FDA authorizes emergency use of remdesivir, latest on other COVID-19 treatments

On Friday, the Food and Drug Administration authorized the emergency use of remdesivir to treat COVID-19, President Trump announced.

Excitement is building over remdesivir as a treatment for COVID-19, while enthusiasm tempers for the malaria-drug hydroxychloroquine. These two drugs are arguably the most-hyped COVID-19 treatments, and in recent days new data has emerged indicating whether they will actually help patients suffering from this disease.

While the data for remdesivir looks promising, and hydroxychloroquine less so, experts warn data so far is limited, and right now there's no silver bullet cure for COVID-19.

"In this pandemic, the field is changing rapidly. What we know now is changing from what we knew three months ago -- most fields don’t change that rapidly,” said Dr. Neera Ahuja, division chief of hospital medicine at the Stanford School of Medicine. "We have to keep reevaluating as we go along. What drug looks good right now might not be the best looking one in two weeks."

Here is the latest on COVID-19 treatments:

Remdesivir

Promising news for the antiviral remdesivir, the abandoned Ebola drug, as this week we heard early results of a study sponsored by the National Institute of Health's National Institute of Allergy and Infectious Diseases (NIAID). This international study conducted in multiple hospitals across the world gave about 1,000 patients with severe COVID-19 either remdesivir or a placebo. Though awaiting peer review, experts are optimistic because the study is a randomized, placebo-controlled trial -- considered the gold standard for drug research.

Early analysis of some patients in the trial suggest that those who received remdesivir shortened average recovery to 11 days, compared to 15 days for those who received a placebo. The early report also suggests that treatment with remdesivir trended toward a lower death rate, but this needs further analysis.

But Dr. Anthony Fauci, the nation’s top infectious disease doctor and a member of the White House COVID-19 task force said the drug had "a clear-cut, significant positive effect in diminishing the time to recovery."

Separately, early results of a study sponsored by Gilead, the makers of remdesivir, suggest that treating patients with the medication for five days may work equally well as treating them for 10 days.

Importantly, these studies are early analysis that have yet to be peer-reviewed.

Meanwhile, another study on remdesivir based in China -- published Wednesday in the medical journal Lancet -- did not show a clear benefit for patients who received the drug. However, experts aren’t putting as much stock into those results because the study was halted early, limiting the amount of meaningful data that can be drawn.

"I think it may not be a cure, but it could be the first step," said Dr. Marcia Epstein, lead investigator and infectious disease expert Northwell Health’s Feinstein Institutes for Medical Research.

Hydroxychloroquine/Chloroquine

Hydroxychloroquine and chloroquine have been widely used to treat COVID-19, based on very limited data. Though small studies in France and China showed benefit early on, they have been widely criticized for their serious design flaws, non-randomization of patients and missing data.

Dr. Dan Culver, a pulmonologist tasked with leading clinical COVID trials at Cleveland Clinic, called the small French study touted by President Donald Trump, "a horrendous paper that never would have been published during normal times."

President Donald Trump, had repeatedly asserted that patients with COVID-19 should try the unproven anti-malaria drug hydroxychloroquine.

But on April 14, a large, randomized study in China -- that has not yet been peer-reviewed -- did not find clear benefit. Later, a study in Brazil published in JAMA found that patients receiving high doses of chloroquine were actually more likely to die or develop dangerous irregularities in heart rhythm, forcing researchers to stop the study for fear of patients’ safety.

Early reports of an analysis of about 600 patients who received hydroxychloroquine across hospitals in New York did not show a benefit or harm. Though not a rigorous 'gold standard' randomized trial, the results did not bode well for the drug’s future. Final reports, expected in the next week, will offer a more in-depth look at the approximately 1,500 patients who ultimately received the drug as part of the study.

Finally, a review published yesterday in FASEB found that "no high-quality clinical data showing a clear benefit" of these agents exists for COVID-19.

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Beyond the new data, medical experts have said everyone should remain cautiously optimistic about the many COVID-19 treatments currently being tested and that rigorous scientific inquiry takes time.

"There is a lot of excitement and there is a lot going on and you feel desperate to do something for your patients but the smart way is to do it is with science," said Epstein.

"You let the science speak for itself."

What to know about coronavirus:

• How it started and how to protect yourself: Coronavirus explained
• What to do if you have symptoms: Coronavirus symptoms
• Tracking the spread in the U.S. and worldwide: Coronavirus map

Tiffany Kung, M.D., a resident physician at Presbyterian/St. Luke's Hospital in Denver, is a contributor to the ABC News Medical Unit. Sony Salzman is the unit's coordinating producer.