An experimental drug for the coronavirus has a proven benefit, according to Dr. Anthony Fauci, the head of the National Institutes of Allergy and Infectious Diseases.

"The data shows that remdesivir has a clear-cut, significant, positive effect in diminishing the time to recovery," Fauci said at the White House on Wednesday. The data he referred to is from a large study of more than 1,000 patients from multiple sites around the world. Patients either received the drug, called remdesivir, or a placebo.

Results from clinical trials are typically published in medical journals after review from outside experts. That hasn't happened yet with this latest study, but Fauci said that the results were so promising, there is "an ethical obligation to immediately let the placebo group know so they can have access" to the drug.

Fauci said the remdesivir study group was able to be discharged from the hospital within 11 days, on average, compared to 15 days in the placebo group.

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"What it has proven is that a drug can block this virus," Fauci said.

There were indications the drug led to fewer deaths, but that part of the analysis is still under review.

Fauci, who is normally measured in tone, expressed genuine excitement over the results, calling them "reminiscent of 34 years ago in 1986 when we were struggling for drugs for HIV."

Fauci's team uncovered the first drug to show a modest impact on the virus that causes AIDS — research that was built upon over subsequent years to find HIV drug cocktails.

Dr. Michael Saag, associate dean for global health at the University of Alabama at Birmingham, said the results seemed promising. Antiviral drugs such as remdesivir tend to work earlier in the course of an illness, so "the thing that I think is important in this study is the patients had advanced disease," said Saag, who is not involved with any remdesivir trials.

"I think they were trying to give it the toughest test they could."

The study raised questions about whether the Food and Drug Administration would issue emergency use authorization for remdesivir, a move that would expand doctors' ability to use it.

In a statement to NBC News, an FDA official said, "the agency has been engaged in sustained and ongoing discussions with Gilead Sciences regarding making remdesivir available to patients as quickly as possible, as appropriate." It was unclear whether the FDA would take immediate action.

Meanwhile, information on two other remdesivir studies released Wednesday provided seemingly conflicting outcomes.

But both studies had flaws, making results difficult to interpret in the absence of more research.

The first study, from Gilead Sciences, found that patients who were given a 10-day treatment course of the drug "achieved similar improvement in clinical status compared with those taking a 5-day treatment course," the company, which makes the drug, said in a press release Wednesday.

The other study, published in The Lancet, found remdesivir had no effect on reducing COVID-19 death rates, or even on making people feel better faster.

Gilead has not yet released enough information from its trial to show what that "improvement" means for patients. The company said full results would be published "in the coming weeks."

The analysis did not compare remdesivir to a placebo, so it's impossible to determine whether any benefits were due to the drug or whether patients would have improved on their own.

Separately, The Lancet study's conclusion was muddied because the research was stopped early, because the investigators in Wuhan, China, were only able to recruit half of the patients they'd planned to study.

"This is not the outcome we hoped for," Bin Cao, the study's author and a professor at China-Japan Friendship Hospital and Capital Medical University in China, said in a press release. "We are mindful that we were only able to enroll 237 of the target 453 patients because the COVID-19 outbreak was brought under control in Wuhan."

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The Gilead research was meant to determine how long hospitalized patients would need to be on the drug for a potential clinical benefit. If patients only need five days of treatment, rather than 10, it would mean Gilead could double the number of people treated.

"This is particularly important in the setting of a pandemic," Dr. Merdad Parsey, Gilead's chief medical officer, said in the press release.

Remdesivir is not approved by the Food and Drug Administration, and has not been proven as an effective treatment for patients with the coronavirus. Results from other trials are expected in the coming weeks.

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