During a White House briefing on the U.S.’s response to the coronavirus outbreak on Sunday, Trump repeatedly touted hydroxychloroquine as a promising treatment for the coronavirus, despite warnings from Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, that more research needed to be done on the drug’s impact on COVID-19 patients.

Asked to comment on whether it was still the case that the drug required rigorous testing before the White House could champion it as a potential treatment for coronavirus, the National Institute of Allergy and Infectious Diseases said that “although hydroxychloroquine has been used to treat some people with COVID-19, more data is needed to prove that the treatment can improve outcomes in people with COVID-19.”

“Large randomized, controlled clinical trials are the gold standard for determining if a treatment can benefit patients,” NIAID said in a statement sent to Newsweek.

The institute said it was in the “planning stages” for such a trial, adding that NIAID officials would “provide more information about the study when it begins.”

NIAID added that the institute was also “researching other therapies for COVID-19, including broad-spectrum antivirals and antibodies.”

A “large randomized, controlled clinical trial” of the investigational antiviral remdesivir, an anti-viral drug created to treat Ebola, began at the end of February and is still ongoing, the institute said.

On Saturday, Daniel Day, the CEO of U.S. biotech company Gilead, announced that his firm had 1.5 million individual doses of remdesivir in the final stages of production.

Day said his firm planned to release the entirety of the supply to help treat COVID-19 patients with the most severe of symptoms.

Like NIAID, Day sought to make clear that remdesivir is still an investigational medicine. Further, he added that it had yet to be approved by regulatory authorities around the world.

“The…doses are available for compassionate use, expanded access and clinical trials and will be donated for broader distribution following any potential future regulatory authorizations,” he said.

“The safety and efficacy are not yet known so while we feel the greatest sense of urgency in our work with remdesivir, we must take the responsible, ethical approach of determining whether it is indeed a safe, effective treatment. This is why multiple clinical trials for remdesivir are underway, involving thousands of patients with COVID-19 across the world,” he asserted.