Suppression of demyelination by mitoxantrone

Does physical exercise improve or deteriorate treatment of multiple sclerosis with mitoxantrone? Experimental autoimmune encephalomyelitis study in rats

Background

Mitoxantrone has proved efficacy in treatment of multiple sclerosis (MS). The fact that physical exercise could slow down the progression of disease and improve performance is still a debatable issue, hence; we aimed at studying whether combining mitoxantrone with exercise is of value in the management of MS.

Methods

Thirty-six male rats were divided into sedentary and exercised groups. During a 14-day habituation period rats were subjected to exercise training on a rotarod (30 min/day) before Experimental Autoimmune Encephalomyelitis (EAE) induction and thereafter for 17 consecutive days. On day 13 after induction, EAE groups (exercised &sedentary) were divided into untreated and mitoxantrone treated ones. Disease development was evaluated by motor performance and EAE score. Cerebrospinal fluid (CSF) was used for biochemical analysis. Brain stem and cerebellum were examined histopathological and immunohistochemically.

Results

Exercise training alone did not add a significant value to the studied parameters, except for reducing Foxp3 immunoreactivity in EAE group and caspase-3 in the mitoxantrone treated group. Unexpectedly, exercise worsened the mitoxantrone effect on EAE score, Bcl2 and Bax. Mitoxantrone alone decreased EAE/demyelination/inflammation scores, Foxp3 immunoreactivity, and interleukin-6, while increased the re-myelination marker BDNF without any change in tumor necrosis factor-α. It clearly interrupted the apoptotic pathway in brain stem, but worsened EAE mediated changes of the anti-apoptotic Bcl2 and pro-apoptotic marker Bax in the CSF.

Conclusions

The neuroprotective effect of mitoxantrone was related with remyelination, immunosuppressive and anti-inflammatory potentials. Exercise training did not show added value to mitoxantrone, in contrast, it disrupts the apoptotic pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00692-1.

The role of B cells in the immunopathogenesis of multiple sclerosis

There is ongoing debate on how B cells contribute to the pathogenesis of multiple sclerosis (MS). The success of B-cell targeting therapies in MS highlighted the role of B cells, particularly the antibody-independent functions of these cells such as antigen presentation to T cells and modulation of the function of T cells and myeloid cells by secreting pathogenic and/or protective cytokines in the central nervous system. Here, we discuss the role of different antibody-dependent and antibody-independent functions of B cells in MS disease activity and progression proposing new therapeutic strategies for the optimization of B-cell targeting treatments.

Animal models of multiple sclerosis: From rodents to zebrafish

Multiple sclerosis (MS) is a chronic, immune-mediated demyelinating disease of the central nervous system. Animal models of MS have been critical for elucidating MS pathological mechanisms and how they may be targeted for therapeutic intervention. Here we review the most commonly used animal models of MS. Although these animal models cannot fully replicate the MS disease course, a number of models have been developed to recapitulate certain stages. Experimental autoimmune encephalomyelitis (EAE) has been used to explore neuroinflammatory mechanisms and toxin-induced demyelinating models to further our understanding of oligodendrocyte biology, demyelination and remyelination. Zebrafish models of MS are emerging as a useful research tool to validate potential therapeutic candidates due to their rapid development and amenability to genetic manipulation.

Reassessing B cell contributions in multiple sclerosis

There is growing recognition that B cell contributions to normal immune responses extend well beyond their potential to become antibody-producing cells, including roles at the innate-adaptive interface and their potential to modulate the responses of other immune cells such as T cells and myeloid cells. These B cell functions can have both pathogenic and protective effects in the context of central nervous system (CNS) inflammation. Here, we review recent advances in the field of multiple sclerosis (MS), which has traditionally been viewed as primarily a T cell-mediated disease, and we consider antibody-dependent and, particularly, emerging antibody-independent functions of B cells that may be relevant in both the peripheral and CNS disease compartments.

Pharmacological Approaches to the Management of Secondary Progressive Multiple Sclerosis

It is well recognised that the majority of the impact of multiple sclerosis (MS), both personal and societal, arises in the progressive phase where disability accumulates inexorably. As such, progressive MS (PMS) has been the target of pharmacological therapies for many years. However, there are no current licensed treatments for PMS. This stands in marked contrast to relapsing remitting MS (RRMS) where trials have resulted in numerous licensed therapies. PMS has proven to be a more difficult challenge compared to RRMS and this review focuses on secondary progressive MS (SPMS), where relapses occur before the onset of gradual, irreversible disability, and not primary progressive MS where disability accumulation occurs without prior relapses. Although there are similarities between the two forms, in both cases pinpointing when PMS starts is difficult in a condition in which disability can vary from day to day. There is also an overlap between the pathology of relapsing and progressive MS and this has contributed to the lack of well-defined outcomes, both surrogates and clinically relevant outcomes in PMS. In this review, we used the search term 'randomised controlled clinical drug trials in secondary progressive MS' in publications since 1988 together with recently completed trials where results were available. We found 34 trials involving 21 different molecules, of which 38% were successful in reaching their primary outcome. In general, the trials were well designed (e.g. double blind) with sample sizes ranging from 35 to 1949 subjects. The majority were parallel group, but there were also multi-arm and multidose trials as well as the more recent use of adaptive designs. The disability outcome most commonly used was the Expanded Disability Status Scale (EDSS) in all phases, but also magnetic resonance imaging (MRI)-measured brain atrophy has been utilised as a surrogate endpoint in phase II studies. The majority of the treatments tested in SPMS over the years were initially successful in RRMS. This has a number of implications in terms of targeting SPMS, but principally implies that the optimal strategy to target SPMS is to utilise the prodrome of relapses to initiate a therapy that will aim to both prevent progression and slow its accumulation. This approach is in agreement with the early targeting of MS but requires treatments that are both effective and safe if it is to be used before disability is a major problem. Recent successes will hopefully result in the first licensed therapy for PMS and enable us to test this approach.

Risk Mitigation Strategies for Adverse Reactions Associated with the Disease-Modifying Drugs in Multiple Sclerosis

Over the past several years, the number of disease-modifying therapies (DMTs) for the treatment of multiple sclerosis (MS) has doubled in number. The 13 approved agents have shown a wide range of efficacy and safety in their clinical trials and post-marketing experience. While the availability of the newer agents allows for a wider selection of therapy for clinicians and patients, there is a need for careful understanding of the benefits and risks of each agent. Several factors such as the medication efficacy, side-effect profile, patient's preference, and co-morbidities need to be considered. An individualized treatment approach is thus imperative. In this review, risk stratification and mitigation strategies of the various disease-modifying agents are discussed.

The current role of mitoxantrone in the treatment of multiple sclerosis

Mitoxantrone is an immunosuppressive drug approved for aggressive relapsing and progressive multiple sclerosis. In recent years, its use has decreased due to the risk of severe adverse events and the introduction of novel therapies, such as natalizumab or fingolimod. Mitoxantrone is effective in reducing inflammatory activity by decreasing the number of relapses and MRI lesions and simultaneously decreasing the worsening of disability. Apart from its role as a second/third-line therapy, some studies suggest its use as an induction therapy. However, mitoxantrone use is limited because of its potential risk of severe adverse events, such as cardiotoxicity and the induction of therapy-related acute leukemia. Genetic markers are on evaluation to predict side effects and therapeutic efficacy, which is consistent with the direction of personalized treatment. Considering its efficacy and the potential risks, mitoxantrone use is limited to active patients after a careful, individualized evaluation of the risk/benefit balance.

