Mechanisms of action for treatments in multiple sclerosis: Does a heterogeneous disease demand a multi-targeted therapeutic approach?

Alopecia in Multiple Sclerosis Patients Treated with Disease Modifying Therapies

BACKGROUND

There is currently limited literature addressing the reporting of alopecia in multiple sclerosis (MS) patients treated with disease-modifying therapies (DMTs). Anecdotal reports of hair thinning from patients on various DMTs prompted further investigation of a large database.

OBJECTIVE

To analyze total reports, source of reporting, age distribution, and sex distribution of alopecia associated with DMTs.

METHODS

FDA Adverse Event Reporting System (FAERS) public dashboard and OpenFDA database were analyzed for alopecia reports between January 1, 2009, and June 30, 2020, attributed to usage in MS of FDA approved DMTs. The main outcomes included total reports for each drug, age, sex distribution, and reporting source. OpenFDA data was used for statistical analyses including reporting odds ratios (ROR) and information components.

RESULTS

8759 alopecia reports were identified among 44 114 adverse events in skin and subcutaneous tissue disorders (19.9%). 3701 (42.3%) with teriflunomide, 1675 (19.1%) with dimethyl fumarate, 985 (11.2%) with natalizumab, 926 (10.6%) with fingolimod, 659 (7.5%) with interferon beta-1a, 257 (2.9%) with glatiramer acetate, 243 (2.8%) with ocrelizumab, 124 (1.4%) with interferon beta-1b, 117 (1.3%) with alemtuzumab, 36 (.4%) with siponimod, 24 (.3%) with cladribine, and 12 (.1%) with rituximab. Reports were mostly made by patients (78.3%) and highest in fifth and sixth decades of life. OpenFDA analyses showed increased ROR (ROR 95% confidence interval) of alopecia in females with teriflunomide (18.00, 17.12-18.93), alemtuzumab (1.43, 1.16-1.76), dimethyl fumarate (1.26, 1.18-1.34), and ocrelizumab (1.28, 1.11-1.49). Increased ROR in males was associated with teriflunomide (24.65, 20.72-29.31).

CONCLUSION

We identified many reports of alopecia for DMTs in addition to teriflunomide. Within the limitations of the database, increased RORs of alopecia were observed for females treated with alemtuzumab, dimethyl fumarate, and ocrelizumab. The source of reporting was largely driven by female patients. Possible alopecia, even if transient, should be considered during patient education when starting DMTs.

Targeting B cells in relapsing-remitting multiple sclerosis: from pathophysiology to optimal clinical management

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease that is caused by an autoimmune response against central nervous system (CNS) structures. Traditionally considered a T-cell-mediated disorder, the contribution of B cells to the pathogenesis of MS has long been debated. Based on recent promising clinical results from CD20-depleting strategies by three therapeutic monoclonal antibodies in clinical phase II and III trials (rituximab, ocrelizumab and ofatumumab), targeting B cells in MS is currently attracting growing interest among basic researchers and clinicians. Many questions about the role of B and plasma cells in MS remain still unanswered, ranging from the role of specific B-cell subsets and functions to the optimal treatment regimen of B-cell depletion and monitoring thereafter. Here, we will assess our current knowledge of the mechanisms implicating B cells in multiple steps of disease pathology and examine current and future therapeutic approaches for the treatment of MS.

