Background: Alemtuzumab is an anti-CD52 monoclonal antibody used in the treatment of relapsing-remitting multiple sclerosis (MS). Between 20 and 40% of Alemtuzumab-treated MS patients develop autoimmune thyroid disease (AITD) as a side effect. It is currently unknown whether development of AITD correlates with MS disease activity following Alemtuzumab treatment.
Aims: To characterise the types and frequency of AITD that MS patients develop following Alemtuzumab treatment. To determine whether MS disease progression following Alemtuzumab treatment differs in in patients that develop AITD, compared to those who do not.
Methods: A retrospective analysis was performed on all MS patients receiving Alemtuzumab (20122017) at Imperial College Healthcare NHS Trust. Data were collected on patients who did and did not develop AITD following Alemtuzumab including thyroid function, disability outcomes (Expanded Disability Status Scale, EDSS), relapses and new MRI demyelinating lesions.
Results: One-hundred and twenty-six patients were included in the study analysis (33 AITD and 93 non-AITD). Twenty-six percent of Alemtuzumab-treated MS patients developed AITD, 54.5% of which was Graves disease. Patients that developed AITD exhibited a reduction in EDSS score following Alemtuzumab compared to those that did not (median [IQR]; AITD: −0.25 [−1 − 0.5] vs. non-AITD: 0 [1 − 0]. P=0.007). Multivariate regression analysis confirmed that the development of AITD was independently associated with improvement in EDSS score (P=0.011). Moreover, AITD patients had higher relapse-free survival following Alemtuzumab (P=0.023). There was no difference in the number of new MRI lesions developed following Alemtuzumab between the two groups.
Conclusion: Graves disease was the most common form of AITD developed by MS patients following Alemtuzumab. MS patients who develop AITD exhibit a better response to Alemtuzumab, as measured by EDSS score and relapse rate. A large, prospective study to investigate this further is needed.