The news that President Trump and the first lady, Melania Trump, have tested positive for the coronavirus has raised the question of whether they will be treated with experimental drugs for Covid-19.
There are no approved treatments for Covid-19, but two of the most promising candidates, antibody treatments developed by Eli Lilly and Regeneron, are being tested in patients around the country. Initial results have suggested that they can reduce the level of the virus in the body and possibly shorten hospital stays — when they are given early in the course of infection.
A spokeswoman for Eli Lilly declined to comment on Friday about whether the company had been contacted about providing a treatment to Mr. Trump. “Thanks for your question,” the spokeswoman, Molly McCully, said in an email. “However, we cannot answer it.” She did not immediately comment on whether the company has already provided its coronavirus treatment to people who are not participating in its trials.
A spokeswoman for Regeneron, Hala Mirza, said the company doesn’t “identify individuals who have or have not submitted a request or who are participating in our clinical trials without their consent.”
She said that for its coronavirus treatment, “our first priority is to maintain a sufficient supply in order to conduct rigorous clinical trials,” adding, “there is limited product available for compassionate use requests that are approved under certain exceptional circumstances on a case-by-case basis.”
Asked whether Mr. Trump is taking the malaria drug hydroxychloroquine as a treatment for the virus, Mark Meadows, the White House chief of staff, said he would not talk about specifics related to the president’s medical care.
“Well, I’m not going to get into any particular treatment that he may or may not have,” Mr. Meadows told reporters during a brief gaggle in front of the West Wing on Friday morning.
Regeneron’s chief executive, Dr. Leonard S. Schleifer, has known Mr. Trump casually for years, having been a member of his golf club in Westchester County. Dr. Schleifer ended a call on Friday morning before a reporter could ask a question about whether Mr. Trump was receiving any treatments, and did not respond to a text asking him for comment.
Eli Lilly also has ties to the Trump administration. Alex M. Azar II, the secretary of the Department of Health and Human Services, is a former executive at the company.
Although neither company’s product has been authorized for emergency use by the Food and Drug Administration, companies can grant access to their experimental treatments through what is known as compassionate use, for example, if all other options have failed and a patient might die without trying the drug.
During the pandemic, Mr. Trump has promoted a range of unproven or scientifically questionable treatments for the virus, and himself took hydroxychloroquine in the hopes that it could prevent infection. The Food and Drug Administration authorized hydroxychloroquine for emergency use this spring, then revoked its approval after concluding that the drug’s potential benefits did not outweigh the risks.
Mr. Trump has also enthusiastically endorsed the use of convalescent plasma and pushed for the F.D.A. to authorize the treatment for emergency use even though there is still not good evidence that it works. He suggested that injecting a disinfectant like bleach could help combat the virus, although later said he was joking.
Other treatments — an inexpensive steroid, dexamethasone, and remdesivir, an antiviral drug developed by Gilead — have been shown in clinical trials to help patients with Covid-19 who are sick enough to be hospitalized. Neither drug has gone through the rigorous F.D.A. approval process to determine that it is safe and effective, although dexamethasone is widely available for other uses, and remdesivir has received emergency authorization.
Mr. Trump in 2018 signed the Right to Try law, which allows patients and their doctors to directly request an experimental treatment from a company, without first seeking approval from the F.D.A., which typically approves the vast majority of such requests. The Right to Try law is rarely used, however, with most doctors and hospitals preferring to use the existing process of seeking agency approval.
Some ethics experts said it would not be surprising if President Trump were given the drugs on an experimental basis, given that they have passed safety trials.
“Presidential medicine is and has been unique,” said Arthur L. Caplan, a professor of medical ethics at the N.Y.U. Grossman School of Medicine. “If his doctors think an intervention might be helpful, and if that judgment is confirmed by outside experts they talk to, and if things look dire or serious, then the president will get access to any and all agents.”
Other experts said that if Mr. Trump or his doctors revealed that he or the first lady have received an experimental treatment, the drug companies developing them would need to be prepared for what could be a flood of requests from the public.
“One would anticipate that providing access to the president of the United States would lead to significant requests for that experimental treatment by people who are in the same or in potentially worse medical conditions or states,” said Kenneth I. Moch, a senior adviser at the Global Health Crisis Coordination Center in Atlanta.
In 2014, Mr. Moch came under intense criticism after the company where he was chief executive, Chimerix, initially refused to provide an experimental treatment to a 7-year-old boy who was close to dying from a viral infection. After a social media campaign, the company started a new clinical trial that allowed the boy to get the treatment.
Eli Lilly and Regeneron are the furthest along of several companies and teams of researchers in developing what are known as monoclonal antibodies to fight Covid-19. Researchers identify powerful antibodies that fight infection, then manufacture them in large quantities. They are then given to sick patients, or to people who have been exposed to the virus, in the hopes that they will help boost the body’s immune response.
Antibody treatments have shown promise against other viruses, including Ebola. On Tuesday, Regeneron said that its treatment, a cocktail of two antibodies, hastened recovery time and reduced the amount of virus in the nasal cavities of a small number of volunteers in its ongoing study.
The new results were from a study of 275 volunteers who were treated after being diagnosed with Covid-19. Half received one infusion of the drug while the rest were given a placebo. Those who were not making their own antibodies at the start of the trial benefited the most, Regeneron reported. Their symptoms resolved in an average of 6 to 8 days, compared with 13 days in those who received the placebo.
In September, Eli Lilly reported that a single infusion of its monoclonal antibody markedly reduced levels of the coronavirus in newly infected patients and lowered the chances that they would need hospitalization.
More than 450 newly diagnosed patients received Eli Lilly’s monoclonal antibody or a placebo infusion. Some 1.7 percent of those who received the drug were hospitalized, compared with 6 percent of those who received a placebo — a 72 percent reduction in risk, the company reported.
In both cases, the companies were reporting initial results that had not been reviewed by independent scientists or published in peer-reviewed journals, and the studies have not been completed. It is still unclear whether they will be proven to be effective against the virus, although they have largely been shown to be safe.
Despite their early promise, monoclonal antibodies are difficult and expensive to manufacture, and some have raised questions about whether the companies will be able to make enough to meet global demand if they are proven to work.
Regeneron has been awarded more than $500 million from the federal government to develop and manufacture its product before the clinical trials have concluded. In August, the company announced it was teaming up with a larger company, Roche, to ramp up production.
Gina Kolata and Michael D. Shear contributed reporting.