Clinical efficacy of BG-12 (dimethyl fumarate) in patients with relapsing-remitting multiple sclerosis: subgroup analyses of the DEFINE study

In the double-blind, placebo-controlled, Phase 3 DEFINE study in patients with relapsing–remitting multiple sclerosis, oral BG-12 (dimethyl fumarate) significantly reduced the proportion of patients relapsed (primary endpoint), the annualized relapse rate (ARR), and confirmed disability progression (secondary endpoints) at two years compared with placebo. We investigated the efficacy of BG-12 240 mg twice daily (BID) and three times daily (TID) in patient subgroups stratified according to baseline demographic and disease characteristics including gender, age, relapse history, McDonald criteria, treatment history, expanded disability status scale score, T2 lesion volume, and gadolinium-enhancing lesions. The clinical efficacy of BG-12 was generally consistent across patient subgroups and reflected positive findings in the overall DEFINE study population. Treatment with BG-12 BID and TID reduced the proportion of patients relapsed and the ARR at two years compared with placebo in all patient subgroups. Reductions in the risk of relapse with BG-12 BID vs. placebo ranged from 68% [hazard ratio 0.32 (95% confidence interval (CI) 0.16-0.62)] to 26% [0.74 (0.51-1.09)] and from 66% [0.34 (0.23-0.50)] to 25% [0.75 (0.42-1.36)] with BG-12 TID vs. placebo. BG-12 also reduced the risk of disability progression at two years compared with placebo in most subgroups of patients treated with the BID dosing regimen and in all subgroups treated with the TID regimen. These analyses indicate that treatment with BG-12 is consistently effective across a wide spectrum of patients with relapsing–remitting multiple sclerosis with varied demographic and disease characteristics.

Clinical efficacy of BG-12 (dimethyl fumarate) in patients with relapsing-remitting multiple sclerosis: subgroup analyses of the CONFIRM study

In the phase 3, randomized, placebo-controlled and active reference (glatiramer acetate) comparator CONFIRM study in patients with relapsing-remitting multiple sclerosis, oral BG-12 (dimethyl fumarate) reduced the annualized relapse rate (ARR; primary endpoint), as well as the proportion of patients relapsed, magnetic resonance imaging lesion activity, and confirmed disability progression, compared with placebo. We investigated the clinical efficacy of BG-12 240 mg twice daily (BID) and three times daily (TID) in patient subgroups stratified according to baseline demographic and disease characteristics including gender, age, relapse history, McDonald criteria, treatment history, Expanded Disability Status Scale score, T2 lesion volume, and gadolinium-enhancing lesions. BG-12 treatment demonstrated generally consistent benefits on relapse-related outcomes across patient subgroups, reflecting the positive findings in the overall CONFIRM study population. Treatment with BG-12 BID and TID reduced the ARR and the proportion of patients relapsed at 2 years compared with placebo in all subgroups analyzed. Reductions in ARR with BG-12 BID versus placebo ranged from 34% [rate ratio 0.664 (95% confidence interval 0.422-1.043)] to 53% [0.466 (0.313-0.694)] and from 13% [0.870 (0.551-1.373)] to 67% [0.334 (0.226-0.493)] with BG-12 TID versus placebo. Treatment with glatiramer acetate reduced the ARR and the proportion of patients relapsed at 2 years compared with placebo in most patient subgroups. The results of these analyses indicate that treatment with BG-12 is effective on relapses across a broad range of patients with relapsing-remitting multiple sclerosis with varied demographic and disease characteristics.

Myelin basic protein immunosensor for multiple sclerosis detection based upon label-free electrochemical impedance spectroscopy

