MANAGEMENT OF ENDOCRINE DISEASE: Rituximab therapy for Graves' orbitopathy - lessons from randomized control trials.

Rituximab (RTX) use in open-label series has been associated with very encouraging responses in patients with active and moderate-to-severe Graves' orbitopathy (GO). Recently, randomized controlled trials of RTX have been performed in such patients to answer the question of clinical efficacy and the safety profile of this agent. That data, reported separately, focused on Clinical Activity Score (CAS) and indicated in one trial a strong benefit of RTX in comparison with IV glucocorticoids, whereas the other trial noted the absence of a benefit by comparison with placebo. The outcome was reanalyzed post hoc here, using EUGOGO criteria, and the results were not significantly different. The authors comment further on the differences between the two trials regarding populations treated, methodology, analysis of outcomes and the adverse effect profile of RTX. The populations treated appear different with younger patients, lower TRAb and shorter duration of disease prevalent in the Italian trial, all elements favoring a better response. Smoking, usually diminishing a response, was also more prevalent in some patients. The combined outcome proposed by EUGOGO revealed similar results with CAS regarding RTX efficacy; yet, it might be a more comprehensive outcome. The adverse events of concern relate mainly to the risk of DON, which seems to be increased by the use of RTX in a certain subset of patients. Based on available data, a multicenter trial using the EUGOGO-proposed outcomes might be the next best step to define the role of RTX in GO therapy.