Antiviral in Development for COVID-19 and HCV Treatment

Antiviral therapies will continue to play a significant role in infectious disease. A new investigational antiviral, bemnifosbuvir (BEM, AT-527), is currently in phase 3 development for COVID-19 and phase 2 development for hepatitis C (HCV) in combination with ruzasvir (an oral NS5A inhibitor).

Bemnifosbuvir was developed by Boston-based Atea Pharmaceuticals and has a novel approach with a dual-targeting mechanism of action designed to be less prone to develop resistance.

At the International Conference on Antiviral Research (ICAR 2023) that took place back in March, the company presented data from its phase 1 human absorption, distribution, metabolism, and excretion (ADME) study for bemnifosbuvir demonstrating a favorable profile supportive of the dosing regimen used in SUNRISE-3, a global, multicenter phase 3 registrational trial for the treatment of COVID-19.

In vitro metabolism and transporter interaction studies showed bemnifosbuvir had a low risk for interactions with medicines commonly prescribed to patients at risk for COVID-19 progression and for those with HCV infection.

In addition, in vitro studies also demonstrated advantages of bemnifosbuvir’s mechanism of action, which targets conserved regions of the viruses that cause COVID-19 and HCV infection. These advantages include a higher barrier to resistance and maintenance of antiviral activity in the presence of COVID-19 variants.

Looking at HCV treatment, the combination of bemnifosbuvir and ruzasvir demonstrated potent in vitro synergistic antiviral activity and in vivo preclinical safety without adverse interactions.

“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, lead investigator, Architecture et Fonction des Macromolécules Biologiques, CNRS and Aix-Marseille University, stated.

Contagion spoke to Canard and Jean-Pierre Sommadossi, PhD, founder, chairman and CEO of Atea about the investigational therapy’s novel mechanism of action, findings from its clinical trials, and when it expects to report new data.