Imidazol-1-ylethylindazole voltage-gated sodium channel ligands are neuroprotective during optic neuritis in a mouse model of multiple sclerosis

A series of imidazol-1-ylethylindazole sodium channel ligands were developed and optimized for sodium channel inhibition and in vitro neuroprotective activity. The molecules exhibited displacement of a radiolabeled sodium channel ligand and selectivity for blockade of the inactivated state of cloned neuronal Nav channels. Metabolically stable analogue 6 was able to protect retinal ganglion cells during optic neuritis in a mouse model of multiple sclerosis.

Lesional-targeting of neuroprotection to the inflammatory penumbra in experimental multiple sclerosis

Progressive multiple sclerosis is associated with metabolic failure of the axon and excitotoxicity that leads to chronic neurodegeneration. Global sodium-channel blockade causes side effects that can limit its use for neuroprotection in multiple sclerosis. Through selective targeting of drugs to lesions we aimed to improve the potential therapeutic window for treatment. This was assessed in the relapsing-progressive experimental autoimmune encephalomyelitis ABH mouse model of multiple sclerosis using conventional sodium channel blockers and a novel central nervous system-excluded sodium channel blocker (CFM6104) that was synthesized with properties that selectively target the inflammatory penumbra in experimental autoimmune encephalomyelitis lesions. Carbamazepine and oxcarbazepine were not immunosuppressive in lymphocyte-driven autoimmunity, but slowed the accumulation of disability in experimental autoimmune encephalomyelitis when administered during periods of the inflammatory penumbra after active lesion formation, and was shown to limit the development of neurodegeneration during optic neuritis in myelin-specific T cell receptor transgenic mice. CFM6104 was shown to be a state-selective, sodium channel blocker and a fluorescent p-glycoprotein substrate that was traceable. This compound was >90% excluded from the central nervous system in normal mice, but entered the central nervous system during the inflammatory phase in experimental autoimmune encephalomyelitis mice. This occurs after the focal and selective downregulation of endothelial p-glycoprotein at the blood-brain barrier that occurs in both experimental autoimmune encephalomyelitis and multiple sclerosis lesions. CFM6104 significantly slowed down the accumulation of disability and nerve loss in experimental autoimmune encephalomyelitis. Therapeutic-targeting of drugs to lesions may reduce the potential side effect profile of neuroprotective agents that can influence neurotransmission. This class of agents inhibit microglial activity and neural sodium loading, which are both thought to contribute to progressive neurodegeneration in multiple sclerosis and possibly other neurodegenerative diseases.

Results from the 5-year, phase IV RENEW (Registry to Evaluate Novantrone Effects in Worsening Multiple Sclerosis) study

Background

Registry to Evaluate Novantrone Effects in Worsening Multiple Sclerosis (RENEW) was a 5-year, phase IV study in which the safety of Mitoxantrone was monitored in a patient cohort from the United States (US). The objective of the study was to evaluate the long-term safety profile of Mitoxantrone in patients with secondary progressive multiple sclerosis (SPMS), progressive relapsing multiple sclerosis (PRMS), and worsening relapsing-remitting multiple sclerosis (RRMS).

Methods

Overall, 509 patients (395 SPMS, 81 worsening RRMS, 33 PRMS) were enrolled and treated at 46 multiple sclerosis (MS) treatment centers located in the US. Patients received Mitoxantrone in accordance with the package insert every 3 months. During the treatment phase, patients received laboratory workups and cardiac monitoring every 3 months and then annually for a total of 5 years.

Results

Five hundred and nine subjects were enrolled in this trial and received at least one infusion of Mitoxantrone. Overall, 172 (33.8%) completed the 5-year trial (i.e., participated for 5 years ± 3 months [treatment + follow-up]); 337 (66.2%) did not complete the 5-year trial. Annual follow-up data were available for 250 of 509 enrolled patients. Left ventricular ejection fraction reduction under 50% was reported in 27 (5.3%) patients during the treatment phase (n = 509) and 14 (5.6%) patients during the annual follow-up phase (n = 250). Signs and symptoms of congestive heart failure were observed in 10 (2.0%) patients (six during treatment phase and four during the annual follow-up phase). Post-hoc analyses of the risk for cardiotoxicity outcomes revealed that cumulative dose exposure is the primary risk factor associated with the risk of cardiac toxicity with Mitoxantrone. Therapy-related leukemia was reported in three (0.6%) patients who received total cumulative Mitoxantrone doses of 73.5 mg/m², 107.3 mg/m², and 97.1 mg/m² respectively. During the treatment phase, persistent amenorrhea developed in 22% (28/128) of women with regular menses and 51% (25/49) of women with irregular menses at baseline. During the annual follow-up phase, persistent amenorrhea developed in 5% (4/73) of women with regular menses at baseline.

Conclusion

RENEW results are consistent with the known safety profile of Mitoxantrone, and provide additional long-term safety data for Mitoxantrone in MS patients.

The benefits and detriments of macrophages/microglia in models of multiple sclerosis

The central nervous system (CNS) is immune privileged with access to leukocytes being limited. In several neurological diseases, however, infiltration of immune cells from the periphery into the CNS is largely observed and accounts for the increased representation of macrophages within the CNS. In addition to extensive leukocyte infiltration, the activation of microglia is frequently observed. The functions of activated macrophages/microglia within the CNS are complex. In three animal models of multiple sclerosis (MS), namely, experimental autoimmune encephalomyelitis (EAE) and cuprizone- and lysolecithin-induced demyelination, there have been many reported detrimental roles associated with the involvement of macrophages and microglia. Such detriments include toxicity to neurons and oligodendrocyte precursor cells, release of proteases, release of inflammatory cytokines and free radicals, and recruitment and reactivation of T lymphocytes in the CNS. Many studies, however, have also reported beneficial roles of macrophages/microglia, including axon regenerative roles, assistance in promoting remyelination, clearance of inhibitory myelin debris, and the release of neurotrophic factors. This review will discuss the evidence supporting the detrimental and beneficial aspects of macrophages/microglia in models of MS, provide a discussion of the mechanisms underlying the dichotomous roles, and describe a few therapies in clinical use in MS that impinge on the activity of macrophages/microglia.

Mitoxantrone for multiple sclerosis

BACKGROUND

This is an updated Cochrane review of the previous published version.Mitoxantrone (MX) has been shown to be moderately effective in reducing the clinical outcome measures of disease activity in multiple sclerosis (MS) patients.

OBJECTIVES

The main objective was to assess the efficacy and safety of MX compared to a control group in relapsing-remitting (RRMS), progressive relapsing (PRMS) and secondary progressive (SPMS) MS participants.

SEARCH METHODS

We searched the Cochrane Multiple Sclerosis and Rare Diseases of the Central Nervous System Group Specialised Register (June 2012) and reference lists of articles. We also undertook handsearching and contacted trialists and pharmaceutical companies.

SELECTION CRITERIA

Randomised, double-blinded, controlled trials (RCTs) comparing the administration of MX versus placebo or MX plus steroids treatment versus placebo plus steroids treatment were included.

DATA COLLECTION AND ANALYSIS

The review authors independently selected articles for inclusion. They independently extracted clinical, safety and magnetic resonance imaging (MRI) data, resolving disagreements by discussion. Risk of bias was evaluated to assess the quality of the studies. Treatment effect was measured using odds ratios (OR) with 95% confidence intervals (CI) for the binary outcomes and mean differences (MD) with 95% CI for the continuous outcomes. If heterogeneity was absent, a fixed-effect model was used.

