The FDA can grant an [emergency use authorization, or EUA] to a drug to treat COVID-19 to facilitate the distribution of new therapeutics when there are no alternatives. EUAs are an important tool during the early stages of any pandemic because they loosen restrictions on novel treatment options. The problem is that they end up interfering with clinical trials that would provide the best evidence on whether these drugs are safe and effective.
The FDA granted hydroxychloroquine EUA status on April 27, and less than two months later, on June 15, it was revoked after it became clear that at least one study supporting its use was based on questionable data and new scientific evidence showed that it had little to no effect in treating COVID-19 patients. Other research even indicated adverse events in patients who took it.
In all cases, even if a drug does turn out to be effective, granting a therapy EUA before it has completed clinical testing undermines the data and stunts the ability to properly collect and analyze that information to ultimately inform treatment decisions. When the FDA granted an EUA for remdesivir, our clinical trials on the drug came to a stop.