Ruxolitinib, whose commercial name is Jakavi, is a tyrosine kinase inhibitor and more specifically Janus kinase 1 (JAK1) and Janus kinase 2 (JAK2) which are JAK-targeting tyrosine kinases.  Ruxolitinib is used for the treatment of certain myeloproliferative syndromes such as myelofibrosis. It is also used for the treatment of Vaquez disease (essential polyglobulia or polycythemia vera or rubra), characterized by polyglobulia and an increase in total blood cell volume.

The Novartis group, which markets Jakavi, began studying the effects of this drug on Covid-19 caused by SARS-CoV-2. The purpose of this clinical study is to determine whether ruxolitinib could mitigate the potential complications of Covid-19 and involves patients with Covid-19-related cytokine shock. This Phase III clinical study is based on the fact that the JAK-STAT pathway is fundamental to many biological processes related to immunity and inflammation, including the mobilization of a cytokine response.