Drugs For Relapsing-remitting Multiple Sclerosis Research Articles

Combining randomized and non-randomized data to predict heterogeneous effects of competing treatments.

Some patients benefit from a treatment while others may do so less or do not benefit at all. We have previously developed a two-stage network meta-regression prediction model that synthesized randomized trials and evaluates how treatment effects vary across patient characteristics. In this article, we extended this model to combine different sources of types in different formats: aggregate data (AD) and individual participant data (IPD) from randomized and non-randomized evidence. In the first stage, a prognostic model is developed to predict the baseline risk of the outcome using a large cohort study. In the second stage, we recalibrated this prognostic model to improve our predictions for patients enrolled in randomized trials. In the third stage, we used the baseline risk as effect modifier in a network meta-regression model combining AD, IPD randomized clinical trial to estimate heterogeneous treatment effects. We illustrated the approach in the re-analysis of a network of studies comparing three drugs for relapsing-remitting multiple sclerosis. Several patient characteristics influence the baseline risk of relapse, which in turn modifies the effect of the drugs. The proposed model makes personalized predictions for health outcomes under several treatment options and encompasses all relevant randomized and non-randomized evidence.

Novel Gastroprotective and Thermostable Cocrystal of Dimethyl Fumarate: Its Preparation, Characterization, and In Vitro and In Vivo Evaluation.

Crystallization has revolutionized the field of solid-state formulations by modulating the physiochemical and release profile of active pharmaceutical ingredients (APIs). Dimethyl fumarate (DF), an FDA-approved first-line drug for relapsing-remitting multiple sclerosis, has a sublimation problem, leading to loss of the drug during its processing. To tackle this problem, DF cocrystal has been prepared by using solvent evaporation technique using nicotinamide as a coformer, which has been chosen based on in silico predictions and their ability to participate in hydrogen bonding. Fourier transform infrared (FT-IR), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and sublimation analysis have characterized the cocrystal and its thermostability. Comparative analysis of the release profile has been done by the dissolution and pharmacokinetic study of DF and its cocrystal. Formulated cocrystal is noncytotoxic, antioxidant and inhibits interleukin-6 and tissue necrosis factor-α in peripheral blood mononuclear cells induced by lipopolysaccharide. We have obtained a thermostable cocrystal of DF with a similar physicochemical and release profile to that of DF. The formulated cocrystal also provides a gastroprotective effect which helps counterbalance the adverse effects of DF by reducing lipid peroxidation and total nitrite levels.

Fingolimod-Associated Macular Edema in the Treatment of Multiple Sclerosis.

Multiple sclerosis is a neurological disorder categorized by inflammatory processes with a high prevalence worldwide. It affects both motor and sensory pathways and is also associated with the visual pathway.Fingolimod is a commonly used drug for relapsing-remitting multiple sclerosis. It is a sphingosine 1-phosphate modulator acting on its receptors for immune cell accumulation, neuronal function, embryological development, vascular permeability, smooth muscle cell function, and endothelial barrier maintenance.This review aims to understand the processes, mechanisms, risks, and management of fingolimod-associated macular edema. Due to the anti-inflammatory properties of fingolimod, it decreases various cytokines, including interleukin (IL)-1B and IL-6, spike wave, and spike amplitude, in electrophysiological activities and decreases insoluble receptors for advanced glycation end productligand. A daily dosage of 0.5 mg of fingolimod has an increased association with macular edema. The serious adverse events of fingolimod are lymphopenia, cardiovascular events, ocular events, and carcinoma. Fingolimod decreases brain volume and increases vascular permeability, resulting in increased macular volume and damage to the blood-retinal barrier, which causes an increased risk for macular edema. Cystoid macular edema is more common in older individuals suffering from comorbidities affecting the retina, such as diabetes, or those undergoing ophthalmological surgeries. This review also highlights the importance of regular ophthalmology examinations on patients consuming fingolimod both in the initial stages and chronic use. The treatment options for macular edema include nonsteroidal anti-inflammatory drugs, acetazolamide, triamcinolone, ketorolac, corticosteroids, and intravitreal procedures.

