As the FDA continues to expedite the authorization of COVID-19 medical products, the agency is clarifying its existing Emergency Use Authorizations (EUAs) as well as how and when some of the authorizations could expire or be rescinded.
On April 29, the FDA issued an FAQ document related to its EUA process and how and when an EUA can be rescinded.
For EUAs to be issued in the first place, a public health emergency must be declared by the secretary of HHS and there must be “no adequate, approved, and available alternative to the candidate product for diagnosing, preventing or treating the disease or condition.” In the case of SARS-CoV-2, the virus that causes COVID-19, HHS Secretary Alex Azar declared a public health emergency on Feb. 4.
According to the FAQ, the EUAs for COVID-19 will no longer be in effect once the declared health emergency is terminated, or they could be “revised or revoked” if it is “appropriate to protect the public health or safety.”
The document refers to the FDA’s 2017 guidance, which outlines in more detail the criteria under which an EUA can be revoked before the expiration of the public health emergency, including if the criteria for the EUA are no longer met, such as if a product is approved, if there are “significant adverse inspectional findings,” or reports of adverse events are linked to the product, or if new emerging data suggest that the product is no longer effective.
As of Tuesday, the FDA had issued over 100 EUAs: for diagnostic and serology tests (82), therapeutics (2), PPE (10) and other categories of medical products (14) during the COVID-19 pandemic. Most recently, the agency granted an EUA to a second therapy, remdesivir, to treat hospitalized patients with severe cases. It also issued an EUA on May 2 for a serology test that showed 99.8% sensitivity and 100% specificity.
However, the agency has also had to rein in some of the EUAs or guidance documents it has issued. It sent a warning letter to healthcare providers about the first therapy that received an EUA, chloroquine/hydroxychloroquine, and issued a clarification of its policy regarding serology tests after unauthorized tests flooded the market.
On May 4, the FDA updated its policy for COVID-19 tests during the public health emergency to include more details around the steps manufacturers should take to obtain an EUA for serology tests. The agency will allow commercial manufacturers to develop and distribute serology tests after validation for a “limited period of time, while an EUA is being prepared for submission to FDA.”
Manufacturers must submit the EUA requests with their validation data within 10 business days, and the FDA has provided specific performance threshold recommendations in two templates published online (here and here).
If manufacturers fail to submit an EUA within 10 business days after it has started to market the test, the FDA will warn the public. Additionally, “We encourage states, hospitals and consumers to be on high alert and to make informed purchasing decisions regarding these tests,” wrote Drs. Anand Shah and Jeff Shuren in an FDA blog post on May 4. Shah is deputy commissioner for medical and scientific affairs, and Shuren is director of the Center for Devices and Radiological Health.
The authors added that “even a high-performing antibody test when used on individuals in a population that does not have many cases of COVID-19 infection—a population with low prevalence—may produce as many or more false results as true results because the likelihood of finding someone who has been infected is very small.”
As the agency attempts to clarify existing EUAs for COVID-19, there is precedent for the FDA to rescind EUAs either during or after a public health emergency.
During the H1N1 pandemic in 2009-10, the agency issued numerous EUAs for diagnostic tests, therapeutics and PPE. However, when the public health emergency declaration expired in June 2010, 15 months after it was issued, the EUAs granted for therapeutics, PPE and in vitro diagnostics were all terminated.
More recently, the FDA has revoked the EUAs for specific products before the public health emergency has abated.
According to the FDA’s EUA website, 15 products are still authorized for emergency use to address the 2016 Zika virus outbreak. However, the agency has revoked four EUAs because of performance issues or because it has approved “adequate” alternatives. In one case, the manufacturer discontinued the product and requested that the corresponding EUA be rescinded. The Zika virus public health emergency is still in effect.