The effect of tocilizumab on cytokine release syndrome in COVID-19 patients

Abstract

Background: This study was aimed to assess the efficacy and safety of tocilizumab (TCZ) and to investigate the factors related to the progress and mortality of patients with a secondary cytokine release syndrome caused by SARS-CoV-2.

Methods: A retrospective descriptive observational study of hospitalised patients with a positive polymerase chain reaction (PCR) result for SARS-CoV-2 and whose clinical evolution required the administration of one or more doses of TCZ was conducted. Demographic variables, clinical evolution, radiologic progress and analytical parameters were analysed on days 1, 3 and 5 after administration the first dose of TCZ.

Results: A total of 75 patients with a clinical history of Accurate Respiratory Distress Syndrome (ARDS) were analysed, among whom, 19 had mild ARDS (25.3%), 37 moderate ARDS (49.4%) and 19 severe ARDS (25.3%). Lymphocytopenia and high levels of PCR, D-Dimer and IL-6 were observed in almost all the patients (91.8%). Treatment with TCZ was associated with a reduction of lymphocytopenia, C-reactive protein (CRP) levels, severe ARDS cases and fever. Although a better evolution of PaO₂/FiO₂ was observed in patients who received two or more doses of TCZ (38/75), there was an increase in their mortality (47.4%) and ICU admission (86.8%). The 30-day mortality rate was 30.7% (20.5-42.4% CI) being hypertension, high initial D-dimer levels and ICU admission the only predictive factors found.

Conclusion: Based on our results, treatment with TCZ was associated with a fever, swelling and ventilator support improvement. However, there is no evidence that the administration of two or more doses of TCZ was related to a mortality decrease.

Keywords: Cytokine release syndrome; IL-6; SARS-CoV-2; Tocilizumab.