The candidate, AZD7442 mimics natural antibodies and is being investigated to both prevent and treat the virus.
It could be used as an agent complementary to vaccines, for people for whom a jab may not be appropriate, or to provide added protection for high-risk populations, the FTSE 100-listed company said.
One trial with 5,000 participants will evaluate the candidate’s safety and efficacy in preventing infection for up to 12 months, while the second will be on 1,000 patients to evaluate treatment after exposure to the virus.
AstraZeneca is also planning additional trials to evaluate AZD7442 in 4,000 patients for the treatment of COVID-19.
The pharma giant will supply up to 100,000 doses starting towards the end of 2020 and the US government can acquire up to an additional 1mln doses in 2021 under a separate agreement.
The agreement is not anticipated to impact the firm's financial guidance for 2020 as the US funding is offset by expenses for the clinical trials as well as manufacturing process and upscaling costs.
If approved it will be distributed at commercial terms during and after the current coronavirus pandemic, while the Oxford vaccine, also produced by AstraZeneca, will not be sold for a profit if approved during the pandemic.