Exploring the Cost Effectiveness of Shared Decision Making for Choosing between Disease-Modifying Drugs for Relapsing-Remitting Multiple Sclerosis in the Netherlands: A State Transition Model.

BackgroundUp to 31% of patients with relapsing-remitting multiple sclerosis (RRMS) discontinue treatment with disease-modifying drug (DMD) within the first year, and of the patients who do continue, about 40% are nonadherent. Shared decision making may decrease nonadherence and discontinuation rates, but evidence in the context of RRMS is limited. Shared decision making may, however, come at additional costs. This study aimed to explore the potential cost-effectiveness of shared decision making for RRMS in comparison with usual care, from a (limited) societal perspective over a lifetime.MethodsAn exploratory economic evaluation was conducted by adapting a previously developed state transition model that evaluates the cost-effectiveness of a range of DMDs for RRMS in comparison with the best supportive care. Three potential effects of shared decision making were explored: 1) a change in the initial DMD chosen, 2) a decrease in the patient’s discontinuation in using the DMD, and 3) an increase in adherence to the DMD. One-way and probabilistic sensitivity analyses of a scenario that combined the 3 effects were conducted.ResultsEach effect separately and the 3 effects combined resulted in higher quality-adjusted life years (QALYs) and costs due to the increased utilization of DMD. A decrease in discontinuation of DMDs influenced the incremental cost-effectiveness ratio (ICER) most. The combined scenario resulted in an ICER of €17,875 per QALY gained. The ICER was sensitive to changes in several parameters.ConclusionThis study suggests that shared decision making for DMDs could potentially be cost-effective, especially if shared decision making would help to decrease treatment discontinuation. Our results, however, may depend on the assumed effects on treatment choice, persistence, and adherence, which are actually largely unknown.

Early evidence of disease activity during fingolimod predicts medium-term inefficacy in relapsing-remitting multiple sclerosis

Background: Fingolimod (FTY) is an effective second-line drug for relapsing-remitting multiple sclerosis, with ~50% patients showing no evidence of disease activity (NEDA) after 2 years. Nonetheless, the early identification of non-responders is extremely important, to promptly address them to more aggressive drugs. Objectives: This cohort study evaluates FTY medium-term effectiveness, searching for early markers of treatment failure. Patients and methods: Three hundred eighty patients starting FTY were enrolled and classified according to NEDA and time to first relapse criteria at 4-year follow-up. Logistic and Cox regression analyses were applied to identify early predictors of non-response. Results: At 4 years, 65.6% of patients were free from relapses and 35.4% had NEDA. Female gender was associated with a higher risk of non-response. Moreover, evidence of clinical and/or magnetic resonance imaging (MRI) activity during the first year of treatment was highly predictive of disease activity in the follow-up: the positive predictive value for non-response was 0.74 for the presence of ⩾1 relapse, 0.73 for the presence of ⩾1 active MRI lesion, and 0.83 for the presence of both clinical and MRI activity. Conclusions: FTY effectiveness persists at medium-term follow-up; a close monitoring during the first year of treatment is warranted to early identify non-responders requiring treatment optimization.

Gut microbiota composition during a 12-week intervention with delayed-release dimethyl fumarate in multiple sclerosis - a pilot trial.

