Eli Lilly & Co. is developing the covid-19 neutralizing antibody with its Canadian partner, AbCellera Biologics Inc. (Victor J. Blue/Bloomberg News)

The first covid-19 treatment to protect people with mild illness from developing severe disease was granted emergency use authorization by regulators Monday evening.

The drug, a laboratory-brewed antibody that imitates the immune system’s attack on the virus, is made by Eli Lilly & Co. Health experts have championed the class of medicine as a powerful tool to change the course of the pandemic and work as a bridge to a vaccine. It is in the same family of medication as an experimental treatment President Trump received when he was stricken with covid-19, the illness the novel coronavirus causes.

But the initial scarcity of the drug and the logistical complexities of administering it could mute its immediate impact on the pandemic and raise questions about whether it is being distributed to people in the greatest need.

The drug, bamlanivimab, must be delivered by intravenous infusion early in the illness. It was authorized for use in patients with mild or moderate cases of the coronavirus who are at high risk of severe disease or hospitalization. Risk factors include being older than 65, diabetes, obesity with different body mass index cutoffs depending on age, a suppressed immune system, and cardiovascular disease or high blood pressure in people over age 55.

“Bamlanivimab, when given early in the disease course, may help patients clear the virus and reduce covid-related hospitalizations, supporting our belief that neutralizing antibodies can be an important therapeutic option for patients fighting this virus,” Daniel Skovronsky, Eli Lilly’s chief scientific officer, said in a statement.

As part of his VIP treatment regimen, Trump received an experimental antibody drug made by Regeneron Pharmaceuticals through a compassionate use program. Chris Christie, former Republican governor of New Jersey, received access to the Eli Lilly drug.

Emergency authorization for the drugs was touted as imminent in early October by Trump, but Regeneron’s drug has not been cleared for broader use. It took weeks for career scientists at the Food and Drug Administration to make the decision to authorize bamlanivimab.

“The FDA remains committed to expediting the development and availability of potential covid-19 treatments and providing sick patients timely access to new therapies where appropriate, while at the same time supporting research to further evaluate whether they are safe and effective,” FDA Commissioner Stephen M. Hahn said in a statement.

Emergency use authorization is a mechanism to provide access to an unapproved treatment when the known and potential benefits outweigh the risk.

Now the formidable mechanics of delivering the drugs to people loom.

The number of doses available will be dwarfed by soaring need, with more than 500,000 coronavirus cases counted over the past week alone. By the end of the year, Lilly projects 1 million doses could be available. The United States has negotiated contracts for 300,000 of those doses.

“This treatment and others like it will help protect the health and well-being of millions of vulnerable Americans until a safe and effective vaccine is approved for use," White House spokesman Michael Bars said in a statement.

But physicians raised concerns about whether there would be enough doses and whether distribution would be given to those in greatest need.

“There is a very real concern of inequitable distribution, unless we are very thoughtful about ensuring that facilities to administer the treatment are in disadvantaged communities,” said Douglas White, a critical care physician and medical ethicist at the University of Pittsburgh School of Medicine. “We’ve already seen that testing centers for covid are disproportionately in wealthier areas of towns and cities, and that introduces an inequity. If the same thing were to happen with treatment centers with the [monoclonal antibodies], it would be deeply ethically problematic.”

The drugs must be given in lengthy infusions, and the network of emergency rooms or clinics that will provide them is not clear, particularly because patients will be contagious and can’t get them alongside patients with cancer and autoimmune diseases at established infusion clinics without infection control. A government document on payment policy released last month mentions that providers could give the drugs in “temporary expansion sites, such as an erected tent, a retrofitted convention center, or the beneficiary’s home.”

“One of the questions will be equity, creating a platform where these drugs can be delivered in areas where there aren’t big hospitals, like Boston,” said Nahid Bhadelia, an infectious-disease specialist at Boston University School of Medicine.

Because most people recover from covid-19 without serious symptoms, giving the drugs to people broadly could waste a precious resource, and the FDA warned that in severely ill patients who require high-flow oxygen or are on a ventilator, the drug may be linked to worse outcomes. A test of Eli Lilly’s drug in hospitalized patients was discontinued after an interim analysis found the drug was unlikely to have benefit.

Through Operation Warp Speed, the Trump administration effort to speed up treatments and vaccines, the government has bought 300,000 doses each from Eli Lilly and Regeneron at a cost of about $1,250 and $1,500 per dose, respectively.

Government health officials said they will allocate those doses, free of charge, following a strategy similar to what is used for remdesivir, an antiviral drug administered to hospitalized patients. Each state will receive an allotment based on an algorithm that evaluates confirmed coronavirus cases over the previous week. Then the states will select administration sites, and wholesaler AmerisourceBergen will distribute the drug, probably for use in emergency rooms or special clinics.

The process of predicting where the drug is needed will be a little more complicated than it was for hospitalized patients, Paul Mango, deputy chief of staff for policy for the Department of Health and Human Services, said at a briefing last month.

“Here, we have the task of getting it to them before they’re admitted” to the hospital, Mango said. “There will be an allocation based on perceived need by state. And then the state will be the final kind of arbiter, if you will, of where the supply goes within its jurisdiction. We’ll keep track of every dose, where it is, whether it’s being used or not, and readjust as necessary.”

In addition to distributing the drugs, administering them is not trivial — or free because health-care facilities charge for administering the medication, which can take hours. It is not clear whether some patients might be billed for some costs.

“The administration is working to reduce obstacles so every American has access to life-saving therapeutics,” HHS spokeswoman Natalie Baldassarre said in an email.

People will need to have a covid-19 diagnosis and be early in their illness, which could exacerbate inequities, with patients who don’t get tested right away or have a lag in their results less likely to benefit.

“You have to get tested and get tested in a quick turnaround, and the people who have an advantage are the people who get tested and immediately doctors figure out how to get their therapy,” said Walid F. Gellad, director of the Center for Pharmaceutical Policy and Prescribing at the University of Pittsburgh. “That’s not going to happen quickly in certain areas of the country — and to certain kinds of patients.”

Those distribution questions will be amplified as the pandemic rages not only in the United States but across the world. Access to the pricey drugs is likely to follow the pattern of other monoclonal antibody drugs, 80 percent of which are sold to the United States, Canada or Europe, according to a recent study.

“If the monoclonal antibodies for covid treatment and prevention are shown to be safe and efficacious, and really potentially the best-in-class drugs for the treatment for covid disease … and are only available in high income countries, that will be very disappointing,” said Mark Feinberg, president of IAVI, a scientific research nonprofit group.

Coronavirus: What you need to know

End of the public health emergency: The Biden administration ended the public health emergency for the coronavirus pandemic on May 11, just days after WHO said it would no longer classify the coronavirus pandemic as a public health emergency. Here’s what the end of the covid public health emergency means for you.

Tracking covid cases, deaths: Covid-19 was the fourth leading cause of death in the United States last year with covid deaths dropping 47 percent between 2021 and 2022. See the latest covid numbers in the U.S. and across the world.

The latest on coronavirus boosters: The FDA cleared the way for people who are at least 65 or immune-compromised to receive a second updated booster shot for the coronavirus. Here’s who should get the second covid booster and when.

New covid variant: A new coronavirus subvariant, XBB. 1.16, has been designated as a “variant under monitoring” by the World Health Organization. The latest omicron offshoot is particularly prevalent in India. Here’s what you need to know about Arcturus.

Would we shut down again? What will the United States do the next time a deadly virus comes knocking on the door?

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