Atea Pharmaceuticals has reported positive interim data from the Phase II study where its antiviral drug candidate, AT-527, reduced viral load levels in mild-to-moderate Covid-19 patients in the hospital setting.

Co-developed by Atea and Roche, AT-527 is an oral direct-acting antiviral (DAA) agent.

The global, randomised, double-blind, placebo-controlled, multi-centre Phase II trial is analysing the safety, tolerability, clinical and antiviral efficacy of AT-527 in moderate Covid-19 patients.

Within five days of onset of symptoms, the trial subjects were given a twice-daily dose of either AT-527 550mg or placebo for five days.

The interim analysis included findings from 70 high-risk subjects hospitalised with Covid-19, of which 62 were evaluable for virology assessment.

Data showed that AT-527 quickly decreased viral load levels and subjects in the treatment group had an 80% improved mean reduction from baseline viral load versus placebo at day two.

Furthermore, a sustained difference in a drop in viral load levels was maintained till the eighth day.

Nearly 47% of subjects in the AT-527 group and 22% in the placebo arm showed no detectable ribonucleic acid virus by day 14.

In addition, the oral drug was observed to be safe and well-tolerated, which is in line with earlier studies.

No serious adverse events or new safety risks linked to AT-527 were noted in the trial.

Atea Pharmaceuticals founder and CEO Jean-Pierre Sommadossi said: “We are very pleased with the potent antiviral activity of AT-527 demonstrated by the rapid inhibition of SARS-CoV-2 replication.

“Such potent activity may lead to faster recovery time for patients with Covid-19 while minimising the transmission of infection.”

Atea and Roche are currently studying AT-527 in the Phase III MORNINGSKY trial and Phase II MOONSONG virology study in mild or moderate Covid-19 patients in an outpatient setting.

Multi-cohort data from the MOONSONG study is anticipated in the third quarter of this year.