Dataset Information

Effect of dimethyl fumarate on lymphocytes in RRMS: Implications for clinical practice.

ABSTRACT:

Objective

To assess functional changes in lymphocyte repertoire and subsequent clinical implications during delayed-release dimethyl fumarate (DMF) treatment in patients with multiple sclerosis.

Methods

Using peripheral blood from several clinical trials of DMF, immune cell subsets were quantified using flow cytometry. For some patients, lymphocyte counts were assessed after DMF discontinuation. Incidence of adverse events, including serious and opportunistic infections, was assessed.

Results

In DMF-treated patients, absolute lymphocyte counts (ALCs) demonstrated a pattern of decline followed by stabilization, which also was reflected in the global reduction in numbers of circulating functional lymphocyte subsets. The relative frequencies of circulating memory T- and B-cell populations declined and naive cells increased. No increased incidence of serious infection or malignancy was observed for patients treated with DMF, even when stratified by ALC or T-cell subset frequencies. For patients who discontinued DMF due to lymphopenia, ALCs increased after DMF discontinuation; recovery time varied by ALC level at discontinuation. T-cell subsets closely correlated with ALCs in both longitudinal and cross-sectional analyses.

Conclusions

DMF shifted the immunophenotype of circulating lymphocyte subsets. ALCs were closely correlated with CD4⁺ and CD8⁺ T-cell counts, indicating that lymphocyte subset monitoring is not required for safety vigilance. No increased risk of serious infection was observed in patients with low T-cell subset counts. Monitoring ALC remains the most effective way of identifying patients at risk of subsequently developing prolonged moderate to severe lymphopenia, a risk factor for progressive multifocal leukoencephalopathy in DMF-treated patients.

Trial registration numbers

EUDRA CT 2015-001973-42, NCT00168701, NCT00420212, NCT00451451, and NCT00835770.

SUBMITTER: Mehta D

PROVIDER: S-EPMC6511089 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceWith few approved multiple sclerosis therapies in the pediatric population, there is a need for further approved treatment options. Limited data exist for dimethyl fumarate (DMF) treatment in pediatric-onset multiple sclerosis (POMS).ObjectiveTo compare the efficacy, safety, and tolerability of DMF vs intramuscular interferon β-1a (IFNβ-1a) in POMS.Design, setting, and participantsThe CONNECT study was an active-controlled, open-label, rater-blinded 96-week randomized clinical trial in patients with POMS aged 10 to less than 18 years treated between August 2014 and November 2020. Data were analyzed from January through October 2021.InterventionsPatients were randomized to DMF or IFNβ-1a.Main outcomes and measuresThe primary end point was the proportion of patients free of new or newly enlarging (N or NE) T2 hyperintense lesions at week 96 among trial completers. Secondary end points included number of N or NE T2 lesions, proportion of patients free of relapse, annualized relapse rate (ARR), and safety. The estimated proportion of participants who were relapse free up to week 96 was calculated based on the Kaplan-Meier method. Adjusted ARR was obtained from a negative binomial regression adjusted for baseline relapse rate, baseline Expanded Disability Status Scale (EDSS) score, and age group.ResultsAmong 150 patients with POMS in the intention-to-treat (ITT) population (median [range] age, 15 [10-17] years; 101 [67.3%] female patients), 78 individuals received DMF and 72 individuals received IFNβ-1a. At week 96, the proportion of patients with no N or NE T2 hyperintense lesions among 103 trial completers was 16.1% (95% CI, 8.0%-27.7%) for DMF vs 4.9% (95% CI, 0.6%-16.5%) for IFNβ-1a, and in a sensitivity analysis among the ITT population, the proportions were 10 patients receiving DMF (12.8%) vs 2 patients receiving IFNβ-1a (2.8%). The estimated proportion of patients who remained relapse free at week 96 was 66.2% for DMF vs 52.3% for IFNβ-1a. Adjusted ARR (95% CI) at week 96 was 0.24 (95% CI, 0.15-0.39) for DMF vs 0.53 (95% CI, 0.33-0.84) for IFNβ-1a; the rate ratio for DMF vs IFNβ-1a was 0.46 (95% CI, 0.26-0.80; P = .006). The number of treatment-emergent adverse events (TEAEs; 74 patients [94.9%] vs 69 patients [95.8%]), serious TEAEs (18 patients [23.1%] vs 21 patients [29.2%]), and treatment discontinuations due to TEAEs (5 patients [6.4%] vs 8 patients [11.1%]) was similar for DMF vs IFNβ-1a.Conclusions and relevanceThis study found that more pediatric patients with POMS treated with DMF were free of new or newly enlarging T2 lesions and that the adjusted ARR was lower among these patients compared with those treated with interferon β-1a. DMF was well tolerated.Trial registrationClinicalTrials.gov Identifier: NCT02283853.