AstraZeneca has struck a $486 million deal with HHS’ Biomedical Advanced Research and Development Authority to develop and manufacture AZD7442, a monoclonal antibody for treatment of COVID-19.

Under the agreement, AZ will conduct two phase 3 studies of the antibody, which is derived from the plasma of recovered COVID-19 patients, and will begin manufacturing it for U.S. distribution, contingent upon the FDA’s approval.

The first study will enroll 5,000 participants and will evaluate the treatment for prevention of COVID-19 infection for up to 12 months. The second will enroll 1,100 postexposure participants.

AZ said it hopes to start distributing an estimated 100,000 doses by year’s end.