Roche has ended its collaboration with Atea Pharmaceuticals for developing a COVID-19 antiviral after the pill disappointed in a mid-stage study.

In late October, the companies announced that their investigational pill, AT-527, failed to meet the primary endpoint of reducing the amount of SARS-CoV-2 virus in patients with mild or moderate COVID-19 vs. placebo in a 100-patient phase 2 trial.

Roche paid Atea $350 million upfront to co-develop the antiviral last year, but the companies have since lagged Merck and Pfizer, who have already filed for FDA authorization of two oral antivirals for COVID-19.

Atea said it isn’t giving up on AT-527 and expects to report data from an ongoing phase 3 trial in the latter half of 2022.