5PSQ-040 Dimethyl fumarate safety in the treatment of relapsing-remitting multiple sclerosis

<h3>Background and Importance</h3> Dimethyl fumarate (DMF) is a drug with anti-inflammatory and immunomodulatory properties used as a first-line treatment for Relapsing-Remitting Multiple Sclerosis (RRMS). Due to its poor tolerability and high number of adverse reactions (ARs), it is important to monitor it more closely, especially in the first months of treatment. <h3>Aim and Objectives</h3> To analyse the safety of DMF in the treatment of RRMS. <h3>Material and Methods</h3> Retrospective observational study of patients with RRMS starting DMF between 2022 and 2023. All included patients had to have a treatment time (PBR2) of greater than or equal to 6 months. Demographic data (gender and age) and previous treatments were collected. The safety of DMF was measured by analysis of treatment duration, treatment interruptions due to the presence of ARs and the causative Ars. <h3>Results</h3> Ninety-two patients were analysed (77.2% women) with a median age of 41 years (range 17–66). Of the studied patients, 54 were treatment-naive, 34 had received previous treatment (19 glatiramer acetate, 12 interferon beta, three teriflunomide), and four patients restarted DMF. 22.8% of patients discontinued treatment at 6 months due to ARs, with a mean treatment time of 5.1 months. Of these, six patients discontinued treatment in the first few days after starting three at one and a half months, 10 at 3 months, and four at 6 months. The ARs included: digestive disorders (42.9%), lymphopenia (38.1%), elevated liver enzymes (14.3%), hypereosinophilia (9.5%), itching and shortness of breath (9.5%), and vasovagal reaction (4.8%). Of the patients who discontinued DMF due to ARs, 47.8% had been previously treated with another drug. Only one patient, who had previously been treated with teriflunomide, discontinued the DMF treatment at the beginning due to persistent lymphopenia. <h3>Conclusion and Relevance</h3> ARs related to DMF are a significant cause of treatment interruption in the early months, mainly due to digestive disorders and lymphopenia. As is common in clinical practice, initial monitoring of patients after starting treatment is necessary for early detection of ARs and should be a priority for patients who have been previously treated, which could be considered a risk factor for the development of ARs. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest