Effect of dimethyl fumarate on lymphocyte subsets in patients with relapsing multiple sclerosis

LymphoTEC: a Retrospective Real-World Study on Lymphocyte Reconstitution After Lymphopenia in Patients with Multiple Sclerosis Treated with Dimethyl Fumarate in France

INTRODUCTION

Dimethyl fumarate (DMF) has demonstrated a favorable benefit-risk profile in patients with relapsing-remitting multiple sclerosis (RRMS). Some patients may develop lymphopenia on DMF; therefore, LymphoTEC evaluated absolute lymphocyte count (ALC) reconstitution after DMF discontinuation.

METHODS

LymphoTEC was a retrospective, multicenter study of patients with RRMS in the Observatoire Français de la Sclérose en Plaques registry. Times to ALC reconstitution and lymphopenia were estimated by the Kaplan-Meier method. Univariate and multivariate analyses evaluated factors associated with ALC reconstitution after DMF discontinuation or lymphopenia after DMF initiation. Patients treated with DMF for ≥ 3 months with ≥ 1 ALC in the 6 months before/close to DMF initiation and ≥ 1 ALC during treatment were included.

RESULTS

Overall, 1429 RRMS patients were included; 356 patients developed lymphopenia, of whom 183 discontinued DMF. Overall, ALC decreased by 33% over the first year and plateaued thereafter. The probability of developing lymphopenia was 18.2% after 1 year. In patients with lymphopenia, median times to ALC reconstitution after DMF discontinuation were 3.8 months overall, 4.0 months for Grade 1 lymphopenia, 3.0 months for Grade 2, and 9.7 months for Grade 3. At 12 months, 83.0% had reconstituted ALC. In DMF discontinuers, median time to discontinuation was 1.2 years. There was no increased risk of serious or opportunistic infections in patients with lymphopenia. No cases of progressive multifocal leukoencephalopathy were reported. First ALC reconstitution after DMF discontinuation was associated with diabetes, DMF duration, DMF duration before lymphopenia, and DMF duration after lymphopenia; first lymphopenia after DMF initiation was associated with age and ALC at DMF initiation.

CONCLUSION

LymphoTEC confirms previous reports on DMF-induced lymphopenia; the benefit-risk profile of DMF remains favorable. Most cases of lymphopenia were not severe and ALC reconstitution typically occurred within 4 months of DMF discontinuation. Patients with shorter and milder lymphopenia had faster ALC reconstitution.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04756687.

Real-World Safety and Effectiveness of Dimethyl Fumarate in Patients with MS: Results from the ESTEEM Phase 4 and PROCLAIM Phase 3 Studies with a Focus on Older Patients

INTRODUCTION

Real-world studies in the USA report that 41-56% of patients with multiple sclerosis (MS) are ≥ 50 years old, yet data on their response to disease-modifying therapies (DMTs) is limited. Dimethyl fumarate (DMF) is an oral DMT approved for treating relapsing MS. This analysis evaluated the safety, efficacy, and immunophenotype changes of DMF in patients ≥ 50 years compared with patients < 50 years.

METHODS

ESTEEM, a 5-year, real-world, observational phase 4 study, assessed the safety and effectiveness of DMF, including treatment-emergent serious adverse events (SAEs) and adverse events (AEs) leading to treatment discontinuation. Absolute lymphocyte counts (ALCs) were recorded from a subset of patients. The PROCLAIM study, a phase 3b interventional study, reported safety outcomes and lymphocyte subset changes in patients with relapsing-remitting MS (RRMS) treated with DMF. The study evaluated safety outcomes by analyzing the incidence of SAEs and detailed changes in CD4+ and CD8+ T cell compartments over 96 weeks of DMF treatment.

RESULTS

ESTEEM included 4020 patients aged < 50 years and 1069 aged ≥ 50 years. AEs leading to discontinuation were reported by 19.6% patients < 50 years and 29.6% of patients ≥ 50 years, with gastrointestinal disorders being the most common. SAEs were reported by 5.2% of patients < 50 years and 8.9% those ≥ 50 years. In PROCLAIM, SAEs were reported in 13% of patients < 50 years and 10% of those ≥ 50 years. Median ALC decreased by 35% in patients < 50 years and 50% in those ≥ 50 years in ESTEEM, with similar patterns observed in PROCLAIM.

CONCLUSIONS

ESTEEM found no unexpected safety signals in older patients and annualized relapse rates (ARRs) were significantly reduced in both age groups. Both studies indicated that DMF is efficacious and has a favorable safety profile in patients with RRMS aged ≥ 50 years.

CLINICAL TRIAL REGISTRATION

ESTEEM (NCT02047097), PROCLAIM (NCT02525874).

Maternal and fetal outcomes in an Italian multicentric cohort of women with multiple sclerosis exposed to dimethyl fumarate during pregnancy

BACKGROUND

Evidence on the impact of dimethyl fumarate (DMF) during pregnancy in women with multiple sclerosis (MS) is limited.

