Pharmacodynamics, pharmacokinetics, and safety of multiple doses of FTY720 in stable renal transplant patients: a multicenter, randomized, placebo-controlled, phase I study

Molecular and neuroimmune pharmacology of S1P receptor modulators and other disease-modifying therapies for multiple sclerosis

Multiple sclerosis (MS) is a neurological, immune-mediated demyelinating disease that affects people in the prime of life. Environmental, infectious, and genetic factors have been implicated in its etiology, although a definitive cause has yet to be determined. Nevertheless, multiple disease-modifying therapies (DMTs: including interferons, glatiramer acetate, fumarates, cladribine, teriflunomide, fingolimod, siponimod, ozanimod, ponesimod, and monoclonal antibodies targeting ITGA4, CD20, and CD52) have been developed and approved for the treatment of MS. All the DMTs approved to date target immunomodulation as their mechanism of action (MOA); however, the direct effects of some DMTs on the central nervous system (CNS), particularly sphingosine 1-phosphate (S1P) receptor (S1PR) modulators, implicate a parallel MOA that may also reduce neurodegenerative sequelae. This review summarizes the currently approved DMTs for the treatment of MS and provides details and recent advances in the molecular pharmacology, immunopharmacology, and neuropharmacology of S1PR modulators, with a special focus on the CNS-oriented, astrocyte-centric MOA of fingolimod.

Using an animal model to predict the effective human dose for oral multiple sclerosis drugs

The objective of this study was to determine the potential usefulness of an animal model to predict the appropriate dose of newly developed drugs for treating relapsing remitting multiple sclerosis (RRMS). Conversion of the lowest effective dose (LEffD) for mice and rats in the experimental autoimmune encephalomyelitis (EAE) model was used to predict the human effective dose utilizing the body surface area correction factor found in the 2005 US Food and Drug Administration (FDA) Guidance for Industry in selecting safe starting doses for clinical trials. Predictions were also tested by comparison with doses estimated by scaling up the LEffD in the model by the human to animal clearance ratio. Although initial proof-of-concept studies of oral fingolimod tested the efficacy and safety of 1.25 and 5 mg in treating RRMS, the EAE animal model predicted the approved dose of this drug, 0.5 mg daily. This approach would have also provided useful predictions of the approved human oral doses for cladribine, dimethyl fumarate, ozanimod, ponesimod, siponimod, and teriflunomide, drugs developed with more than one supposed mechanism of action. The procedure was not useful for i.v. dosed drugs, including monoclonal antibodies. We maintain that drug development scientists should always examine a simple allometric method to predict the therapeutic effective dose in humans. Then, following clinical studies, we believe that the animal model might be expected to yield useful predictions of other drugs developed to treat the same condition. The methodology may not always be predictive, but the approach is so simple it should be investigated.

Effect of fluoxetine treatment on neurotoxicity induced by lysolecithin in male rats

Demyelination disorder is an unusual pathologic event, which occurs in the central nervous system (CNS). Multiple sclerosis (MS) is an inflammatory demyelinating disease that affects the CNS, and it is the leading cause of disability in young adults. Lysolecithin (LPC) is one of the best toxin-induced demyelination models. In this study, a suitable model is created, and the effect of fluoxetine treatment is examined on this model. In this case, it was assumed that daily fluoxetine treatment had increased the endogenous remyelination in the LPC model. This study was focused on investigating the influence of the fluoxetine dose of 5 or 10 mg/kg per day for 1 and 4 weeks on LPC-induced neurotoxicity in the corpus callosum region. It was performed as a demyelinating model in male Wistar rats. After 3 days, fluoxetine was injected intraperitoneally (5 or 10 mg/kg per day) for 1 and 4 weeks in each group. After completing the treatment course, the corpus callosum was removed to examine the gene expression and histological analysis was performed. The results of the histopathological study of hematoxylin and eosin staining of the corpus callosum showed that in 1 and 4-week treatment groups, fluoxetine has reduced the level of inflammation at the LPC injection site (5 and 10 mg/kg per day). Fluoxetine treatment in the luxol fast blue (LFB) staining of the corpus callosum has been led to an increase in myelination capacity in all doses and times. The results of the genetic study showed that the fluoxetine has significantly reduced the expression level of tumor necrosis factor-α, nuclear factor κβ, and induced nitric oxide synthase in comparison with the untreated LPC group. Also, the fluoxetine treatment has enhanced the expression level of the forkhead box P3 (FOXP3) gene in comparison with the untreated group. Fluoxetine has increased the expression level of myelination and neurotrophic genes such as myelin basic protein (MBP), oligodendrocyte transcription factor 2 (OLIG2), and brain-derived neurotrophic factor (BDNF). The outcomes demonstrated that fluoxetine reduces inflammation and strengthens the endogenous myelination in the LPC-induced demyelination model; however, supplementary studies are required for specifying the details of its mechanisms.

Sphingosine-1-Phosphate Metabolism and Signaling in Kidney Diseases

In the past few decades, sphingolipids and sphingolipid metabolites have gained attention because of their essential role in the pathogenesis and progression of kidney diseases. Studies in models of experimental and clinical nephropathies have described accumulation of sphingolipids and sphingolipid metabolites, and it has become clear that the intracellular sphingolipid composition of renal cells is an important determinant of renal function. Proper function of the glomerular filtration barrier depends heavily on the integrity of lipid rafts, which include sphingolipids as key components. In addition to contributing to the structural integrity of membranes, sphingolipid metabolites, such as sphingosine-1-phosphate (S1P), play important roles as second messengers regulating biologic processes, such as cell growth, differentiation, migration, and apoptosis. This review will focus on the role of S1P in renal cells and how aberrant extracellular and intracellular S1P signaling contributes to the pathogenesis and progression of kidney diseases.

Fingolimod in multiple sclerosis: profile of use in habitual practice

OBJECTIVES

Fingolimod is the first oral drug indicated in monotherapy as a modifier of the course of very active relapsing-remitting multiple sclerosis (RRMS). The safety profile of fingolimod is well established in clinical trials and post-marketing studies. Our objective was to study the profile of fingolimod use in our health area.

METHODS

A retrospective, observational, descriptive study was performed on the use of fingolimod in adult patients diagnosed with RRMS between January 2015 and February 2017 or until suspension of treatment in a reference hospital in north-western Spain.

RESULTS

A total of 55 patients were included with a mean±SD time of treatment with fingolimod of 26±14.6 months (range 2-53). Thirteen patients permanently discontinued the treatment (10 due to outbreaks/disease progression and 3 due to adverse effects). No statistically significant differences were found between the percentage of patients who discontinued fingolimod and who had received only one previous treatment and those who had received two or more treatments. No cases of symptomatic bradycardia were reported.

CONCLUSIONS

Fingolimod is a safe treatment for patients with multiple sclerosis.

Discovery of fingolimod based on the chemical modification of a natural product from the fungus, Isaria sinclairii

Fingolimod is a first-in-class of sphingosine-1-phosphate (S1P) receptor modulator and is widely used a therapeutic drug for multiple sclerosis (MS), autoimmune disease in the central nervous system. About 25 year ago, a natural product, myriocin was isolated from culture broths of the fungus Isaria sinclairii. Myriocin, a rather complex amino acid having three successive asymmetric centers, was found to show a potent immunosuppressive activity in vitro; however, it induced a strong toxicity in vivo. To find out a less toxic immunosuppressive candidate, the chemical structure of myriocin was simplified to a nonchiral symmetric 2-substituted-2-aminoproane-1,3-diol framework. Finally, a highly potent immunosuppressant, fingolimod was found by the extensive chemical modification and pharmacological evaluation using skin allograft model in vivo. Throughout the analyses of the mechanism action of fingolimod, it is revealed that S1P receptor 1 (S1P₁) plays an essential role in lymphocyte circulation and that the molecular target of fingolimod is S1P₁. Phosphorylated fingolimod acts as a "functional" antagonist at S1P₁, modulates lymphocyte circulation, and shows a potent immunosuppressive activity. Fingolimod significantly reduced the relapse rate of MS in the clinical studies and has been approved as a new therapeutic drug for MS in more than 80 countries.