MAIN RESULTS

Three trials were selected and 221 participants were included in the analyses. MX reduced the progression of disability at two years follow-up (proportion of participants with six months confirmed progression of disability (OR 0.30, 95% CI 0.09 to 0.99 and MD -0.36, 95% CI- 0.70 to -0.02; P = 0.04)). Significant results were found regarding the reduction in annualised relapse rate (MD -0.85, 95% CI -1.47 to -0.23; P = 0.007), the proportion of patients free from relapses at one year (OR 7.13, 95% CI 2.06 to 24.61; P = 0.002) and two years (OR 2.82, 95% CI 1.54 to 5.19; P = 0.0008), and the number of patients with active MRI lesions at six months or one year only (OR 0.24, 95% CI 0.10 to 0.57; P = 0.001). Side effects reported in the trials (amenorrhoea, nausea and vomiting, alopecia and urinary tract infections) were more frequent in treated patients than in controls, while no major adverse events have been reported. These results should be considered with caution because of the heterogeneous characteristics of included trials in term of drug dosage, inclusion criteria and quality of included trials. Moreover, it was not possible to estimate the long-term efficacy and safety of MX.

AUTHORS' CONCLUSIONS

MX shows a significant but partial efficacy in reducing the risk of MS progression and the frequency of relapses in patients affected by worsening RRMS, PRMS and SPMS in the short-term follow-up (two years). No major neoplastic events or symptomatic cardiotoxicity related to MX have been reported; however studies with longer follow-up (not included in this review) have raised concerns about the risk of systolic disfunction (˜12%) and therapy-related acute leukaemias (0.8%), which are increasingly reported in the literature.MX should be limited to treating patients with worsening RRMS and SPMS and with evidence of persistent inflammatory activity after a careful assessment of the individual patients' risk and benefit profiles. Assessment should also consider the present availability of alternative therapies with less severe adverse events.

Management of secondary progressive multiple sclerosis: prophylactic treatment-past, present, and future aspects

OPINION STATEMENT

Whereas the number of treatment options in relapsing-remitting multiple sclerosis (RRMS) is growing constantly, alternatives are rare in the case of secondary-progressive multiple sclerosis (SPMS). Besides mitoxantrone in North America and Europe, interferon beta-1b and beta-1a are approved for treatment in Europe. Glucocorticosteroids, azathioprine, intravenous immunoglobulins (IVIG) and cyclophosphamide (CYC), although not approved, are commonly utilized in SPMS. Currently monoclonal antibodies (mab), and masitinib are under examination for treatment for SPMS. Hematopoietic stem cell transplantation and immunoablative stem cell transplantation are therapies with the aim of reconstitution of the immune system. This review gives information on the different therapeutics and the trials that tested them. Pathophysiological considerations are presented in view of efficacy of the therapeutics. In addition, therapeutics that showed no efficacy in trials or with unacceptable side effects are topics of this review.

Current and future disease-modifying therapies in multiple sclerosis

The development of disease-modifying therapies (DMT) in multiple sclerosis (MS) has rapidly evolved over the last few years and continues to do so. Prior to the United States Food and Drug Administration approval of the immunomodulatory agent, interferon-beta1b in 1993, no other drug had been shown to alter the course of the disease in a controlled study of MS. At present, there are five licenced disease-modifying agents in MS - interferon-beta1b, interferon-beta1a, glatiramer acetate, natalizumab and mitoxantrone. All have shown significant therapeutic efficacy in large controlled trials. However, current therapies are only partially effective and are not free from adverse effects. Moreover, available DMTs are overwhelmingly biased in favour of those with relapsing-remitting disease. Effective treatment for progressive MS is severely limited, with only interferon-beta1b and mitoxantrone having licenced use in secondary progressive, but not primary progressive disease. Monoclonal antibodies, such as natalizumab selectively target immune pathways involved in the pathogenic process of MS. Alemtuzumab, daclizumab and rituximab are other notable monoclonal antibodies currently undergoing phase II and III trials in MS. Alemtuzumab has so far shown promising therapeutic benefit in relapsing disease, although immunological adverse effects have been a problem. Oral therapies have the benefit of improved tolerability and patient compliance compared with current parenteral treatments. Cladribine and fingolimod (FTY720) have shown encouraging results in their phase III clinical trials. It is also worth noting the evidence for starting DMT in patients with clinically isolated syndrome, whereby early treatment has shown to delay the onset of clinically definite MS in separate phase III studies.

Restoring immune suppression in the multiple sclerosis brain

Multiple sclerosis is a very disabling inflammatory demyelinating disease of the brain of unknown etiology. Current therapies can reduce new lesion development and partially prevent clinical disease activity, but none can halt the progression, or cure the disease. We will review current therapeutic strategies, which are mostly discussed in literature in terms of their effective inhibition of T cells. However, we argue that many of these treatments also influence the myeloid compartment. Interestingly, recent evidence indicates that myelin phagocytosis by infiltrated macrophages and activated microglia is not just a hallmark of multiple sclerosis, but also a key determinant of lesion development and disease progression. We reason that severe side effects and/or insufficient effectiveness of current treatments necessitates the search for novel therapeutic targets, and postulate that these should aim at manipulation of the activation and phagocytic capacity of macrophages and microglia. We will discuss three candidate targets with high potential, namely the complement receptor 3, CD47-SIRPalpha interaction as well as CD200-CD200R interaction. Blocking the actions of complement receptor 3 could inhibit myelin phagocytosis, as well as migration of myeloid cells into the brain. CD47 and CD200 are known to inhibit macrophage/microglia activation through binding to their receptors SIRPalpha and CD200R, expressed on phagocytes. Triggering these receptors may thus dampen the inflammatory response. Our recent findings indicate that the CD200-CD200R interaction is the most specific and hence probably best-suited target to suppress excessive macrophage and microglia activation, and restore immune suppression in the brain of patients with multiple sclerosis.

Daclizumab treatment for multiple sclerosis

Multiple sclerosis is a chronic inflammatory and demyelinating disease of the central nervous system and the leading cause of neurologic disability in young adults. Established therapies, such as interferon and glatiramer, have only partial effects, and they offer limited or no effect on the progression of multiple sclerosis. The etiology of multiple sclerosis is unclear; however, the disease is presumed to be a T-cell-mediated autoimmune disease influenced by genetic and environmental factors. Therefore, targeting of lymphocytes may be a promising means of therapy for multiple sclerosis. Daclizumab is a humanized monoclonal antibody approved for use in preventing renal allograft rejection. The agent is under investigation in phase II trials for the treatment of multiple sclerosis and has demonstrated positive clinical outcomes, including decreased relapse rates. Adverse events included urinary tract infections, respiratory tract infections, paresthesias, mild leukopenia, transient elevations in liver enzyme and bilirubin levels, rash, postinfusion reactions (fever), lymphadenopathy, transient thrombocytopenia, and nausea. Daclizumab may be an alternative or add-on therapy when conventional immunomodulators fail or when existing approved therapies cannot be used. Besides ongoing phase II trials, additional phase II or III trials are required to determine the extended benefits of the agent, as well as clinical outcomes.

[Use of mitoxantrone in early multiple sclerosis with malignant disease course. Observational study in 30 patients with clinical and MRI outcomes after one year]

INTRODUCTION

In an observational multicenter study, we analyzed retrospectively 30 patients with malignant form of multiple sclerosis (MS) treated with mitoxantrone the year following the first neurological event.

METHODS

The 30 patients were selected according to Weinshenker criteria of malignant MS (either a "catastrophic" relapse or a quickly aggressive form). We compared clinical and MRI findings the year before with the year following mitoxantrone onset treatment: annualized relapse rates (ARR), EDSS score and percentage of patients with gadolinium enhancing lesions on MRI.

