OBJECTIVES: To assess the effectiveness of the antiinterleukin-6 receptor monoclonal antibody tocilizumab in patients with moderate-to-severe Graves' orbitopathy(GO) in clinical practice.

METHODS: A retrospective observational study of a series of patients with moderate-severe GO on subcutaneous tocilizumab treatment 162mg once a week was performed. Medical records of patients who received tocilizumab between September 2015 and May 2023 were reviewed. Effectiveness was assessed by CAS(Clinical Activity Score) reduction before and after treatment. A reduction of CAS ≥2 points together with obtaining inactivity(CAS < 3) was considered a favourable response. Measurements of proptosis and best-corrected visual acuity(BCVA) were also used to evaluate improvement in GO.

RESULTS: 22 patients were treated with tocilizumab during the study period, 20 women and 2 men, with a mean age of 54 years. 8(36,4%) patients were active smokers, 3(13,6%) ex-smokers and 11(50%) non-smokers. Patients received tocilizumab for a mean of 44,6 weeks (range 4-83 weeks). Of 22 patients, 4(18.2%) are currently on treatment, 4(18,2%) dropped out(one patient due to adverse event) and 14(63,6%) completed treatment until remission. Among those who finished treatment, the median duration was 54,6 weeks(39-83). The mean initial CAS was 4,6/7 and the final CAS was 1,7/10. The CAS score was reduced by a mean of 2,8 points. 21 patients achieved favourable response:2/4 who continued, 3/4 patients who dropped out and 13/14 who finished. Furthermore, 40,5% of treated eyes achieved CAS ≤1(none of the smokers reached it). The mean initial BCVA was 0,76 and the final BCVA was 0,89. Initial exophthalmos mean size was 22,66mm and it was 21,65mm after treatment.

CONCLUSIONS: The efficacy of tocilizumab is excellent in terms of rapid onset of action and ability to reduce severity in GO. Our results are similar to the outcomes of other published studies so it represents a great alternative in moderate-severe patients even in short courses of treatment.