Fingolimod Attenuates Lung Injury and Cardiac Dysfunction after Traumatic Brain Injury

Acute lung injury (ALI) and cardiac dysfunction are common in traumatic brain injury (TBI) patients and always indicate poor outcomes. Inflammatory responses play important roles in TBI-induced cardiac and pulmonary damage. Fingolimod, an immunomodulatory agent, alleviates brain edema, restores the integrity of the blood-brain barrier (BBB), and improves functional deficits by inhibiting multiple inflammatory responses. Fingolimod (1 mg/kg) was injected intraperitoneally at 2 h after the controlled cortical impact (CCI) model was established in adult male mice. The concentration of inflammatory cytokines in the lung and heart after TBI was measured with a cytokine array. The lung wet/dry weight ratio and Evans blue dye leakage were used to quantify pulmonary edema and capillary leakage. Immunofluorescence, electron microscopy, and echocardiographic examination were used to assess the pathology and functional deficits in hearts. We found that TBI caused significant heart and lung damage. The administration of fingolimod significantly reduced the elevated inflammatory cytokine production, neutrophil infiltration, the leakage of protein in bronchoalveolar lavage fluid (BALF), and the wet/dry weight ratio in lung tissue at 3 days after TBI. In addition, fingolimod treatment also alleviated the inflammatory response in the heart; decreased cardiac apoptosis, fibrosis, and histological microstructural changes; and improved cardiac function from 3 days after TBI and maintained it for 30 days after TBI as measured by echocardiography. These results suggest that TBI resulted in significant cardiac and pulmonary damage accompanied by significant inflammatory responses in heart and lung tissue. Fingolimod treatment reduced the inflammatory response and alleviated TBI-induced lung and heart injury.

Improving the in-vivo biological activity of fingolimod loaded PHBV nanoparticles by using hydrophobically modified alginate

Uncontrolled distribution of nanoparticles (NPs) within the body can significantly decrease the efficiency of drug therapy and is considered among the main restrictions of NPs application. The aim of this study was to develop a depot combination delivery system (CDS) containing fingolimod loaded poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) NPs dispersed into a matrix of oleic acid-grafted-aminated alginate (OA-g-AAlg) to minimize the nonspecific biodistribution (BD) of PHBV NPs. OA-g-AAlg was synthesized in two step; First, Alg was aminated by using adipic dihydrazide (ADH). The degree of hyrazide group substitution of Alg was determined by trinitro-benzene-sulfonic acid (TNBS) assay. Second, OA was attached to AAlg through formation of an amide bond. Chemical structure of OA-g-AAlg was confirmed with FTIR and HNMR spectroscopy. Furthermore, rheological properties of OA-g-AAlg with different grafting ratios were evaluated. In-vitro release studies indicated that 47% of fingolimod was released from the CDS within 28 days. Blood and tissue samples were analyzed using liquid chromatography/tandem mass spectrometry following subcutaneous (SC) injection of fingolimod-CDS into Wistar rats. The elimination phase half-life of CDS-fingolimod was significantly higher than that of fingolimod (∼32 d vs. ∼20 h). To investigate the therapeutic efficacy, lymphocyte count was assessed over a 40 day period in Wistar rats. Peripheral blood lymphocyte count decreased from baseline by 27 ± 8% in 2 days after injection. Overall, the designed CDS represented promising results in improving the pharmacokinetic properties of fingolimod. Therefore, we believe that this sustained release formulation has a great potential to be applied to delivery of various therapeutics.

Fingolimod-induced decrease in heart rate may predict subsequent decreasing degree of lymphocytes

Here, we determined whether degree of decreased heart rate due to fingolimod treatment correlates with decreasing degree of lymphocytes in relapse-remitting multiple sclerosis (RRMS). In total, 30 patients with RRMS were treated with 0.5 mg fingolimod and their heart rate recorded every 30 minutes for 24 hours. Time trends of heart rate were characterised as three individual amplitudes and phase angles from three cosine curves using a mixed-effect model. Spearman’s correlation coefficient and regression analysis were used to determine the effect of heart rate information on change in lymphocyte count pre- and post-fingolimod treatment. Moreover, the degree of decreased lymphocytes induced by fingolimod treatment on heart rate was compared between low and high influence groups. Positive correlation between amplitude from the second curve and difference in lymphocyte number (p = 0.006) was observed. Regression analysis was also significant (p = 0.002). Moreover, the second curve derived from the high amplitude group exhibited a greater decrease in lymphocyte number after fingolimod treatment than the low amplitude group (p < 0.001). We suggest that the degree of decreased lymphocytes after fingolimod treatment (main effect) may be predicted by estimating the influence of degree in heart rate (side effect).

Targeting S1P in Inflammatory Bowel Disease: New Avenues for Modulating Intestinal Leukocyte Migration

Sphingosine 1 phosphate [S1P] is a bioactive lipid mediator involved in the regulation of several cellular processes though the activation of a G protein-coupled receptor family known as the S1P receptors [S1PRs]. Advances in the understanding of the biological activities mediated by S1PRs have sparked great interest in the S1P/S1PRs axes as new therapeutic targets for the modulation of several cellular processes. In particular, the S1P/S1PR1 axis has been identified as key regulator for lymphocyte migration from lymph nodes. The blockade of this axis is emerging as a new therapeutic approach to control the aberrant leukocyte migration into the mucosa in inflammatory bowel disease [IBD]. This review briefly summarises the current evidence coming from clinical studies, and discusses the future prospects of S1P inhibitors for treatment of inflammatory bowel disease.

Determination of Seminal Concentration of Fingolimod and Fingolimod-Phosphate in Multiple Sclerosis Patients Receiving Chronic Treatment With Fingolimod

The safety profile of fingolimod 0.5 mg, approved therapy for relapsing multiple sclerosis, is well established in clinical and real‐world studies. As fingolimod is teratogenic in rats, it was considered important to assess the concentrations of fingolimod and its active metabolite, fingolimod‐phosphate, in the semen of male patients on treatment and the risk of harming a fetus in a pregnant partner. In this multicenter open‐label study, 13 male patients receiving fingolimod for at least 6 months provided 1 semen and 1 blood sample for analyte concentration measurements. The steady‐state seminal concentrations of fingolimod and fingolimod‐phosphate were close to those simultaneously observed in blood. The amount of fingolimod‐related material in 10 mL of ejaculate was estimated to be 47.5 ng. The estimated fingolimod and fingolimod‐phosphate blood C_max values in a woman having regular sexual intercourse with a male patient treated with fingolimod 0.5 mg were approximately 400 and 2400 times smaller than the estimated values in the embryo‐fetal development study in rats at the no‐observed‐adverse‐event level. Consequently, the risk of harming a fetus in a pregnant woman is considered extremely unlikely.

Clinical pharmacology, efficacy, and safety aspects of sphingosine-1-phosphate receptor modulators

INTRODUCTION

Sphingosine-1-phosphate (S1P) receptor modulators, of which one has received marketing approval and several others are in clinical development, display promising potential in the treatment of a spectrum of autoimmune diseases.

