President Trump is prescribed a third drug to combat his COVID-19 infection

During a news conference on Sunday morning, Conley confirmed for the first time that the president had received oxygen support, at least once, and that he had been started on dexamethasone on Saturday. Trump’s oxygen saturation levels have fallen twice below 95%, which is considered the low-side of a normal reading.

“In response to transient low oxygen levels…we did initiate dexamethasone therapy,” Dr. Brian Garibaldi, director of the biocontainment unit at Johns Hopkins Medicine and one of the physicians on Trumps’s care team at Walter Reed National Military Medical Center, said during the news conference on Sunday. “Our plan is to continue that for the time being.”

Since Trump tweeted Friday that he and First Lady Melania Trump had tested positive for the coronavirus, there has been conflicting information released from White House officials about the president’s health, including the date of his last negative COVID-19 and when he began treatment.

Conley had initially said Saturday morning that Trump was diagnosed 72 hours ago, which would be Wednesday morning — about 36 hours before he disclosed his diagnosis, and that he had received the Regeneron experimental therapy 48 hours ago, which would be Thursday morning. A statement issued Saturday evening by the White House said Conley misspoke, and Trump had been diagnosed Thursday night and received the first infusion of the Regeneron drug on Friday.

Trump is also taking zinc, vitamin D, an acid reducer, melatonin and aspirin, according to Conley, who noted Saturday that Trump is on a five-day regimen of remdesivir.

Trump’s diagnosis highlights one of the still challenging clinical elements of the COVID-19 pandemic, that there are few treatment options available for patients with COVID-19.

For people with severe forms of the disease, treatment can include convalescent plasma, the steroid dexamethasone, and/or remdesivir. Most of the available treatments for COVID-19 infections target severely ill patients who have been hospitalized. This includes remdesivir and convalescent plasma, which is gathered from people who have recovered from COVID-19 infections — both therapies have received emergency use authorization during the pandemic.

Dexamethasone is another option for hospitalized patients who are in need of oxygen support. The steroid, which is approved by the FDA for other indications, demonstrated in clinical trials in the U.K. that it can reduce mortality in some severely ill COVID-19 patients.

“Dexamethasone is a cheap, widely available, definitively effective therapy for patients on oxygen support in the hospital,” Raymond James analyst Steven Seedhouse told investors in June. “To be clear, it has no apparent benefit in patients not on oxygen or not hospitalized.”

For people with mild to moderate forms of the disease, there are no FDA-authorized or approved drugs, though two drug makers including Eli Lilly & Co. LLY, +0.63% and Regeneron recently shared promising results for a pair of still-investigational antibody-based treatments. Neither drug has been authorized or approved by the FDA at this time.

“There really aren’t a lot of very effective therapies we have at this stage of the disease,” said Dr. Steven Shapiro, chief medical and scientific officer at UPMC, a hospital system based in Pittsburgh, who is not involved in Trump’s treatment. “The thing that we know that is most effective right now are steroids. But that tends to work later in the disease when someone develops the pneumonia.”

Regeneron’s REGN-COV2 and Lilly’s LY-CoV555 are both being tested in clinical trials, for people with mild to moderate forms of the disease. Like convalescent-plasma treatments, these drugs also rely on antibodies, and both have shown so far that they help reduce viral load, based on interim data shared in the past month. Raymond James analysts predicted Friday morning that one of these investigational drugs would be prescribed to Trump.

That said, physicians have the discretion to prescribe medications that are not approved or authorized by the FDA for a specific use. This is called off-label prescribing, and it’s common in the U.S. health care system. (One 2006 study estimates that one-fifth of U.S. prescriptions are off-label.)

Trump in May disclosed that he was taking the antimalarial hydroxychloroquine that he spent months promoting as a potential COVID-19 treatment. At that time it was being tested in clinical trials as both a treatment and to see if it could prevent infections in people who had been exposed to the virus. The FDA had granted the drug an emergency use authorization in March but revoked that authorization in June.

Health-care providers around the world have tested the efficacy of zinc, vitamin C, vitamin D and the antibiotic azithromycin to COVID-19 patients; however, none of those treatments has so far shown a clinical benefit, according to Shapiro.

“It’s watching, waiting … just supportive care, in general. Isolate,” he said. “Masks are really important. That is our vaccine right now. It’s really good at preventing the spread. And if not entirely, it certainly will lower the dosage and make the disease less severe. So that’s one lesson I think that everyone should learn from this.”