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Eli Lilly and Company’s monoclonal antibody combination therapy helped prevent symptomatic Covid-19 infection among nursing home residents and staff in a Phase 3 trial, the company announced on Thursday.

The study findings were described in a company news release, but Eli Lilly noted that the full results will be submitted for publication in a peer-reviewed clinical journal.

Nursing home residents who received the drug – known as LY-CoV555, also called bamlanivimab – had up to an 80% lower risk of contracting symptomatic Covid-19 versus residents in the same facility who received a placebo, according to drugmaker Eli Lilly.

The findings suggest a key preventive use of the antibody treatment, which was issued an emergency use authorization by the US Food and Drug Administration in November to treat mild to moderate coronavirus infections in adults and children. The treatment is administered as an infusion in a hospital or other health care setting.

Eli Lilly now will consider requesting FDA regulators to extend the drug’s authorized emergency use from being just to treat Covid-19, but also to prevent the spread of Covid-19 in long-term care facilities where someone may have tested positive for the disease.

“We’re glad bamlanivimab is already available as a treatment for patients at high risk for progressing to severe COVID-19 illness or hospitalization, including those in nursing homes, and look forward to working with regulators to explore expanding the emergency use authorization to prevent the spread of COVID-19 in these facilities,” Dr. Daniel Skovronsky, Lilly’s chief scientific officer and president of Lilly Research Laboratories, said in the company news release Thursday.

“We are exceptionally pleased with these positive results, which showed bamlanivimab was able to help prevent COVID-19, substantially reducing symptomatic disease among nursing home residents, some of the most vulnerable members of our society,” Skovronsky said.

The study included 1,097 residents and staff of long-term care facilties who were randomly given either 4,200 milligrams of bamlanivimab or a placebo.

The trial results showed that after eight weeks, among only the residents in the study who originally tested negative for Covid-19, four died from the disease – but the deaths all occurred in residents who were given a placebo. There were no Covid-19 deaths among residents who were given bamlanivimab, the company announcement said.

Among only the residents who originally tested positive, four people also died but they were all given a placebo and there were no deaths among those given bamlanivimab, the announcement noted.

During the entire trial, there were a total of 16 deaths reported, including deaths not related to Covid-19, and all deaths were among residents, not staff members, according to the announcement. Eleven of those deaths occurred among people given a placebo and five were among those given the therapy.

“The antiviral activity seen with bamlanivimab treatment emphasizes the importance of early intervention to help counter the devastating impact the virus has had in this vulnerable population and other high-risk patients,” Dr. Myron Cohen, co-principal investigator and director of the Institute for Global Health and Infectious Diseases at the University of North Carolina at Chapel Hill, said in Eli Lilly’s announcement on Thursday.

While the announcement provides limited information, the findings “exceed” expectations, Dr. Nick Cammack, the Covid-19 Therapeutics Accelerator lead at Wellcome Trust in the United Kingdom, said in a statement released by the UK-based Science Media Centre on Thursday.

“These results exceed our expectations, demonstrating that this class of treatments can be used to both prevent and treat disease,” Cammack said in the statement.

“Reducing the risk of getting Covid-19 by up to 80% would be remarkable, and could have a dramatic impact on outbreaks among the most vulnerable groups globally,” Cammack said in part. “Monoclonal antibodies are traditionally the most expensive class of treatments in the world. Covid-19 must be the pivot moment where they move from the rich world to the whole world and become part of mainstream therapeutics.”

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In the United States, anyone sick with mild-to-moderate Covid-19 who is at high risk for progressing to a more severe illness should be able to access bamlanivimab or ask their doctor for a monoclonal antibody infusion.

Studies show these treatments can prevent high-risk Covid-19 patients from developing severe symptoms, yet health officials say not enough of the available treatments have been used.

CNN’s Jen Christensen contributed to this report.