FDA Authorizes First Test to Detect Zika Antibodies

The U.S. Food and Drug Administration authorized marketing of a diagnostic test to detect Zika virus immunoglobulin (IgM) antibodies in human blood. The ZIKV Detect 2.0 IgM Capture ELISA is the first Zika diagnostic test the FDA has allowed to be marketed in the U.S.; previously, tests for detecting Zika virus IgM antibodies—including the ZIKV Detect 2.0 IgM Capture ELISA—had been authorized only for emergency use under the FDA’s Emergency Use Authorization (EUA) authority.
 
“At the onset of the Zika virus outbreak, when little was known about the disease or how to diagnose it, the FDA worked quickly with manufacturers to encourage the development of diagnostic tests and ensure they were available using our emergency use authorities,” said FDA Acting Commissioner Ned Sharpless, M.D. “This marketing authorization is a great demonstration of the FDA’s work to protect the public health in emergency response situations. We ensured there were tests made available quickly under EUA, but we continued to work with diagnostic manufacturers to take the next step of ensuring products were FDA reviewed for safety and effectiveness and authorized under our traditional premarket authorities.”
 
The Zika virus is spread to people primarily through the bite of an infected Aedes species mosquito. While many people with Zika virus infection experience no symptoms, the virus can pose potentially serious risks to the public health. Links between Zika virus infection and neurological complications (i.e., Guillain-Barré Syndrome), as well as microcephaly (abnormal smallness of the head) and other poor outcomes associated with Zika virus infection during pregnancy, have increased the importance of having diagnostic tests available for Zika virus. In 2016, the Centers for Disease Control and Prevention (CDC) announced that limited local mosquito-borne Zika virus transmission had been reported in the continental U.S. In 2018 and 2019, no local mosquito-borne Zika virus transmission was reported in the continental U.S.
The ZIKV Detect 2.0 IgM Capture ELISA is designed to identify proteins (antibodies) produced by the body’s immune system when it tests for Zika virus infection in the blood. IgM antibodies indicate an early immune response. The FDA reviewed data from a clinical study of 807 test samples and a variety of analytical studies, which demonstrated that the ZIKV Detect 2.0 IgM Capture ELISA was safe and effective at identifying IgM antibodies against Zika virus in blood.
 
The ZIKV Detect 2.0 IgM Capture ELISA is for use only in patients with clinical signs and symptoms consistent with Zika virus infection, and/or who meet the CDC’s Zika virus epidemiological criteria, such as history of residence in or travel to a geographic region with active Zika transmission at the time of travel. Results of this test are intended to be used in conjunction with clinical observations, patient history, epidemiological information and other laboratory evidence to make patient management decisions. Negative results may be seen in specimens collected before day four after the onset of symptoms or after the window of detectable IgM closes, and therefore do not preclude the possibility of Zika virus infection, past or present. This test is not authorized by the FDA for testing blood or plasma donors.
 
Prior to now, all of the available Zika tests had been authorized for use under an EUA, in which the agency allows use of unapproved medical products, or unapproved uses of approved medical products, in an emergency to diagnose, treat or prevent serious or life-threatening diseases or conditions caused by chemical, biological, radiological or nuclear agents. The FDA can only issue an EUA when specific criteria are met, including that there are no adequate, approved and available alternatives. With the marketing authorization granted for the ZIKV Detect 2.0 IgM Capture ELISA the FDA has also revoked the EUA for this device, which was initially authorized for emergency use in 2016. In addition, the FDA is considering whether the ZIKV Detect 2.0 IgM Capture ELISA test is an adequate, approved and available alternative to other currently available Zika virus antibody diagnostic tests available under EUAs. Currently, there are 18 other active EUAs for tests to diagnose Zika virus infection, four of which detect Zika virus antibodies like the ZIKV Detect 2.0 IgM Capture ELISA. The FDA is communicating with the four EUA holders to gather information to evaluate whether the FDA should revoke the EUAs for these specific tests. This marketing authorization does not impact the availability of the 14 other Zika nucleic acid diagnostics available under EUAs.
 
The FDA reviewed data for the ZIKV Detect 2.0 IgM Capture ELISA test through the de novo premarket review pathway, a regulatory pathway for low-to-moderate-risk devices of a new type. Along with this authorization, the FDA is establishing criteria, called special controls, that determine the requirements for demonstrating accuracy, reliability and effectiveness of tests intended to identify Zika virus antibodies. These special controls, when met along with general controls, provide a reasonable assurance of safety and effectiveness for tests of this type. This action also creates a new regulatory classification, which means that subsequent devices of the same type with the same intended use may go through the FDA’s 510(k) pathway, whereby devices can obtain clearance by demonstrating substantial equivalence to a predicate device.
 
The FDA granted marketing authorization of the ZIKV Detect 2.0 IgM Capture ELISA to InBios International Inc.