Editorial: Tocilizumab, a Humanized Therapeutic IL-6 Receptor (IL-6R) Monoclonal Antibody, and Future Combination Therapies for Severe COVID-19.

Vaccinated, non-vaccinated, and immunosuppressed individuals will continue to be infected with SARS-CoV-2. Therefore, there is a priority to develop treatments that reduce the severity of COVID-19 in patients who require hospital admission. Interleukin-6 (IL-6) is a proinflammatory cytokine. In 2011, a humanized monoclonal antibody to the IL-6 receptor (IL-6R), tocilizumab, was approved by the US Food and Drug Administration (FDA) for the treatment of rheumatoid arthritis, juvenile idiopathic arthritis, giant cell arteritis, and Castleman's disease. In 2017, tocilizumab was approved to treat chimeric antigen receptor (CAR) T-cell therapy-induced cytokine release syndrome (CRS). In 2021, the results of the REMAP-CAP clinical trial (NCT02735707) and the COVID-19 Therapy (RECOVERY) clinical trial (NCT04381936) supported FDA Emergency Use Authorization (EUA) for tocilizumab to treat hospitalized patients with moderate and severe COVID-19. Monoclonal antibodies are currently in clinical development or undergoing clinical trials to treat COVID-19. Further clinical trials will provide safety and efficacy data on targeting IL-6 and IL-6R and provide rationales for more personalized combination treatments to control the systemic effects of SARS-CoV-2 infection in hospitalized patients with moderate and severe COVID-19. This Editorial aims to present the background to the recent authorization of tocilizumab, a humanized therapeutic monoclonal antibody to the IL-6 receptor (IL-6R), for hospitalized patients with moderate and severe COVID-19 and future combination therapies.