FDA Authorizes Serology Test to Detect Neutralizing Antibodies

FDA recently authorized the first COVID-19 serology test that detects neutralizing antibodies from recent or prior SARS-CoV-2 infection. 

The emergency use authorization went to biotechnology company GenScript for its cPass SARS-CoV-2 Neutralizing Antibody Detection Kit. The test is the first to be approved by the FDA to specifically detect neutralizing antibodies in patient samples without the use of a live virus.

FDA determined that the benefits of the serology test outweigh the known and potential risks and authorized the test to be distributed to and used by authorized laboratories under the emergency use authorization. 

“The ability to detect neutralizing antibodies can help us gain additional insight into what the existence of antibodies may mean for patients as we continue the fight against COVID-19,” Tim Stenzel, MD, PhD, Director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, said in the announcement. 

“There are still many unknowns about what the presence of SARS-CoV-2 antibodies may tell us about potential immunity, but today’s authorization gives us another tool to evaluate those antibodies as we continue to research and study this virus,” Stenzel continued.

The cPass SARS-CoV-2 Neutralizing Antibody Detection Kit utilizes pure proteins that can be produced in a more reproducible way, a GenScript spokesperson said in a press release.

Most laboratories can detect the presence of neutralizing antibodies in patients in about an hour, according to the company. The quick turnaround time makes the test more broadly available and consistent between different facilities.

"Unlike commercially available antibody-based tests that are routinely used for detecting prior exposure to the virus, the cPass™ kit can assess both prior exposure and the presence of neutralizing antibodies in convalescent patients," David Martz, vice president of new product management in life science group at GenScript, said in the press release.

"The cPass™ kit is also a valuable tool for assessing vaccine performance. When vaccine companies start phase II or III trials, a standardized test that can detect neutralizing antibodies will be needed for a large cohort of patients to evaluate the efficacy of vaccines within different populations and regions,” Martz said

FDA previously issued emergency use authorizations to over 50 antibody tests, but these tests could only detect the presence of binding antibodies, which bind to a pathogen, but may not decrease the infection and destruction of cells. 

Experts believe that if an individual develops antibodies to the novel coronavirus, then they may have at least temporary immunity from reinfection, although this is still unproven and the parameters of that immunity are still unknown.

FDA authorized the first emergency use authorization for a COVID-19 serology test back in May.

The agency granted the emergency use authorization to Abbott for its SARS-CoV-2 IgG lab-based serology blood test on the Alinity I system.

The authorization was Abbott’s fourth COVID-19 test to receive FDA emergency use authorization. And company shipped nearly 30 million of its serology test globally in May.

The Alinity i system was designed to offer greater efficiencies to lab clinicians running tests. The systems are in use in hospital and academic centers as well as in laboratories around the world.

Since then, major pharmaceutical companies have invested in developing similar serology tests to detect COVID-19 antibodies in patients. The tests can help pinpoint how many people have already been infected with the novel coronavirus, which can aid research and surveillence efforts, the CDC says.