What happened Shares of Atea Pharmaceuticals (NASDAQ: AVIR), a clinical-stage biopharmaceutical company, are falling hard after the company shared disappointing clinical-trial data. Investors are worried about what will become of AT-527, an oral COVID-19 treatment, after failing a phase 2 study. The stock was down 61.9% as of 11:26 a.m. EDT on Tuesday. So what Atea Pharmaceuticals and its big pharma partner Roche (OTC: RHHBY) are developing AT-527 as an easy-to-swallow antiviral for COVID-19. Unfortunately, treatment with the antiviral didn't lower the amount of circulating SARS-CoV-2 virus for mild or moderate patients when measured against patients who received a placebo. Image source: Getty Images. Since AT-527 was developed using Atea Pharmaceuticals' proprietary platform, this failure makes it far more difficult to cheer for antivirals the company has in earlier stages of development. There was a glimmer of hope in the failed phase 2 study. A closer look at results from high-risk patients with underlying health conditions suggests AT-527 works as intended. Viral loads for this patient group fell by around two-thirds. This might be enough to improve outcomes, but it's hardly remarkable. Now what In collaboration with Roche, Atea Pharmaceuticals is running a phase 3 study with around 1,400 mild-to-moderate COVID-19 patients. Atea Pharmaceuticals will try to modify the phase 3 trial to include more high-risk patients. While there's a chance for success in the ongoing phase 3 study with AT-527, if the company can modify it to include more high-risk patients, this biotech stock probably isn't worth the risk right now. Another oral COVID-19 treatment candidate from Merck called molnupiravir is miles ahead and it's going to be tough to beat. Earlier this month, Merck stopped a phase 3 trial after an interim assessment showed it reduced the risk of hospitalization or death by about half. 10 stocks we like better than Atea Pharmaceuticals, Inc.When our award-winning analyst team has a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* They just revealed what they believe are the ten best stocks for investors to buy right now... and Atea Pharmaceuticals, Inc. wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of September 17, 2021 Cory Renauer has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Atea Pharmaceuticals, Inc. The Motley Fool has a disclosure policy.Source