Ascletis Pharma has reported that its oral small molecule drug candidate ASC11 showed potential for the treatment of Covid-19.
Discovered in-house using various technologies of the company, including molecular docking, ASC11 is an inhibitor of 3-chymotrypsin like protease (3CLpro) with worldwide intellectual property rights.
The company plans to submit the Investigational New Drug application for ASC11 in the second half of this year and conclude a Phase I clinical trial in healthy participants by the end of the year.
ASC11 demonstrated an antiviral potency (EC₉₀) 31-fold to that of Nirmatrelvir, 120-fold to S-217622, 16-fold and seven-fold to that of PBI-0451 and EDP-235, respectively, in antiviral cellular assays with infectious SARS-CoV-2.
Furthermore, the 3CLpro inhibitor was found to retain activity against various variants of the SARS-CoV-2 virus.
Molecular docking revealed that ASC11 formed robust hydrogen bond interaction with 3CLpro’s Glutamic acid 166, made new hydrogen bonds with other vital amino acids of 3CLpro and attached strongly in hydrophobic Pocket 4 of 3CLpro compared to Nirmatrelvir.
This resulted in an increased antiviral potency (EC₉₀) of ASC11.
In addition, ASC11’s safety window (cytotoxicity versus antiviral potency) was over 10,000-fold in Vero E6 cells.
Along with other preclinical findings such as in vitro metabolism, microsomal stability, Caco-2 permeability and animal pharmacokinetic studies, ASC11 was found to become a potential antiviral treatment for Covid-19.
Another 3CLpro preclinical candidate of the company also showed antiviral potency and safety window in Vero E6 cells in line with ASC11.
Ascletis founder, chairman and CEO Dr Jinzi Wu said: “We are excited about our oral small molecule preclinical drug candidates for their potential to be best-in-class antiviral treatment of Covid-19.
“These preclinical drug candidates demonstrate our discovery capability as a leading antiviral biotech.”
This January, the company dosed the first subject in the Phase III trial of ASC40 plus bevacizumab for the treatment of recurrent glioblastoma.