A novel highly sensitive impedimetric Myelin Basic Protein (MBP) immunosensor for the determination of a Multiple Sclerosis (MS) autoantibody, Anti-Myelin Basic Protein (Anti-MBP) was developed by immobilization of MBP on Gelatin and Gelatin-Titanium Dioxide (TiO₂) modified platinium electrode. Cyclic voltammetric (CV) and Electrochemical Impedance Spectroscopic (EIS) methods were employed in determination of the electrode responses and applicability. Gelatin-MBP and gelatin-TiO₂-MBP electrodes were prepared by chemical immobilization of the substrates onto the platinium electrodes. The formal potentials of MBP confined on gelatin-MBP and gelatin-TiO₂-MBP surfaces are estimated to be 195 and 205 mV, respectively. Thus, a little more reversible electron transfer reaction occurs on the gelatin-TiO₂-MBP immunosensor surface. The peak separations of MBP (150 mV and 110 mV s(-1) at 100 mV s(-1)) and the asymmetric anodic and cathodic peak currents indicate that the electron transfer between Anti-MBP and gelatin-MBP/gelatin-TiO₂-MBP immunosensor is quasireversible. Control samples containing a nonspecific human immunoglobulin G (hIgG) antibody were also studied, and calibration curves were obtained by subtraction of the responses for specific and nonspecific antibody-based sensors. Gelatin-MBP and gelatin-TiO₂-MBP immunosensors have detection limit of 0.1528 ng ml(-1) and 0.1495 ng ml(-1) respectively. This immunosensor exhibits high sensitivity and low response times (58 s for gelatin-MBP and 46 s for gelatin-TiO₂-MBP immunosensor). The developed label-free impedimetric immunosensors also provide a simple and sensitive detection method for the specific determination of Anti-MBP in human cerebrospinal fluid (CSF) and serum samples.

First-line disease-modifying therapies in paediatric multiple sclerosis: a comprehensive overview

Paediatric multiple sclerosis (MS) is defined as the onset of MS before the age of 18 years. Immunomodulatory disease-modifying therapies (i.e. the interferons [IFNs] and glatiramer acetate) are considered first-line treatments in adult patients with MS, but they are largely understudied in the paediatric population. IFNβ is a type 1 IFN produced by fibroblasts. The therapeutic effect achieved by IFNβ in MS is believed to be the result of a variety of mechanisms, including the inhibition of T-cell proliferation and a shift in cytokine production. There are currently two forms of recombinant IFNβ used therapeutically for MS: IFNβ-1a and IFNβ-1b. Two formulations of IFNβ-1a exist, one administered as an intramuscular injection once weekly and the other by subcutaneous injection three times per week. Only one type of IFNβ-1b product is on the market, a subcutaneous injection administered every other day. Pharmacokinetic studies of these agents in children do not exist and available data are primarily from studies in healthy adults. It does not appear that the various formulations differ significantly in terms of bioavailability or efficacy in adults. The toxicity profiles of the interferon formulations are similar, with the most common adverse effects in children including flu-like symptoms, injection site reactions and transient elevations in liver enzymes. Glatiramer acetate is a mixture of synthetic polypeptide chains consisting of four different amino acids. Glatiramer acetate appears to mimic the antigenic properties of myelin basic protein (MBP), and by doing so, alters T-cell activation in the periphery. Glatiramer acetate is administered as a once-daily subcutaneous injection. Similar to the IFNβ formulations, there are no pharmacokinetic studies of this agent in children. The most common adverse effects include injection site reactions and transient chest tightness. Fingolimod, a sphingosine 1-phosphate receptor modulator, is a new disease-modifying therapy that was approved by the US FDA in 2010 for the first-line treatment of relapsing forms of MS in adults. However, due to a lack of information and clinical data on this agent in the paediatric population, it is not included in this discussion. Dose-finding studies of the IFNs and glatiramer acetate in the paediatric population are limited. Dosing recommendations are largely based on tolerability studies, with most children and adolescents tolerating the full adult doses. Clinical studies of IFNs in children have not been objectively designed to establish the efficacy of these therapies, and evidence is limited to that of observational trials and retrospective case reports. However, the largest cohort (130 cases) of paediatric MS patients studied to date reported a reduction in annual relapse rate with all three of the different IFNβ formulations and glatiramer acetate after a follow-up period of more than 4 years. Treatment with one of the first-line agents should be offered to any patient after the occurrence of a second demyelinating episode. The efficacy of the four first-line disease-modifying agents is considered to be relatively equivalent, and the choice of agent should be determined on an individual patient basis, taking into account potential adverse effects and patient preferences. Current data suggest that the IFNs and glatiramer acetate are safe and effective therapies in paediatric patients with MS. However, further studies evaluating the pharmacokinetics, appropriate dosing and comparisons of efficacy among these agents are needed to determine the most appropriate and evidence-based treatment decisions in this population.