AREAS COVERED

Administration of S1P1 receptor modulators leads to functional receptor antagonism triggering sustained inhibition of the egress of lymphocytes from lymphoid organs. First-dose administration is associated with transient cardiovascular effects. We compiled and discussed available pharmacokinetic, pharmacodynamic, and safety data of selective and non-selective S1P receptor modulators that were investigated in recent years.

EXPERT OPINION

The safety profile of S1P receptor modulators is considered better than other classes of immunomodulators and was further improved by the development of up-titration regimens to mitigate first-dose effects. S1P receptor modulators display similar pharmacodynamic effects but have very different pharmacokinetic profiles. Drugs with a rapid elimination are of interest in case of opportunistic infections or pregnancy, whereas the need of re-initiation of up-titration in case of treatment interruption can present a challenge.

From Natural Product to the First Oral Treatment for Multiple Sclerosis: The Discovery of FTY720 (Gilenya™)?

Multiple sclerosis is a devastating chronic autoimmune disease affecting women and men of all ages. Inflammation of the central nervous system causes demyelination and ultimately neuropsychological dysfunction. Myriocin, a natural product with strong immunosuppressant activity was interrogated leading to a new class of immunomodulator with a unique mode of action. In this review, we will summarize these findings, the mechanism hypothesis and discuss the data's ultimately leading to the approval of Gilenya™ as the first oral treatment for multiple sclerosis.

Effect of FTY720 (fingolimod) on graft survival in renal transplant recipients: a systematic review protocol

INTRODUCTION

Studies have shown that FTY720 has inconsistent effects in kidney transplant recipients. Several review articles on FTY720 have been published, but most have focused on the mechanism of action of FTY720. Therefore, this review aims to evaluate and determine the beneficial and harmful effects of FTY720 therapy in kidney transplant recipients.

METHODS AND ANALYSIS

We electronically searched the following databases: PubMed, Scopus, the Web of Sciences, EMBASE, Cochrane databases and the Cochrane Central Registry of Controlled Trials. Any clinical, randomised controlled trials relating to FTY720 for treating kidney transplant recipients were included without publication status or language restriction. Study selection, data extraction and assessment of study quality were performed independently by two researchers. Data were synthesised by either the fixed effects or the random effects model according to a heterogeneity test. If the extracted data were suitable for meta-analysis, STATA software was used to combine the relative risks for dichotomous outcomes, and the mean differences for continuous outcomes with 95% CIs were measured. Death, loss of function and incidence of acute kidney rejection were assessed as the primary outcomes. Renal graft function, malignancy, delayed graft function and infection were evaluated as secondary outcomes.

ETHICS/DISSEMINATION

This review does not require formal ethics approval because the data are not individualised. The resulting review article will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

CRD42015024648.

Fingolimod therapy modulates circulating B cell composition, increases B regulatory subsets and production of IL-10 and TGFβ in patients with Multiple Sclerosis

Fingolimod, an oral therapeutic agent approved for patients with relapsing-remitting Multiple Sclerosis (MS), has been shown to prevent lymphocyte egress from secondary lymphoid tissues; however the specific drug effect on B cells in fingolimod-treated patients remains to be fully elucidated. We present here a comprehensive analysis on the proportions of B cell subsets in the periphery, and the levels of activation, functional surface markers and cytokine profile of B cells in MS patients, following initiation of fingolimod therapy, using flow cytometry and cytokine bead array. Fingolimod therapy increased the ratio of naïve to memory cells, elevated the percentage of plasma cells and highly increased the proportion of transitional B cells as well as additional regulatory subsets, including: IL10(+), CD25(+) and CD5(+) B cells. The percentage of activated CD69(+) cells was highly elevated in the remaining circulating B cells, which produced increased levels of IL10, TGFβ, IL6, IL4, LTα, TNFα and IFNγ cytokines, with an overall increased ratio of TGFβ to pro-inflammatory cytokines. Furthermore, fingolimod therapy reduced ICAM-1(+) cells, suggesting a possible reduction in antigen-presenting capacity. Phosphorylated-fingolimod was shown in vitro to reduce S1PR1 RNA and protein, to slightly increase viability and to activate anti-apoptotic Bcl2 in transformed B cells of patients with MS. In conclusion, fingolimod therapy modulates significantly the composition of circulating B cells, promoting regulatory subsets and an anti-inflammatory cytokine repertoire.

Topical Application of Fingolimod Perturbs Cutaneous Inflammation

The prevalence of allergies, including rhinitis, eczema, and anaphylaxis, is rising dramatically worldwide. This increase is especially problematic in children who bear the greatest burden of this rising trend. Increasing evidence identifies neutrophils as primary perpetrators of the more severe and difficult to manage forms of inflammation. A newly recognized mechanism by which neutrophils are recruited during the early phase of histamine-induced inflammation involves the sphingosine kinase (SK)/sphingosine-1-phosphate axis. This study examines whether topical application of fingolimod, an established SK/sphingosine-1-phosphate antagonist already in clinical use to treat multiple sclerosis, may be repurposed to treat cutaneous inflammation. Using two mouse models of ear skin inflammation (histamine- and IgE-mediated passive cutaneous anaphylaxis) we topically applied fingolimod prophylactically, as well as after establishment of the inflammatory response, and examined ear swelling, SK activity, vascular permeability, leukocyte recruitment, and production of proinflammatory mediators. The present study reveals that when applied topically, fingolimod attenuates both immediate and late-phase responses to histamine with reduced extravasation of fluid, SK-1 activity, proinflammatory cytokine and chemokine production, and neutrophil influx and prevents ear swelling. Intravital microscopy demonstrates that histamine-induced neutrophil rolling and adhesion to the postcapillary venules in the mouse ears is significantly attenuated even after 24 h. More importantly, these effects are achievable even once inflammation is established. Translation into humans was also accomplished with epicutaneous application of fingolimod resolving histamine-induced and allergen-induced inflammatory reactions in forearm skin. Overall, this study demonstrates, to our knowledge for the first time, that fingolimod may be repurposed to treat cutaneous inflammation.

Enhanced remyelination following lysolecithin-induced demyelination in mice under treatment with fingolimod (FTY720)

Multiple sclerosis (MS) is a chronic, progressive demyelinating disorder which affects the central nervous system (CNS) and is recognized as the major cause of nervous system disability in young adults. Enhancing myelin repair by stimulating endogenous progenitors is a main goal in efforts for MS treatment. Fingolimod (FTY720) which is administrated as an oral medicine for relapsing-remitting MS has direct effects on neural cells. In this study, we hypothesized if daily treatment with FTY720 enhances endogenous myelin repair in a model of local demyelination induced by lysolecithin (LPC). We examined the response of inflammatory cells as well as resident OPCs and evaluated the number of newly produced myelinating cells in animals which were under daily treatment with FTY720. FTY720 at doses 0.3 and 1mg/kg decreased the inflammation score at the site of LPC injection and decreased the extent of demyelination. FTY720 especially at the lower dose increased the number of remyelinated axons and newly produced myelinating cells. These data indicate that repetitive treatment with FTY720, behind an anti-inflammatory effect, exerts beneficial effects on the process of endogenous repair of demyelinating insults.

Second-line therapy with fingolimod for relapsing-remitting multiple sclerosis in clinical practice: the effect of previous exposure to natalizumab

BACKGROUND

To evaluate efficacy and safety of fingolimod for relapsing-remitting multiple sclerosis, particularly in patients previously exposed to natalizumab.