IntroductionPatients with multiple sclerosis may have a distinct gut microbiota profile. Delayed-release dimethyl fumarate is an orally administered drug for relapsing–remitting multiple sclerosis, which has been associated with gastrointestinal side-effects in some patients.ObjectivesThe purpose of this study was to determine if dimethyl fumarate alters the abundance and diversity of commensal gut bacteria, and if these changes are associated with gastrointestinal side-effects.MethodsThirty-six patients with relapsing–remitting multiple sclerosis received either dimethyl fumarate (n = 27) or an injectable multiple sclerosis disease-modifying therapy (glatiramer acetate or interferons, n = 9) for 12 weeks. Stool samples were collected at baseline, two and 12 weeks. We included 165 healthy individuals as controls.ResultsAt baseline, 16 microbial genera were altered in multiple sclerosis patients compared with healthy controls. In the dimethyl fumarate-treated patients (n = 21) we observed a trend of reduced Actinobacteria (p = 0.03, QFDR = 0.24) at two weeks, mainly driven by Bifidobacterium (p = 0.06, QFDR = 0.69). At 12 weeks, we observed an increased abundance of Firmicutes (p = 0.02, QFDR = 0.09), mostly driven by Faecalibacterium (p = 0.01, QFDR = 0.48).ConclusionsThis pilot study did not detect a major effect of dimethyl fumarate on the gut microbiota composition, but we observed a trend towards normalization of the low abundance of butyrate-producing Faecalibacterium after 12 weeks treatment. The study was underpowered to link microbiota to gastrointestinal symptoms.

Increased NK Cell Count in Multiple Sclerosis Patients Treated With Dimethyl Fumarate: A 2-Year Longitudinal Study.

Background: Dimethyl fumarate (DMF) is a disease-modifying drug for relapsing-remitting multiple sclerosis. Among others, DMF impedes immune activation by shifting the balance between inflammatory and regulatory cell types and by inducing apoptosis-triggered lymphopenia. Although the decrease in lymphocyte count is an early effect of the drug in several patients, the long-term impact on lymphocyte subsets is largely unknown.Methods: We performed a 2-years observational study on total lymphocyte count and subsets thereof by flow cytometry of peripheral blood of 38 multiple sclerosis patients in treatment with DMF. Data were collected at the beginning and after 3, 6, 12, and 24 months of therapy.Results: Total lymphocyte count decreased in relation to time of exposure to DMF. Mean absolute B cell count decreased by 34.1% (p < 0.001) within the first 3 months of therapy and then remained stable over time. Mean absolute CD3+ T cells count decrement reached 47.5% after 12 months of treatment (p < 0.001). NK cells count showed a heterogeneous trend, increasing by 85.9% (p < 0.001) after 2 years of treatment. CD4+ T cells and CD8+ T cells substantially decreased, with a significant increase of CD4+/CD8+ ratio during the first year of therapy.Conclusions: NK cells showed a heterogeneous behavior during DMF treatment with a significant increase over time. Since NK cells may also have a regulatory effect on immune system modulation, their increase during DMF treatment might play a role in the efficacy and safety of the drug.

Discontinuation of teriflunomide and dimethyl fumarate in a large Italian multicentre population: a 24-month real-world experience.

Teriflunomide (TRF) and Dimethyl fumarate (DMF) are licensed drugs for relapsing-remitting Multiple Sclerosis (RRMS). We aimed to compare the rate and the time to discontinuation among persons with RRMS (pwRRMS), newly treated with TRF and DMF. A retrospective study on prospectively collected data was performed in nine tertiary MS centers, in Italy. The 24-month discontinuation rate in the two cohorts was the primary study outcome. We also assessed the time to discontinuation and reasons of therapy withdrawn. Discontinuation of TRF and DMF was defined as a gap of treatment ≥ 60 days. A cohort of 903 pwRRMS (316 on TRF and 587 on DMF) was analyzed. During 24 months of follow-up, pwRRMS on TRF and DMF showed similar discontinuation rates. The analysis of predictors with Cox regression model showed differences between the two groups (p for log-rank test = 0.007); male gender [HR 2.21 (1.00-4.90); p = 0.01] and the number of previous switches [HR 1.47 (1.16-1.86); p = 0.01] were associated with higher hazard of discontinuation in the DMF group. In a real-world setting, pwRRMS on TRF and DMF had similar discontinuation rates over 24 months. Male pwRRMS on DMF with a previous history of therapeutic failure are at more risk of discontinuation therapy.

