Use of Janus kinase inhibitors in COVID-19: a prospective observational series in 522 individuals

Janus kinase (JAK) inhibitors for the treatment of hospitalised patients with COVID-19 have been extensively studied. Initially, at the start of the pandemic outside of China, baricitinib was shown using artificial intelligence to have a potential dual anticytokine and antiviral effect, computer predictions that were then supported by mechanistic data.1–3 This included kinase assays demonstrating inhibition of host numb-associated kinases, notably AP-2-associated protein kinase 1 (AAK1) and cyclin G-associated kinase (GAK), responsible for activating protein-1 (AP-1)-mediated viral propagation and super-resolution microscopy which showed inhibition of SARS-CoV-2 entry into primary human liver spheroids.4 Based on double-blind randomised data from the Adaptive COVID-19 Treatment Trial-II (ACTT-II) under the National Institutes of Allergy and Infectious Diseases,5 it received an Emergency Use Authorisation from the United States Food and Drug Administration in November 2020, in combination with remdesevir for the treatment of hospitalised individuals with COVID-19...