METHOD

Prospective observational single-centre second-line cohort study.

RESULTS

Among 71 patients treated with fingolimod 0.5 mg/day for a mean duration of 21.75 ± 12.60 months, the annualized relapse rate was 0.66 (C.I. 95% 0.27-1.05) with a significant difference between 26 patients with prior natalizumab exposure (1.15; C.I. 95% 0.12-2.17) and 45 not exposed (0.38; C.I. 95% 0.18-0.57; p = 0.002). In a multivariate negative regression model, only previous exposure to natalizumab (p = 0.049) and duration of fingolimod treatment (p < 0.001) significantly correlated with the annualized relapse rate. Previous exposure to natalizumab (p = 0.028) and duration of treatment with fingolimod (p < 0.001) were confirmed by restricting the analysis to the first 12 months of treatment with fingolimod, but were no longer statistically significant by analysing only patients (n = 51) with at least 12 months of treatment with fingolimod (0.32; C.I. 95% 0.08-0.55 vs. 0.22; C.I. 95% 0.11-0.32; p = NS). No differences were observed in neuroradiological outcomes and disability progression in patients exposed to natalizumab and not exposed. The rate of discontinuation due to adverse events was 11.3%, with no differences between the two groups.

CONCLUSIONS

Our study confirms efficacy and side effects of fingolimod in a second-line clinical practice cohort. Prior natalizumab exposure and duration of treatment with fingolimod are independent predictors of annualized relapse rate during the first 12 months of treatment with fingolimod, but not in the long-term, and may be influenced by the 3 months washout period between the two drugs.

Myelin recovery in multiple sclerosis: the challenge of remyelination

Multiple sclerosis (MS) is the most common demyelinating and an autoimmune disease of the central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. T cell subsets (Th1, Th2, Th17, CD8⁺, NKT, CD4⁺CD25⁺ T regulatory cells) and B cells are involved in this disorder, thus new MS therapies seek damage prevention by resetting multiple components of the immune system. The currently approved therapies are immunoregulatory and reduce the number and rate of lesion formation but are only partially effective. This review summarizes current understanding of the processes at issue: myelination, demyelination and remyelination—with emphasis upon myelin composition/architecture and oligodendrocyte maturation and differentiation. The translational options target oligodendrocyte protection and myelin repair in animal models and assess their relevance in human. Remyelination may be enhanced by signals that promote myelin formation and repair. The crucial question of why remyelination fails is approached is several ways by examining the role in remyelination of available MS medications and avenues being actively pursued to promote remyelination including: (i) cytokine-based immune-intervention (targeting calpain inhibition), (ii) antigen-based immunomodulation (targeting glycolipid-reactive iNKT cells and sphingoid mediated inflammation) and (iii) recombinant monoclonal antibodies-induced remyelination.

A novel liposomal formulation of FTY720 (fingolimod) for promising enhanced targeted delivery

We describe here the development and characterization of the physicochemical and pharmacokinetic properties of a novel liposomal formulation for FTY720 delivery, LP-FTY720. The mean diameter of LP-FTY720 was ~157 nm, and the FTY720 entrapment efficiency was ~85%. The liposomal formulation protected FTY720 from degradation in aqueous buffer and showed toxicity in CLL patient B cells comparable to that of free FTY720. Following intravenous injection in ICR mice, LP-FTY720 had an increased elimination phase half-life (~28 vs. ~19 hr) and decreased clearance (235 vs. 778 mL/h/kg) compared to the free drug. Antibodies against CD19, CD20 and CD37 were incorporated into LP-FTY720, which provided targeted delivery to CLL patient B cells and thus achieved higher killing efficacy. The novel liposomal carrier of FTY720 demonstrated improved pharmacokinetic properties, comparable activity, and a potential platform for targeted delivery to CLL by overcoming the limited application of free FTY720 to B malignancy treatment.

FROM THE CLINICAL EDITOR

This team reports on a novel liposomal formulation for FTY720 delivery, demonstrating improved pharmacokinetic properties, comparable activity, and a potential platform for targeted delivery to CLL using antibodies incorporated in the liposomes. The method expected to overcome the limited application of free FTY720 to B malignancy treatment.

Temporal profile of lymphocyte counts and relationship with infections with fingolimod therapy

BACKGROUND

Reduction in peripheral blood lymphocytes is an expected pharmacodynamic outcome of fingolimod therapy.

OBJECTIVE

The objective of this article is to evaluate lymphocyte dynamics during and after fingolimod therapy and assess the relationship between lymphocyte counts and infections.

METHODS

Lymphocyte counts and their relationship with infections were evaluated in three multiple sclerosis (MS) populations: (Group A) FREEDOMS phase 3 core study group (n = 1272); (Group B) All Studies group (one phase 2 and two phase 3 studies, plus their extensions; n = 2315); and (Group C) Follow-up group (after fingolimod discontinuation; n = 538).

RESULTS

Administration of fingolimod 0.5 mg led to reductions in lymphocyte counts to a steady-state of 24%-30% of baseline values within two weeks, which remained stable while on therapy. Following fingolimod discontinuation, average counts exceeded the lower limit of normal range within six to eight weeks, and were 80% of baseline values by three months. In Group A, infection rates per patient-year were 1.4 with placebo and 1.0 in fingolimod-treated patients who had the lowest lymphocyte counts (< 0.2 × 10(9)/l). No evidence was seen for an increase in serious or opportunistic infections.

CONCLUSIONS

Fingolimod induces a rapid and reversible reduction in lymphocyte counts without an increase in infections relative to placebo. Because fingolimod reduces blood lymphocyte counts via redistribution in secondary lymphoid organs, peripheral blood lymphocyte counts cannot be utilized to evaluate the lymphocyte subset status of a patient.

FTY720: Placebo-Controlled Study of the Effect on Cardiac Rate and Rhythm in Healthy Subjects

The purpose of this double-blind, placebo-controlled study was to measure the effects of FTY720, a novel immunomodulator, on heart rate and rhythm in healthy volunteers. Subjects (n = 66) were randomized to FTY720 1.25 mg or 5 mg or placebo administered once daily for 7 days. Continuous telemetry revealed an acute, dose-dependent decrease in mean heart rate (10-bpm decrease vs placebo) following the first dose of FTY720, with a nadir generally 4 hours postdose. Although a persistent FTY720-related decrease in heart rate was measured from day 2 to day 7, additional doses of FTY720 after day 2 resulted in no further incremental decreases. Mean PR interval increased by approximately 8 to 10 msec in FTY720-treated subjects on day 1. FTY720 did not increase the QRS or QT interval. These results confirm that the first dose of FTY720 has a mild to moderate negative chronotropic effect.

Discovery of fingolimod, the sphingosine 1-phosphate receptor modulator and its application for the therapy of multiple sclerosis

Fingolimod (FTY720) is a first-in-class, orally active, sphingosine 1-phosphate (S1P)-receptor modulator with a structure closely related to sphingosine. The compound was discovered by chemical modification of a natural product, myriocin. Phosphorylated form of FTY720 acts as a functional antagonist at S1P receptor type 1 (S1P(1)), inhibits lymphocyte egress from secondary lymphoid organs and shows immunomodulating effects. Phase III studies in multiple sclerosis demonstrated that oral FTY720 had superior efficacy compared with intramuscular IFN-β1a (AVONEX(®)) with regard to reducing the rate of relapse and the number of inflammatory lesions in the CNS. FTY720 has been approved as a new therapeutic drug for multiple sclerosis in more than 50 countries, including the USA, Japan and some of those in the EU.

