The experimental drug remdesivir has been approved to treat hospitalized patients with severe Covid-19, the US Food and Drug Administration said in a letter on Friday.
Remdesivir is the first authorized therapy drug for Covid-19 in the United States, FDA Commissioner Stephen Hahn said on Friday.
"This is an important clinical advance that showed a statistically significant reduction in time to recovery for patients with Covid-19 and is the first authorized therapy for Covid-19." Hahn said.
The FDA issued an emergency-use authorization on Friday, saying the benefits of the drug outweigh its risks in patients. An emergency-use authorization is a lower regulatory bar than full FDA approval.
Denise Hinton, the FDA's chief scientist, said in the authorization letter that there is "no adequate, approved, and available alternative to the emergency use of remdesivir for the treatment of COVID-19."
The FDA limited its authorization of the drug to adults and children with suspected or laboratory-confirmed Covid-19 and severe disease, which includes low blood oxygen levels, the need for oxygen therapy or the need for a ventilator or other intensive breathing support.
Possible side effects of remdesivir include increased levels of liver enzymes -- which may be a sign of inflammation or damage to cells in the liver -- and infusion-related reactions like low blood pressure, nausea, vomiting, sweating and shivering, the FDA said.
President Donald Trump, speaking in the Oval Office on Friday, called remdesivir a "very promising situation."
"An important treatment for hospitalized corona patients and something I spoke with Dr. Hahn and Dr. (Andrew) Fauci. I spoke with Deborah (Birx) about it. It is really a very promising situation," Trump said.
The federal government is expected to control the distribution of the drug, the FDA letter says, in order to consistently use the drug with the "terms and conditions" of the authorization.
The drug must be administered intravenously. While the optimal dosing is still unknown, Gilead Sciences, the drug's marker, recommends that patients on ventilators take the drug for 10 days and non-ventilator patients only five days.
Gilead has donated the existing supply of the drug, which could cover at least 140,000 treatment courses for patients with Covid-19.
"The company has set a goal of producing at least 500,000 treatment courses by October, 1 million treatment courses by December 2020 and millions more in 2021, if required," the company said in a statement on Friday.
"We will be working very closely to get that to patients, working with FEMA, working with other parts of the government to make sure that we get that to the patients in need as quickly as possible because there are patients out there that can benefit from this medicine today that are hospitalized," said Daniel O'Day, chief executive officer of Gilead Sciences at the Oval Office on Friday. "We don't want any time to waste for that."
O'Day thanked the patients and caregivers who participated in the drug's early clinical trials.
Earlier this week, a government-funded study found that patients who took remdesivir recovered faster than patients who did not. The drug improved recovery time for coronavirus patients from 15 to 11 days. That's similar to the effect that the influenza drug Tamiflu has on flu. Tamiflu also doesn't cure patients quickly, but can reduce how long they are sick.
CNN's Nicole Chavez and Jason Hoffman contributed to this report.
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