Outcomes in patients on alemtuzumab with thyroid adverse events

In alemtuzumab-treated patients from the CARE-MS core and extension trials, the thyroid adverse events (AEs) encountered over 6 years were independently characterised [1]. Graves’ disease was the most common thyroid AE detected in 40% of the patients within 4 years after the last alemtuzumab course. The favourable MS disease outcomes over a 6-year period were however similar in patients with or without thyroid AEs.

An expert panel of 3 independent endocrinologists reviewed all reported thyroid-related laboratory abnormalities and AEs from the CARE-MS trials.

Over 6 years, 378 of 811 (47%) patients treated with alemtuzumab had a laboratory abnormality (n=36) or thyroid AE (n=342; 44 serious). A consensus on thyroid AEs was reached in 292 cases, adjudicated as follows:

• Graves’ disease: 40%;
• Hashimoto’s disease: 17%;
• transient thyroiditis: 8%;
• Graves’ disease switching to hypothyroidism 6%;
• Hashimoto’s disease switching to hyperthyroidism: 3%; and
• uncertain: 2%.

More than 97% of thyroid AEs were detected within 4 years of the last alemtuzumab course; 83% within 2 years. Patients with or without thyroid AEs received similar numbers of alemtuzumab courses. MS disease outcomes were similar in both groups in terms of annualised relapse rate, EDSS score change, brain volume loss, and being disease activity-free on MRI.

Treatment of thyroid AEs consisted of oral thyroid medications in 84%, primarily levothyroxine/levothyroxine sodium (64%) or thiamazole (43%). Another 11% underwent thyroidectomy, 9% had radioiodine therapy. At the most recent follow-up, cases were recovered (53%), ongoing (46%), or unknown (0.3%).

1. Dayan C, et al. Outcomes in Alemtuzumab-Treated Patients With Thyroid Adverse Events: 6-Year Pooled CARE-MS Data. MSVirtual 2020, Abstract P0128.