Subcutaneous recombinant interferon-β-1a (Rebif®): a review of its use in the treatment of relapsing multiple sclerosis

Subcutaneous recombinant interferon-β-1a (SC IFNβ-1a) [Rebif®] is indicated as monotherapy for the prevention of relapses and progression of physical disability in patients with relapsing multiple sclerosis (MS). This article reviews the efficacy and tolerability of SC IFNβ-1a in this indication, with further discussion of its pharmacological properties and pertinent pharmacoeconomic studies. SC IFNβ-1a efficacy and tolerability were evaluated in randomized, double-blind, multinational trials in patients with relapsing-remitting MS (RRMS). Its efficacy was demonstrated in the 2-year PRISMS trial, as SC IFNβ-1a 22 or 44 μg three times weekly (tiw) significantly reduced relapse rates, with an ≈30% relative risk reduction compared with placebo. SC IFNβ-1a was also associated with significantly delayed progression of disability, and lower disease activity according to MRI, relative to placebo. In the 24-week EVIDENCE trial, a significantly higher proportion of SC IFNβ-1a 44 μg tiw than intramuscular IFNβ-1a (Avonex®) 30 μg once weekly recipients remained relapse free. A serum-free formulation of SC IFNβ-1a 44 μg tiw was more efficacious than placebo in preventing the development of brain lesions in the 16-week IMPROVE trial. In the 96-week REGARD trial, the efficacy of SC IFNβ-1a 44 μg tiw was not significantly different to that of glatiramer acetate for clinical endpoints, although it was associated with reduced development of brain lesions compared with glatiramer acetate, according to some MRI endpoints. In the 36-month CAMMS223 trial, alemtuzumab led to significantly lower relapse rates and risk of developing sustained disability than SC IFNβ-1a 44 μg tiw, and was generally more efficacious according to other clinical and MRI endpoints. Across trials, influenza-like symptoms, injection-site reactions, haematological disturbances and hepatic enzyme abnormalities were the most common treatment-emergent adverse events occurring with SC IFNβ-1a. In the PRISMS trial, SC IFNβ-1a 22 and 44 μg tiw recipients had more injection-site reactions than placebo recipients and, at the higher dosage, haematological disturbances and increases in ALT levels were also significantly more frequent than with placebo. Pooled data from clinical trials and postmarketing surveillance indicate that haematological and hepatic adverse events are generally asymptomatic and rarely result in treatment discontinuation. Nevertheless, some cases of serious hepatic complications have been reported. In cost-utility studies, first-line therapies for RRMS, including SC IFNβ-1a, all exceeded commonly accepted US thresholds for incremental cost per quality-adjusted life-years gained relative to symptomatic treatment. However, because of patient need and the difficulty in adequately assessing cost utility in a gradually progressive disease, these agents have been made available to many patients worldwide through special access programmes. Overall, SC IFNβ-1a has a favourable risk-benefit ratio and is a valuable first-line treatment option for patients with relapsing MS.

Cladribine: mode of action and implications for treatment of multiple sclerosis

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease of the central nervous system. The inflammation is driven significantly by autoreactive lymphocytes, which recruit cells of the innate immune system such as macrophages that contribute to subsequent tissue damage, ultimately resulting in demyelination and axonal damage that are characteristic in MS lesions. Cladribine (2-chlorodeoxyadenosine [2-CdA]) is a synthetic chlorinated deoxyadenosine analog that is biologically active in selected cell types and provides targeted and sustained reduction of circulating T and B lymphocytes implicated in the pathogenesis of MS. The biologic activity of cladribine depends on the preferential accumulation of cladribine phosphates in cell types with a high intracellular ratio of deoxycytidine kinase to 5'-nucleotidases. Cladribine-phosphates interfere with DNA synthesis and repair through incorporation into DNA and through inhibition of enzymes involved in DNA metabolism, including DNA polymerase and ribonucleotide reductase. This in turn leads to DNA strand breaks and ultimately cell death. This review explores the mechanism of action of cladribine further, in the context of recent clinical data, after completion of the phase III, 96-week, placebo-controlled CLARITY study. In this study, cladribine tablets demonstrated significant efficacy on clinical and neuroimaging outcomes in relapsing-remitting MS.