Lipid transporter Spns2 promotes microglia pro-inflammatory activation in response to amyloid-beta peptide.

Accumulating evidence indicates that neuroinflammation contributes to the pathogenesis and exacerbation of neurodegenerative disorders, such as Alzheimer's disease (AD). Sphingosine-1-phosphate (S1P) is a pleiotropic bioactive lipid that regulates many pathophysiological processes including inflammation. We present evidence here that the spinster homolog 2 (Spns2), a S1P transporter, promotes microglia pro-inflammatory activation in vitro and in vivo. Spns2 knockout (Spns2KO) in primary cultured microglia resulted in significantly reduced levels of pro-inflammatory cytokines induced by lipopolysaccharide (LPS) and amyloid-beta peptide 1-42 oligomers (Aβ42) when compared with littermate controls. Fingolimod (FTY720), a S1P receptor 1 (S1PR1) functional antagonist and FDA approved drug for relapsing-remitting multiple sclerosis, partially blunted Aβ42-induced pro-inflammatory cytokine generation, suggesting that Spns2 promotes microglia pro-inflammatory activation through S1P-signaling. Spns2KO significantly reduced Aβ42-induced nuclear factor kappa B (NFκB) activity. S1P increased, while FTY720 dampened, Aβ42-induced NFκB activity, suggesting that Spns2 activates microglia inflammation through, at least partially, NFκB pathway. Spns2KO mouse brains showed significantly reduced Aβ42-induced microglia activation/accumulation and reduced levels of pro-inflammatory cytokines when compared with age-matched controls. More interestingly, Spns2KO ameliorated Aβ42-induced working memory deficit detected by Y-Maze. In summary, these results suggest that Spns2 promotes pro-inflammatory polarization of microglia and may play a crucial role in AD pathogenesis.

Predicting therapeutic response to fingolimod treatment in multiple sclerosis patients.

Fingolimod, an orally active immunomodulatory drug for relapsing-remitting multiple sclerosis (RRMS), sequesters T cells in lymph nodes through functional antagonism of the sphingosine-1-phosphate receptor, reducing the number of potential autoreactive cells that migrate to the central nervous system. However, not all RRMS patients respond to this therapy. Our aim was to test the hypothesis that by immune-monitoring RRMS patient's leukocyte subpopulations it is possible to find biomarkers associated with clinical response to fingolimod. Prospective study. Analysis of peripheral blood mononuclear cell subpopulations by multiparametric flow cytometry, at baseline and +1, +3, +6, +12months of follow-up in 40 RRMS patients starting fingolimod therapy. Fingolimod treatment induced a severe lymphopenia affecting mainly T and B cells. A relative increase in Treg (memory Treg : 3.8±1.0% baseline vs 8.8±4.4% month +1; activated Treg : 1.5±0.7% baseline vs 3.7±2.1% month +1, P<0.001) as well as transitional B cells (10.5±12.3% baseline vs 18.7±14.6% month +1, P<0.001) was observed. Interestingly, lymphocyte subpopulations were already at baseline significantly different in responder patients. The percentage of recent thymic emigrants (RTE) used to stratify fingolimod responder, and no responder patients was the best biomarker (4.0±1.4% vs 7.4±1.9%, respectively [P<0.001]). The results support that immune-monitoring of lymphocyte subpopulations in peripheral blood is a promising tool to select RRMS candidate for fingolimod treatment.

Drug holiday therapy of fingolimod in Japanese relapsing-remitting multiple sclerosis

Background: Fingolimod is a once-daily drug for relapsing-remitting multiple sclerosis (RRMS). Drug holiday therapy is proposed to manage adverse effects such as lymphopenia and liver dysfunction which affect the continuous drug administration.

