ZURICH, Oct 22 (Reuters) - Roche Holding and Atea Pharmaceuticals have joined forces to develop an antiviral oral treatment called AT-527, now in phase 2 clinical trials, as a potential treatment for COVID-19 patients, the companies said on Thursday.

If the pill is approved, Boston-based Atea will distribute it in the United States and Roche will be responsible for global manufacturing and distribution outside the U.S. market. Atea will get an upfront payment of $350 million in cash from Roche with potential for future milestone payments and royalties. (Reporting by Michael Shields Editing by Riham Alkousaa)