Background and importance Alemtuzumab is a humanised monoclonal antibody that selectively targets CD52, indicated in adult patients with relapsing–remitting multiple sclerosis (RRMS).

Aim and objectives To assess the effectiveness and safety of alemtuzumab for RRMS in the clinical setting.

Material and methods A retrospective observational study of all patients with RRMS treated with at least one course of alemtuzumab from July 2016 to March 2019 was carried out. The drug was administered by intravenous infusion on 5 consecutive days at baseline and on 3 consecutive days 12 months later. All patients received prophylaxis with methylprednisolone, antihistamines, antipyretics and acyclovir.

Alemtuzumab was started in adults with active disease, defined by clinical or imaging features despite the use of immunomodulating therapies, or having a fast and aggressive course. The variables studied were sex, age, time from diagnosis, expanded disability status scale (EDSS), previous treatment, number of cycles, adverse events (AE) and number of relapses post-treatment (NRPT). Data were collected from medical records and the electronic prescription programme. Effectiveness was evaluated in terms of NRPT with alemtuzumab. Safety was assessed by reported treatment of AE.

Results Eleven patients, 63.6% women, mean age 38 (24–54) years, were included. Median time from RRMS diagnosis was 10 (4–20) years and mean baseline EDSS was 3.5 (2–5.5).

Patients were previously treated with a median of 3 (2–4) drugs: interferon beta-1a (IFNβ-1a) intramuscularly (45.5%), IFNβ-1a subcutaneously (27.3%), glatiramer acetate (27.3%), natalizumab (90.9%), fingolimod (27.3%) and dimethyl fumarate (18.2%). Seven patients completed two courses of alemtuzumab, and the second course is pending in three patients. One administration was suspended due to an infusion related reaction (IRR), requiring intensive care. The mean relapse rate was 0.36 (0–2). All patients experienced IRRs: lymphopenia (63.6%) and skin disorders (72.7%). Most were mild and limited in time, except for one patient with skin rash, pruritus and oedema, requiring discontinuation of treatment. Other AE were urinary tract infection (18.2%) and herpes zoster infections (9.1%).

Conclusion and relevance According to our results, alemtuzumab was effective in clinical practice due to a low relapse rate. However, further studies with a larger number of patients are needed to confirm these results. IRRs were frequent. Nevertheless, AE were mild and well tolerated.

References and/or acknowledgements None.

No conflict of interest.