Graves' disease induced by Alemtuzumab in relapsing-remitting multiple sclerosis patients: an observational study in a reference center.

OBJECTIVES: Graves' disease induced by Alemtuzumab (GD-IA) is one of the most frequently observed adverse events in patients with multiple sclerosis (MS) treated with this drug. The aim of this study is the sequencing and description of these events, along with the identification of the risk factors leading to their development. MATERIALS AND METHODS: We conducted a retrospective observational study identifying patients with relapsing-remitting multiple sclerosis (RRMS) and GD-IA, studying their baseline clinical features and variables related to the natural history of the disease. RESULTS: A total of 121 participants treated with Alemtuzumab were included, of whom 41 developed GD-IA (33.9%). A higher percentage of first-degree relatives with autoimmune thyroid disease was documented in the subgroup who developed the abovementioned event (14.6% vs 1.5%; p < 0.01). A total of 70.7% of patients diagnosed with GD-IA (n = 29/41) had fluctuations in thyroid function during follow-up, and 24.4% (n = 10/41) required total thyroidectomy for resolution of the condition. In 54.8% of participants diagnosed with GD-IA, a pattern of significant TSH decline was identified in the month prior to diagnosis of the event, with high predictive ability and associated with a more favorable clinical course (fewer weeks to normalization of thyroid function, HR = 8.99; 95% CI [2.11-38.44]; p = 0.0003). CONCLUSION: GD-IA has an atypical course compared to classical forms of the disease. The identification of risk factors for the development of the disease before starting treatment with Alemtuzumab and early monitoring of thyroid function once this treatment is initiated prove to be useful strategies in the diagnosis and clinical management of this condition.