EFFECTIVENESS OF SUBCUTANEOUS ANTI-INTERLEUCINE 6 TREATMENT IN PATIENTS WITH ACTIVE MODERATE-SEVERE GRAVES' ORBITOPATHY REFRACTORY TO CONVENTIONAL THERAPY.

Background: Graves’ Orbitopathy (OG) is the main extrathyroid manifestation of Graves’ disease (GD). Up to 25% of patients have moderate-severe inflammatory activity with a risk of major sequelae. Intravenous (i.v.) glucocorticoids (GC) pulses are the standard therapy. In refractory cases, several classic and some biological immunosuppressantsare used, obtaining variable responses. Interleukin 6 (IL6) is involved in the pathogenesis of OG, which has justified the off-label treatment with Tocilizumab (TCZ)1, whose use by route i.v. has shown favorable results in published small case series and a single multicenter trial2. Objectives: To analyse the ocular effectiveness of anti-IL6 therapy used subcutaneously (s.c.) in patients with moderate-severe active refractory OG in usual clinical practice. Methods: Retrospective descriptive observational study of a series of cases of moderate-severe OG patients treated with anti-IL6 s.c. The patient medical records of those who had received at least 1 cycle of anti-IL6 treatment were reviewed (December 2013-December 2019). The primary effectiveness outcome was the change of the Clinical Activity Score (CAS). Favorable response was considered: reduction of CAS≥2 points together with obtaining inactivity (CAS Results: 12 of the 15 patients (80%) were women with a mean of 50.27 years (21-72). 60% (n=9) had smoking history, 40% (n=6) active. 26.7% (n=4) were diabetic, all without retinopathy. 100% of patients received imidazole antithyroid treatment. 46.7% (n=7) required β-blockers and 20% (n=3) diuretics. 66.7% thyroidectomy (n=10) and 20% (n=3) decompressive eye surgery and/or blepharoplasty were performed. Thyroid and ocular radiotherapy were used in 2 patients. 3 patients received botox. 80% (n=12) of them had previously received GC. 93.3% (n=14) were naive to biological therapy, only 1 patient previously used Rituximab. All except one patient who was treated with SRL received TCZ as IL6 therapy. A significant favorable response was obtained in 100% of the patients (p=0.008), decreasing CAS average from 4.9 (2-7) to 1.7 (0-2) at the end of the therapy [Figure 1]. The severity of the OG changed from being moderate in 72.7% of the patients to mild in 66.7% of the total. The median time to inactivity was 8 months (2-15). 73.3% (n=11) of the patients finished the treatment reaching inactive OG, the rest (although inactive) maintained therapy. After 6 months, 100% of those who completed the treatment remained inactive with average CAS of 1.3 (0-2). Smoking did not influence the response, nor any other variable collected. Adverse events appeared in 26.7% (n=4) of the cases, all of them mild and without widrawal. Conclusion: Treatment with anti-IL6 s.c. steadily decreases the clinical activity measured by CAS in patients with moderate-severe refractory OG, despite poor prognosis factors (such as smoking), with a good safety profile. References: [1]Taylor PN, Zhang L, Lee RWJ, Muller I, Ezra DG, Dayan CM, et al. New insights into the pathogenesis and nonsurgical management of Graves’ orbitopathy. Nat Rev Endocrinol. 2020 Feb;16(2):104-116. [2]Perez-Moreiras JV, Gomez-Reino JJ, Maneiro JR, Perez-Pampin E, Romo Lopez A, Rodriguez Alvarez FM, et al. Efficacy of Tocilizumab in Patients With Moderate-to-Severe Corticosteroid-Resistant Gravesˊ Orbitopathy: A Randomized Clinical Trial. Am J Ophthalmol. 2018;195:181–90. Disclosure of Interests: None declared