WASHINGTON (NEXSTAR) — The White House said Friday that President Donald Trump remains “fatigued” after contracting COVID-19 and has been injected with an experimental antibody cocktail for the virus that has killed more than 205,000 Americans and spread to the highest reaches of the U.S. government.

Trump’s physician, Navy Commander Dr. Sean Conley, revealed on Friday the commander-in-chief received a dose of an experimental antibody cocktail by Regeneron that is in clinical trials. 

“He completed the infusion without incident,” Dr. Conley said in the statement.

Dr. Conley said Trump “remains fatigued but in good spirits” and that a team of experts was evaluating both the president and first lady in regard to next steps.

Trump is also taking zinc, Vitamin D, melatonin and other medications.

The first lady, who is 50, has a “mild cough and headache,” Conley reported, and the remainder of the first family, including the Trumps’ son Barron, who lives at the White House, tested negative.

In a statement late Friday, Regeneron confirmed Trump was provided the REGN-COV2 antibody cocktail as part of a “compassionate use request,” which is when the Food and Drug Administration allows for unapproved treatments to be made available to treat ill patients when no other treatment is available.

The company’s compassionate use program defines it as being intended for patients with serious or life-threatening conditions who do not have any viable or available treatment options, and are unable to participate in ongoing clinical trials.”

What is Regeneron polyclonal antibody cocktail?

Trump is receiving a two-antibody combo drug that’s currently in late-stage studies from Regeneron Pharmaceuticals Inc. The company previously developed a successful treatment for Ebola using a similar approach.

It’s given as a one-time treatment through an IV.

Trump’s physician, Dr. Sean Conley, said the drug was being given “as a precautionary measure,” and that Trump also was taking zinc, vitamin D, an antacid called famotidine, melatonin and aspirin. None of those have been proven to be effective against COVID-19.

Trump apparently is not receiving hydroxychloroquine, a drug he widely promoted that has been shown in many studies to be ineffective for preventing or treating COVID-19.

Released earlier this week, the first data from a trial using Regeneron’s COVID-19 antibody cocktail is encouraging. The top dose of the treatment relieved symptoms more quickly than the placebo for patients not sick enough to be hospitalized.

The initial phase included 275 patients in the phased study. The most significant improvements were seen in patients who had not already mounted a natural response, the company said.

Jeanne Marrazzo, the director of the division of infectious diseases at the University of Alabama at Birmingham, told CNN the results appear “very promising.”

The company said the treatment is intended as a therapeutic substitute for a natural response to the virus. According to a news release, Regeneron said it is hoping to confirm their initial findings in a second group of patients.

“What I think is fascinating is that it shows that antibodies really matter and the antibody to the spike protein was really helpful, particularly when people made the antibodies themselves,” said Marrazzo. “Whether it’s antibody therapy or vaccine that target these proteins, it sounds like we are on the right track. I think that’s really encouraging.”

Antibodies are proteins the body makes when an infection occurs; they attach to a virus and help it be eliminated. The blood of survivors is being tested as a treatment for COVID-19 patients because it contains such antibodies, but the strength and types of antibodies varies depending on each donor, and doing this on a large scale is impractical.

The drugs that Regeneron and other companies are testing are concentrated versions of specific antibodies that worked best against the coronavirus in lab and animal tests, and can be made in large, standardized doses.

They are being tested to treat newly diagnosed COVID-19 patients in hope of preventing serious disease or death, and to try to prevent infection in people at high risk of that such as nursing home residents and health workers.

The Associated press contributed to this report.