Key clinical point: A significant reduction in absolute lymphocyte counts (ALC) early after the initiation of dimethyl fumarate (DMF) was strongly associated with the development of severe lymphopenia in patients with relapsing multiple sclerosis (MS).
Major finding: A decline in mean ALC of ≥21.2% within the first 3 months of treatment increased the risk for DMF associated-lymphopenia by 6.5-fold (adjusted hazard risk [aHR] 6.503), whereas a decline of ≥40.2% increased the risk for severe lymphopenia by 12.67-fold (aHR 12.67; both P < .001).
Study details: The findings come from a multicenter, noninterventional, prospective real-world study involving 532 patients with relapsing MS who initiated taking DMF.
Disclosures: No funding was received for conducting this study. The authors, including the lead author, declared serving on the advisory board or receiving research/travel grants and speaker/consultancy fees from various sources.
Source: Sainz de la Maza S et al. Mult Scler Relat Disor. 2022;59:103669 (Feb 4). Doi: 10.1016/j.msard.2022.103669.