On Mar. 18, 2020, Mateon Therapeutics reported significant progress in deploying its phase 3 clinical asset, OT-101, against coronavirus. In an in vitro antiviral testing performed by an independent laboratory, OT-101 has an 50% effective concentration (EC50) of 7.6 ﾵg/mL and is not toxic at the highest dose of 1000 ﾵg/mL giving a safety index (SI) value of >130, which is considered highly active.

Mateon intends to work with the FDA to permit OT-101 to enter into clinical testing against COVID-19 as soon as preclinical testing is completed.