Temporal clinical and laboratory response to interleukin-6 receptor blockade with Tocilizumab in 89 hospitalized patients with COVID-19 pneumonia

Abstract: Background:. Emerging evidence links morbidity and mortality of pandemic COVID-19 pneumonia to an inflammatory cytokine storm. Methods: Eighty nine patients with COVID-19 pneumonia and heightened systemic inflammation (elevated serum C reactive protein and interleukin-6 levels) were treated with Tocilizumab (TCZ), a human monoclonal IgG1 antibody to the interleukin-6 receptor. Results: Clinical and laboratory improvement was seen comparing baseline and 1-2 day post-infusion indices. Among 72 patients not receiving mechanical ventilation, NEWS2 scores fell from 5 to 2 (p 30 mg/L) and low lymphocyte counts (<1000/uL) before TCZ administration. Conclusions: Inflammation and lymphocytopenia are linked to mortality in COVID-19. Inhibition of IL-6 activity by administration of Tocilizumab, an anti IL-6 receptor antibody is associated with rapid improvement in both CRP and lymphocyte counts and in clinical indices. Controlled clinical trials are needed to confirm the utility of IL-6 blockade in this setting. Additional interventions will be needed for patients requiring mechanical ventilation.