Author Of 1 Presentation
P0620 - QSM detects greater rate of reduction in lesion magnetic susceptibility in patients treated with Dimethyl Fumarate over Glatiramer Acetate treatment (ID 1783)
Abstract
Background
Chronic active multiple sclerosis (MS) lesions, characterized by a hyperintense rim (rim+) on quantitative susceptibility mapping (QSM), have been shown to contain iron-enriched, activated microglia and macrophages. QSM is a potential biomarker to monitor treatments directed toward the CNS inflammation. Studies have suggested that dimethyl fumarate (DMF) may reduce the pro-inflammatory innate immune response in the CNS. A comparison to other disease modifying therapies (DMTs) is warranted to evaluate this potential benefit.
Objectives
To determine if dimethyl fumarate (DMF) reduces the iron load, as measured on QSM, in chronic active MS lesions at a greater rate than glatiramer acetate (GA) treatment.
Methods
Sixty-one patients (41 female, 20 male, mean age: 42.1 years +/- 10.9 and EDSS 0.82 +/- 1.2), were considered for this analysis. Fifty-six patients had relapsing-remitting MS and 5 had clinically-isolated syndrome; 37 patients were treated with DMF and 24 with GA. The two treatment groups had similar baseline clinical characteristics; however, DMF patients had less time on treatment as compared to GA (3.86 +/- 1.75 years vs 5.99 +/- 2.67 years, p<0.001). Patients had a QSM scan prior to treatment and a minimum of two on-treatment QSM MRIs. Lesions were classified as rim+ or rim- negative based upon a review of two independent reviewers. To compare longitudinal QSM change in the rim+ lesions among treatment groups, a linear mixed effects model was utilized.
Results
At baseline, patients treated with GA had more QSM rim+ lesions (9.4%) as compared to those starting DMF (4.5%), p=0.0004, however the number of patients having at least one rim+ lesion was similar (16 vs 18 patients) among the treatment groups. DMF patients with rim+ lesions had a longer disease duration as compared to rim+ GA patients (8.15 +/- 6.82 vs 3.55 +/- 4.85 years, p= 0.032). In the subset of patients with QSM rim+ lesions, there was a significantly larger decrease in susceptibility in rim+ lesions with DMF treatment as compared to GA, p< 0.0009. There was minimal reduction of susceptibility in rim- lesions, which was similar among treatment groups; all patients (p=0.92) and QSM rim+ only patients (p=0.11).
Conclusions
This study suggests that DMF reduces the iron load in rim+ MS lesions at a greater rate than GA. These results support QSM to evaluate the effectiveness of various DMTs on the CNS innate immune response in chronic active MS lesions.