A recent study by researchers in non-human primate rhesus monkeys revealed that baricitinib is effective against COVID-19. The hyperactive immune response in COVID-19 involves both innate and adaptive immunity. Chemokines and pro-inflammatory cytokines are seen at high levels. This has promoted the use of Janus-Kinase inhibitors, which inhibit cytokine release via these pathways. Baricitinib is currently being used in moderate to severe rheumatoid arthritis. It almost completely inhibited the expression of inflammatory cytokines and neutrophil chemotactic factors in the lung macrophages of the monkeys within just 48 hours of treatment.
The researchers observed decreased inflammatory markers, cytokines and lung pathology in monkeys. It did not reduce type-1 IFN responses observed by reduced neutrophil infiltration into the lungs and deficient T-cell activation in peripheral blood and the bronchoalveolar lavage post-treatment. Baricitinib also led to increased NETosis (neutrophil extracellular traps). Single-cell RNA sequencing methods revealed a steep decline in immune activation markers, and macrophage trafficking profiles. Baricitinib also achieved sufficient concentrations in CNS and lungs. However, it did not arrest viral replication in infected rhesus monkeys.
Ref link: https://www.biorxiv.org/content/10.1101/2020.09.16.300277v1