Atea-Roche COVID antiviral disappoints in trial

Oct. 19, 2021

Atea Pharmaceuticals and Roche announced that a phase 2 trial of their promising oral antiviral for COVID-19 failed to meet the primary endpoint in the overall study population.

The partners are jointly developing an oral direct-acting antiviral, AT-527, for the treatment of COVID-19. But the global phase 2 MOONSONG trial evaluating AT-527 in the outpatient setting failed to reduce the amount of SARS-CoV-2 virus in patients with mild or moderate COVID-19 compared to placebo in the overall study population — of which approximately two-thirds of patients were low-risk with mild symptoms.

Optimism in the antiviral space had been high following the news that Merck (MSD) and Ridgeback Biotherapeutics submitted an Emergency Use Authorization application to the U.S. FDA for molnupiravir, their investigational oral antiviral medicine for the treatment of mild-to-moderate COVID-19 — just 10 days after posting positive phase 3 data. The submission was based on positive results from a planned interim analysis from the MOVe-OUT clinical trial, which found that molnupiravir reduced the risk of hospitalization or death by approximately 50% in at-risk, non-hospitalized adult patients with mild-to-moderate COVID.

There was some good news for Atea and Roche: In high-risk patients with underlying health conditions, a reduction of viral load at day 7, as compared to the placebo, was observed.

Now, the partners are "assessing potential modifications to the phase 3 MORNINGSKY protocol that may likely lead to improved clinical outcomes." The reassessment, however, will push the timeline back a full year, to the second half of 2022.