Drugmaker Eli Lilly and Co and insurer UnitedHealth Group on Friday said they have partnered to conduct a study of Lilly’s COVID-19 antibody treatment bamlanivimab in high-risk Medicare patients.

The Food and Drug Administration last month authorized emergency use of bamlanivimab for treating non-hospitalized COVID-19 patients who are at risk of becoming severely ill, either because they are over the age of 65 or because they have underlying health conditions such as diabetes.

UnitedHealth is inviting members of its Medicare Advantage program to volunteer for the study. Study participants who indicate they have symptoms of COVID-19 and test positive will be administered bamlanivimab, which is given by intravenous infusion, by a nurse sent to their home.

By treating people as early as possible in the course of illness, the study aims to determine if Lilly’s drug reduces the severity of COVID-19, UnitedHealth’s chief scientific officer, Ken Ehlert, said on a conference call.

Bamlanivimab, custom-designed to target the coronavirus, is part of a class of drugs known as monoclonal antibodies.