RESULTS

A total of 87 relapses were observed in the 5.7 months before and 10 during the year following onset of mitoxantrone treatment. The ARR decreased by 95% (6.0+/-2 before and 0.3+/-0.7 after). Twenty-four patients (80%) were relapse-free one year after onset of mitoxantrone treatment. The EDSS score improved in 87% of MS patients and the mean EDSS decreased by 1.9. Ninety-seven percent had at least gadolinium enhancing lesions before the start of mitoxantrone treatment as compared to 17% after.

CONCLUSION

In our experience, mitoxantrone had a rapid and strong impact on the malignant forms of MS with a short disease duration. In this MS subgroup, mitoxantrone should be considered as an early treatment option.

Disease-modifying drugs for multiple sclerosis: current and future aspects

Multiple sclerosis (MS) is the most common inflammatory demyelinating disorder of the human CNS, affecting an estimated 2.5 million people in the world. Until the 1990s, treatment was mainly symptomatic, but a new era began with the introduction of disease-modifying therapy that seems to alter the natural course of MS. Current drugs include three interferons (IFNs): IFN-beta1a (Avonex intramuscular; Biogen, Cambridge, USA; Rebif subcutaneous; Serono, Geneva, Switzerland), IFN-beta1b (Betaseron subcutaneous; Schering, Berlin, Germany) and glatiramer acetate (Copaxone subcutaneous; Teva, Petach Tikva, Israel). Ongoing research targeting a variety of mechanisms and processes means there is much promise for the future treatment of MS.

Management of worsening multiple sclerosis with mitoxantrone: a review

BACKGROUND

Mitoxantrone, an intravenously administered immunosuppressant that inhibits T-cell, B-cell, and macrophage proliferation, is indicated for reducing neurologic disability and relapse frequency in patients with secondary progressive multiple sclerosis (SPMS), progressive relapsing MS, or worsening relapsing-remitting MS (RRMS).

OBJECTIVE

This article reviews the pathogenesis and natural history of MS and examines the available treatment options for patients with RRMS, worsening RRMS, or SPMS, with a focus on mitoxantrone.

METHODS

MEDLINE (1966-present) and the Cochrane Central Register of Controlled Trials (1994-present) were searched for relevant randomized, blinded, controlled clinical trials using the terms mitoxantrone, Novantrone, and multiple sclerosis.

RESULTS

Five randomized, blinded, controlled trials and an ongoing open-label Phase IV safety study were identified and included in this review. In one randomized, double-blind trial (N=25), patients with RRMS who received mitoxantrone 8 mg/m2 monthly had significantly reduced relapse rates at 1 year compared with those who received placebo (P=0.014). In a 2-year, randomized, partially blinded trial (N=51), patients with active RRMS who received mitoxantrone 8 mg/m2 monthly had significantly fewer relapses compared with those who received placebo (P<0.001), and significantly fewer patients had confirmed progression of disability (1-point increase in Expanded Disability Status Scale [EDSS] score) (P=0.02). In a randomized, double-blind trial (N=49), patients with relapsing SPMS who received mitoxantrone 12 mg/m2 monthly for 3 months followed by 12 mg/m2 g3mo for up to 32 months had significant improvements in EDSS scores compared with those who received methylprednisolone 1 g IV monthly for 3 months followed by 1 g IV g3mo (P=0.002 at 1 year, P=0.045 at 2 years) and significant reductions in the number of gadolinium-enhancing lesions on magnetic resonance imaging (MRI) (P=0.002 at 1 and 2 years, P=0.03 at 3 years). In a randomized, partially blinded Phase II trial in 42 patients with active RRMS or SPMS, patients who received mitoxantrone 20 mg IV monthly and methylprednisolone 1 g IV monthly had significantly fewer new gadolinium-enhancing lesions on MRI (P<0.001) and significantly fewer relapses (P<0.01) at 6 months compared with those who received methylprednisolone alone. In a pivotal Phase III trial (N=194), patients with worsening RRMS or SPMS who received mitoxantrone 12 mg/m2 g3mo for 2 years had significantly fewer relapses (P<0.001) and significantly less deterioration in disability, as measured by change in EDSS score (P=0.019), compared with those who received placebo. In a nonrandomized subgroup of patients from this study (n=110), those who received mitoxantrone 12 mg/m2 g3mo had a significant reduction in the number of T2-weighted MRI lesions at 24 months (P=0.027). The most common adverse events in these studies included nausea and/or vomiting (18%-85%), alopecia (33%-61%), amenorrhea (8%-53%), urinary tract infections (6%-32%), and upper respiratory tract infections (4%-53%). Leukopenia was reported in 10% to 19% of patients. Use of mitoxantrone can lead to serious adverse effects, particularly cardiotoxicity, myelosuppression, and, rarely, leukemia. Long-term use of mitoxantrone may compromise left ventricular function. Limited cardiotoxicity was reported in the clinical studies; in the pivotal clinical trial, 2 patients who received mitoxantrone 12 mg/m2 had decreases in left ventricular ejection fraction to <50% of baseline.

CONCLUSIONS

In the available clinical trials, mitoxantrone provided effective treatment for worsening RRMS or SPMS. When mitoxantrone is used as recommended, the risks of substantial myelosuppressive and cardiotoxic effects can be reduced by careful patient selection, drug administration, and monitoring. The lifetime cumulative dose should be strictly limited to 140 mg/m2, or 2 to 3 years of therapy.

Étude observationnelle de la mitoxantrone dans les formes rémittentes actives de sclérose en plaques: suivi à long terme d’une cohorte de 100 patients consécutifs

INTRODUCTION

On the basis of the French and British (FB) MS Trial, Mitoxantrone (MITOX) was approved by the AFSAPPS in October 2003 in patients with aggressive multiple sclerosis (MS), given as induction therapy monthly for 6 months (ELSEP). We report an observational study of 100 aggressive relapsing remitting (RR) MS patients treated by induction therapy with MITOX and followed up to 5 years.

METHODS

One hundred patients with aggressive RR MS received an induction therapy with MITOX 20 mg monthly combined with methylprednisolone 1 g for 6 months. MRI data within 12 months before and 6 months after MITOX induction were collected (mean cumulative dose 65 mg/m2). Clinical evaluation was performed every 6 months and data (relapses and EDSS scores) were prospectively recorded in the EDMUS Database. After MITOX, a maintenance therapy was given to 57 patients (MITOX every 3 months: 21; Interferon beta: 13; Azathioprine: 14; Methotrexate: 7; Glatiramer acetate: 2). The mean follow-up period was of 3.8 years.

RESULTS

Patients were treated at a mean age of 27 +/- 9 years after 5 +/- 3 years of MS duration. Within the 12 months preceding MITOX onset, the annual relapse rate (ARR) was 3.2, the mean EDSS increased by 2.2 +/- 1 points (to a score of 4 at M0), 87 patients worsened by 1 point EDSS or more and 85 percent of patients had Gd enhancing lesions on MRI. During the 12 months following MITOX onset, the inflammatory activity of the disease dropped dramatically with a reduction of the ARR by 91 percent whereas 76 percent of patients were free of new relapse and MRI activity was reduced by 89 percent. In addition, the mean EDSS decreased by 1.2 points (p<10-6) and 60 percent of patients improved by 1 point EDSS or more. At a longer term, the reduction of the ARR was confirmed (0.28-0.37 up to 5 years) and the median time to the first relapse was 2.8 years. A significant improvement of disability was maintained until 4 years and got back to the initial level at year 5. The ARR was significantly lower (0.09) for patients treated with MITOX every 3 months as maintenance therapy than for patients treated by other disease modifying therapies (0.33-0.39) or not (0.43) after the induction. Three patients presented an asymptomatic decrease of the left ventricular ejection fraction under 50 percent, reversible in one case.

