Patient outcomes influenced by reduced lymphocyte counts after dimethyl fumarate initiation
To examine the temporal profile of absolute and lymphocyte subset data from dimethyl fumarate (DMF) start and relationships to disease behavior.Methods:
A retrospective study performed on patients with an existing diagnosis of MS and a history of DMF exposure from a single MS center. Demographic, laboratory, and corresponding clinical relapse and MRI data were recorded from baseline and in 3–4-month intervals after treatment initiation extending to 3 years. The Spearman rank coefficient and mixed-effects models were used to assess longitudinal correlations between cell counts and measures of disease activity.Results:
A total of 292 patients with MS (228 women; median age at DMF initiation: 40.6 years, range: 16.1–66.7 years) were identified. An increased risk of disease activity was associated with higher absolute lymphocyte count (ALC) values at 3 months (p = 0.001, OR: 1.82) and at 6 months (p = 0.032, hazard ratio: 1.73). A reduced risk of disease evolution in patients with lower ALC values < 1,200 cells/μL compared with midtier (1,210–1,800 cells/μL) and the highest tertile (>1,810 cells/μL) was observed (p = 0.01).Conclusions:
Reductions in ALC values at months 3 and 6 after treatment initiation appear to be associated with improved clinical and radiologic outcomes. These data alone may help to provide a better understanding of both the safety and efficacy of DMF.