Signaling and regulatory functions of bioactive sphingolipids as therapeutic targets in multiple sclerosis

Spingolipids (SLs) are an important component of central nervous system (CNS) myelin sheaths and affect the viability of brain cells (oligodendrocytes, neurons and astrocytes) that is determined by signaling mediated by bioactive sphingoids (lyso-SLs). Recent studies indicate that two lipids, ceramide and sphingosine 1-phosphate (S1P), are particularly involved in many human diseases including the autoimmune inflammatory demyelination of multiple sclerosis (MS). In this review we: (1) Discuss possible sources of ceramide in CNS; (2) Summarize the features of the metabolism of S1P and its downstream signaling through G-protein-coupled receptors; (3) Link perturbations in bioactive SLs metabolism to MS neurodegeneration and (4) Compile ceramide and S1P relationships to this process. In addition, we described recent preclinical and clinical trials of therapies targeting S1P signaling, including 2-amino-2-propane-1,3-diol hydrochloride (FTY720, fingolimod) as well as proposed intervention to specify critical SL levels that tilt balances of apoptotic/active ceramide versus anti-apoptotic/inactive dihydroceramide that may offer a novel and important therapeutic approach to MS.

Clinical pharmacokinetics of fingolimod

Fingolimod (FTY720), a sphingosine 1-phosphate receptor modulator, is the first in a new class of therapeutic compounds and is the first oral therapy approved for the treatment of relapsing forms of multiple sclerosis (MS). Fingolimod is a structural analogue of endogenous sphingosine and undergoes phosphorylation to produce fingolimod phosphate, the active moiety. Fingolimod targets MS via effects on the immune system, and evidence from animal models indicates that it may also have actions in the central nervous system. In phase III studies in patients with relapsing-remitting MS, fingolimod has demonstrated efficacy superior to that of an approved first-line therapy, intramuscular interferon-β-1a, as well as placebo, with benefits extending across clinical and magnetic resonance imaging measures. The pharmacokinetic profiles of fingolimod and fingolimod phosphate have been extensively investigated in studies in healthy volunteers, renal transplant recipients (the indication for which fingolimod was initially under clinical development, but the development was subsequently discontinued) and MS patients. Results from these studies have demonstrated that fingolimod is efficiently absorbed, with an oral bioavailability of >90%, and its absorption is unaffected by dietary intake, therefore it can be taken without regard to meals. Fingolimod and fingolimod phosphate have a half-life of 6-9 days, and steady-state pharmacokinetics are reached after 1-2 months of daily dosing. The long half-life of fingolimod, together with its slow absorption, means that fingolimod has a flat concentration profile over time with once-daily dosing. Fingolimod and fingolimod phosphate show dose-proportional exposure in single- and multiple-dose studies over a range of 0.125-5 mg; hence, there is a predictable relationship between dose and systemic exposure. Furthermore, fingolimod and fingolimod phosphate exhibit low to moderate intersubject pharmacokinetic variability. Fingolimod is extensively metabolized, with biotransformation occurring via three main pathways: (i) reversible phosphorylation to fingolimod phosphate; (ii) hydroxylation and oxidation to yield a series of inactive carboxylic acid metabolites; and (iii) formation of non-polar ceramides. Fingolimod is largely cleared through metabolism by cytochrome P450 (CYP) 4F2. Since few drugs are metabolized by CYP4F2, fingolimod would be expected to have a relatively low potential for drug-drug interactions. This is supported by data from in vitro studies indicating that fingolimod and fingolimod phosphate have little or no capacity to inhibit and no capacity to induce other major drug-metabolizing CYP enzymes at therapeutically relevant steady-state blood concentrations. Population pharmacokinetic evaluations indicate that CYP3A inhibitors and CYP3A inducers have no effect or only a weak effect on the pharmacokinetics of fingolimod and fingolimod phosphate. However, blood concentrations of fingolimod and fingolimod phosphate are increased moderately when fingolimod is coadministered with ketoconazole, an inhibitor of CYP4F2. The pharmacokinetics of fingolimod are unaffected by renal impairment or mild-to-moderate hepatic impairment. However, exposure to fingolimod is increased in patients with severe hepatic impairment. No clinically relevant effects of age, sex or ethnicity on the pharmacokinetics of fingolimod have been observed. Fingolimod is thus a promising new therapy for eligible patients with MS, with a predictable pharmacokinetic profile that allows effective once-daily oral dosing.

Fifty years in the vineyard of transplantation: looking back

The past 5 decades have documented remarkable advances in basic knowledge and clinical expertise in transplantation. The first 12 years of this half century of my participation in the enterprise were consumed with the isolation, chemical characterization, and application of histocompatibility antigens purified from mouse, guinea pig, and human tissues, demonstrating that their specificity was based on unique amino acid sequences in protein structures. Initial unsuccessful attempts to use native molecules to induce tolerance in rat renal or heart transplantation models were followed by limited success when they were administered with a brief perioperative course of cyclosporine (CsA). Production of allochimeric constructs of class I major histocompatibility complex molecules bearing donor-type amino acid substitutions into the host-type C-terminal portion of the α1 helix yielded tolerogens whose activity was not dependent on conditioning with CsA or total lymphoid irradiation (TLI). The allochimeric molecules serve as altered peptide ligands that induce an aberrant T-cell signal 1 response producing transplantation tolerance. The potent activity of CsA in this experimental model was extended to clinical settings. Pharmacologic tools were employed to explore intra- and interindividual variations in drug exposure leading to the development of a better drug formulation. However, the intrinsic nephrotoxicity of CsA necessitated marked 80% reductions in de novo drug exposure as were achieved by exploiting the synergistic pharmacodynamic and pharmacokinetic interactions of CsA with sirolimus. The final decade in this 50-year experience includes editorship of this journal with marked changes in its direction. These experiences have afforded insights into future avenues for preclinical exploration and therapeutic drug development.

Population pharmacokinetics of fingolimod phosphate in healthy participants

Fingolimod (FTY720) is a sphingosine 1-phosphate receptor (S1PR) modulator currently being evaluated for the treatment of multiple sclerosis. Fingolimod undergoes phosphorylation in vivo to yield fingolimod phosphate (fingolimod-P), which modulates S1PRs expressed on lymphocytes and cells in the central nervous system. The authors developed a population model, using pooled data from 7 phase 1 studies, to enable characterization of fingolimod-P pharmacokinetics following oral administration of fingolimod and to evaluate the impact of key demographic variables on exposure. The fingolimod-P concentration-time course after either single or multiple doses of fingolimod was described by a 2-compartment model with first-order apparent formation and elimination, lag time in the apparent formation, and dose-dependent relative bioavailability and apparent central volume of distribution. Body weight and ethnicity were identified as demographic covariates correlated with the disposition of fingolimod-P. Model predictions indicated no need for dose adjustment of fingolimod based on body weight; the effect of ethnicity on the disposition of fingolimod requires further investigation. The accurate prediction of the pharmacokinetic profile of fingolimod-P determined empirically in 2 large phase 3 trials provides external validation of the model.

Shining a light on intestinal traffic

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is associated with enhanced leukocyte infiltration to the gut, which is directly linked to the clinical aspects of these disorders. Thus, leukocyte trafficking is a major target for IBD therapy. Past and emerging techniques to study leukocyte trafficking both in vitro and in vivo have expanded our knowledge of the leukocyte migration process and the role of inhibitors. Various strategies have been employed to target chemokine- and integrin-ligand interactions within the multistep adhesion cascade and the S1P/S1PR1 axis in leukocyte migration. Though there is an abundance of preclinical data demonstrating efficacy of leukocyte trafficking inhibitors, many have yet to be confirmed in clinical studies. Vigilance for toxicity and further research is required into this complex and emerging area of IBD therapy.