OBJECTIVES

To investigate disease activity and pregnancy outcomes in a retrospective cohort of women exposed to DMF in early pregnancy.

METHODS

Women discontinuing DMF after pregnancy confirmation were identified from 29 Italian MS Centers. Disease activity 12 months before conception, during pregnancy, and 12 months postpartum were recorded, exploring reactivation predictors. Pregnancy and fetal outcomes were assessed.

RESULTS

The study analyzed 137 pregnancies (12 pregnancy losses, 125 live births) from 137 women (mean age 32.9 ± 4.7 years), discontinuing DMF within a median (interquartile range (IQR)) interval of 4.9 (3.7-5.7) weeks from conception. In live birth pregnancies, annualized relapse rate (ARR) significantly decreased during pregnancy (ARR = 0.07, 95% confidence interval (CI): 0.03-0.14, p = 0.021) compared to pre-conception (ARR = 0.21 (95% CI: 0.14-0.30)) and increased postpartum ((ARR = 0.22 (95% CI: 0.15-0.32), p = 0.006). Median time to first relapse (TTFR) was 3.16 (IQR: 1:87-5.42) months. Higher pre-conception relapse number (hazard ratio (HR) = 2.33, 95% CI: 1.08-5.02) and Expanded Disability Status Scale (EDSS; HR = 1.81, 95% CI: 1.17-2.74) were associated with shorter TTFR, while treatment resumption with longer TTFR (HR = 0.29, 95% CI: 0.11-0.74). Fetal outcomes were unaffected by DMF exposure.

CONCLUSION

DMF discontinuation does not increase relapse risk during pregnancy. Early therapy restart prevents postpartum relapses. Early DMF exposure shows no adverse fetal outcomes.

Beyond Antioxidation: Keap1-Nrf2 in the Development and Effector Functions of Adaptive Immune Cells

Ubiquitously expressed in mammalian cells, the Kelch-like ECH-associated protein 1 (Keap1)-NF erythroid 2-related factor 2 (Nrf2) complex forms the evolutionarily conserved antioxidation system to tackle oxidative stress caused by reactive oxygen species. Reactive oxygen species, generated as byproducts of cellular metabolism, were identified as essential second messengers for T cell signaling, activation, and effector responses. Apart from its traditional role as an antioxidant, a growing body of evidence indicates that Nrf2, tightly regulated by Keap1, modulates immune responses and regulates cellular metabolism. Newer functions of Keap1 and Nrf2 in immune cell activation and function, as well as their role in inflammatory diseases such as sepsis, inflammatory bowel disease, and multiple sclerosis, are emerging. In this review, we highlight recent findings about the influence of Keap1 and Nrf2 in the development and effector functions of adaptive immune cells, that is, T cells and B cells, and discuss the knowledge gaps in our understanding. We also summarize the research potential and targetability of Nrf2 for treating immune pathologies.

Astrocytes and Inflammatory T Helper Cells: A Dangerous Liaison in Multiple Sclerosis

Multiple Sclerosis (MS) is a neurodegenerative autoimmune disorder of the central nervous system (CNS) characterized by the recruitment of self-reactive T lymphocytes, mainly inflammatory T helper (Th) cell subsets. Once recruited within the CNS, inflammatory Th cells produce several inflammatory cytokines and chemokines that activate resident glial cells, thus contributing to the breakdown of blood-brain barrier (BBB), demyelination and axonal loss. Astrocytes are recognized as key players of MS immunopathology, which respond to Th cell-defining cytokines by acquiring a reactive phenotype that amplify neuroinflammation into the CNS and contribute to MS progression. In this review, we summarize current knowledge of the astrocytic changes and behaviour in both MS and experimental autoimmune encephalomyelitis (EAE), and the contribution of pathogenic Th1, Th17 and Th1-like Th17 cell subsets, and CD8⁺ T cells to the morphological and functional modifications occurring in astrocytes and their pathological outcomes.

Varicella-Zoster Reactivation in a Non-immunized Elderly Multiple Sclerosis Patient While on Delayed-Release Dimethyl Fumarate With Grade 2 Lymphopenia and Profoundly Low CD4+ and CD8+ Cell Counts: A Case Report

Increased susceptibility to opportunistic infections (OI) in multiple sclerosis (MS) patients is a real concern amongst neurologists when using disease-modifying therapies (DMTs). DMTs used in modulating or suppressing the immune system for MS management may risk the patient with lymphocytopenia, raising the possibility of OI; however, this lymphopenia may contemplate as a biomarker for drug response, degree of immunomodulation, and drug compliance. The OI could be reactivation of varicella-zoster, progressive multifocal leukoencephalopathy (PML) induced by John Cunningham virus (JC virus), Pneumocystis jirovecii infection, cryptococcal meningitis, atypical mycobacteria, and many more.