CONCLUSION

MITOX as induction therapy monthly for 6 months was safe and had a rapid and strong impact on the inflammatory process and on the evolution of disability. The drug might be a good candidate as induction therapy followed by a maintenance therapy in patients with aggressive MS.

Mitoxantrone for multiple sclerosis

BACKGROUND

Mitoxantrone (MX) has been shown to be moderately effective in reducing the clinical outcome measures of disease activity in multiple sclerosis (MS) patients.

OBJECTIVES

The objective was to assess the efficacy and safety of MX in relapsing-remitting MS (RRMS), progressive relapsing MS (PRMS) and secondary progressive MS (SPMS).

SEARCH STRATEGY

We searched the Cochrane MS Group Trials Register (searched April 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2004), MEDLINE (Pub Med) (January 1966 to April 2005), EMBASE (January 1974 to April 2005), and reference lists of articles. We also undertook hand searching and contacting trialists and pharmaceutical companies.

SELECTION CRITERIA

The trials were selected if double-blinded, placebo-controlled, randomised, irrespective of eventual additive therapy (such as steroids).

DATA COLLECTION AND ANALYSIS

Three reviewers independently selected articles for inclusion, assessed trials' quality and extracted data.

MAIN RESULTS

Four trials involving 270 participants were included. MX was found to reduce the progression of disability at 2 years follow-up (proportion of participants with 6-months confirmed progression of disability: Odds Ratios (OR) 0.3, p = 0.05). Similar figures were found regarding the reduction in annualised relapse rate and the proportion of patients free from relapses at 1 and 2 years, as well as the number of patients with active MRI lesions at 6 months/ 1 year only. Side effects reported in the trials were more frequent in treated patients than in controls. Caution must be exercised in drawing conclusions from such data because of the heterogeneous quality and characteristics of the included trials, which are different in terms of treatment schedule and type of enrolled patients. More than half of the included patients came from a single study. Moreover, from the included trials, it was not possible to estimate the long-term efficacy and safety of MX, which may raise concerns about the risk of cardiotoxicity and therapy-related leukemias, which is increasingly reported in the literature.

AUTHORS' CONCLUSIONS

MX is moderately effective in reducing the disease progression and the frequency of relapses in patients affected by RR, PR and SP MS in the short-term follow-up (2 years), even if the results are based on trials heterogeneous in terms of drug dosage and inclusion criteria. No major neoplastic or symptomatic cardiotoxicity related to MX have been reported from the trials. However, longer follow-up studies are highly warranted to better explore the efficacy and safety of the drug, mainly as regards the long-term risk of therapy-related leukemias and cardiotoxicity. As a conclusion, MX has a partial efficacy, but, due to its unclear long-term safety profile, it should be used to treat patients with worsening RR and SP MS with evidence of worsening disability.

Therapeutic role of mitoxantrone in multiple sclerosis

Mitoxantrone is approved by several health authorities for treatment of active forms of relapsing-remitting or secondary progressive multiple sclerosis (SPMS). This review provides an outline on relevant preclinical as well as clinical studies, places mitoxantrone in the context of other therapeutic approaches against multiple sclerosis (MS), and discusses relevant side effects. The current knowledge of the putative mechanisms of action of the compound is discussed.

Biozzi mice: Of mice and human neurological diseases

In 1972 Guido Biozzi selectively bred mice to study the immunopathological mechanisms underlying polygenic diseases. One line, the Biozzi antibody high (AB/H) mouse (now designated the ABH strain) was later found to be highly susceptible to many experimentally induced diseases such as autoimmune encephalomyelitis, autoimmune neuritis, autoimmune uveitis, as well as virus-induced demyelination and has thus been a key mouse strain to study human inflammatory neurological diseases. In this paper we discuss the background of the Biozzi ABH mouse and review how studies with these mice have shed light on the pathogenic mechanisms operating in chronic neurological disease.

Autoimmune tolerance eliminates relapses but fails to halt progression in a model of multiple sclerosis

To date there has been poor translation of immunotherapies from rodent models to treatment of progressive multiple sclerosis (MS). In the robust, relapsing Biozzi ABH mouse model of MS, using a combination of a transient deletion of T cells followed by intravenous (i.v.) myelin antigen administration, established relapsing disease in EAE can be effectively silenced. However, when treatment was initiated in late stage chronic-relapsing disease, despite inhibition of further relapses, mice demonstrated evidence of disease progression shown by a deterioration in mobility and development of spasticity and indicates that targeting relapsing, immunological components of MS alone is unlikely to be sufficient to control progression in the late stages of MS.

Mitoxantrone as rescue therapy in worsening relapsing-remitting MS patients receiving IFN-beta

We assessed the action of mitoxantrone (MX) when given as rescue therapy in patients with relapsing-remitting (RR) multiple sclerosis (MS), whose disease activity worsens despite IFN-beta treatment. Ten very active RR MS patients received MX 12 mg/m2 monthly, for 3 months, and then returned to the original treatment with IFN-beta. Following treatment with MX, 70% of patients were able to return to IFN-beta treatment, stabilising EDSS and relapse rate during a follow-up period of 15-18 additional months. In contrast, in 30% of the patients who were taken off MX and returned to IFN-beta treatment the EDSS score deteriorated and the number of exacerbations increased significantly. The latter patients were switched again to MX treatment at 3-month intervals, stabilising EDSS and relapse rate during 15-18 additional months. Clinical findings correlated with the number of Gd-enhancing lesions disclosed in MRI scans. Immunological data were consistent with the clinical and MRI benefits observed. We conclude that brief courses of MX may provide a safe treatment alternative for RR MS patients who experience rapid and severe worsening of their disease despite IFN-beta treatment.

Management of secondary-progressive multiple sclerosis

The majority of patients with relapse-onset multiple sclerosis (MS) will go on to develop secondary-progressive MS (SPMS) disease, with approximately 50% developing SPMS after 10 years. It remains unknown whether the relapsing and progressive phases of MS differ qualitatively. The pathogenesis of SPMS is poorly understood. The specific role that inflammation plays in disease progression is not well defined. Immunosuppressive therapies, which are capable of reducing or stopping clinical relapses and suppressing MRI activity, generally do not stop disease progression. Recent natural history studies suggest that disease progression occurs regardless of the presence of superimposed relapses. However, poor recovery from clinical relapses does account for the acquisition of disability. Therefore, stopping relapses with appropriate therapy delays the acquisition of disability but does not necessarily delay or prevent the development of SPMS. At present, the only disease-modifying therapies licensed for use in SPMS are interferon-beta-1b in Europe and the US, and mitoxantrone in the US. These agents can only be recommended for patients who continue to have relapses. Symptomatic therapies remain the cornerstone of treatment for patients with SPMS. Delivering high-quality, effective symptomatic therapies requires a multidisciplinary approach. The aim of symptomatic therapies should not only be to reduce neurological impairments but also to decrease disability and handicap and to improve the emotional well-being and health-related quality of life of patients with SPMS.

