Tocilizumab (TCZ) is the only biologic therapy approved for giant cell arteritis (GCA). There is general agreement on the initial/maintenance dose, duration of TCZ therapy is not well established. In GiACTA trial, after one year on TCZ, most patients had GCA relapse after withdrawal. The aim of this study is to assess the effectiveness and safety of TCZ therapy optimisation in a large unselected series of patients with GCA in a clinical practice scenario.

Multicentre study on 471 GCA patients treated with TCZ. Once prolonged remission was achieved (n=231) and based on a decision between patient and physician, TCZ was optimised (n=125). We compared optimised (TCZOPT) and not optimised (TCZNON-OPT) groups. Prolonged remission defined as normalisation of clinical and laboratory data for 6 months. Optimisation was carried out by decreasing TCZ dose and/or increasing dosing interval.

We evaluated 231 GCA patients on TCZ in prolonged remission. At TCZ onset, no differences in demographic, clinical, or laboratory data were observed. First TCZ optimisation was performed after a median follow-up of 12[6-17] months. Intravenous TCZ was optimised from 8 to 4mg/kg/4weeks in 44% patients, while subcutaneous TCZ was optimised from 162mg/w to 162mg/every-other-week in 65% cases. At the end of follow-up, prolonged remission (78.2% vs. 84.2%; p=0.29) and relapses (5.6% vs. 10.4%, p=0.177) were similar in TCZOPT vs. TCZNON-OPT. Severe infections were more frequent in TCZNON-OPT (12.9% vs. 6.6%; p=0.009).

TCZ optimisation may be done once complete remission is achieved by reducing dose or increasing dosing interval. This seems to be effective, safe and cost-effective therapeutic scheme.