The U.S. Food and Drug Administration said Monday it had issued an emergency use authorization for Eli Lilly and Co's monoclonal antibody therapy to treat mild to moderate coronavirus infections in adults and children.

The single antibody treatment, called bamlanivimab, must be infused in a hospital or other health care setting. It is the first monoclonal antibody to be authorized for use in treating coronavirus. The idea is to kick-start an immune response against infection.

"Monoclonal antibodies are laboratory-made proteins that mimic the immune system's ability to fight off harmful antigens such as viruses. Bamlanivimab is a monoclonal antibody that is specifically directed against the spike protein of SARS-CoV-2, designed to block the virus' attachment and entry into human cells," the FDA said in a statement.

"The FDA's emergency authorization of bamlanivimab provides health care professionals on the frontline of this pandemic with another potential tool in treating COVID-19 patients," Dr. Patrizia Cavazzoni, acting director of the FDA's Center for Drug Evaluation and Research, said in the statement. "We will continue to evaluate new data on the safety and efficacy of bamlanivimab as they become available."

FDA authorization was based on a study published in the New England Journal of Medicine in October. It found the treatment seemed to lower the risk of hospitalization and ease some symptoms in a small number of patients with mild to moderate cases of COVID-19.

The Phase 2 trial involved 452 patients, some who received the treatment and some who got a placebo, which does nothing. Only 1.6% of patients given the treatment had symptoms progress enough that they had to be hospitalized or seek care at the emergency room. For patients who got the placebo, the rate of hospitalization was 6.3%.

Lilly announced it had struck a US$375 million deal with the government for 300,000 vials of the antibody treatment, pending EUA, to be delivered in the two months after. Lilly applied for EUA in October. The company said it planned to have 100,000 doses ready to ship within days and would manufacture a million doses by the end of 2020. The treatment would be provided to patients at no cost.

"Lilly will begin shipping bamlanivimab immediately to AmerisourceBergen, a national distributor, which will distribute it as directed by the U.S. government's allocation program," the company said in a statement.


"The issuance of an EUA is different than FDA approval," the FDA noted.

"Based on the FDA's review of the totality of the scientific evidence available, the agency determined that it is reasonable to believe that bamlanivimab may be effective in treating non-hospitalized patients with mild or moderate COVID-19," the FDA said.

"And, when used to treat COVID-19 for the authorized population, the known and potential benefits outweigh the known and potential risks for the drug. There are no adequate, approved and available alternative treatments to bamlanivimab for the authorized population."

The treatment should be given as soon as possible after a positive COVID-19 test result, within 10 days of the onset of symptoms, the FDA said. It can only be given in a health care setting where doctors also have access to medication in case the patient has a bad reaction to the infusion. Providers who use the treatment also need to let the FDA know if there are any serious adverse events, according to the EUA.

The treatment is not authorized for patients who are hospitalized or require oxygen therapy, as it does not seem to help them.

For months, hope has been building around monoclonal antibody therapies as a potential treatment for COVID-19.

As soon as the pandemic hit the U.S. in January, Lilly's scientists went to work to identify an antibody, one of the proteins the body makes to naturally fight infection, that would best protect against the novel coronavirus.

Scientists sifted through thousands of antibodies generated by a patient who had recovered from COVID-19. They found, selected and then copied those they thought would best neutralize the virus and chose one for a cutting-edge treatment that went into human clinical trials in June.

Regeneron has also applied for an emergency use authorization for its antibody therapy. That's the one given to U.S. President Trump last month when he caught coronavirus.

There are 79 antibody therapies under investigation.

"Authorization of this new Eli Lilly antibody treatment is a significant step forward in treating patients and bridging us to the rollout of safe and effective vaccines, with all of these efforts made possible by Operation Warp Speed," Health and Human Services Secretary Alex Azar said in a statement.

"Operation Warp Speed is helping to ensure that therapeutics like Lilly's can reach patients without a day wasted."

Lilly is also testing bamlanivimab in combination with another monoclonal it has developed. A peer-reviewed study in August showed the Regeneron "cocktail" approach that used two antibodies with its treatment worked in the lab even when the novel coronavirus mutated.