While phase II and III trials indicate that teprotumumab therapy can significantly reduce proptosis and Clinical Activity Score (CAS) in patients with recent-onset (< 8 months), untreated TED (except for steroid therapy > 6 months prior), data are lacking on the effects of teprotumumab treatment in patients with longer-standing disease (>8 months) or disease that is refractory to orbital radiotherapy (OR). For a small case series, five patients with TED of 11 months or longer duration, including two with previous OR, were treated with an eight-dose, 24-week course of teprotumumab. Each of the five patients experienced a reduction in proptosis of at least 2 mm in each eye, as well as an improvement in CAS of more than 2. All patients with baseline diplopia improved by at least one grade on the Gorman diplopia score, and all but one eye with lagophthalmos improved or resolved. Only three patients reported self-limited, mild adverse events. “These observations support the early data that teprotumumab may be safe and efficacious for those with TED or longer duration than studies in previous clinical trials, and in those who have undergone prior OR,” wrote the study authors.