(Bloomberg) --

Eli Lilly & Co. will begin testing its Covid-19 antibody drug in nursing homes, a treatment with potential to protect vulnerable groups that vaccines may not cover.

The trial, dubbed BLAZE-2, will kick off on Monday at several nursing homes in the U.S. and marks the third phase of testing for the monoclonal antibody that Lilly co-developed with Canadian start-up AbCellera Biologics Inc. The study will enroll up to 2,400 participants across nursing homes who are either diagnosed with Covid-19 or at the risk of exposure.

They will be given one dose of the antibody -- isolated from one of the first Covid-19 patients to recover in the U.S. -- to see how it can reduce infection rates, or treat those already infected, in four and eight weeks’ time respectively, the company said in a press release.

Antibody Therapies Take the Spotlight as Covid-19 ‘Plan B’

Antibody treatments are seen as a complement to vaccines, which may not elicit the necessary immune response when administered to elderly people or those with compromised immune systems. As these are the very groups most at risk for severe disease or death if they contract the coronavirus, a successful antibody treatment could have marked effect on lowering the death toll of the pandemic, which has sickened over 18 million and killed almost 700,000 worldwide.

Nursing and long-term care homes in particular have been tragic spreading grounds for infection as older people with less robust immune systems and pre-existing conditions like hypertension and diabetes often succumb quickly to the coronavirus. Antibody treatments are more expensive and challenging to manufacture in bulk than traditional vaccines.“The rapid spread of SARS-CoV-2 among residents of long-term care facilities combined with the higher mortality rate for the elderly creates the urgent need for therapies to prevent COVID-19 in this vulnerable population,” said the company’s statement, which noted that over 40% of Covid-19 deaths in the U.S. have been linked to long-term care homes.

In addition to Lilly, global pharmaceutical companies including AstraZeneca Plc and GlaxoSmithKline Plc are also developing similar treatments. An antibody cocktail made by Regeneron Pharmacuticals Inc. has already won a $450 million contract from the U.S. government to ramp up production although it’s still in the midst of testing.

Eli Lilly expects to make more than 100,000 doses by the end of the year if the treatment is shown to work. The Indianapolis, Indiana-based company is also working with Chinese biotech firm Shanghai Junshi Biosciences Co. to develop another antibody candidate.

©2020 Bloomberg L.P.