Pharmacological relevance and potential of sphingosine 1-phosphate in the vascular system

Sphingosine-1-phosphate (S1P) was identified as a crucial molecule for regulating immune responses, inflammatory processes as well as influencing the cardiovascular system. S1P mediates differentiation, proliferation and migration during vascular development and homoeostasis. S1P is a naturally occurring lipid metabolite and is present in human blood in nanomolar concentrations. S1P is not only involved in physiological but also in pathophysiological processes. Therefore, this complex signalling system is potentially interesting for pharmacological intervention. Modulation of the system might influence inflammatory, angiogenic or vasoregulatory processes. S1P activates G-protein coupled receptors, namely S1P(1-5) , whereas only S1P(1-3) is present in vascular cells. S1P can also act as an intracellular signalling molecule. This review highlights the pharmacological potential of S1P signalling in the vascular system by giving an overview of S1P-mediated processes in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs). After a short summary of S1P metabolism and signalling pathways, the role of S1P in EC and VSMC proliferation and migration, the cause of relaxation and constriction of arterial blood vessels, the protective functions on endothelial apoptosis, as well as the regulatory function in leukocyte adhesion and inflammatory responses are summarized. This is followed by a detailed description of currently known pharmacological agonists and antagonists as new tools for mediating S1P signalling in the vasculature. The variety of effects influenced by S1P provides plenty of therapeutic targets currently under investigation for potential pharmacological intervention.

Fingolimod: a review of its use in the management of relapsing-remitting multiple sclerosis

Oral fingolimod (Gilenya™), a sphingosine 1-phosphate (S1P) receptor agonist, is the first oral agent and the first in a novel class of disease-modifying therapies (DMTs) to be approved for use in the US for the treatment of relapsing forms of multiple sclerosis (MS). In the EU, fingolimod is approved for use as a single-agent DMT in selected patients with highly-active, relapsing-remitting (RR) MS. This article reviews the pharmacological properties and clinical use of the drug in patients with RRMS. Fingolimod is rapidly converted in vivo to the active moiety S-fingolimod-phosphate, which binds with high affinity to S1P receptors, thereby sequestering lymphocytes in the lymph nodes and preventing their egress into the peripheral circulation. As a consequence, there is a reduction in the infiltration of autoaggressive lymphocytes into the CNS. Fingolimod-phosphate also acts as a functional antagonist, as its binding to S1P receptors results in their internalization and degradation, thereby downregulating S1P receptors on the lymphocyte cell surface. Since fingolimod crosses the blood : brain barrier, it also potentially acts at S1P receptors on neural cells in the CNS to mitigate neuropathological processes associated with MS. In large multinational trials in adult patients with RRMS, oral fingolimod 0.5 mg/day was more effective than oral placebo (FREEDOMS) and recommended dosages of intramuscular interferon-β (IFNβ)-1a (TRANSFORMS) in reducing the annualized relapse rate and was also generally more effective at slowing progression of neurological disability and at reducing the burden and activity of disease. Fingolimod was generally well tolerated in these trials of up to 2 years' duration, with most adverse events being manageable and of mild to moderate severity; there were two deaths from opportunistic infections, albeit these occurred with fingolimod 1.25 mg/day (higher than the recommended dosage). Limited long-term data indicated that no new safety concerns had arisen after 5 years of fingolimod treatment. However, further clinical experience is required to fully determine the long-term safety profile of fingolimod, particularly with regard to any potentially serious or life-threatening adverse events. In the absence of robust pharmacoeconomic studies and of head-to-head trials comparing fingolimod with other formulations of IFNβ and glatiramer acetate, the relative position of fingolimod with respect to other DMTs remains to be fully determined. In the meantime, given its convenient once-daily oral treatment regimen and better efficacy than intramuscular IFNβ-1a, fingolimod is a valuable emerging option for the treatment of adult patients with relapsing forms of MS.

Oral fingolimod for the treatment of patients with relapsing forms of multiple sclerosis

Fingolimod, a sphingosine 1-phosphate receptor modulator, is the first oral treatment approved by the US Food and Drug Administration for the treatment of relapsing forms of multiple sclerosis (MS). The aim of this review was to provide a concise, comprehensive overview of the clinically relevant mechanism of action, efficacy and safety information available for fingolimod. Key data were derived from two international, Phase III, double-blind, randomised trials (TRANSFORMS and FREEDOMS) performed over 12 and 24 months, respectively, which evaluated fingolimod 0.5 and 1.25 mg daily in 1703 patients with relapsing forms of MS. In TRANSFORMS, there was a 52% reduction in the annualised relapse rate (ARR) with fingolimod 0.5 mg vs. 30 μg intramuscular interferon beta-1a (0.16 vs. 0.33; p < 0.001) at 1 year. In FREEDOMS, there was a 55% decrease in ARR at 2 years with fingolimod 0.5 mg vs. placebo (0.18 vs. 0.40; p < 0.001). Risk of disability progression, confirmed at 3 months, was also reduced by 30% over the 2-year study period with fingolimod vs. placebo (p = 0.02). Significantly fewer new or enlarged lesions on T(2) -weighted images were seen in both studies (TRANSFORMS, p = 0.002 vs. interferon beta-1a at 1 year; FREEDOMS, p < 0.001 vs. placebo at 2 years). Overall, fingolimod 0.5 mg was well tolerated by patients. Transient, generally asymptomatic bradycardia and infrequent atrioventricular block were seen with the administration of the first dose. Macular oedema and serious infections occurred infrequently. Reversible, asymptomatic elevations of liver enzymes could also occur. As the first approved oral disease-modifying treatment, fingolimod offers patients a convenient alternative to regular self-injection for the treatment of relapsing forms of MS. In addition to high efficacy with a relatively acceptable safety profile, fingolimod provides a therapy with a new mechanism of action.

Mechanisms of fingolimod's efficacy and adverse effects in multiple sclerosis

Until recently, all approved multiple sclerosis (MS) disease treatments were administered parenterally. Oral fingolimod was approved in September 2010 by the US Food and Drug Administration to reduce relapses and disability progression in relapsing forms of MS. In the clinical trials that led to approval, fingolimod reduced not only acute relapses and magnetic resonance imaging lesion activity but also disability progression and brain volume loss, suggesting preservation of tissue. Fingolimod's mechanism of action in MS is not known with certainty. Its active form, fingolimod-phosphate (fingolimod-P), is a sphingosine 1-phosphate receptor (S1PR) modulator that inhibits egress of lymphocytes from lymph nodes and their recirculation, potentially reducing trafficking of pathogenic cells into the central nervous system (CNS). Fingolimod also readily penetrates the CNS, and fingolimod-P formed in situ may have direct effects on neural cells. Fingolimod potently inhibits the MS animal model, experimental autoimmune encephalomyelitis, but is ineffective in mice with selective deficiency of the S1P₁ S1PR subtype on astrocytes despite normal expression in the immune compartment. These findings suggest that S1PR modulation by fingolimod in both the immune system and CNS, producing a combination of beneficial anti-inflammatory and possibly neuroprotective/reparative effects, may contribute to its efficacy in MS. In clinical trials, fingolimod was generally safe and well tolerated. Its interaction with S1PRs in a variety of tissues largely accounts for the reported adverse effects, which were seen more frequently with doses 2.5 to 10x the approved 0.5 mg dose. Fingolimod's unique mechanism of action distinguishes it from all other currently approved MS therapies.