Atacicept: targeting B cells in multiple sclerosis

Multiple sclerosis (MS) has traditionally been considered to be a T-cell-mediated disease. However, there is an increasing body of evidence for the involvement of B cells and autoantibodies in the pathology of this disease, providing a rationale for treatments directed against B cells. In this paper we summarize evidence for the key role of B cells in the immunopathology of MS and review data supporting the use of a novel B-cell targeted therapy, atacicept, in this condition. Atacicept is a human recombinant fusion protein that comprises the binding portion of a receptor for both BLyS (B-Lymphocyte Stimulator) and APRIL (A PRoliferation-Inducing Ligand), two cytokines that have been identified as important regulators of B-cell maturation, function and survival. Atacicept has shown selective effects on cells of the B-cell lineage, acting on mature B cells and blocking plasma cells and late stages of B-cell development while sparing B-cell progenitors and memory cells. The efficacy of atacicept in animal models of autoimmune disease and the biological activity of atacicept in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) has been demonstrated. Clinical studies were initiated to investigate the safety, tolerability and efficacy of atacicept in patients with MS. An unexpected increase in inflammatory activity in one of the trials, however, led to suspension of all atacicept trials in MS.

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.

[Atacicept: a new B lymphocyte-targeted therapy for multiple sclerosis]

Multiple sclerosis (MS) has traditionally been considered to be a T cell-mediated disease. However, there is an increasing body of evidence for the involvement of B cells and autoantibodies in the pathology of this disease, providing a rationale for treatment strategies directed against B cells. This paper summarizes the evidence for a key role of B cells in the immunopathology of MS and reviews data supporting the use of a novel B cell-targeted therapy, atacicept, for this condition. Atacicept is a human recombinant fusion protein that comprises the binding portion of a receptor for both BLyS (B Lymphocyte Stimulator) and APRIL (A PRoliferation-Inducing Ligand), two cytokines that have been identified as important regulators of B cell maturation, function and survival. Atacicept has shown selective effects on cells of the B cell lineage, acting on mature B cells and blocking plasma cells and late stages of B cell development while sparing B cell progenitors and memory cells. The efficacy of atacicept in animal models of autoimmune disease and the biological activity of atacicept in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) has been demonstrated. Ongoing clinical studies are investigating the safety, tolerability and efficacy of atacicept in patients with MS, SLE and RA.

Neutralizing antibodies explain the poor clinical response to interferon beta in a small proportion of patients with multiple sclerosis: a retrospective study

Background

Neutralizing antibodies (NAbs) against Interferon beta (IFNβ) are reported to be associated with poor clinical response to therapy in multiple sclerosis (MS) patients. We aimed to quantify the contribution of NAbs to the sub-optimal response of IFNβ treatment.

Methods

We studied the prevalence of NAbs in MS patients grouped according to their clinical response to IFNβ during the treatment period. Patients were classified as: group A, developing ≥ 1 relapse after the first 6 months of therapy; group B, exhibiting confirmed disability progression after the first 6 months of therapy, with or without superimposed relapses; group C, presenting a stable disease course during therapy. A cytopathic effect assay tested the presence of NAbs in a cohort of ambulatory MS patients treated with one of the available IFNβ formulations for at least one year. NAbs positivity was defined as NAbs titre ≥ 20 TRU.

