Safety and Effectiveness of Cladribine in Multiple Sclerosis: Real-World Clinical Experience From 5 Tertiary Hospitals in Portugal.

Objectives: Cladribine is a selective and oral immunological reconstitution treatment, approved in Europe for very active multiple sclerosis (MS) with relapses. Aims were to assess the safety and effectiveness of cladribine in real-world setting, during treatment follow-up.

Methods: This was a multicentric, longitudinal, observational study with retrospective and prospective data collection of clinical, laboratory, and imaging data. This interim analysis reports data from July 1, 2018 (study onset), to March 31, 2021.

Results: A total of 182 patients were enrolled: 68.7% were female; mean age at onset was 30.1 ± 10.0 years, and mean age at first cycle of cladribine treatment was 41.1 ± 12.1; 88.5% were diagnosed with relapse-remitting MS and 11.5% with secondary progressive MS. Mean disease duration at cladribine start was 8.9 ± 7.7 years. Most patients (86.1%) were not naive, and median number of previous disease-modifying therapies was 2 (interquartile range, 1-3). At 12 months, we observed no significant Expanded Disability Status Scale score worsening (P = 0.843, Mann-Whitney U test) and a significantly lower annualized relapse rate (0.9 at baseline to 0.2; 78% reduction). Cladribine treatment discontinuation was registered in 8% of patients, mainly (69.2%) due to disease activity persistence. Most frequent adverse reactions were lymphocytopenia (55%), infections (25.2%), and fatigue (10.7%). Serious adverse effects were reported in 3.3%. No patient has discontinued cladribine treatment because of adverse effects.

Conclusion: Our study confirms the clinical efficacy and the safety profile of cladribine for treating MS patients with a long-term active disease in the real-world setting. Our data contribute to the body of knowledge of the clinical management of MS patients and the improvement of related clinical outcomes.