How did alemtuzumab fare in real clinical practice?

Mechanism of action of alemtuzumab

Alemtuzumab is a humanized monoclonal antibody used in the treatment of relapsing-remitting multiple sclerosis (RRMS). It binds to CD52, a surface antigen present on T (CD3⁺) and B (CD19⁺) lymphocytes and to a lesser extent on NK cells, monocytes, and macrophages. Alemtuzumab acts through antibody-dependent cellular cytolysis and complement-mediated lysis upon binding to the surface of T and B lymphocytes. The reduction in circulating B and T cells, followed by repopulation, can lower the risk of MS relapses, ultimately delaying disease progression. According to clinical studies, alemtuzumab reduces the number of relapses, slows brain atrophy, neurological disability progression, and changes seen on MRI.

Study methodology and results

The retrospective observational study from real clinical practice included 60 patients with RRMS. All had been treated with at least 2 other disease-modifying drugs (DMDs) before alemtuzumab. Clinical assessments were based on medical records. The mean age of patients at the time of the first infusion was 45 years, with women comprising 78% of the cohort, and the mean disease duration among these patients was 8 years. The median Expanded Disability Status Scale (EDSS) score was 2.5.

The occurrence and frequency of adverse effects were consistent with data from clinical trials. The mean follow-up period for patients on therapy was 2.6 years. During this time, there was even a small but significant reduction in neurological disability among patients. After 2 years of follow-up, 61% of patients met the criteria for no evidence of disease activity (NEDA-3), meaning they did not experience relapses, EDSS progression, or MRI activity.

Conclusion

At present, alemtuzumab is considered a highly effective treatment option for RRMS. Data from clinical studies were very promising. The effectiveness of alemtuzumab was subsequently confirmed through observations from real clinical practice, even in patients for whom other highly effective treatments, including therapies targeting the CD20 molecule, had failed.

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Source: Herman J. A., Khalighinejad F., York K. et al. A real-world cohort analysis of alemtuzumab outcomes in relapsing multiple sclerosis. Mult Scler Relat Disord 2021 Jan; 47: 102619, doi: 10.1016/j.msard.2020.102619.