Intraorbital injection of rituximab: a new approach for active thyroid-associated orbitopathy, a prospective case series

Aim. The aim of this paper was to examine the efficacy and the safety of intraorbital administration of the monoclonal anti-CD20 antibody rituximab (RTX) to treat patients affected by thyroid-associated orbitopathy (TAO) unresponsive to conventional therapy. Methods. Five patients with active moderately-severe TAO unresponsive to systemic glucocorticoids were studied. After a complete ophthalmological examination, disease activity and severity were assessed by the clinical activity score (CAS) and the NO SPECS scoring system. Computed tomography scans were performed in all patients. Patients were treated with intraorbital injection of RTX 10 mg once a week for one month repeated once one month apart. The patients were followed every three months until 18 months. Results. In all patients treated with RTX, CAS was significantly reduced (p< 0,005), inactive phase of TAO was reached in four out of five patients. No patients experienced major side effects, minor side effects were reported in two patients. Conclusion. Intraorbital injection of RTX is a safe and useful promising therapeutic option for active TAO.