BackgroundTreatment with tocilizumab has been associated with an increase in transaminase levels which may be related to treatment discontinuation.PurposeTo examine changes of transaminase levels (AST/ALT) in patients with rheumatic diseases treated with tocilizumab, as well as analyse the checking interventions.Material and methodsRetrospective observational study. Patients on treatment with tocilizumab between January 2007 and July 2014 were included. The data collected were: demographic, diagnosis, duration and dosage pattern of treatment, AST/ALT levels and concomitant treatment with methotrexate. The data were collected through outpatient electronic medical records.ResultsWe included 21 patients (86% male, 45.6 ± 13.8 years). 71% of patients had rheumatoid arthritis. The mean treatment duration was 24.4 ± 15.8 months. After the start of treatment with tocilizumab, 52% patients had values above the upper limit of normality (ULN, ALT > 50 U/L and AST > 40 U/L); 36% of them received methotrexate. In 9 patients (82%) the results reached values 1–3 times >ULN and in 2 patients (18%) values were observed 3–5 times >ULN. In 64% of patients the levels remained >ULN during treatment. Higher ALT/AST levels occurred in two patients who received doses of 8 mg/kg of tocilizumab. One of them was also on methotrexate treatment.The increase of AST/ALT levels occurred in 73% of patients between the first and third doses of treatment. In 3 patients a pharmacological intervention was made. The interventions were to decrease the tocilizumab dose (2 patients) and to decrease both the dose of tocilizumab and methotrexate.1 Two of them succeeded in normalising AST/ALT levels.ConclusionHalf of the patients treated with tocilizumab suffer an increase in AST/ALT levels, which in most cases is maintained over time. Concomitant treatment with methotrexate seems to predispose to an earlier increase of transaminase levels.Tocilizumab risk management should include continuous monitoring of transaminase levels so as to identify patients with a higher risk.ReferencesRheumatology (Oxford) 2012;51(Suppl 5):v38–47Reumatol Clin 2014;10(2):94–100Adherencia Paciente Prefiero 2013;7:653–66No conflict of interest.

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