By Michael Dabaie

Atea Pharmaceuticals Inc. said the Phase 2 Moonsong trial evaluating AT-527 didn't meet the primary endpoint in the overall population of patients with mild or moderate Covid-19, who were mostly low-risk with mild symptoms.

The company said the study didn't meet the primary endpoint of reduction from baseline in the amount of SARS-CoV-2 virus in patients with mild or moderate Covid-19 compared with a placebo in the overall study population. About two thirds of patients were low-risk with mild symptoms.

However, it said that in high-risk patients with underlying health conditions, a reduction of viral load of about 0.5 log(10) at day 7 was observed at 550 mg for the prespecified subgroup analysis and 1,100 mg BID for the exploratory subgroup analysis compared with placebo.

Atea and its partner Roche Holding AG are assessing potential modifications to the global Phase 3 Morningsky trial including the trial's primary endpoint and patient population.

As a result, the company said it now anticipates Phase 3 Morningsky data in the second half of 2022.

"The primary endpoint was not achieved in the overall study population in patients with mild or moderate Covid-19, however, Moonsong topline data suggest that AT-527 has antiviral activity in high-risk patients with underlying health conditions as we previously reported in the Phase 2 hospitalized study," Atea Chief Executive Jean-Pierre Sommadossi said.

Atea and Roche are jointly developing AT-527 as an oral direct-acting antiviral for the treatment of Covid-19.

Write to Michael Dabaie at michael.dabaie@wsj.com

(END) Dow Jones Newswires

10-19-21 0751ET