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AB0534 EFFICACY OF TOCILIZUMAB IN LARGE-VESSEL GIANT CELL ARTERITIS: A SINGLE-CENTER REAL-LIFE EXPERIENCE

Background: In a significant proportion of giant cell arteritis (GCA) patients, large vessels (LV) are affected1. GiACTA trial showed tocilizumab (TCZ) to be effective for the treatment of GCA2 but did not differentiate between patients with and without LV involvement and did not evaluate LV-imaging response. Objectives: To assess efficacy of TCZ in LV-GCA, evaluating both clinical symptoms and vascular inflammation on PET scan. Methods: Data from GCA patients followed-up at our Institution between January 2003 and December 2019 were retrospectively collected. Only TCZ-treated patients, with evidence of LV 18F-FDG-uptake at baseline (T0) and who repeated a PET scan after at least 6 months of treatment (T1) were included. All patients received subcutaneous TCZ 162 mg weekly. PET scans were read by 2 physicians blinded with regard to clinical data and to each other’s assessment; vascular inflammation was quantified using the PETVAS score3. Clinical symptoms, prednisone (PDN) dosage, and PETVAS score between T0 and T1 were compared. Flares and adverse events were recorded. Non parametric tests were used. Results: 61 TCZ-treated GCA patients were identified. Of these, 28 (45.9%) had evidence of vascular inflammation at T0, and 14 of them (10 female, mean age 66.2±7.4 years) repeated a PET scan during follow-up, after a median of 13 months (IQR, 9.5-17.5). 10 patients started TCZ upon GCA relapse, with a median delay from GCA diagnosis of 7.5 (3-15.8) months; 4 patients were newly diagnosed and started TCZ at diagnosis. At T0, 10 patients had systemic symptoms, 6 patients had cranial symptoms, and 7 had polymyalgia rheumatica (PMR). 12/14 patients were on concomitant steroids, with a median PDN daily dose of 15 (15-25) mg. Erythrocyte sedimentation rate and C-reactive protein levels were respectively 35 (21-39) mm/h and 7.8 (3.2-11) mg/L. Median PETVAS was 7 (3.3-11). At T1, 13/14 patients were asymptomatic; 1 patient had a PMR relapse. No GCA flare was recorded. Median PDN daily dose was 1.25 (0-2.5), p=0.002, and PDN suspension was achieved in 5 patients. Median PETVAS was 0 (0-0.8), p=0.003; only in 1 patient PETVAS increased between T0-T1 (from 2 to 5), in absence of clinical symptoms. This was the patient with the longest delay between diagnosis and TCZ start (124 months) and suspended TCZ for 3 months due to oral aphthosis. No patients had severe infections; 1 patient definitively suspended TCZ at T1 due to severe leukopenia. Conclusion: In LV-GCA patients, TCZ seems to be effective in obtaining clinical remission and in reducing vascular inflammation on PET scan. References: [1]Dejaco C, et al. Nature Reviews Rheumatology (2017) [2]Stone JH, et al. N Engl J Med (2017) [3]Grayson PC, et al. Arthritis Rheumatol (2018) Disclosure of Interests: Alessandro Tomelleri: None declared, Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Silvia Sartorelli: None declared, Elena Baldissera Speakers bureau: Novartis, Pfizer, Roche, Alpha Sigma, Sanofi, Lorenzo Dagna Grant/research support from: Abbvie, BMS, Celgene, Janssen, MSD, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, SG, SOBI, Consultant of: Abbvie, Amgen, Biogen, BMS, Celltrion, Novartis, Pfizer, Roche, SG, and SOBI