Fingolimod Is Cytotoxic in Acute Myeloid Leukemia Independent of Additional Chemotherapeutic Agents

INTRODUCTION:Conventional treatment of acute myeloid leukemia (AML) remains largely unchanged for over thirty years. With poor overall survival and disease cure rates, novel therapies are needed. The SET oncoprotein has been implicated in AML as essential for proliferation through inhibition of the tumor suppressor protein phosphatase 2A (PP2A). Interaction between SET and PP2A leads to inactivation of PP2A, leaving cell survival and proliferation signals unchecked. PP2A has been postulated to be an important target in AML. Fingolimod (FTY720), an FDA approved drug for relapsing-remitting multiple sclerosis, is a sphingosine-1 phosphate receptor agonist that has off-target activity to activate PP2A. In this work, we show evidence of FTY720's efficacy in AML cells derived from cell lines and patients, and provide preliminary data regarding SET expression in AML cell lines.METHODS:Cytotoxicity experiments were performed using HL-60, THP-1, MV-4, and Kasumi-3 cell lines, as well as patient-derived samples of AML, obtained through an IRB-approved protocol. Cells were incubated overnight with varied concentrations of FTY720, azacitidine, idarubicin, cytarabine, or drugs in combination. After incubation, cells were analyzed by colorimetric assay. Percent cytotoxicity was estimated as a proportion of light absorbance compared with blank media and untreated control cells. Inhibitory concentration of 50% of cells (IC50) was estimated using GraphPad Prism software, version 6.0. Flow cytometry experiments for confirmation of cytotoxicity were also performed with antibodies against Annexin V and propidium iodide. For estimation of SET expression, we performed ELISA with antibodies against SETα and SETß and quantified measurements by light absorption.RESULTS:FTY720inhibits growth of AML cells independently in both cell lines and patient-derived samples. In the THP-1 cell line, we estimated the IC50 of FTY720 to be 3.4 μM (Figure 1). In the HL-60 cell line, we estimated the IC50 to be 2.5 μM. In patient-derived samples of AML, we had similar findings. The mean IC50 was 3.24 μM (SD = 1.32, n = 8). Flow cytometry of tested samples confirmed induction of both apoptosis and cell death within a 3-hour time frame (Figure 2).Samples were also incubated with combination of FTY720 and conventional cytotoxic chemotherapeutic agents used in AML (Table 1). In the HL-60 cell line, the following IC50s were estimated for these drugs: idarubicin (0.02 μM); cytarabine (0.6 μM); azacitidine (5.7 μM). In combination with FTY720, there was no appreciable change.Results of ELISA showed measurable but low SETα and SETß levels, when compared to a known positive control, the Ramos cell line for Burkitt’s lymphoma (Table 2). In the MV-4 AML cell line, the SETα/ß ratio was 0.096. In Kasumi-3 cells, the α/ß ratio was measured at 0.063.DISCUSSION:These data support the assertion that FTY720 is a cytotoxic agent in AML. This effect is independent of other cytotoxic agents, as no additive or synergistic effect was demonstrated when drugs were combined. The micromolar cytotoxicity poses challenges to the adoption of this agent as an active drug in AML, as serum concentrations from currently prescribed doses in multiple sclerosis have been shown to achieve only nanomolar concentrations. It is notable that the volume of distribution of FTY720 is very high and over 90% is concentrated in blood cells, so actual cell concentrations may be substantially higher.Our work has not yielded the same results others have reported with increased SET α/ß ratios in AML cells. In other tumor types, high SET alpha ratios have been associated with higher SET activity; thus, these results would not be suggestive of such a role in AML. Despite our findings, the activity of FTY720 in these cells merits further investigation into SET expression in AML. We have recently a flow cytometric assay for SETα and SETß that can be used to quantify SET levels, and we plan to analyze patient samples used in cytotoxicity experiments to help identify the SET α/ß ratio in AML. We hope that these experiments will establish SET and PP2A as targets for drug development in AML. [Display omitted] [Display omitted] [Display omitted] DisclosuresRao:Gilead, Inc.: Employment.