Results

Seventeen patients (12.1%) were NAbs positive. NAbs positivity correlated with poorer clinical response (p < 0.04). As expected, the prevalence of NAbs was significantly lower in Group C (2.1%) than in Group A (17.0%) and Group B (17.0%). However, in the groups of patients with a poor clinical response (A, B), NAbs positivity was found only in a small proportion of patients.

Conclusion

The majority of patients with poor clinical response are NAbs negative suggesting that NAbs explains only partially the sub-optimal response to IFNβ.

The effect of interferon-beta on mouse neural progenitor cell survival and differentiation

Interferon-beta (IFN-beta) is a mainstay therapy for relapse-remitting multiple sclerosis (MS). However, the direct effects of IFN-beta on the central nervous system (CNS) are not well understood. To determine whether IFN-beta has direct neuroprotective effects on CNS cells, we treated adult mouse neural progenitor cells (NPCs) in vitro with IFN-beta and examined the effects on proliferation, apoptosis, and differentiation. We found that mouse NPCs express high levels of IFNalpha/beta receptor (IFNAR). In response to IFN-beta treatment, no effect was observed on differentiation or proliferation. However, IFN-beta treated mouse NPCs demonstrated decreased apoptosis upon growth factor withdrawal. Pathway-specific polymerase chain reaction (PCR) arrays demonstrated that IFN-beta treatment upregulated the STAT 1 and 2 signaling pathway, as well as GFRA2, NOD1, Caspases 1 and 12, and TNFSF10. These results suggest that IFN-beta can directly affect NPC survival, possibly playing a neuroprotective role in the CNS by modulating neurotrophic factors.

Interferon beta-1a for the maintenance of remission in patients with Crohn's disease: results of a phase II dose-finding study

BACKGROUND

Crohn's disease (CD) and multiple sclerosis (MS) share common pathogenic processes. Interferon (IFN) beta-1a is effective and generally well tolerated in patients with MS and has been shown to down-regulate the expression of interleukin-12, a cytokine that is thought to be involved in mucosal degeneration in CD. IFN beta-1a therefore offers promise as a treatment for CD.

METHODS

In this multicentre, double-blind, placebo-controlled, phase II, dose-finding study, patients with steroid-induced clinical remissions of CD were randomized 1:1:1:1 to subcutaneous IFN beta-1a: 66 mcg three times weekly (tiw), 44 mcg tiw, 44 mcg twice weekly (biw), or matching placebo tiw with steroid tapering. The primary endpoint was the proportion of patients relapse-free at Week 26. Safety was also assessed.

RESULTS

This study was terminated early following a planned interim analysis at 26 weeks. Of the planned 192 patients, 67 were randomized to treatment: placebo (n = 16), or IFN beta-1a 44 mcg biw (n = 17), 44 mcg tiw (n = 16) or 66 mcg tiw (n = 18). In total, 20/67 patients (29.9%) completed 26 weeks and 7 patients (10.4%) completed 52 weeks. The proportion of patients who remained relapse-free at Week 26 did not differ significantly between the placebo group (5/16, 31%) and the IFN beta-1a 44 mcg biw (6/17, 35%; p = 0.497), 44 mcg tiw (7/16, 44%; p = 0.280) or 66 mcg tiw (2/18, 11%; p = 0.333) groups. There was little difference between treatment groups in secondary efficacy endpoints. IFN beta-1a was generally well tolerated at all doses. Adverse events (AEs) were generally mild or moderate in IFN beta-1a-treated patients, with the most common AEs (influenza-like symptoms, headache, injection-site reactions) being similar to those reported with IFN beta-1a in MS.

CONCLUSION

There was no difference in efficacy between patients with CD receiving IFN beta-1a or placebo. However, these results should be considered in the context of the low patient numbers and high dropout rate. Overall, IFN beta-1a was generally well tolerated, with a safety profile that was consistent with previous experience in MS.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00304252.

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.

