OP0051 Evolution of the vascular involvement objectified by pet/tac in patients with giant cell arteritis treated with tocilizumab

Background Giant cell arteritis (GCA) is a large-vessel vasculitis which can involve the aorta and/or its major branches. Tocilizumab (TCZ) seems to be effective in giant cell arteritis (GCA).1–4 Objectives Our aim was to assess if the clinical and analytical improvement yielded in patients with GCA treated with TCZ is accompanied by a reduction of the vascular inflammation evaluated by PET/CT. Methods Study of 36 patients who had a baseline and follow-up PET/CT from a multicenter series of 134 patients with GCA in treatment with TCZ. The evolution of the vascular involvement objectified by PET/CT was assessed. In addition clinical efficacy, analytical improvement (acute phase reactants) and the reduction of corticosteroid dose was studied. Results The 36 patients (28 women and 8 men) had an mean age of 69.83±8.66 years. After TCZ onset, a rapid and maintained clinical improvement was observed (table 1). In addition, during the first twenty-four months of follow-up, C-reactive protein decreased from 2.4 [0.9–6.8] to 0.1 [0.0–0.5] mg/dL and the erythrocyte sedimentation rate from 41.5 [16.7–58.5] to 4 [2–12.5] mm/1 st hour. On the other hand, the levels of haemoglobin experienced an increase from 12.3 [11.3–13.0] to 13.3 [13.0–13.9] g/dL. The median dose of prednisone decreased from 12.5 [9.4–26.2] to 0.0 [0.0–0.0] mg/day. However, the decrease in F18-fluordeoxyglucose uptake in the PET/CT study was not as evident. Conclusions Although TCZ seems to be an important therapeutic agent in the treatment of GCA, achieving a rapid and sustained clinical and analytical improvement, the decrease in vessel inflammation assessed by F18-fluordeoxyglucose uptake seems to take a slower course. References [1] Loricera J, et al. Tocilizumab in giant cell arteritis: Multicenter open-label study of 22 patients. Semin Arthritis Rheum2015;44:717–723. [2] Loricera J, et al. Tocilizumab in refractory aortitis: Study on 16 patients and literature review. Clin Exp Rheumatol2014;32(3 Suppl 82):S79–89. [3] Loricera J, et al. Use of positron emission tomography (PET) for the diagnosis of large-vessel vasculitis. Rev Esp Med Nucl Imagen Mol2015;34:372–377. [4] Loricera J, Blanco R, Hernandez JL, et al. Tocilizumab in patients with Takayasu arteritis: A retrospective study and literature review. Clin Exp Rheumatol2016;34(3 Suppl 97):S44–53. Disclosure of Interest None declared