Antibody tests for the coronavirus will face tougher scrutiny as scientists learn more about how the disease spreads and whether patients can catch the virus again.
The first antibody tests hit the market with minimal Food and Drug Administration oversight. Their accuracy varied widely, with lawmakers deriding some of the tests as “junk.” Accurate antibody tests can help determine how far the virus has spread and whether policies to contain it are working.
As researchers learn more about the virus, the FDA’s demands on test makers will change, Commissioner Stephen Hahn said this week at BIO Digital, the first virtual conference of the Biotechnology Innovation Organization. Those changes could lead to more accurate tests. For now, potentially faulty tests can stay on the market while under FDA review.
“We update that data as additional information comes in to us,” Hahn said. “We totally expect that some of the operating characteristics of the tests, we’ll learn more about them as we get more data, and we’ll update our emergency use authorization and then update the information that we give to end users.”
While it’s unknown for certain if people can catch the virus a second time, the presence of antibodies could lead them to assume they are immune. That could drive them to alter their behavior, spreading the virus further.
The FDA can take a lighter regulatory touch when the federal government declares a public health emergency. That’s why the agency allowed companies making commercial antibody tests to sell them without much oversight in March.
That let companies sell their antibody tests without an emergency use authorization—a label the FDA gives companies that have submitted some accuracy and safety information for review. While not as robust as reviews for standard device approvals, the emergency authorization gives the agency some control over the quality of products.
“When they made it an option not to submit it to FDA, that’s an option nearly everyone took,” Patrick Gallagher, chair of Duane Morris’ pharmaceuticals group, said.
“That’s the cautionary tale for the therapeutics and the vaccine for FDA and regulators around the world to make sure they’re making the process as efficient as possible but still making sure they’re getting enough data to be sure they’re comfortable and confident,” he said.
Without some sort of agency review, the accuracy of some of those initial antibody tests was “basically a coin toss,” Gigi Kwik Gronvall, an immunologist and professor at the Johns Hopkins Bloomberg School of Public Health, said.
The FDA in May required test makers without authorizations to submit applications with specific accuracy thresholds. As test accuracy increases, the FDA will likely tighten those requirements even further, Gronvall said.
While lawyers called the rapid policy shifts the FDA made to battle the Covid-19 pandemic overwhelming, Hahn said the standards for tests that determine either the presence of the virus or antibodies in people who have already been infected will remain a moving target.
“There are just so many FDA policies and there’s so much activity, we have a whole team of people trying to stay up to date,” Bethany J. Hills, a partner in Morrison Foerster’s New York office, said. “It literally changes on a day-to-day basis.”
The FDA uses the companies’ data to verify the antibody tests are accurate, but the standards keep changing, lawyers for the companies said.
The FDA has started to independently verify data on the antibody tests’ accuracy with help from outside partners. Some companies inform consumers about whether their data has be independently validated through paperwork that comes with tests, Gronvall said, but it’s not clear if that’s happening across the market.
Even with more concrete guidelines for antibody tests, their accuracy will still vary widely depending on how long it’s been since the suspected infection, Gronvall said. Antibodies change the more time passes between the sickness and when patients are tested. Certain tests are better at picking up one type of antibody over another.
That variety will likely cause even more confusion for those looking for simple answers, Gronvall said. The FDA has accuracy levels for antibody tests it has authorized on its website, but it is still complicated for a layperson to decipher.
Both the agency and companies should be making more effort to clearly display, in a consumer-friendly way, what a test can do and what data they’re relying on to reach that decision.
“Otherwise it’s just a buyers beware situation,” Gronvall said.
—With assistance from Jeannie Baumann