Effects of Three Months Fingolimod Therapy on Heart Rate.

Fingolimod is a novel disease-modifying drug for relapsing-remitting multiple sclerosis (RRMS). Fingolimod initiation associates with a decrease in heart rate (HR). However, the long-term effects of fingolimod on HR are not known. The aim of this study was prospectively investigate the effect of 3-month fingolimod therapy on HR. Twenty-seven RRMS patients underwent 24-h ambulatory electrocardiogram recording 20 ± 16 days before (baseline) and at the day of fingolimod initiation (1 day). Twenty-four patients completed 3 months follow-up (3 months). The average HR over 24-h and the average HR for daytime and nighttime were assessed at baseline, 1 day and 3 months. Fingolimod initiation resulted in slowing of HR from 82 ± 11 1/min at baseline to 63 ± 9.5 1/min at 5 h after the initiation of the therapy. The average HR during 24-h was lower at 1d (66 ± 7.8 1/min;p < 0.001) and also at 3 months (69 ± 8.3 1/min;p < 0.001) as compared to baseline (74 ± 10 1/min). The average daytime HR at 1 day (68 ± 8.4 1/min) was lower as compared to baseline (78 ± 11 1/min, p < 0.001), whereas no difference was found between the average daytime HR at baseline and at 3 months (79 ± 10 1/min). The average nighttime HR at 1 day (59 ± 8.8 1/min;p < 0.001) and at 3 months (60 ± 9.2 1/min;p < 0.05) both were lower than at baseline (64 ± 9.9 1/min). In conclusion, fingolimod resulted in HR decrease reaching the nadir at 5 h after the first dose. HR remained lower after 3 months fingolimod treatment as compared to baseline. Particularly, HR at daytime recovered whereas the nighttime HR showed not recovery as compared to the day of fingolimod initiation.

MRI lesions as a surrogate for relapses in multiple sclerosis: a meta-analysis of randomised trials

A meta-analysis of randomised trials in relapsing-remitting multiple sclerosis published in 2009 showed a quantitative relation between the treatment effects detected on MRI lesions and clinical relapses. We aimed to validate that relation using data from a large and independent set of clinical trials in multiple sclerosis. We searched Medline for clinical trials that assessed disease-modifying drugs for relapsing-remitting multiple sclerosis published from Sept 1, 2008, to Oct 31, 2012. We extracted data for the treatment effects on MRI lesions and on relapses from each trial, and the correlation of log transformed relative measures of these treatment effects was assessed with a weighted linear regression analysis. The R(2) value was estimated to quantify the strength of the correlation, and we used an interaction test to test for a difference in slope from the previously estimated equation. We also ran several sensitivity analyses. We identified 31 eligible trials, which provided data for 18 901 patients with relapsing-remitting multiple sclerosis. The regression equation derived using data from these studies showed a relation between the concurrent treatment effects on MRI lesions and relapses (slope=0·52; R(2)=0·71), much the same as was previously estimated (pinteraction=0·45). Analysis of trials that tested the same drugs in phase 2 and phase 3 studies showed that the effects on MRI lesions over short follow-up periods (6-9 months) can also predict the effects on relapses over longer follow-up periods (12-24 months), with reported effects on relapses that were within the 95% prediction intervals in eight of nine trials. Our findings indicate that the effect of a treatment on relapses can be accurately predicted by the effect of that therapy on MRI lesions, implying that the use of MRI markers as primary endpoints in future clinical trials of treatments for multiple sclerosis can be considered, in specific situations, such as in trials testing generics or biosimilars of drugs with a well known mechanism of action or in paediatric trials testing drugs already approved for adults. None.

