INTRAVENOUS VERSUS SUBCUTANEOUS TOCILIZUMAB IN A SERIES OF 471 PATIENTS WITH GIANT CELL ARTERITIS

BackgroundTocilizumab (TCZ) has shown efficacy in large-vessel vasculitis, including Giant Cell Arteritis (GCA) (1-3). Clinical trials with TCZ in GCA was performed with intravenous (iv) TCZ in a phase 2 trial (3), and with subcutaneous (sc) TCZ in the phase 3 GiACTA (4). However, in GCA there are no studies comparing IV vs SC TCZ.ObjectivesTo compare the efficacy of TCZ in GCA patients according to the route of administration IV-TCZ vs SC-TCZ.MethodsMulticentre study of 471 patients diagnosed with GCA and treated with TCZ. They were divided into 2 groups according to the route of administration: a) IV, and b) SC. GCA was diagnosed by: a) ACR criteria, and/or b) temporal artery biopsy, and/or c) imaging techniques. Sustained remission was established according to EULAR definitions (5).ResultsWe studied 471 patients (mean age, 74±9 years) treated with TCZ, 238 with IV-TCZ and 233 with SC-TCZ (Table 1). The time between diagnosis of GCA and TCZ onset was shorter in the SC TCZ group. Regarding acute phase reactants at the beginning of TCZ, no differences were found between both groups. There were no significant differences in sustained remission or in glucocorticoid-sparing effect of TCZ (Figure 1). Patients on IV TCZ treatment suffered more relevant adverse effects during follow-up.Table 1.Main characteristics of GCA patients treated with intravenous and subcutaneous tocilizumabIV TCZ (n= 238)SC TCZ (n=233)PBaseline characteristics at TCZ onsetAge(years), mean±SD73.3±8.773.7±9.30.63Sex, female/male (% female)175/63 (73)167/66 (72)0.65Time from GCA diagnosis to TCZ onset (months), median [IQR]8 [3-23.5]5 [2-15]0.016ESR, mm 1st hour, median [IQR]30.5 [12.5-53]28 [10-56.5]0.66CRP, mg/dL, median [IQR]1.4 [0.5-2.8]1.4 [0.4-4]0.92Prednisone dose, mg/day, median [IQR]20 [10-40]20 [10-36.2]0.69Safety after TCZ onsetFollow-up, (months), median [IQR]27 [16-44]14 [6-26.7]<0.001Relevant adverse events, n (%)80 (34)46 (19)<0.001Relevant adverse events per 100 patients-year12.715.2NSSerious infections, n (%)44 (18)21 (9)0.44Serious infections per 100 patients-year6.77.2NSMACEs, n (%)/1 (0.4)0 (0)-MACEs per 100 patients-year0.10NSMalignancies, n (%)4 (1.7)1 (0.4)0.20Malignancies per 100 patients-year0.60.3NSAbbreviations: CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; GCA: giant cell arteritis; IQR: interquartile range; IV: intravenous; MACEs: major adverse cardiovascular events; NS: non significant; SC: subcutaneous; SD: standard deviationConclusionIn GCA, TCZ seems equally effective and safe regardless of the route of administration IV or SC.References[1]Calderón-Goercke M, et al. Semin Arthritis Rheum. 2019; 49: 126-135. PMID: 30655091[2]Prieto-Peña D, et al. Ther Adv Musculoskelet Dis. 2021; 13: 1759720X211020917. PMID: 34211589[3]Villiger PM, et al. Lancet. 2016; 387:1921-1927. PMID: 26952547[4]Stone JH, et al. N Engl J Med. 2017; 377:317-328. PMID: 28745999Hellmich B, et al. Ann Rheum Dis. 2020; 79: 19-30. PMID: 31270110Disclosure of InterestsNone declared