Bcr-Abl tyrosine kinase inhibitor imatinib as a potential drug for COVID-19

The rapid geographic expansion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the infectious agent of Coronavirus Disease 2019 (COVID-19) pandemic, poses an immediate need for potent drugs. Enveloped viruses infect the host cell by cellular membrane fusion, a crucial mechanism required for virus replication. The SARS-CoV-2 spike glycoprotein, due to its primary interaction with the human angiotensin-converting enzyme 2 (ACE2) cell-surface receptor, is considered as a potential target for drug development. Based on in silico screening followed by in vitro studies, here we report that the existing FDA-approved Bcr-Abl tyrosine kinase inhibitor, imatinib, inhibits SARS-CoV-2 with an IC50 of 130 nM. We provide evidence that although imatinib binds to the receptor-binding domain (RBD) of SARS-CoV-2 spike protein with an affinity at micromolar, i.e., 2.32 {+/-} 0.9 M levels, imatinib does not directly inhibit the spike RBD:ACE2 interaction - suggesting a Bcr-Abl kinase-mediated fusion inhibition mechanism is responsible for the inhibitory action. We also show that imatinib inhibits other coronaviruses, SARS-CoV, and MERS-CoV via fusion inhibition. Based on promising in vitro results, we propose the Abl tyrosine kinase inhibitor (ATKI), imatinib, to be a viable repurposable drug against COVID-19.