Mitoxantrone: a review of its use in multiple sclerosis

Mitoxantrone (Novantrone), a synthetic anthracenedione derivative, is an antineoplastic, immunomodulatory agent. Its presumed mechanism of action in patients with multiple sclerosis (MS) is via immunomodulatory mechanisms, although these remain to be fully elucidated. Intravenous mitoxantrone treatment improved neurological disability and delayed progression of MS in patients with worsening relapsing-remitting (RR) [also termed progressive-relapsing (PR) MS] or secondary-progressive (SP) disease. In a pivotal randomised, double-blind, multicentre trial, mitoxantrone 12 mg/m(2) administered once every 3 months for 2 years provided significant improvements in neurological disability ratings, including Kurtzke Expanded Disability Status Scale (EDSS), Ambulatory Index (AI) and Standardised Neurological Status (SNS) scores, compared with placebo. The drug also significantly reduced the mean number of corticosteroid-treated relapses and prolonged the time to the first treated relapse, with the beneficial effects on disease progression supported by magnetic resonance imaging. Post hoc analyses suggest that the benefits associated with mitoxantrone treatment may be sustained for at least 12 months after cessation of treatment, mean changes from baseline at 36 months in EDSS, AI and SNS scores of 0.10, 0.61 and 0.19, respectively, in the mitoxantrone group versus 0.46, 1.13 and 3.38 with placebo. Concomitant intravenous mitoxantrone 20mg plus intravenous methylprednisolone 1g once every month for 6 months was more effective than intravenous methylprednisolone monotherapy in preventing the development of new gadolinium-enhanced lesions in patients with very active RRMS or SPMS. The drug was generally well tolerated in patients with MS. Adverse events were generally mild to moderate in severity and usually resolved upon discontinuation of treatment or with appropriate pharmacotherapy. At the recommended dosage, mitoxantrone appears to have a low potential to cause cardiotoxicity. In conclusion, intravenous mitoxantrone reduces the relapse rate and slows progression of the disease in patients with worsening RRMS, PRMS or SPMS; thus providing a new option for the management of these patients. The drug was generally well tolerated at the recommended dosage, although potential cardiotoxicity limits the total cumulative dose to 140 mg/m(2). Further studies are warranted to determine which patients with worsening RRMS, PRMS or SPMS are most likely to benefit from mitoxantrone treatment and to more fully define the long-term safety and tolerability of mitoxantrone, including the use of concomitant cardioprotectants to extend the therapeutic lifespan of the drug. Pharmacodynamic Profile. Mitoxantrone, a synthetic anthracenedione derivative, is an established cytotoxic, antineoplastic agent. Its presumed mechanism of action in multiple sclerosis (MS) is immunosuppression. In antineoplastic studies, the drug showed several immunomodulatory effects, inducing macrophage-mediated suppression of B-cell, T-helper and T-cytotoxic lymphocyte function. Currently, the pharmacodynamic properties of mitoxantrone have not been investigated to any extent in patients with MS. In one study, 6 months' treatment with intravenous mitoxantrone generally had no effect on the distribution of cytokine-positive peripheral blood monocyte cells in patients with MS. In an animal model of the disease, mitoxantrone suppressed the development and progression of both actively and passively induced acute experimental allergic encephalomyelitis (EAE). It appeared to be 10-20 times more effective than cyclophosphamide in the suppression of EAE. Moreover, mitoxantrone approximately doubled the mean time to onset of EAE versus control animals (279 vs 148 days after immunisation; p < 0.00005). In vitro, mitoxantrone 10 and 100 micro g/L inhibited myelin degradation by leucocytes and peritoneal macrophages derived from mice with acute EAE by approximately 60% and 100%. Pharmacokinetic Profile. Currently, there are no published pharmacokinetic data for intravenous mitoxantrone in pitoxantrone in patients with MS, paediatric patients or in those with renal impairment. All studies, to date, have been in patients with cancer receiving a single, approximately 30-minute intravenous infusion of mitoxantrone 5-14 mg/m(2). The drug exhibits triexponential pharmacokinetics, with a rapid initial distribution (alpha) phase, an intermediate distribution (beta) phase and a much slower elimination (gamma) phase. The mean half-life of the alpha phase appears to be 6-12 minutes and that of the beta phase 1.1-3.1 hours. Mitoxantrone has a high affinity for tissue, with a volume of distribution of up to 2248 L/m(2). Mitoxantrone persists for prolonged periods in tissues and was detectable in autopsy tissue from patients who last received the drug up to 272 days before death. At concentrations of 10-10000 ng/mL, the drug was 70-80 % bound to plasma proteins in dogs. Elimination of mitoxantrone occurs predominantly through biliary excretion and may be impaired in patients with hepatic dysfunction or third space abnormalities (e.g. ascites). The mean terminal elimination half-life of mitoxantrone ranged from 23 hours to 215 hours. Renal clearance accounts for 10 % of the total clearance of the drug. Total clearance of mitoxantrone ranged from 13 to 34.2 L/h/m(2) and renal clearance from 0.9 to 2.7 L/h/m(2). The drug appears to have a low potential for interaction with other concomitantly administered agents. Therapeutic Efficacy. Intravenous mitoxantrone (infusion of > or = 5 minutes), either as monotherapy or in combination with intravenous methylprednisolone, delayed the progression of the disease in patients with secondary-progressive (SP) or worsening relapsing-remitting (RR) MS (the latter is also termed progressive-relapsing MS) in comparative, randomised, multicentre trials. In a double-blind, monotherapy trial (Mitoxantrone In Multiple Sclerosis [MIMS] trial), mitoxantrone 12 mg/m(2) (n = 60) once every 3 months for 2 years significantly improved neurological disability relative to placebo (n = 64), as assessed by changes in mean Kurtzke Expanded Disability Status Scale (EDSS) score, mean Ambulatory Index (AI) score and mean Standardised Neurological Status (SNS) score. The drug also significantly reduced the mean number of corticosteroid-treated relapses per patient and prolonged the time to the first treated relapse. A Wei-Lachin multivariate analysis of these five efficacy variables indicated that the global difference between the two treatment groups was 0.30 (p < 0.0001). Mitroxantrone was also more effective than placebo according to secondary endpoints in this study, with fewer mitoxantrone recipients experiencing a relapse, a deterioration of > or =1 EDSS point or a confirmed deterioration in EDSS score over a 3-month period. Mitoxantrone recipients also showed less deterioration in quality-of-life ratings and had fewer hospital admissions, whereas more placebo recipients had new gadolinium-enhanced lesions at study end (the latter parameter was assessed using magnetic resonance imaging [MRI] in a subgroup of 110 patients, including 40 patients who received an exploratory 5 mg/m(2) dose). Furthermore, post hoc analyses indicated that the beneficial effects of mitoxantrone treatment on EDSS, SNS and AI scores were sustained for at least 12 months after cessation of treatment, with mean changes from baseline at 36 months in EDSS, AI and SNS scores of 0.10, 0.61 and 0.19, respectively, in the mitoxantrone group versus 0.46, 1.13 and 3.38 with placebo. Preliminary data from a cost-minimisation analysis based on results from the MIMS trial indicated that approximately half of the cost of mitoxantrone was offset by cost savings in other areas associated with the treatment of MS (direct and indirect major costs), with a total annual incremental cost for mitoxantrone of dollar 1661 per patient. Combination therapy once-monthly with intravenous mitoxantrone 20mg plus intravenous methylprednisolone 1g was more effective than intravenous methylprednisolone 1g once every month in preventing the development of gadolinium-enhanced lesions in patients with very active RRMS or SPMS (double-blind assessment using MRI scans). After 6 months, significantly more combination therapy recipients had no new gadolinium-enhanced lesions (90.5% vs 31.3% with monotherapy; p < 0.001) [primary endpoint]. There were also significant reductions in both the mean number of new enhancing lesions and the total number of gadolinium-enhanced lesions in patients receiving combination therapy versus methylprednisolone monotherapy.Tolerability. Mitoxantrone was generally well tolerated in patients with MS. Treatment-emergent adverse events occurring significantly more frequently with mitoxantrone (12 mg/m(2) once every 3 months for 2 years) than placebo were nausea, alopecia, menstrual disorders, urinary tract infection, amenorrhoea, leucopenia and elevated gamma-glutamyltranspeptidase levels. Adverse events were usually mild to moderate in severity and generally resolved with discontinuation of treatment or when treated with appropriate pharmacotherapy. Eight percent of patients discontinued treatment in the mitoxantrone 12 mg/m(2) group due to an adverse event versus 3% of placebo recipients. The incidence of drug-related acute myelogenous leukaemia was very low (0.12%) in a cohort of 802 patients with MS receiving mitoxantrone. Evidence suggests that the risk of cardiotoxicity is low in patients with MS. After 1 year of monotherapy, 3.4% of mitoxantrone recipients had a reduction in left ventricular ejection fraction (LVEF) to < or =50% compared with 0% of placebo recipients; at the end of the second year, respective incidences were 1.9% and 2.9% (total cumulative dose of mitoxantrone per patient was 96 mg/m(2) after 2 years' treatment). (ABSTRACT TRUNCATED)

