To Örebro University

Background: Alemtuzumab (ALZ) is a modulatory drug for patients with relapsing-remitting multiple sclerosis (RRMS). Post-marketing surveillance is important to assess the long-term safety and effectiveness in a real-world setting where ALZ was included into the Swedish post-market surveillance study “Immunomodulation and Multiple Sclerosis Epidemiology Study 3” (IMSE 3) upon launch in Sweden (March 2014).

Objective: To follow up the effectiveness and long-term safety of ALZ in a real-world setting.

Methods: Swedish MS patients are registered in the nationwide Swedish Neuro Registry (NeuroReg).

IMSE 3 includes patients starting ALZ treatment with annual clinical measures obtained from NeuroReg; 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 Dimension Test (EQ-5D) and Visual Analogue Scale (VAS). The Wilcoxon signed-rank test was used to assess changes in effectiveness.

Results: 118 patients (59% female; 95% RRMS) have been included in IMSE 3 between March 2014 and April 2021. Mean age at treatment start was 34 years. At cut-off date 85 patients had been treated with ALZ with at least 48 months of follow-up. Mean values at baseline compared to 48 months showed significant improvements for MSSS and SDMT while EQ-5D, EDSS, MSIS-29 and VAS scores showed tendencies of improvement.

The largest proportion of the entire cohort switched from natalizumab (39%) or were treatment naïve (14%) prior ALZ. The number of relapses per 1,000 patient years decreased from 441 before ALZ initiation to 84 during ALZ treatment (16% missing data). 36 adverse events (AEs) were reported to the Swedish Medical Products Agency. 23 were classified as serious and the most common AEs categories were infections and infestations and blood and lymphatic system disorders (23% respectively). For non-serious events endocrine disorders (43%) was the most common category. Two patients died during ALZ treatment, one of which was associated to ALZ treatment, and died in association with the first ALZ treatment cycle due to fulminant viral hepatitis.

Conclusions: Patients treated with ALZ for at least 48 months improved or remained stable across all effectiveness measures. Continued follow-up is needed to evaluate the real-world effectiveness and safety of ALZ.