Long-term tocilizumab therapy in patients with corticosteroid-resistant active moderate-to-severe thyroid eye disease

OBJECTIVE: To evaluate the efficacy of long-term tocilizumab (TCZ) therapy in patients with corticosteroid-resistant moderate-to-severe thyroid eye disease. DESIGN: We conducted a single-center retrospective study involving 26 patients treated with 12 months of TCZ. The primary endpoint was the proportion of patients achieving a clinical activity score (CAS) < 3 six months (M6) after TCZ initiation. Secondary outcomes included measuring changes in proptosis, diplopia, intraocular pressure, and the detection of thyroid-stimulating immunoglobulin at 3-month intervals until M18, compared to baseline. The signal intensity ratio was assessed on T2 fat-saturated sequence magnetic resonance imaging before treatment and M6 after commencing TCZ. RESULTS: At M6, 58% of patients achieved a CAS < 3 (P < .001). The proportion of patients with a CAS < 3 significantly increased, and the median CAS declined from M3 to M18 compared to baseline, as well as from M9 and M12 compared to M6. There was a significant reduction in the proportion of patients experiencing proptosis, diplopia, the median IOP, and the detection of TSI throughout the follow-up period. At M12, 2 patients (7.7%) persisted with a CAS ≥ 3, and 2/24 patients (8.3%) experienced a relapse by M18. Additionally, a significant decrease in both the SIR and the thickness of orbital muscles was observed between M0 and M6. CONCLUSIONS: Six months-TCZ therapy results in control of more than half of patients with corticosteroid-resistant TED and may provide additional improvements beyond M6. MRI might assist in the management of TED.