Clinical effectiveness and safety of cladribine tablets for patients treated at least 12 months in the swedish post-market surveillance study 'immunomodulation and multiple sclerosis epidemiology 10' (IMSE 10)

Background: Cladribine is a deoxyadenosine analogue prodrug that selectively induces immune reconstitution by targeting B- and T-lymphocytes. Cladribine tablets (CladT) are administered in two courses, 12 months apart, for patients with relapsing multiple sclerosis (RMS). CladT are included in the Swedish post-market surveillance study “Immunomodulation and Multiple Sclerosis Epidemiology” (IMSE). Objective: To assess the safety and effectiveness of CladT with focus on patients treated at least 12 months. Methods: Descriptive data of Extended Disability Status Scale (EDSS), Multiple Sclerosis Severity Scale (MSSS), Symbol Digit Modalities Test (SDMT), Multiple Sclerosis Impact Scale (MSIS-29), European Quality of Life-5 Dimensions Test (EQ-5D), Visual Analog Scale (VAS), relapses and Adverse Events (AEs) is obtained from the nationwide Swedish Neuro Registry (NeuroReg). Effectiveness measures were assessed using the Wilcoxon Signed Rank Test and relapse rates were tested using the paired samples T-test. Results: 140 patients were included in the IMSE 10 study since the Swedish market launch in April 2018 with a one year drug survival rate of 96.5%. 6 patients discontinued treatment, of which 2 later restarted. 18 AEs were reported of which 5 were serious. The most common AE reported were infection and infestation (8 reports). 22% of the patients was treated with CladT as their first MS drug. 18% were treated with natalizumab and 11% with dimethyl fumarate prior to CladT. 83 patients were treated for at least 12 months. Relapse data was available for 47 of 83 patients in the 12-month cohort. The number of relapses decreased significantly from 249.6 per 1,000 patient years before treatment start to 53.5 during treatment. Only 5 patients in this cohort experienced a relapse during treatment.Significant improvements in mean values at 12 months of treatment compared to baseline were noted for MSSS (p=0.007) and VAS (p=0.029) for the 12-month cohort. All other tests remai