The role of B cells in multiple sclerosis: rationale for B-cell-targeted therapies

Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system with no clear etiology. Until recently, most studies have emphasized the role of T cells in the pathogenesis of multiple sclerosis. Data suggesting that B cells play a role in the pathogenesis of multiple sclerosis have been accumulating for the past five decades, demonstrating that the cerebrospinal fluid and central nervous system tissues of multiple sclerosis patients contain B cells, plasma cells, antibodies, and immunoglobulins. Data suggest that B cells are involved in antigen capture and presentation to T cells, cytokine production, antibody secretion, demyelination, tissue damage, and remyelination in multiple sclerosis. These advances in the understanding of B-cell and antibody roles in the pathophysiology of multiple sclerosis provide a strong rationale for B-cell-targeted therapies.

B-cell-targeted treatment for multiple sclerosis: mechanism of action and clinical data

Strategies for treating autoimmune disorders are increasingly employing targeted therapies rather than non-specific, multitargeted treatments. Accumulating evidence on the involvement of B lymphocytes in the pathophysiology of autoimmune demyelinating disease has led to a renewed interest in B cells as potential therapeutic targets. In particular, antigen presentation between B cells and T cells, increased trafficking of B cells across the blood-brain barrier, and autoantibodies produced by plasma cells may contribute to the pathophysiology of autoimmune disorders such as multiple sclerosis. Several B-cell-targeted, depletion therapies are currently in development, including rituximab, epratuzumab, diphtheria toxin-single chain Fv (DC2219), belimumab, atacicept, abatacept, and abetimus sodium. Of these agents, only rituximab and abatacept have been evaluated in multiple sclerosis patients. Preliminary results of a phase II trial of rituximab in multiple sclerosis suggest that rituximab is well tolerated and significantly reduces the number of gadolinium enhancing lesions over 24 weeks of treatment. Results of an exploratory analysis suggest the potential promise of abatacept 10 mg/kg for multiple sclerosis. It is expected that future clinical trials will establish a role for B-cell-targeted therapies in the treatment of multiple sclerosis and other autoimmune neurological diseases. This article describes the mechanism of action behind B-cell-targeted depletion therapies in development and reviews available clinical data.

Interferon-β stabilizes barrier characteristics of the blood–brain barrier in four different species in vitro

Background

Blood–brain barrier (BBB) breakdown is an early event in the pathogenesis of multiple sclerosis (MS). In a previous study we have found a direct stabilization of barrier characteristics after treatment of bovine brain capillary endothelial cells (BCECs) with human recombinant interferon-β-1a (IFN-β-1a) in an in vitro BBB model. In the present study we examined the effect of human recombinant IFN-β-1a on the barrier properties of BCECs derived from four different species including humans to predict treatment efficacy of IFN-β-1a in MS patients.

Methods

We used primary bovine and porcine BCECs, as well as human and murine BCEC cell lines. We investigated the influence of human recombinant IFN-β-1a on the paracellular permeability for 3H-inulin and 14C-sucrose across monolayers of bovine, human, and murine BCECs. In addition, the transendothelial electrical resistance (TEER) was determined in in vitro systems applying porcine and murine BCECS.

Results

We found a stabilizing effect on the barrier characteristics of BCECs after pretreatment with IFN-β-1a in all applied in vitro models: addition of IFN-β-1a resulted in a significant decrease of the paracellular permeability across monolayers of human, bovine, and murine BCECs. Furthermore, the TEER was significantly increased after pretreatment of porcine and murine BCECs with IFN-β-1a.

Conclusion

Our data suggest that BBB stabilization by IFN-β-1a may contribute to its beneficial effects in the treatment of MS. A human in vitro BBB model might be useful as bioassay for testing the treatment efficacy of drugs in MS.

