Clinical predictors of Dimethyl Fumarate response in multiple sclerosis: a real life multicentre study.

ABSTRACT

BACKGROUND: Dimethyl-fumarate (DMF) was effective and safe in relapsing-remitting multiple sclerosis (MS) in randomized clinical trials. We aimed to evaluate the efficacy and safety of DMF and factors related to drug response in real-life setting. METHODS: We analysed prospectively collected demographic and clinical data for patients treated with DMF in six multiple sclerosis (MS) centers from 2015 to 2017 in Campania region, Italy. We performed univariate and multivariate analyses to assess relationships between baseline parameters and DMF efficacy outcomes, Annualized Relapse Rate (ARR), Expanded Disability Status Scale (EDSS) progression and No Evidence of Disease Activity (NEDA-3) status. RESULTS: we analyzed data of 456 patients (67% female subjects, mean age 40 ± 12 years, mean disease duration 9 ± 9 years, mean treatment duration 18 ± 11 months, median EDSS 2.5, 0-8). Proportion of Naïve versus pretreated with other DMTs patients was 149/307 (32.7%), with 122 patients switching to DMF for disease activity (26.7%) and 185 for safety and tolerability issues (40.6%). During treatment with DMF, the annualized relapse rate was reduced by 75% respect to the pre-treatment ARR [incidence-rate-ratio (IRR) = 0.25, p < 0.001, CI 0.18-0.33]. Factors influencing ARR rate while on DMF were relapsing remitting (RR) MS course (IRR = 2.0, p = <0.001, CI 1.51-2.73) and previous DMTs status de-escalating from second-line therapies was associated to higher risk of relapsing (IRR = 1.8, p < 0.001, CI 1.39-2.31). At multivariable Cox proportional hazard model, only age of onset was related with rate or relapses, with younger age being protective (HR 0.96, p = 0,02). EDSS remained stable in 88% of patients. Disease duration was associated with higher rate of NEDA-3 failure, that was instead maintained in 65% of patients at 24 months. 109 patients (22%) discontinued therapy after a mean of 1.1 ±+ 0.7 years. Reasons for DMF discontinuation over time were lack of efficacy (50%), safety issues (30%), tolerability (7%), poor compliance (7%), and pregnancy (4%). Higher pre-treatment EDSS was associated with DMF discontinuation (p = 0.009). Only 33 patients dropped out due to safety reasons (7%), the most frequent safety issues driving to drop out being lymphopenia, liver/pancreatic enzymes increase, gatrointestinal severe tolerability issues. We recorded 95 cases (24%) of lymphopenia 60 grade I (13%), 31 grade II (7%) and 4 grade III (1%). CONCLUSIONS: We confirm that DMF shows a good efficacy in both naïve patients and patients switching from other first-line DMTs, especially in patients with early onset of disease. Higher baseline EDSS was a risk factor for discontinuing DMF therapy, while shorter disease duration was protective for both EDSS progression and NEDA-3 status maintenance.