Background Baseline characteristics of patients from GiACTA trial have been recently reported at the ACR-2016 conference (1). GiACTA trial is a randomized, phase III controlled clinical trial evaluating the efficacy of tocilizumab (TCZ) in giant cell arteritis (GCA) (2). We had previously published a multicenter study on the use of TCZ in refractory GCA in a clinical practice setting (3).
Objectives Our aim was to compare both studies, emphasizing on the baseline characteristics of the patients.
Methods Comparative study between the GiACTA trial and our multicenter clinical practice study. In the latter, the diagnosis of GCA was established by the ACR-1990 criteria and in the GiACTA trial by the ACR modified criteria. In the clinical practice study, TCZ was used at standard IV dose (8 mg/kg/month), while in the GiACTA trial it was given subcutaneously (162 mg every 1 or 2 weeks, depending on the therapeutic arm). Quantitative variables were expressed as mean ± SD and were compared with the Student's t-test. Dichotomous variables were expressed as percentages and compared using the chi-square test.
Results In the GiACTA trial, 47.4% were newly diagnosed GCAs, while in the clinical practice study were all refractory to conventional treatment. The TABLE summarizes the main baseline characteristics of both studies. Compared with the GiACTA trial, in the clinical practice study were significantly greater: a) the mean time between the diagnosis of GCA and the onset of TCZ, b) the proportion of patients with polymyalgia rheumatica and ischemic optic neuritis, c) the proportion of positive PET/CT scans, d) the mean value of ESR, and e) the proportion of patients who had received conventional immunosuppressant agents (mainly MTX) before starting TCZ. There was also a significant lower proportion of sustained remission in the clinical practice study. When only GiACTA patients with relapsing-GCA were analyzed, these differences were maintained, except for the mean time from GCA diagnosis and the prevalence of ischemic optic neuropathy. Data on remissions were not available in this subgroup of GiACTA patients.
Conclusions Patients receiving TCZ in the clinical practice study have several baseline clinical and laboratory differences with regard to those included in the GiACTA trial and, therefore, data of this trial should be taken cautiously when applied in a real-world scenario.
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Tuckwell K et al. Semin Arthritis Rheum. 2016 Nov 15. pii: S0049–0172(16)30275-X.
Loricera J et al. Semin Arthritis Rheum. 2015; 44: 717–23.
Disclosure of Interest None declared
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