Current disease-modifying drugs (DMDs) for MS require regular and frequent parenteral administration and are associated with limited long-term treatment adherence. Of all the potential new oral MS agents in development, cladribine is the only therapy with the potential for short-course dosing. Cladribine is an immunosuppressant that offers targeted, sustained regulation of the immune system and that has a well-characterized safety profile, derived from more than 15 years of use of the parenteral formulation in oncology indications and MS. This paper discusses the need for new MS therapies to improve treatment adherence, and reviews the mechanism of action, existing efficacy and safety data, and the clinical development of oral cladribine. The need for continuous risk monitoring for all new potent immunoactive drugs under development is emphasized. Preliminary results of the 96-week, double-blind, randomized, placebo-controlled, multicenter CLARITY (CLAdRIbine Tablets Treating MS OrallY) study are encouraging and provide the first complete phase III data on an oral DMD for MS.

Risks vs benefits of glatiramer acetate: a changing perspective as new therapies emerge for multiple sclerosis

An understanding of the risks, benefits, and relative value of glatiramer acetate (GA) in multiple sclerosis (MS) has been evolving based on recently completed head-to-head studies: REGARD (REbif vs Glatiramer Acetate in Relapsing MS Disease); BEYOND (Betaseron Efficacy Yielding Outcomes of a New Dose); and BECOME (BEtaseron vs COpaxone in Multiple Sclerosis with Triple-Dose Gadolinium and 3-Tesla MRI Endpoints). Outcomes in the primary endpoints of these trials showed no significant differences between GA and high-dose beta-interferons (IFNβs). Results of the PreCISe (Early GA Treatment in Delaying Conversion to Clinically Definite Multiple Sclerosis [CDMS] in Subjects Presenting With a Clinically Isolated Syndrome [CIS]) trial led to the US Food and Drug Administration approval of GA in patients with a CIS. Furthermore, the ongoing follow-up study to the original pivotal GA trial, now extending beyond 15 years, continues to support the safety of GA. Currently, GA and IFNβs are no longer the only immunomodulators available for MS. Introduction of the monoclonal antibody, natalizumab (Tysabri^®; Biogen Idec, Inc., Cambridge, MA, USA) provides an alternative immunomodulator for MS and has changed the therapeutic landscape dramatically. However, the rare but serious cases of progressive multifocal leukoencephalopathy that have occurred with natalizumab have raised concerns among clinicians and patients about using this agent and some of the emerging agents. The potential risks and benefits of the emerging therapies (cladribine, alemtuzumab, rituximab, fingolimod, laquinimod, teriflunomide, and dimethyl fumarate) based on phase II/III trials, as well as their use for indications other than MS, will be presented. This review provides available data on GA, natalizumab, and the emerging agents to support new developments in our understanding of GA and how its long-standing role as a first-line therapy in MS will evolve within the increasingly complex MS therapeutic landscape.

Cladribine inhibits a diltiazem-induced increase in red blood cell purine nucleotide concentrations in a zebrafish model

Minimizing drug interactions is paramount to improving the efficacy and tolerability of cancer therapy. The zebrafish represents an innovative cancer model due to highly conserved genetics and inherent capacity for high-throughput chemical screening. This pilot study extends the utility of the zebrafish to a preclinical model for pharmacodynamics by examining the interaction of the nucleoside analogue, cladribine with the calcium channel blocker, diltiazem. Cladribine (0.7-3.5 mM) and/or diltiazem (2.4 mM), was injected intraperitoneally into adult zebrafish and red blood cell (RBC) lysates were assayed by HPLC for levels of purine nucleotides (e.g. ATP), potential biomarkers of cardiovascular health. Diltiazem increased RBC ATP concentrations, which were inhibited by co-injection of cladribine. These results suggest a novel drug interaction and highlight the feasibility of the zebrafish as an in vivo model for pharmacodynamic studies.

Cladribine: not just another purine analogue?

Cladribine was synthesized as a purine analogue drug that inhibited adenosine deaminase. It received FDA approval in the 1980s for treatment of hairy cell leukemia. Given its toxicity towards lymphocytes and its corresponding immunosuppressive effects, it has been studied and found efficacious in a variety of hematologic malignancies and autoimmune conditions, most recently multiple sclerosis. This review highlights pharmacological, toxicological and clinical data for the use of cladribine. It also discusses existing and new mechanisms that may contribute to its unique clinical activity. Emerging data show that in addition to its known purine nucleoside analogue activity, cladribine possesses epigenetic properties, inhibiting S-adenosylhomocysteine hydrolase and DNA methylation. This may contribute to its efficacy and highlights the importance of studying combination therapy with other epigenetic or targeted agents. Clinical trials are underway in a variety of malignant and nonmalignant conditions.

Multiple sclerosis therapies: molecular mechanisms and future

The current treatments for multiple sclerosis (MS) are, by many measures, not satisfactory. The original interferon-β therapies were not necessarily based on an extensive knowledge of the pathophysiological mechanisms of the disease. As more and more insight has been acquired about the autoimmune mechanisms of MS and, in particular, the molecular targets involved, several treatment approaches have emerged. In this chapter, we highlight both promising preclinical approaches and therapies in late stage clinical trials that have been developed as a result of the improved understanding of the molecular pathophysiology of MS. These clinical stage therapies include oral agents, monoclonal antibodies, and antigen-specific therapies. Particular emphasis is given to the molecular targets when known and any safety concerns that have arisen because, despite the need for improved efficacy, MS remains a disease in which the safety of any agent remains of paramount importance.

