Benzinga | Jan 28, 2022 11:43AM EST

Sorrento's COVID-19 Main Protease Inhibitor Neutralizes Omicron

Sorrento Therapeutics Inc's (NASDAQ: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 (NYSE: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.