Results are Announced for Investigational Antiviral for COVID-19, Hepatitis C Studies

Clinical stage biopharmaceutical company, Atea Pharmaceuticals, announced results from their studies with their investigational antiviral, bemnifosbuvir, for COVID-19 (phase 3 development) and hepatitis C (phase 2 development) in combination with ruzasvir (an oral NS5A inhibitor).

The studies' data demonstrated a favorable profile based upon results from in vitro metabolism and transporter studies. These results were presented at the 2023 International Conference on Antiviral Research (ICAR) that is going on this week in France. Key highlights from the presentations include results from a phase 1 human absorption, distribution, metabolism, and excretion (ADME) study for bemnifosbuvir demonstrating a favorable ADME profile supportive of the dosing regimen used in SUNRISE-3, a global, multicenter registrational trial for the treatment of COVID-19 in non-hospitalized patients at high risk for disease progression.

According to the investigators, bemnifosbuvir retained activity against all SARS-CoV-2 variants of concern evaluated as well as other human coronaviruses such as HCoV-229E, HCoV-OC43, and SARS-CoV-1. A synergistic antiviral effect was observed for the combination of bemnifosbuvir and ruzasvir against hepatitis C (HCV).

“The data presented at ICAR demonstrate bemnifosbuvir’s unique metabolic activation pathway and how it inhibits enzymes essential to the viral replication of COVID-19 and HCV and its potential to play an important role in the treatment of these serious viral diseases,” Bruno Canard, PhD, said in a statement. Canard was the lead investigator of the in vitro studies of bemnifosbuvir conducted at Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille University.

Bemnifosbuvir is an oral, direct-acting antiviral that targets the SARS-CoV-2 RNA polymerase (nsp12), a highly conserved gene that is unlikely to change as the virus mutates and new variants continue to emerge. This gene is responsible for both replication and transcription of SARS-CoV-2. Bemnifosbuvir has a unique mechanism of action, with dual targets consisting of chain termination (RdRp) and nucleotityltransferase (NiRAN) inhibition, which has the potential to create a high barrier to resistance. In vitro data confirm that bemnifosbuvir is active with similar efficacy against all variants of concern and variants of interest that have been tested, including Omicron subvariants BA4 and BA5.

“As COVID-19 becomes endemic, it is essential to have new oral antiviral medicines that are safe, well tolerated and address the current limitations of existing treatments,” Canard said.