Fingolimod: a novel oral immunomodulatory treatment for multiple sclerosis

Fingolimod (FTY720), an immunomodulator that acts on sphingosine-1-phosphate receptors, is the first oral disease-modifying agent to be approved by the US FDA for the treatment of relapsing forms of multiple sclerosis (MS). Compared with other disease-modifying agents, fingolimod is unique in its mechanisms of action: it sequesters lymphocytes into lymph nodes without directly inhibiting effector functions, and it exerts pleiotropic actions on cultured oligodendrocytes and oligodendrocyte progenitors. Whether the latter contributes to the favorable response to this drug is currently being investigated. Results from Phase II and III clinical trials demonstrate that fingolimod is highly effective in relapsing–remitting MS. In this article, we review the background on MS therapy, the mechanisms and pharmacology of fingolimod and its benefit–risk profile as a novel therapy in MS.

Safety and efficacy of fingolimod in treatment-naïve multiple sclerosis patients

Fingolimod was recently approved for use in the United States after two phase III trials confirmed its effectiveness in reducing disease activity in relapsing-remitting multiple sclerosis. These positive results, coupled with the important fact that this is the first oral disease-modifying therapy, has lead to considerable enthusiasm amongst physicians and patients. However, fingolimod is associated with rare but serious adverse events. In addition, unlike conventional disease-modifying therapies, cardiopulmonary, ophthalmological and dermatological safety monitoring unfamiliar to both neurologists and patients is required before and during treatment. This paper will discuss these issues from the perspective of using fingolimod as a first-line disease-modifying therapy in treatment-naïve relapsing-remitting multiple sclerosis patients.

Effect of Cordyceps sinensis on renal function of patients with chronic allograft nephropathy

OBJECTIVE

To investigate the effect of Cordyceps sinensis (Bailing capsule, fermented agent of C. sinensis) on renal function of patients with chronic allograft nephropathy (CAN).

METHODS

A total of 231 CAN patients who underwent transplantation between 2005 and 2008 and experienced chronic graft dysfunction were randomly divided into 2 groups. Patients in group A (n = 122) were treated with immunosuppressive agents and C. sinensis (2.0 g/day, 3 times a day), while patients in group B (n = 109) were treated with traditional immunosuppressive drugs. Serum creatinine (SCr), blood urea nitrogen (BUN), creatinine clearance rate (C(Cr)) and urinary protein in 24 h (24-hour Upro) of all patients were measured before and after treatment. Urinary concentrations of transforming growth factor (TGF)-β(1), retinol-binding protein (RBP) and β(2)-microglobulin (β(2)-MG) were detected at the same time.

RESULTS

After 6-month treatment with C. sinensis, SCr and C(Cr) in group A were significantly improved (p < 0.05), while there was no significant improvement observed for group B. There was no significant change in BUN in groups A and B (p > 0.05). 24-hour Upro, RBP and β(2)-MG were lower in group A after treatment with C. sinensis (p < 0.05 or p < 0.01), and urinary TGF-β(1) in group A was significantly lower than the values before C. sinensis treatment (p < 0.05), but showed no change in patients of group B. In group A, renal function had improved in 72 cases, stabilized in 38 cases, and worsened in 12 cases. In group B, renal function had improved in 14 cases, stabilized in 50 cases, and worsened in 45 cases (p < 0.05).

CONCLUSION

C. sinensis therapy is advantageous in improving renal function of CAN patients by retarding CAN progression.

Vascular biology: the role of sphingosine 1-phosphate in both the resting state and inflammation

The vascular and immune systems of mammals are closely intertwined: the individual components of the immune system must move between various body compartments to perform their function effectively. Sphingosine 1-phosphate (S1P), a bioactive lipid mediator, exerts effects on the two organ systems and influences the interaction between them. In the resting state, the vascular S1P gradient contributes to control of lymphocyte recirculation through the blood, lymphoid tissue and lymphatic vasculature. The high level of S1P in blood helps maintain endothelial barrier integrity. During the inflammatory process, both the level of S1P in different immune compartments and S1P receptor expression on lymphocytes and endothelial cells are modified, resulting in functionally important changes in endothelial cell and lymphocyte behaviour. These include transient arrest of lymphocytes in secondary lymphoid tissue, crucial for generation of adaptive immunity, and subsequent promotion of lymphocyte recruitment to sites of inflammation. This review begins with an outline of the basic biochemistry of S1P. S1P receptor signalling is then discussed, followed by an exploration of the roles of S1P in the vascular and immune systems, with particular focus on the interface between them. The latter part concerns crosstalk between S1P and other signalling pathways, and concludes with a look at therapies targeting the S1P-S1P receptor axis.

Evidence-based assessment of potential use of fingolimod in treatment of relapsing multiple sclerosis

Multiple sclerosis is an autoimmune inflammatory demyelinating disease of the central nervous system and represents one of the most common causes of chronic neurologic disability in young adults. All the current disease-modifying drugs are administered parenterally, and can be associated with varying degrees of injection site or infusion-related reactions. Together with other side effects, the parenteral route of administration is one of the key factors affecting adherence to therapy in multiple sclerosis. Fingolimod (FTY720) is an immunomodulator that acts on sphingosine 1-phosphate (S1P) receptors and is the first oral drug approved by the US Food and Drug Administration for the treatment of relapsing-remitting multiple sclerosis. Downmodulation of S1P receptor type 1 (S1P₁) slows the egress of lymphocytes from lymph nodes and recirculation to the central nervous system, reduces astrogliosis, and inhibits angiogenesis during chronic neuroinflammation. Fingolimod also regulates the migration of B cells and dendritic cells, and enhances endothelial barrier function. Results from Phase II and III clinical trials provide robust evidence of the efficacy of fingolimod in relapsing-remitting multiple sclerosis. While some caution should be exercised in terms of safety issues, the introduction of fingolimod represents a great advance in the treatment of relapsing-remitting multiple sclerosis. The pharmacologic data on fingolimod and its efficacy and safety in multiple sclerosis are reviewed in this paper.

Use of kidney function end points in kidney transplant trials: a systematic review

BACKGROUND

Clinical trials in kidney transplantation are beginning to include markers of kidney function as end points now that traditional outcomes, such as acute rejection, become increasingly rare events. The frequency and type of kidney function end points used are unknown.

STUDY DESIGN

Systematic review.

SETTING & POPULATION

Randomized controlled trials in adult kidney transplant recipients reported in 5 major general medical journals and 5 major subspecialty journals in nephrology and transplantation between January 2003 and November 2008.

SELECTION CRITERIA

Inclusion of at least one kidney function end point at least 1 month posttransplant.

RESULTS

133 (79%) of 169 randomized trials identified used a kidney function end point. Of these, 37 (28%) used one or more measures of kidney function as the primary end point, and 81 (61%), as a secondary end point. For the primary end point, 21 (57%) trials used a creatinine-based estimated glomerular filtration rate (eGFR), 18 (49%) used serum creatinine level, and 7 (19%) used measured GFR. Overall, eGFR was an end point in 81 (61%) trials, and measured GFR, in 12 (9%) trials.

LIMITATIONS

This review is limited by the poor quality of the included trials, with many not defining either primary or secondary end points.

CONCLUSIONS

Measures of kidney function are used commonly as surrogate end points in kidney transplant trials, with eGFR becoming more frequently used over time. Further data are needed to properly validate these surrogate end points and fully understand their limitations when designing and interpreting randomized trials.