We present a non-immunized case of varicella-zoster reactivation with dimethyl fumarate (DMF) therapy. Surprisingly, the patient’s lymphocyte count trend during her previous follow-up visits remained in the range of normal to grade 1 lymphopenia but with her current flared-up rash presentation, she had a profoundly low CD8+ and CD4+ cell counts (CD8+ cell count << CD4+ cell counts) despite an absolute lymphocyte (ALC) level far above 500 cells/µl; in fact, it was 13.6% higher when compared to her last quarterly levels. Controlled trials with DMF claimed no serious infection even with a lymphopenia range of 500-800 cells/µl, which is untrue in real clinics and it would be wise and reasonable to follow the lymphocyte subsets along with ALC to prevent potential opportunistic infections.

Recently, comprehensive strategies were evolved to mitigate OI risk for MS patients while on DMTs. These were not only limited to lymphocyte threshold monitoring but extended to address features in terms of screening recommendation, vaccination advice, the need for antibiotic prophylaxis, neuroimaging, laboratory checkups, medication dosing, and behavioral modifications. Our patient was not immunized with zoster vaccine and, unfortunately, DMF has no proper structured guidelines regarding vaccination against OI prevention as other few DMTs have. Our case could suggest that MS patients need proper vaccination guidelines from the Centers for Disease Control and Prevention (CDC) before starting DMF.

A retrospective analysis of changes in lymphocyte levels in patients with multiple sclerosis during and after Tecfidera® treatment

Background

There are currently no best practice recommendations for lymphocyte subset monitoring for patients with multiple sclerosis (pwMS) on disease-modifying therapies including Tecfidera® (dimethyl fumarate, DMF). However, there have been several cases of pwMS on DMF without severe lymphopenia who had high CD4:CD8 T cell ratios and went on to develop progressive multifocal leukoencephalopathy.

Objective

Our objective was to characterize the changes in immune profile during and after DMF treatment in pwMS.

Methods

A retrospective analysis of longitudinal data from 299 pwMS who have been treated with DMF at the Fraser Health Multiple Sclerosis Clinic in British Columbia, Canada. The blood test results were taken from January 1, 2013 to April 1, 2020.

Results

Our results suggest that CD8+ T cells had the highest proportional decrease compared to other lymphocyte subset populations and overall lymphocyte count in response to DMF treatment. CD56+ Natural Killer cells were similarly decreased in response to DMF treatment. CD4:CD8 T cell ratio was the measurement that had the highest rate of change in response to DMF initiation and discontinuation.

Conclusion

CD8+ T cell count and CD4:CD8 T cell ratio may be a more sensitive measurement of the immune landscape of patients with MS on DMF.

Encephalitogenic and Regulatory CD8 T Cells in Multiple Sclerosis and Its Animal Models

Multiple sclerosis (MS), a neuroinflammatory disease that affects millions worldwide, is widely thought to be autoimmune in etiology. Historically, research into MS pathogenesis has focused on autoreactive CD4 T cells because of their critical role in the animal model, experimental autoimmune encephalomyelitis, and the association between MS susceptibility and single-nucleotide polymorphisms in the MHC class II region. However, recent studies have revealed prominent clonal expansions of CD8 T cells within the CNS during MS. In this paper, we review the literature on CD8 T cells in MS, with an emphasis on their potential effector and regulatory properties. We discuss the impact of disease modifying therapies, currently prescribed to reduce MS relapse rates, on CD8 T cell frequency and function. A deeper understanding of the role of CD8 T cells in MS may lead to the development of more effective and selective immunomodulatory drugs for particular subsets of patients.

Predictors of lymphocyte count recovery after dimethyl fumarate-induced lymphopenia in people with multiple sclerosis

BACKGROUND

Dimethyl fumarate (DMF) is an oral drug approved for Relapsing Multiple Sclerosis (RMS) patients. Grade III lymphopenia is reported in 5-10% DMF-treated patients. Data on lymphocyte count (ALC) recovery after DMF withdrawal following prolonged lymphopenia are still scarce.

OBJECTIVES

To characterize ALC recovery and to identify predictors of slower recovery after DMF interruption.

METHODS

Multicenter data from RMS patients who started DMF and developed lymphopenia during treatment were collected. In patients with grade II-III lymphopenia, ALCs were evaluated from DMF withdrawal until reaching lymphocyte counts > 800/mm³.

RESULTS

Among 1034 patients who started DMF, we found 198 (19.1%) patients with lymphopenia and 65 patients (6.3%) who discontinued DMF due to persistent grade II-III lymphopenia. Complete data were available for 51 patients. All patients recovered to ALC > 800 cells/mm³ with a median time of 3.4 months. Lower ALCs at DMF suspension (HR 0.98; p = 0.005), longer disease duration (HR 1.29; p = 0.014) and prior exposure to MS treatments (HR 0.03; p = 0.025) were found predictive of delayed ALC recovery.

CONCLUSION

ALC recovery after DMF withdrawal is usually rapid, nevertheless it may require longer time in patients with lower ALC count at DMF interruption, longer disease duration and previous exposure to MS treatments, potentially leading to delayed initiation of a new therapy.