Sorrento's COVID-19 Main Protease Inhibitor Neutralizes Omicron

Sorrento Therapeutics Inc's SRNE late-stage preclinical Mpro inhibitor, STI-1558, effectively inhibits omicron virus entry and replication in cell-based assays.

• In VeroE6 cells challenged with omicron variant, STI-1558 alone (without efflux inhibitor) showed significant antiviral activity with an EC50 value of 360 nM, equivalent to that seen against the Delta variant (EC50 value, 370 nM). 
• Related: Sorrento Therapeutics' COVID-19 Antibody Works Against Omicron Variant.
• In an omicron S protein-mediated pseudovirus entry assay, STI-1558 effectively inhibited pseudovirus entry into cells, whereas EUA-approved Pfizer Inc's PFE nirmatrelvir (Paxlovid) showed no inhibition. 
• STI-1558 showed improved human liver metabolic stability compared to nirmatrelvir, and its oral bioavailability does not depend on the ritonavir co-administration. 
• Without the need to co-administer Ritonavir, STI-1558 potentially avoids significant adverse drug-drug interactions.
• Price Action: SRNE shares are down 0.35% at $2.87 during the market session on the last check Friday.