President Trump on Saturday expressed optimism about two drugs that he said could be “one of the biggest game changers” in medicine.

“HYDROXYCHLOROQUINE & AZITHROMYCIN, taken together, have a real chance to be one of the biggest game changers in the history of medicine,” Trump wrote on Twitter. “The FDA has moved mountains – Thank You!”

“Hopefully they will BOTH (H works better with A, International Journal of Antimicrobial Agents)…..be put in use IMMEDIATELY. PEOPLE ARE DYING, MOVE FAST, and GOD BLESS EVERYONE!”

HYDROXYCHLOROQUINE & AZITHROMYCIN, taken together, have a real chance to be one of the biggest game changers in the history of medicine. The FDA has moved mountains – Thank You! Hopefully they will BOTH (H works better with A, International Journal of Antimicrobial Agents)….. — Donald J. Trump (@realDonaldTrump) March 21, 2020

Hydroxychloroquine is a drug used in the treatment and prevention of malaria. Azithromycin is an antibiotic that is used to treat many different types of infections in the respiratory system, eyes, ears, and skin, as well as sexually transmitted diseases.

In his tweet, Trump was referring to a French study that the drug combo can be effective in counteracting the coronavirus COVID-19, which has spread across the world after emerging in China.

“Despite its small sample size, our survey shows that hydroxychloroquine treatment is significantly associated with viral load reduction/disappearance in COVID-19 patients and its effect is reinforced by azithromycin,” the study found.

“French confirmed COVID-19 patients were included in a single arm protocol from early March to March 16th, to receive 600mg of hydroxychloroquine daily and their viral load in nasopharyngeal swabs was tested daily in a hospital setting,” the researchers wrote in an abstract, Fox News reported. “Depending on their clinical presentation, azithromycin was added to the treatment.”

Six patients in the study were asymptomatic, while 22 had upper respiratory tract infection symptoms and eight had lower respiratory tract infection symptoms. Researchers treated 20 cases in the study. These cases “showed a significant reduction of the viral carriage at D6-post inclusion compared to controls, and much lower average carrying duration than reported of untreated patients in the literature.” “Azithromycin added to hydroxychloroquine was significantly more efficient for virus elimination,” the researchers added. “Despite its small sample size our survey shows that hydroxychloroquine treatment is significantly associated with viral load reduction/disappearance in COVID-19 patients and its effect is reinforced by azithromycin.”

At a White House press briefing Thursday, Trump said that chloroquine and hydroxy-chloroquine will quickly be made available to test, adding that several drug companies, including Bayer, are upping production. “I have directed the FDA to eliminate rules and bureaucracy so work can proceed rapidly, quickly and fast,” Trump said. “We have to remove every barrier.”

But Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, was more cautious in a Friday briefing, saying a protocol still must be followed.

“So, as the Commissioner of FDA and the President mentioned yesterday, we’re trying to strike a balance between making something with a potential of an effect to the American people available, at the same time that we do it under the auspices of a protocol that would give us information to determine if it’s truly safe and truly effective,” he said alongside Trump at a White House press briefing Friday.

On Saturday, Fauci said that reports that the drugs are effective “may be true, but they’re anecdotal.”

“The president is talking about hope for people and it’s not an unreasonable thing to offer hope,” he said. But he added that his job is “to prove” that the medicine can work.