Expression of the inhibitor of apoptosis protein family in multiple sclerosis reveals a potential immunomodulatory role during autoimmune mediated demyelination

A failure of autoreactive T cells to undergo apoptosis may contribute to the pathogenesis of multiple sclerosis (MS). The role of the inhibitor of apoptosis (IAP) family of anti-apoptotic proteins such as X-linked IAP (XIAP), human inhibitor of apoptosis-1 (HIAP-1), human inhibitor of apoptosis-2 (HIAP-2), neuronal apoptosis inhibitory protein (NAIP) and Survivin in relapsing–remitting, secondary-progressive, primary-progressive or benign forms of MS is unclear. We report here that expression of the IAP family of genes in peripheral blood samples and brain tissues from MS cases support a role for differential regulation of these potent anti-apoptotic proteins in the pathology of MS. XIAP mRNA and protein levels were elevated in peripheral blood mononuclear cells from patients with active disease relative to normal subjects. In patients with active MS, HIAP-1 and HIAP-2 mRNA levels were elevated in resting T cells while NAIP mRNA was increased in whole blood. In post-mortem MS brain tissue, XIAP and HIAP-1 in myelin lesions were co-localized with microglia and T cells, respectively. Only in primary-progressive patients was Survivin expression elevated suggestive of a distinct pathological basis for this subtype of MS. Taken together, these results suggest that patterns of inhibitor of apoptosis expression in immune cells may have value in distinguishing between MS subtypes and offer insight into the mechanisms responsible for their distinct clinical courses.

The Rebif new formulation story: it's not trials and error

The rapid evolution of the biopharmaceutical industry and the development of innovative technologies have provided an opportunity to improve recombinant interferon (IFN)-beta formulations. A number of strategies have been developed to improve the stability, tolerability and immunogenicity of IFNbeta formulations that are used in the long-term treatment of patients with multiple sclerosis (MS). This review focuses on the production of recombinant IFNs and discusses the development of one such biopharmaceutical, Rebif New Formulation (RNF).RNF was developed with the aim of further improving the tolerability and immunogenicity of Rebif, an approved IFNbeta-1a formulation administered subcutaneously three times per week (sc tiw). To this end, numerous candidate drug vehicles and formulations were developed. However, unlike other formulations of IFNbeta, the new candidate formulations in this case were free from all serum-derived components. Specifically, each RNF candidate was free from human serum albumin and produced without fetal bovine serum. The physicochemical stability, injection-site tolerability, pharmacokinetic profile and immunogenic potential of each candidate formulation were systematically tested. This involved initial screening of a large pool of formulations for promising candidates. Two candidate formulations were selected and subjected to further, extensive evaluation.Ex vivo T-cell assays were used to compare the immunogenicity of RNF candidates with that of the current (at the time of writing) approved formulation and an IFNbeta standard. A single RNF candidate induced less T-cell activation, in terms of proliferation and proinflammatory cytokine secretion, than the other two formulations. The results provided ex vivo evidence of the improved immunogenic potential of RNF. A murine model was used to compare the relative immunogenicity of RNF in vivo with two approved formulations of IFNbeta-1a. Mice treated with RNF developed neutralising antibodies more slowly and produced lower titres than mice treated with equivalent doses of the current IFNbeta-1a sc tiw formulation or another approved IFNbeta-1a formulation administered intramuscularly once per week (Avonex). RNF also demonstrated better local tolerability than the current IFNbeta-1a sc tiw formulation after single subcutaneous doses in healthy volunteers. One RNF candidate was superior to the others in all preclinical and phase I studies, and was chosen as the final RNF. This formulation is currently undergoing assessment in a 96-week, phase IIIb clinical trial in patients with MS. This single-arm, open-label, multicentre study will compare the immunogenicity and tolerability of RNF with historical data on the current formulation; results of a 48-week, interim analysis indicate that RNF has improved local tolerability and immunogenicity compared with the current formulation. It is anticipated that the benefits of RNF will translate into an improved long-term benefit-to-risk profile. Further assessment of RNF and other MS drugs is ongoing with the aim of enhancing the therapeutic options available for patients with MS.

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.