To Örebro University

Background: Alemtuzumab (ALZ) is an approved disease-modifying therapy (DMT) for relapsing-remitting multiple sclerosis (RRMS). Post-marketing surveillance is important to assess the long term safety and effectiveness in a real-world setting. ALZ has therefore been included into the Swedish post-market surveillance study “Immunomodulation and Multiple Sclerosis Epidemiology Study” (IMSE) upon launch in Sweden (March 2014).

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

Methods: Swedish MS patients are registered into the nationwide Swedish Neuro Registry (NeuroReg). IMSE 3 includes all 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).

Results: A total of 118 MS patients (59% female; 95% RRMS) were included in IMSE 3 between March 2014 and April 2019. 95 patients had started ALZ >24 months ago (63% female; 98% RRMS) at cut-off date (31st of Mars 2019), where only 3 patients had switched to another DMT. Mean age at treatment start for patients treated at least 24 months was 34 years and mean treatment duration was 42 months. Mean number of drugs prior ALZ initiation was 2.3. Most patients (41/95) switched to ALZ from natalizumab, while 14/95 patients were treatment naïve with ALZ. The number of relapses per 1,000 patient years decreased from 471 before ALZ initiation to 65 during ALZ treatment (n=83, missing data; n=12). In patients treated ⩾ 24 months significant improvements in mean were seen for EDSS (1.9 ± 1.4 to 1.6 ± 1.3, n=57), MSSS (3.3 ± 2.6 to 2.4 ± 2.1, n=48) and EQ-5D (0.7 ± 0.3 to 0.8 ± 0.3, n=53), while MSIS-29, SDMT and VAS scores remained stable. A total of 28 adverse events were reported to the Swedish Medical Products Agency, 12 events were classified as serious and 16 events as non-serious. Two patients died during ALZ treatment, of which one patient died in association with the first ALZ treatment cycle due to fulminant viral hepatitis.

Conclusions: Patients treated with ALZ for at least 24 months improved or remained stable across all effectiveness measures. Only a very small percentage of patients switched to other DMTs. Continued follow-up is needed to address long term effectiveness and safety of ALZ.