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).

Objectives

To track effectiveness and long-term safety of ALZ in a real-world setting, with focus on patients treated with ALZ for at least 36 months.

Methods

Swedish MS patients are registered into the nationwide Swedish MS 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 patients (59% female; 95% RRMS) were included in IMSE 3 between March 2014 and June 2020. Out of 118 patients, 93 had been treated for at least 36 months (62% female), of which 10 patients had switched to another DMT. Mean age at treatment start for patients treated ≥ 36 months was 34 years and mean treatment duration was 54 months. Mean number of drugs prior ALZ initiation was 2.4. Most of the patients (40%, n=37) switched to ALZ from natalizumab or were treatment naïve (13%, n=12) prior ALZ. The mean number of relapses was reduced from 0.72 one year before ALZ initiation to 0.10 during the first treatment year, followed by 0.08 the second treatment year and 0.06 the third year of ALZ treatment (n=79, 15% missing data). In patients treated ≥ 36 months significant improvements in mean baseline compared to 36 months were seen for MSSS (3.3 ± 2.7 to 2.3 ± 2.3, n=44) and EQ-5D (0.7 ± 0.3 to 0.8 ± 0.3, n=50), while SDMT showed significantly worsened results after 36 months (64.8 ± 17.5 to 56.2 ± 12.7, n=59). EDSS, MSIS-29 and VAS scores remained stable. A total of 36 adverse events were reported to the Swedish Medical Products Agency, 13 events were classified as serious and 23 events as non-serious. 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 36 months improved or remained stable across all effectiveness measures except SDMT. Continued follow-up is needed to address long term effectiveness and safety of ALZ.

Background

Dimethyl fumarate (DMF) is an oral therapy approved for patients with relapsing-remitting multiple sclerosis (RRMS), and in which lymphocyte decline is a known pharmacodynamic effect of DMF. Currently, research has suggested meaningful lymphocyte reconstitution may occur within 2-4 months after discontinuation of DMF. To date, the only factor shown to be associated with a slower rate of recovery is the duration of lymphopenia.

Objectives

To describe lymphocyte count profiles following discontinuation of Dimethyl fumarate (DMF) due to lymphopenia in a nationwide Swedish population-based setting.

Methods

The IMSE-5 study obtains demographics, clinical and safety data, including absolute lymphocyte count (ALC), from the Swedish population-based Neuro Registry. Key inclusion criteria were RRMS patients, treatment with DMF for at least 3 months, age >18 years at initiation, had ALC values at start of DMF treatment, during treatment, and following discontinuation of DMF treatment. All patients had discontinued DMF due to lymphopenia. The least square mean estimation of ALC values at different time points was calculated using Linear Mixed Models

Results

A total of 18 DMF patients were included, 72% were female and the mean age at treatment start was 51.3 years. The mean treatment duration was 3.1 (SD 0.8) years, and 22% were treatment naïve, 50% had switched from interferons or glatiramer acetate (GA). and three patients switched from natalizumab and fingolimod. The estimated ALC values following discontinuation of DMF due to lymphopenia compared to the time for discontinuation significantly increased during follow up (p<0.001). E.g. at date of drug discontinuation mean ALC was 0.35x10⁹/L (95% CI 0.33-0.37), in 6 weeks following discontinuation ALC was 0.50 x10⁹/L (95% CI 0.26-0.74) and in 12 weeks ALC increased to 0.91 x10⁹/L (95% CI 0.74-1.07). The mean time from discontinuation to a new treatment initiation following DMF was 99.8 (SD 88.5) days; and 50% switched to rituximab and two patients to teriflunomide, and one to GA.

Conclusions

Data from the Swedish IMSE-5 study suggest that a lymphocyte reconstitution occurs within 12 weeks following the discontinuation of DMF. However, larger datasets will be needed to verify this finding

Funding: The IMSE-5 study is funded in a scientific collaboration agreement with Biogen.