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Arbutus Presents AB-343 Data at the 36th International Conference on Antiviral Research
Antiviral potency, selectivity and favorable PK support further development of AB-343 as potential ritonavir-free oral treatment for COVID-19 and other human
About this update from Arbutus Biopharma Corporation
[{"type":"text","content":"Antiviral potency, selectivity and favorable PK support further development of AB-343 as potential ritonavir-free oral treatment for COVID-19 and other human coronaviruses WARMINSTER, Pa., March 14, 2023 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS), a clinical-stage biopharmaceutical company leveraging its extensive virology expertise to develop novel therapeutics that target specific viral diseases, today announced that preclinical data for AB-343, our novel oral SARS-CoV-2 Mpro inhibitor, has been presented in poster format at the 36th International Conference on Antiviral Research (ICAR), in Lyon, France. “We are excited that our preclinical data for AB-343 has been selected for poster presentation at ICAR. We developed AB-343, our newly nominated nsp5 main protease inhibitor, because there is an urgent need for oral antiviral therapies that are potent and active against circulating SARS-CoV-2 variants and do not require ritonavir boosting,” said Dr. Michael J. Sofia, Arbutus’ Chief Scientific Officer. “AB-343 has demonstrated these characteristics in preclinical studies. We look forward to completing IND-enabling studies and initiating a Phase 1 clinical trial with AB-343 in the second half of 2023.” The poster, titled “In Vitro Antiviral Profile of AB-343, a Novel, Oral Potent SARS-CoV-2 Mpro Inhibitor with Pan-coronavirus Activity”, provided an overview of several in vitro preclinical studies conducted with AB-343 to determine its antiviral activity, pan-coronavirus activity and in-vitro selectivity profile. Many of the studies compared AB-343 to nirmatrelvir, the active ingredient in Pfizer’s Paxlovid™ and ensitrelvir, the active ingredient in Shionogi’s Xocova®. The results showed that AB-343 targets SARS-CoV-2 Mpro and inhibits viral replication in vitro (EC50 ~ 20nM). Binding of AB-343 to SARS-CoV-2 Mpro resulted in longer residence times (>99 minutes versus 21.5 minutes for nirmatrelvir and 1.1 minutes for ensitrelvir) indicative of excellent target engagement. AB-343 also demonstrated pan-coronavirus inhibition (Ki 5-45 nM) against Mpro enzymes from multiple human coronaviruses. In enzyme assays against previously reported SARS-CoV-2 Mpro variants isolated in cell culture, AB-343 showed a differentiated in vitro resistance profile versus both nirmatrelvir and ensitrelvir, including a lower fold-in...