Endocrine Abstracts

Objectives: Alemtuzumab, a monoclonal antibody against CD52, is used in the treatment of multiple sclerosis. A side effect to the treatment is development of autoimmune thyroid disease. The aim was to evaluate the rate, type and course of thyroid disease in Danish patients with multiple sclerosis (MS) previously treated with Alemtuzumab.

Methods: The study was a retrospective cohort study of patients treated with first series of alemtuzumab for multiple sclerosis (MS) in the Capital and Zealand regions (population: 2.6 million) of Denmark between 2014 and 2018 (n=60). The following data was collected from patient records: known previous thyroid disease, date of first series of alemtuzumab, onset date of thyroid dysfunction, blood sample result of thyroid hormones and thyroid antibodies and thyroid scintigraphy and ultrasound to determine type of thyroid disease, type of treatment, duration and course of thyroid dysfunction.

Results: The follow-up period was median 58.5 months (31-83, range). Thyroid disease occurred in 24 of the 60 patients (40 %), with a median onset at 24 months after the first alemtuzumab treatment (1-63, range). Graves’ disease (GD) occurred in 18 of 60 patients (30 %) and three of these also had silent or postpartum thyroiditis with undetectable thyroid receptor antibodies (TRAB) before onset or after remission of GD. Isolated silent or subacute thyroiditis occurred in two of 60 patients (3 %), unclassified hyperthyroidism (due to lack of information) in two of 60 patients (3%) and toxic multinodular goitre also in two of 60 patients (3%).

An unusual or unpredictable course of GD was observed in 12 patients, with a rapid change in serum hormone concentrations unrelated to changes in medication, e.g. sudden changes from hyperthyroidism to hypothyroidism, being the most common. Some of these patients were treated with antithyroid hormone or thyroxine titration regimen, while others were switched to block and replace treatment. Full remission of GD, defined as undetectable TRAB, was at the time of data collection only seen in four patients.

Conclusion: Data from this Danish population was in accordance with recent published studies and supports previous observations of both unusual, long-lasting and unpredictable courses of GD in a subgroup of patients. Hypothetically, some of these may benefit from block and replace treatment, to stabilize an otherwise clinically inappropriate fluctuating GD.