In a study of 1,057 patients, sotrovimab resulted in a 79% reduction in risk of hospitalization for more than 24 hours or death due to any cause, the companies said on Monday.
Similar therapies developed by rivals Regeneron and Eli Lilly have been approved by US regulators for treating non-hospitalized COVID-19 patients.
The government has come under pressure to allow private firms to buy vaccines, and said while it welcomes the idea and is willing to help.
A good method is for the government to, under this framework, authorise TSMC and the Yonglin Education Foundation to buy them and then donate to the government.
Several Indian states have reported an acute shortage of vaccines, forcing many regions, including the capital New Delhi, to again prioritise those aged above 45.
The Europe director for the World Health Organization (WHO) has said that the authorized COVID-19 vaccines are effective against all variants, including the one that is running rampant in India