Sorrento Therapeutics (NSDQ:SRNE) revealed that its late-stage preclinical main protease inhibitor STI-1558 inhibited omicron virus entry and replication in cell-based assays.
Prior research indicates that STI-1558 offers broad-spectrum activity against SARS-CoV-2.
STI-1558 is distinct from Pfizer’s SARS-CoV-2 drug Paxlovid (nirmatrelvir), which pairs the SARS-CoV-2-3CL protease inhibitor PF-07321332 with ritonavir, which works as a pharmacokinetic enhancer. Sorrento developed STI-1558 to offer optimized human liver microsomal stability to avoid the need for ritonavir.
The company anticipates that STI-1558 will thus have fewer issues with drug-drug interactions.
Sorrento also noted that STI-1558 inhibited pseudovirus entry into cells in an omicron S protein-mediated pseudovirus entry assay, whereas nirmatrelvir did not.
“With omicron becoming a globally dominant variant of SARS-CoV-2 in such a short period of time, we are focused on develop…