Sirolimus for Graves' Orbitopathy (GO)

Graves\' Orbitopathy (GO) is a disabling and disfiguring condition associated with Graves\' Disease, due to autoimmunity against antigens expressed by the thyroid and orbital tissues, and resulting in orbital fibroblast proliferation and release of glycosaminoglycans. The current treatments available, especially glucocorticoids, are not effective in all patients. Two cases of patients with GO treated with Sirolimus have been reported with an excellent response to the drug. The rationale for the use of Sirolimus lies in its mechanisms of action. Sirolimus is able to inhibit T-cell activation as well as fibroblast proliferation. In addition, acts indirectly on the Insulin-Like Growth Factor-1 (IGF-1) pathway, and recent clinical trials have shown that a monoclonal antibody against the IGF-1 receptor (Teprotumumab) is effective in patients with GO. Thus, Sirolimus could be used in GO as monotherapy in patients with GO. The aim of the present drug vs standard treatment, open-label, randomized clinical trial is to evaluate the efficacy of Sirolimus in patients with moderately severe, active GO. 54 patients (27 per group) will be randomized into two groups, A and B. Patients in group A will receive Sirolimus for 12 weeks. Patients in group B will receive methylprendnisolone for 12 weeks. The primary objective of the study is the response of GO at 24 weeks based on a composite evaluation. The secondary Objectives will be: 1) the response of of GO at 12, 36 and 48 weeks; 2) Relapse of GO at 36 and 48 weeks (worsening compared with the 24-week evaluation); 3) The reduction of proptosis at 12, 24, 36 and 48 weeks (proportion of patients with a reduction of proptosis of at least 2 mm); 4) Reduction of the GO clinical activity score (CAS) at 12, 24, 36 and 48 weeks; 5) Quality of life (Qol) at 12, 24, 36 and 48 weeks. The safety objectives will be adverse events, adverse drug reactions, unexpected adverse reaction, suspected unexpected adverse reactions and death, across the study and at 12, 24, 36 and 48 weeks.