Fingolimod (FTY720): discovery and development of an oral drug to treat multiple sclerosis

The discovery of fingolimod (FTY720/Gilenya; Novartis), an orally active immunomodulatory drug, has opened up new approaches to the treatment of multiple sclerosis, the most common inflammatory disorder of the central nervous system. Elucidation of the effects of fingolimod--mediated by the modulation of sphingosine 1-phosphate (S1P) receptors--has indicated that its therapeutic activity could be due to regulation of the migration of selected lymphocyte subsets into the central nervous system and direct effects on neural cells, particularly astrocytes. An improved understanding of the biology of S1P receptors has also been gained. This article describes the discovery and development of fingolimod, which was approved by the US Food and Drug Administration in September 2010 as a first-line treatment for relapsing forms of multiple sclerosis, thereby becoming the first oral disease-modifying therapy to be approved for multiple sclerosis in the United States.

Elimination of a hydroxyl group in FTY720 dramatically improves the phosphorylation rate

The new immunosuppressant FTY720 (fingolimod), an analog of the endogenous lipid sphingosine, induces transient lymphopenia through the sequestration of lymphocytes in secondary lymphoid organs. Phosphorylation of FTY720 by sphingosine kinase 2 (SphK2) yields the active metabolite FTY720-phosphate (FTY-P), which induces lymphopenia through agonism of the sphingosine 1-phosphate receptor S1P(1) on endothelial cells and lymphocytes. Dephosphorylation of circulating FTY-P creates an equilibrium between FTY720 and its phosphate, and results with human patients indicate that phosphorylation of FTY720 could be rate limiting for efficacy. We report that the FTY720 derivative 2-amino-4-(4-heptyloxyphenyl)-2-methylbutanol [AAL(R)] is phosphorylated much more rapidly than FTY720 in cultured human cells and whole blood. The K(cat) for AAL(R) with recombinant SphK2 is 8-fold higher than for FTY720, whereas the K(m) for the two substrates is very similar, indicating that the increased rate of phosphorylation results from faster turnover by SphK2 rather than a higher binding affinity. Consequently, treating cells with AAL(R), but not FTY720, triggers an apoptotic pathway that is dependent on excessive intracellular accumulation of long-chain base phosphates. In agreement with the in vitro results, phosphorylation of AAL(R) is more complete than that of FTY720 in vivo (mice), and AAL(R) is a more potent inducer of lymphopenia. These differences may be magnified in humans, because phosphorylation of FTY720 is much less efficient in humans compared with rodents. Our results suggest that AAL(R) is a better tool than FTY720 for in vivo studies with S1P analogs and would probably be a more effective immunosuppressant than FTY720.

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

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

FTY720 reduces inflammation and promotes functional recovery after spinal cord injury

A robust and complex inflammatory cascade is known to be a prominent component of secondary injury following spinal cord injury (SCI). Specifically, the concept of trauma-induced autoimmunity has linked the lymphocyte population with neural tissue injury and neurologic deficit. FTY720, a sphingosine receptor modulator that sequesters lymphocytes in secondary lymphoid organs, has been shown to be effective in the treatment of a variety of experimental autoimmune disorders. Accordingly, by reducing lymphocyte infiltration into the spinal cord following SCI, this novel immunomodulator may enhance tissue preservation and functional recovery. In the present study, a moderate to severe contusion SCI was simulated in adult Long-Evans hooded rats. Using flow cytometry we showed that daily FTY720 treatment dramatically reduced T-cell infiltration into the SCI lesion site at 4 and 7 days post-injury, while other inflammatory cell populations were relatively unaltered. To assess functional recovery, three groups of injured animals (treated, vehicle, and injury only) were evaluated weekly for hindlimb recovery. Animals in the treated group consistently exhibited higher functional scores than animals in the control groups after 2 weeks post-injury. This finding was associated with a greater degree of white matter sparing at the lesion epicenter when cords were later sectioned and stained. Furthermore, treated animals were found to exhibit improved bladder function and a reduced incidence of hemorrhagic cystitis compared to control counterparts. Collectively these results demonstrate the neuroprotective potential of FTY720 treatment after experimental SCI.

Prolonged exposure to sphingosine 1-phosphate receptor-1 agonists exacerbates vascular leak, fibrosis, and mortality after lung injury

Sphingosine 1-phosphate (S1P) is a key endogenous regulator of the response to lung injury, maintaining endothelial barrier integrity through interaction with one of its receptors, S1P(1). The short-term administration of S1P or S1P(1) receptor agonists enhances endothelial monolayer barrier function in vitro, and attenuates injury-induced vascular leak in the lung and other organ systems in vivo. Although S1P(1) agonists bind to and activate S1P(1), several of these agents also induce receptor internalization and degradation, and may therefore act as functional antagonists of S1P(1) after extended exposure. Here we report on the effects of prolonged exposure to these agents in bleomycin-induced lung injury. We demonstrate that repeated administration of S1P(1) agonists dramatically worsened lung injury after bleomycin challenge, as manifested by increased vascular leak and mortality. Consistent with these results, prolonged exposure to S1P(1) agonists in vitro eliminated the ability of endothelial cell monolayers to respond appropriately to the barrier-protective effects of S1P, indicating a loss of normal S1P-S1P(1) signaling. As bleomycin-induced lung injury progressed, continued exposure to S1P(1) agonists also resulted in increased pulmonary fibrosis. These data indicate that S1P(1) agonists can act as functional antagonists of S1P(1) on endothelial cells in vivo, which should be considered in developing these agents as therapies for vascular leak syndromes. Our findings also support the hypothesis that vascular leak is an important component of the fibrogenic response to lung injury, and suggest that targeting the S1P-S1P(1) pathway may also be an effective therapeutic strategy for fibrotic lung diseases.

[New therapeutic approach for autoimmune diseases by the sphingosine 1-phosphate receptor modulator, fingolimod (FTY720)]

Fingolimod (FTY720) is the first substance in the new immunomodulator class called sphingosine 1-phosphate (S1P) receptor modulators. We isolated an immunosuppressive natural product, myrocin, from the culture broth of Isaria sinclairii, a kind of vegetative wasp. The chemical modification of myriocin yielded a new compound, FTY720, which has more potent immunosuppressive activity and less toxicity than myriocin. FTY720 has been shown to be highly effective in experimental allograft models and autoimmune disease models such as autoimmune encephalomyelitis, collagen-induced arthritis, and lupus nephritis. The most striking feature of FTY720 is the induction of a marked decrease in peripheral blood lymphocytes at doses that show immunosuppressive activity in these models. FTY720 is rapidly converted to FTY720-phosphate (FTY720-P) by sphingosine kinases. FTY720-P acts as a potent agonist at S1P receptor type 1 (S1P(1)), internalizes S1P(1) on lymphocytes, and inhibits the migration of lymphocytes toward S1P. It is highly likely that the reduction of peripheral blood lymphocytes by FTY720 is due to the inhibition of S1P(1)-dependent lymphocyte egress from secondary lymphoid organs and thymus. Recently, it has been reported that FTY720 exerted considerable therapeutic effects in a placebo-controlled clinical trail involving patients with relapsing multiple sclerosis. Patients who received FTY720 orally had a significant reduction in the clinical disease activity, the number of lesions in the central nervous system, and the relapse rates. Since FTY720 possesses a new mechanism of action that has not been observed with other immunosuppressive agents, it is believed that FTY720 provides a new therapeutic approach for autoimmune diseases including multiple sclerosis.