Effectiveness and safety profile of cladribine in an Italian real-life cohort of relapsing–remitting multiple sclerosis patients: a monocentric longitudinal observational study

Introduction: Cladribine is approved for the treatment of active relapsing MS (RRMS), but its positioning in MS therapeutic scenario still needs to be fully elucidated. Methods: This is a monocentric, observational, real-world study on RRMS patients treated with cladribine. Relapses, magnetic resonance imaging (MRI) activity, disability worsening, and loss of no-evidence-of-disease-activity-3 (NEDA-3) status were assessed as outcomes. White blood cell, lymphocyte counts and side effects were also evaluated. Patients were analyzed overall and in subgroups according to the last treatment before cladribine. The relationship between baseline characteristics and outcomes was tested to identify predictors of response. Results: Among the 114 patients included, 74.9% were NEDA-3 at 24 months. We observed a reduction of relapses and MRI activity, along with a stabilization of disability. A higher number of gadolinium-enhancing lesions at baseline was the only risk factor for loss of NEDA-3 during follow-up. Cladribine was more efficacious in switchers from first-line therapies or naïves. Grade I lymphopenia was more frequent at month 3 and 15. No grade IV lymphopenia cases were observed. Independent predictors of grade III lymphopenia were a lower baseline lymphocyte count and a higher number of previous treatments. Sixty-two patients presented at least one side effect and globally 111 adverse events were recorded, none of them was serious. Conclusions: Our study confirms previous data on cladribine effectiveness and safety. Cladribine is more effective when placed early in the treatment algorithm. Real-world data on larger populations with longer follow-up are needed to confirm our findings.