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.

Pharmacokinetics of cladribine in a rat model following subcutaneous and intra-arterial injections

Male Sprague Dawley rats (n = 6-8 per group) weighing from 300-450 g were used for the study. Each rat received a single dose of cladribine (CdA) by ia (1 mg/kg) or s.c. (2 mg/kg) injection. Pharmacokinetic data were calculated by standard procedures assuming a 2-compartment open model following i.v. bolus using WinNonLin and Rstrips, and differences between the two modes of injections were considered significance when p < 0.05. The results showed that plasma concentrations of CdA decreased rapidly following a biphasic decline after both ia and s.c. administrations. The AUC and t1/2 beta after a single 1 mg/kg ia and 2 mg/kg s.c. injection of CdA were 0.66 +/- 0.34 vs 1.2 +/- 0.3 microg x h/ml and 3.5 +/- 2.1 vs 4.5 +/- 2.2 h, respectively (p > 0.05). The mean absolute bioavailability following the s.c. injection was close to 90%. The inter-subject variability of plasma concentrations of CdA was 35% and 150% following sc and ia injections, respectively. It is concluded that the rat is a reasonably good animal model to study the pharmacokinetics of CdA in plasma, and that sc injection may produce more favourable pharmacokinetic profiles than ia injection following a single dose.

Immunosuppressive agents in multiple sclerosis

Immunosuppressive agents have been used in multiple sclerosis (MS) for decades. The approval of several immunomodulatory agents against MS beginning in the 1990s, whose putative mechanisms of action appeared "more MS-specific," curtailed the importance of immunosuppressants, which made them treatment options of second choice. However, with the recent approval of mitoxantrone for treatment of patients with active forms of relapsing-remitting or secondary progressive MS and with a number of oral immunosuppressive agents being assessed in phase II and III clinical trials, a "renaissance" of this type of agents is currently occurring. This review provides an outline of the most important clinical studies and discusses relevant side effects of the major immunosuppressants (i.e., mitoxantrone, azathioprine, cyclophosphamide, methotrexate, mycophenolate mofetil, cladribine, and sirolimus/temsirolimus). The current knowledge of the putative mechanisms of action of these compounds is discussed.

Oral disease-modifying treatments for multiple sclerosis: the story so far

Multiple sclerosis (MS) represents the prototypic inflammatory autoimmune disorder of the CNS. It is the most common cause of neurological disability in young adults and exhibits considerable clinical, radiological and pathological heterogeneity. Increased understanding of the immunopathological processes underlying this disease, advances in biotechnology and the development of powerful magnetic resonance imaging (MRI) technologies, together with improvements in clinical trial design, have led to a variety of valuable therapeutic approaches to MS. Therapy for MS has changed dramatically over the past decade, yielding significant progress in the treatment of relapsing remitting and secondary progressive forms; however, most of the clinically relevant therapeutic approaches are not yet available as oral formulations. A substantial number of preliminary and pivotal reports have provided promising results for oral therapies, and various phase III clinical trials are currently being initiated or are already underway evaluating the efficacy of a variety of orally administered agents, including cladribine, teriflunomide, laquinimod, fingolimod and fumaric acid. It is hoped that these trials will advance the development of oral therapies for MS.

Compared benefit of approved and experimental immunosuppressive therapeutic approaches in multiple sclerosis

An important amount has been learnt about the mechanisms of action, efficacy and long-term toxicities of mitoxantrone. Importantly, recent observations strongly suggest that early administration of potent immunosuppressants (mitoxantrone and alemtuzumab) is definitely more effective than approved immunomodulators to delay or even reverse disability progression. Given the cardiotoxicity of mitoxantrone, restricting exposure to the drug to 2 or 3 years, the benefits and risks of immunosuppressants previously used as off-label treatments (cyclophosphamide and cladribine) have been revisited, and the potential efficacy in multiple sclerosis of recent immunosuppressants used in other autoimmune diseases, organ transplantation and cancer therapy has received increasing attention. Those immunosuppressants comprise monoclonal antibodies targeting B cells, lymphocytes and monocytes, IL-2 receptor and alpha4 integrin, as well as new molecules (pixantrone and isoxazole derivatives) and a new generation of immunosuppressants (fingolimod), which modulate lymphocyte re-circulation. This review addresses the most recent data concerning the efficacy and safety of mitoxantrone and of new experimental therapies that are presently in progress.

Current treatment options in multiple sclerosis

Advances in our understanding of the pathogenesis of multiple sclerosis (MS) lesions are leading to the development of more targeted therapies. Axonal transection is likely an important cause of accumulating disability in disease progression and suggests the importance of early and aggressive therapy. Early treatment with disease-modifying therapy should be considered in patients with first episode of demyelination and presence of MRI lesions consistent with MS. Intravenous steroids are the mainstay of treatment of acute MS exacerbations. Although their benefits must be weighed against the potential for complications, natalizumab and mitoxantrone significantly decrease relapses and MRI lesions in patients with relapsing MS. Many new therapies, including oral and infrequently administered infusion therapies, are currently in phase III trials and will likely become available over the next 3 to 4 years.