Treatments for relapsing–remitting multiple sclerosis: summarising current information by network meta-analysis

Oral drugs for relapsing-remitting multiple sclerosis (RRMS) have been recently investigated and, one of these, fingolimod, is already available in several countries. In this framework, an analysis of the data in terms of the comparative effectiveness for all treatments thus far approved for RRMS can be useful to reappraise their place in therapy. After a MEDLINE search, we selected all randomised trials studying the effectiveness of drugs for RRMS and included in our analysis those randomised trials in which interferon, glatiramer, natalizumab or fingolimod were studied. The end-point was the relapse-free rate at 12months, which was compared between the various treatments. Direct comparisons, based on actual randomised trials, were handled by calculating the trial-specific hazard ratio (HR) or the meta-analytic value of HR (when at least 2 trials were available). Indirect comparisons for which data from actual trials were missing were instead managed through a network meta-analysis. Ten randomised trials met the criteria set for our analysis. All active treatments were found to be significantly more effective than placebo (direct comparisons) in terms of freedom from relapse at the 12-month follow-up assessments; the values of HR ranged from 1.28 for glatiramer to 1.53 for interferon beta. The comparisons between active agents revealed that fingolimod was superior to interferon (HR = 1.18; direct comparison) and glatiramer (HR = 1.23; indirect comparison), while the other four head-to-head comparisons of treatments revealed no significant difference. On the basis of the effectiveness data presently available, fingolimod seems to offer the advantage of oral administration together with the most favorable profile in terms of relapse-free rate at the 1-year follow-up assessment.

Identification of targets and new developments in the treatment of multiple sclerosis &amp;ndash; focus on cladribine

Orally available disease-modifying drugs for relapsing-remitting multiple sclerosis (MS) represent an unmet need for this chronic and debilitating disease. Among 5 currently investigated drugs at phase 3 clinical stage, promising efficacy data for fingolimod and oral cladribine have recently been published. However, benefits need to be weighed against the risks to define the role of these compounds within current treatment regimens. In this review, data on the efficacy of a promising compound, oral cladribine, are discussed and balanced with known and anticipated risks in a postmarketing era, and finally gives an outlook on the potential place of this drug in treatment algorithms for MS in the future.

Oral Glatiramer Acetate in Experimental Autoimmune Encephalomyelitis: Clinical and Immunological Studies

Glatiramer acetate (GA, Copaxone, copolymer 1) for injection is an approved drug for relapsing-remitting multiple sclerosis. The clinical and immunological effects of GA were extensively studied in experimental autoimmune encephalomyelitis (EAE), the experimental animal model for MS. The effect of oral administration of GA was tested in both rodents and primates in acute as well as in chronic relapsing (CR) models of EAE. Oral GA was found to suppress acute EAE induced in rats, mice, and rhesus monkeys. The effect of GA was also tested in several models of CR-EAE: proteolipid protein and myelin oligodendrocyte glycoprotein induced CR-EAE in mice, CR-EAE in Biozzi mice, and CR-EAE in cynomolgus monkeys. In all the murine models, oral treatment with GA initiated at the peak of first relapse reduced the severity of disease and suppressed further relapses. Suppression of EAE with oral GA was associated with marked inhibition of spleen cell proliferation and Th1 cytokine (IL-2 and IFN-gamma) response to the respective autoantigens. GA-specific T cell lines of the Th2/3 type that inhibit EAE induction in vivo, similarly to those induced by injection of GA, could be isolated from spleens of GA-fed mice and rats. Furthermore, as demonstrated previously for GA-specific cells induced by the parenteral route, the orally induced GA-specific cells accumulate in the CNS and secrete in situ Th2 cytokines in response to both GA and MBP as well as brain-derived neurotrophic factor (BDNF). Although a clinical trial in MS with two doses of oral GA in enteric-coated tablets did not show a significant effect either at the clinical or immunological level, the results presented here suggest that oral GA may still be developed into a therapeutic modality in MS.