Pixantrone (BBR2778): a new immunosuppressant in multiple sclerosis with a low cardiotoxicity

Mitoxantrone (MX) has been approved by the Food and Drug Administration for the treatment of rapidly progressive multiple sclerosis (MS). Unfortunately, its long-term administration is prevented by the cardiotoxicity. Pixantrone (PIX) is an analogue of MX devoid of toxic effects on cardiac tissue and was developed as a replacement for other anthracenediones in cancer patients. With a view to an application in MS patients, experimental data demonstrated that PIX is as potent as MX in preventing acute experimental allergic encephalomyelitis development as well as the occurrence of relapses in the chronic model. Safety data from animal studies and from phase II trials in cancer patients confirm a very weak cardiotoxicity, if any. A phase I trial with PIX in patients with a rapidly progressive MS seems thus warranted.

The cardioprotector dexrazoxane augments therapeutic efficacy of mitoxantrone in experimental autoimmune encephalomyelitis

The present study investigates the immunological effects of a combination treatment of mitoxantrone and the cardioprotector dexrazoxane in experimental autoimmune encephalomyelitis (EAE). Mitoxantrone, an anthracycline-derived immunosuppressive drug has been approved recently for treatment of very active multiple sclerosis (MS). Its prolonged use is limited due to its cardiotoxic properties. Dexrazoxane (DZR (S)-(+)-1,2-bis (3,5.dioxopiperazinyl)propane, ICRF-187) is an iron III chelator which in animal models and in cancer patients reduces anthracycline and mitoxantrone induced cardiotoxicity when given immediately before these agents. We examined the immunological effects of dexrazoxane in combination with mitoxantrone in experimental autoimmune encephalomyelitis (EAE) in Lewis rats. EAE was induced by active immunization with myelin basic protein (MBP) or by adoptive transfer of MBP specific T cells (AT-EAE). The clinical course, spinal cord pathology, activity of metalloproteinases (MMP-2 and MMP-9) and T cell apoptosis were assessed. Monotherapy with DZR ameliorated slightly the course of actively induced EAE and AT-EAE. The combination of DZR and mitoxantrone was superior to mitoxantrone given alone. Clinical amelioration ran in parallel with the marked reduction of inflammatory infiltration which was nearly abolished by the combination treatment. DZR did not affect the activity of metalloproteinase 9 and did not increase the proportion of apoptotic lymph node cells ex vivo or T cells in situ. We conclude that in addition to its cardioprotective role, DZR augments mitoxantrone-mediated immunosuppressive effects in animal models of human central nervous system (CNS) autoimmune disease. Clinical trials in MS patients are warranted to evaluate the unexpected immunosuppressive efficacy of DZR as add-on treatment.

Mitoxantrone in progressive multiple sclerosis: when and how to treat?

Mitoxantrone (MX) has been approved by the Food and Drug Administration (FDA) for the treatment of patients with worsening relapsing-remitting (RR) or secondary progressive (SP) multiple sclerosis (MS). However, indications should be refined and mitoxantrone reserved as a rescue therapy to: (1) patients in the relapsing-remitting phase with frequent and disabling exacerbations likely leading to permanent severe disability and (2) to patients in the secondary progressive phase whose disability progression rate increases by one EDSS point or more per year and who do not respond to other current therapies. An induction phase with the monthly intravenous administration of 12 mg/m(2) followed by a maintenance phase with 12 mg/m(2) every 3 months for 2 years seems the most effective and safe treatment regimen, not exceeding the maximum cumulative dose of 140 mg/m(2). Given the potent myelosuppressive activity of mitoxantrone, dosage should be carefully adapted to the body surface and hematological changes. Long-term toxicities (amenorrhoea and therapy-related leukemia) seem acceptable but a valid evaluation will need a longer follow-up in more patients. Cardiotoxicity, the major long-term toxicity, is clearly dose-dependent and is a strict treatment duration limiting factor. To reduce the risk of cardiac events, the drug should be administered by slow infusion (over 30 min). Analogs of mitoxantrone with a much lower cardiotoxicity are currently investigated in animal experimental models.

Mitoxantrone in progressive multiple sclerosis: a placebo-controlled, double-blind, randomised, multicentre trial

BACKGROUND

Treatment options for patients with secondary progressive multiple sclerosis are few. Encouraging results in open-label studies prompted this randomised trial of mitoxantrone in such patients.

METHODS

194 patients with worsening relapsing-remitting or secondary progressive multiple sclerosis were assigned placebo or mitoxantrone (5 mg/m(2) [exploratory group] or 12 mg/m(2) intravenously) every 3 months for 24 months. Clinical assessments were made every 3 months for 24 months. The primary endpoint was a multivariate analysis of five clinical measures. Analyses of mitoxantrone 12 mg/m(2) versus placebo were based on patients who received at least one dose and returned for at least one assessment of efficacy.

FINDINGS

Of 194 patients enrolled, 188 were able to be assessed at 24 months. There were no drug-related serious adverse events or evidence of clinically significant cardiac dysfunction. At 24 months, the mitoxantrone group experienced benefits compared with the placebo group for the primary outcome (difference 0.30 [95% CI 0.17-0.44]; p<0.0001) and the preplanned univariate analyses of those measures: change in expanded disability status scale (0.24 [0.04-0.44]; p=0.0194), change in ambulation index (0.21 [0.02-0.40]; p=0.0306), adjusted total number of treated relapses (0.38 [0.18-0.59]; p=0.0002), time to first treated relapse (0.44 [0.20-0.69]; p=0.0004), and change in standardised neurological status (0.23 [0.03-0.43]; p=0.0268).

INTERPRETATION

Mitoxantrone 12 mg/m(2) was generally well tolerated and reduced progression of disability and clinical exacerbations. Further studies are needed to identify the patients with these forms of multiple sclerosis who are most likely to respond to therapy, the best treatment protocols, and the frequency of long-term drug-related side-effects.

Evaluation of mitoxantrone for the treatment of multiple sclerosis

Mitoxantrone (Novantrone((R))), an antineoplastic agent, has been approved for treating patients with secondary progressive multiple sclerosis (MS). Mitoxantrone, which is usually categorised as an immunosuppressant drug, is now also considered to be a specific immunomodulator. Autoimmune mechanism of pathogenesis of MS is the basis of immunosuppressive therapeutic approaches to MS whereas immunoregulatory abnormalities including defective IFN-alpha production provide the rationale for immunomodulating therapies. Clinical trials have shown that mitoxantrone had a statistically significant impact on reduction of relapse rate and delay in disability progression in these patients. Advantages of mitoxantrone as therapy for MS are: (1) considerable information is available about its pharmacokinetics, metabolism and toxicology from previous use in oncology; (2) it requires administration only once in three months which is not only convenient for the patient but also cost-effective; (3) mitoxantrone is one of the two drugs to be approved for secondary progressive MS (the other is IFN-beta1) which offers an advantage over IFN-beta1a preparations and glatiramer acetate which are indicated only for relapsing remitting MS. However, the duration of therapy is usually limited to two to three years because the maximum cumulative dose recommended is 120 mg/m(2) due to concern for possible cardiotoxicity. Potential market value of the mitoxantrone, based on the cost of treatment per patient and the number of patients likely to be treated in the first year of introduction, is US$210 million.

