Safety and Discontinuation Rate of Dimethyl Fumarate (Zadiva(®)) in Patients with Multiple Sclerosis: An Observational Retrospective Study

Background: This study evaluates the real-world safety and discontinuation rate of Zadiva(®) (generic product of dimethyl fumarate (DMF)) in Iranian patients with relapsing–remitting multiple sclerosis (RRMS), supplementing existing clinical evidence from randomized controlled trials. Methods: This retrospective observational study evaluated the real-world safety and discontinuation rate of DMF in RRMS patients from Amir A’lam referral hospital’s neurology clinic. Data on safety, discontinuation rate, and clinical disease activity were collected retrospectively. The study aimed to assess the discontinuation rate, safety, and reasons for discontinuation, as well as the number of patients experiencing a relapse, MRI activity, and EDSS scores. Results: In total, 142 RRMS patients receiving DMF were included in the study, with 15 discontinuing treatment due to adverse events, lack of efficacy, or pregnancy. Notably, a significant reduction in relapse rates was observed, with 90.8% of patients remaining relapse-free throughout the study period. After 1 year of treatment with Zadiva(®), only 17.6% of patients experienced MRI activity, whereas the EDSS score remained stable. Conclusions: This study provides important real-world data on the safety and tolerability of Zadiva(®) in RRMS patients. The results indicate that Zadiva(®) is generally well tolerated and safe, with a low discontinuation rate due to adverse events or lack of efficacy. These findings suggest that Zadiva(®) is an effective and safe treatment option for RRMS patients in real-world practice.