Effects of baseline age and disease duration on the efficacy and safety of siponimod in patients with active SPMS: Post hoc analyses from the EXPAND study.

BACKGROUND: Older age and longer disease duration (DD) may impact the effectiveness of disease-modifying therapies in patients with multiple sclerosis (MS). Siponimod is a sphingosine 1-phosphate receptor modulator approved for the treatment of active secondary progressive MS (SPMS) in many countries. The pivotal phase 3 EXPAND study examined siponimod versus placebo in a broad SPMS population with both active and non-active disease. In this population, siponimod demonstrated significant efficacy, including a reduction in the risk of 3-month confirmed disability progression (3mCDP) and 6-month confirmed disability progression (6mCDP). Benefits of siponimod were also observed across age and DD subgroups in the overall EXPAND population. Herein we sought to assess the clinical impact of siponimod across age and disease duration subgroups, specifically in participants with active SPMS. METHODS: This study is a post hoc analysis of a subgroup of EXPAND participants with active SPMS (≥ 1 relapse in the 2 years before the study and/or ≥ 1 T1 gadolinium-enhancing magnetic resonance imaging lesion at baseline) receiving oral siponimod (2 mg/day) or placebo during EXPAND. Data were analyzed for participant subgroups stratified by age at baseline (primary cut-off: < 45 year ≥ 45 years; and secondary cut-off: < 50 years or ≥ 50 years) and by DD at baseline (< 16 years or ≥ 16 years). Efficacy endpoints were 3mCDP and 6mCDP. Safety assessments included adverse events (AEs), serious AEs, and AEs leading to treatment discontinuation. RESULTS: Data from 779 participants with active SPMS were analyzed. All age and DD subgroups had 31-38% (3mCDP) and 27-43% (6mCDP) risk reductions with siponimod versus placebo. Compared with placebo, siponimod significantly reduced the risk of 3mCDP in participants aged ≥ 45 years (hazard ratio [HR]: 0.68; 95% confidence interval [CI]: 0.48-0.97), < 50 years (HR: 0.69; 95% CI: 0.49-0.98), ≥ 50 years (HR: 0.62; 95% CI: 0.40-0.96), and in participants with < 16 years DD (HR: 0.68; 95% CI: 0.47-0.98). The risk of 6mCDP was significantly reduced with siponimod versus placebo for participants aged < 45 years (HR: 0.60; 95% CI: 0.38-0.96), ≥ 45 years (HR: 0.67; 95% CI: 0.45-0.99), < 50 years (HR: 0.62; 95% CI: 0.43-0.90), and in participants with < 16 years DD (HR: 0.57; 95% CI: 0.38-0.87). Increasing age or longer MS duration did not appear to increase the risk of AEs, with an observed safety profile that remained consistent with the overall active SPMS and overall SPMS populations in EXPAND. CONCLUSIONS: In participants with active SPMS, treatment with siponimod demonstrated a statistically significant reduction in the risk of 3mCDP and 6mCDP compared with placebo. Although not every outcome reached statistical significance in the subgroup analyses (possibly a consequence of small sample sizes), benefits of siponimod were seen across a spectrum of ages and DD. Siponimod was generally well tolerated by participants with active SPMS, regardless of baseline age and DD, and AE profiles were broadly similar to those observed in the overall EXPAND population.

Immune cell subset profiling in multiple sclerosis after fingolimod initiation and continued treatment: The FLUENT study.

Background: Fingolimod is a sphingosine 1-phosphate receptor modulator approved for relapsing MS. Long-term effects on the immunological profile are not fully understood. Objective: Investigate fingolimod's temporal effects on immune cell subsets, and safety outcomes. Methods: In FLUENT, a 12-month, prospective, non-randomized, open-label, phase IV study, adult participants received fingolimod 0.5 mg/day. Changes in immune cell subsets, anti-John Cunningham virus (JCV) antibody index, and serum neurofilament levels were assessed. Results: 165 fingolimod-naive and 217 participants treated for 2-12 years in routine clinical practice were enrolled. Levels of all monitored peripheral lymphocyte subsets were reduced from month 3 in fingolimod-naive participants. Greatest reductions occurred in naive and central memory CD4+ and CD8+ T cells, and in naive and memory B cells. Most lymphocyte subset levels remained stable in the continuous fingolimod group. Components of the innate immune system remained within reference ranges. No increase in JCV seropositivity was observed. No single cellular subset correlated with anti-JCV antibody index at any time point. Neurofilament levels remained within healthy adult reference limits throughout. No opportunistic infections were reported; no new or unexpected safety signals were observed. Conclusion: FLUENT provides insights into the utility of immunological profiling to evaluate therapy response and potential infection risk.

Time to treatment failure following initiation of fingolimod versus teriflunomide for multiple sclerosis: a retrospective US claims study.

Objective: Disease modifying therapies (DMTs) for multiple sclerosis (MS) aim to delay progression and reduce relapses. Evidence is limited on the comparative effectiveness of the oral DMTs fingolimod and teriflunomide. This study evaluated time to treatment failure among patients with MS who initiated fingolimod versus teriflunomide in real-world settings.Methods: The retrospective cohort included 18-64 year old patients diagnosed with MS who initiated fingolimod or teriflunomide during 12 September 2012 to 30 September 2015 within MarketScan Commercial and Medicare Claims. Patients were followed from treatment initiation (index date) until first treatment failure or censoring. Treatment failure was defined as the first occurrence of MS relapse (identified using a validated algorithm) or treatment discontinuation (≥60 day supply gap). Treatment failure was examined through Kaplan-Meier analysis and multivariable Cox regression adjusting for 1 year baseline factors (age, gender, plan type, region, index year, prior DMT use, baseline relapses, Charlson Comorbidity Index [CCI] and MS symptoms).Results: On average, patients treated with fingolimod (n = 2704) were younger (43.6 versus 49.8 years) with lower CCI (0.4 versus 0.7) and more relapses at baseline (0.46 versus 0.42) than those treated with teriflunomide (n = 1859). Median time to treatment failure was 19.5 months with fingolimod versus 9.6 months with teriflunomide (p < .001). After controlling key demographic and clinical characteristics through multivariable regression, fingolimod was associated with 38.9% lower hazards of treatment failure versus teriflunomide (adjusted hazard ratio = 0.611; 95% CI: 0.559-0.669; p < .001).Conclusions: In a large cohort of US adults with MS, controlling for key baseline characteristics, fingolimod was associated with significantly longer time to treatment failure and lower risk of treatment failure compared with teriflunomide.

Macrophage migration inhibitory factor potentiates autoimmune-mediated neuroinflammation.

Macrophage migration inhibitory factor (MIF) is a multipotent cytokine that is associated with clinical worsening and relapses in multiple sclerosis (MS) patients. The mechanism through which MIF promotes MS progression remains undefined. In this study, we identify a critical role for MIF in regulating CNS effector mechanisms necessary for the development of inflammatory pathology in a mouse model of MS, experimental autoimmune encephalomyelitis (EAE). Despite the ability to generate pathogenic myelin-specific immune responses peripherally, MIF-deficient mice have reduced EAE severity and exhibit less CNS inflammatory pathology, with a greater percentage of resting microglia and fewer infiltrating inflammatory macrophages. We demonstrate that MIF is essential for promoting microglial activation and production of the innate soluble mediators IL-1ß, IL-6, TNF-α, and inducible NO synthase. We propose a novel role for MIF in inducing microglial C/EBP-ß, a transcription factor shown to regulate myeloid cell function and play an important role in neuroinflammation. Intraspinal stereotaxic microinjection of MIF resulted in upregulation of inflammatory mediators in microglia, which was sufficient to restore EAE-mediated inflammatory pathology in MIF-deficient mice. To further implicate a role for MIF, we show that MIF is highly expressed in human active MS lesions. Thus, these results illustrate the ability of MIF to influence the CNS cellular and molecular inflammatory milieu during EAE and point to the therapeutic potential of targeting MIF in MS.

TGF-ß signaling via Smad4 drives IL-10 production in effector Th1 cells and reduces T-cell trafficking in EAE.

Effector Th1 cells perpetuate inflammatory damage in a number of autoimmune diseases, including MS and its animal model EAE. Recently, a self-regulatory mechanism was described in which effector Th1 cells produce the immunomodulatory cytokine IL-10 to dampen the inflammatory response in both normal and autoimmune inflammation. While the presence of TGF-ß has been suggested to enhance and stabilize an IFN-γ(+) IL-10(+) phenotype, the molecular mechanism is poorly understood. Additionally, in the context of adoptive transfer EAE, it is unclear whether IL-10 acts on the transferred Th1 cells or on endogenous host cells. In the present study, using myelin-specific TCR-Tg mice, we show that repetitive Ag stimulation of effector Th1 cells in the presence of TGF-ß increases the population of IFN-γ(+) IL-10(+) cells, which correlates with a decrease in EAE severity. Additionally, TGF-ß signaling causes binding of Smad4 to the IL-10 promoter, providing molecular evidence for TGF-ß-mediated IL-10 production from Th1 effector cells. Finally, this study demonstrates that IL-10 not only reduces encephalitogenic markers such as IFN-γ and T-bet on Th1 effector cells expressing the IL-10R but also prevents recruitment of both transferred and host-derived inflammatory T cells. These data establish a regulatory mechanism by which highly activated Th1 effector cells modulate their pathogenicity through the induction of IL-10.