Mitoxantrone immunotherapy in multiple sclerosis

Mitoxantrone, a cytotoxic agent recently developed, was subsequently found a very potent immunosuppressor. Experimental data in experimental allergic encephaloymyelitis demonstrated a dramatic suppression of both active and passive forms. Immune effects concern cellular and humoral components and are particularly persistent. B cell subset is preferentially deleted. Suppressor cells are relatively spared and suppression becomes dominant. In cancer therapy, the main advantages of mitoxantrone are a definitely better immediate tolerance and very low delayed adverse reactions (carcinogenicity, teratogenicity, impact on reproductive organs). Given its major immunosuppressive activity and its better tolerance, mitoxantrone was a potential candidate for multiple sclerosis therapy. Several clinical trials have confirmed the remarkable efficacy of mitoxantrone to reduce both attack and progression rates. Unfortunately the cardiotoxicity was found more frequent than expected and limits the maximum cumulative dose to 120 mg/m2. Mitoxantrone, when employed properly, may be useful in patients with frequent and disabling excerbations and/or rapidly progressing disability. It must be kept in mind that multiple sclerosis is a chronic disease, and that the benefit is limited to the period of administration of any treatment.

Recent advances in the pharmacological control of experimental allergic encephalomyelitis (EAE) and the implications for multiple sclerosis treatment

The autoimmune, cell-mediated condition experimental allergic encephalomyelitis (EAE) is the representative model for the inflammatory central nervous system disease MS. EAE has been extensively employed to determine the efficacy of pharmacological agents that may be of ultimate use in the treatment of MS. A wide variety of drugs has been examined for activity in EAE but, over the last decade, three groups of compounds have emerged with clear and reproducible ability to modify significantly the onset and progression of the disease. The immunosuppressants, the modulators of catecholamine activity and the antineoplastic agents have convincingly altered the course of EAE and, as a consequence, provided understanding of the mechanisms of disease expression and offered further insight into the pathogenesis of MS. The article stresses the usefulness of EAE as a model to identify prospective pharmacological treatments for MS and, in particular, considers those compounds subsequently assessed for their ability to interfere with the progression of the human disease.

Immunopharmacologic modulation of experimental allergic encephalomyelitis: low-dose cyclosporin-A treatment causes disease relapse and increased systemic T and B cell-mediated myelin-directed autoimmunity

Therapies with immunosuppressive drugs in autoimmune experimental diseases often down-regulate disease but sometimes may lead to paradoxical disease exacerbation. To elucidate possible mechanisms behind such phenomena the effects were studied of mitoxantrone (Mx) and cyclosporin A (CsA) given at high and low doses on clinical course, and on autoreactive T- and B-cell responses in actively induced experimental allergic encephalomyelitis (EAE) in Lewis rats. Treatment with Mx and high dose CsA abrogated EAE and decreased dramatically the measured immune responses compared to vehicle-treated control EAE rats. Low-dose CsA treatment caused a disease relapse 20-30 days post immunization (p.i.). This relapse was accompanied by increased numbers of cells spontaneously producing IFN-gamma in the CNS and regional lymph nodes. Furthermore, anti-myelin and anti-MBP secreting cells were increased as were numbers of primed T cells that produced IFN-gamma in response to myelin antigens. It was concluded that these aspects of the myelin autoreactive immune response correlated well with clinical disease and are useful in evaluating immunotherapeutic intervention. Low-dose CsA treatment may interfere with systemic down-regulatory mechanisms acting on both T- and B-cell myelin-directed autoimmunity.

Control of immune-mediated disease of the central nervous system with monoclonal (CD4-specific) antibodies

Chronic relapsing experimental allergic encephalomyelitis (CREAE) was induced in Biozzi AB/H (H-2dq1) mice by active sensitization with spinal cord antigens. A single i.p. injection of CD8-depleting (YTS169.4) monoclonal antibody (mAb) failed to affect the clinical course of CREAE when administered prior to and during the onset of both the initial clinical and subsequent relapse phase of the disease. By contrast similar treatment with both CD4-depleting (YTS191.1) or CD4-blocking/non-depleting (YTS177.9) mAb significantly inhibited disease progression. Treatment shortly before the anticipated onset of clinical EAE prevented the subsequent development of disease, although disease could be provoked following antigen-rechallenge. In contrast, treatment with these antibodies during post-acute remission phase mainly served to delay the incidence of relapse. This suggests that, unless tolerance can be re-induced, treatment of ongoing neuroimmunological disease will require 'pulse' therapy and thus potentiate the problems of long-term immunosuppresion. Despite the findings that CD4-specific antibodies can rapidly reverse overt clinical disease shortly after the onset of disease exacerbation, once neurological dysfunction becomes established anti-CD4 treatment fails to improve the animals clinically, possibly due to the inability to rapidly reverse established demyelination. Although this study does not exclude the potential central action of the injected mAb, the failure to significantly dissociate therapeutic benefit between mAb administered directly into the CNS and that given systemically suggests that a major action of these agents is probably by selectively removing T cells in the peripheral T cell pool.

Control of immune-mediated disease of the central nervous system requires the use of a neuroactive agent: elucidation by the action of mitoxantrone

Mitoxantrone was used as an immunosuppressive probe to elucidate a means for the control of experimental allergic encephalomyelitis (EAE) induced in Biozzi AB/H mice following injection of spinal cord homogenate emulsified in Freund's adjuvant. A single i.p. injection of 2.5 mg/kg of mitoxantrone, 1-2 days before the anticipated onset of EAE, failed to prevent the majority of animals from developing clinical disease, whereas when the compound was injected directly into the central nervous system (CNS), at this time point, significantly increased therapeutic benefit was evident, with most animals failing to develop clinical EAE. Although the clinical use of intrathecal mitoxantrone is strongly contraindicated, these data suggest that increased therapeutic benefit may be achieved in immune-mediated disease of the CNS by targeting immunosuppressive doses of suitable agents, on lymphocyte activation within the CNS. In addition, direct administration of immunosuppressive doses into the CNS may reduce potentially unwanted (side) effects in the periphery.

Therapy of chronic relapsing experimental allergic encephalomyelitis and the role of the blood-brain barrier: elucidation by the action of Brequinar sodium

The immunosuppressive effect of the novel 4-quinoline carboxylic acid derivative Brequinar sodium on the chronic relapsing experimental allergic encephalomyelitis CREAE model in the Biozzi AB/H mouse was investigated. Although Brequinar sodium actively inhibited peripheral immune responses, it showed a limited potential to control an ongoing disease of the central nervous system (CNS). Doses of 25 mg/kg inhibited in vivo induced proliferative response and prevented EAE when treated from day 9 post-inoculation (p.i.). However, when administered from day 12 p.i. or during the post-acute remission phase-limited effects on the course of disease were observed. By comparison, treatment with a single high dose of cyclophosphamide (200 mg/kg) at these time points was significantly effective in controlling disease. As a possible explanation of the observed results it is suggested that for a compound to be effective in treating an ongoing immune response in the CNS, it must be capable of crossing the blood-brain barrier and act on the disease-inducing cells activated within the CNS. This hypothesis is supported by the finding that intracerebral injections of Brequinar sodium on day 12 p.i. significantly inhibited disease progression. This suggests that strategies aimed at controlling immune-mediated disease of the CNS require therapeutic doses of the compounds to be delivered into the CNS.