By Jaimy Lee
The Food and Drug Administration’s decision to crack down on a loose set of regulatory requirements for antibody tests comes in response to their own concerns about test validity and fraud.
Using its emergency powers, the regulator had announced March 16 that it would allow makers of antibody tests to bypass the emergency use authorization process and let laboratories certified by the Centers for Medicare and Medicaid Services use those diagnostics, in hopes of speeding up development of the much in-demand serological tests.
Not all test makers bypassed the EUA. At least 12 commercial and private labs includes Abbott Laboratories /zigman2/quotes/203724446/composite ABT -0.55% , PerkinElmer Inc. /zigman2/quotes/203769792/composite PKI -0.44% and Roche Holding AG /zigman2/quotes/206324342/delayed CH:ROG +0.41% have received an emergency authorization for their antibody tests.
These tests, which can pinpoint which individuals have previously been infected with COVID-19, even asymptomatically, have been held up as key to reopening restaurants, shops, factories, workplaces, and other parts of the still shuttered economy. With viral infections, antibodies can often indicate immunity to future infections, though that pattern is unclear with the coronavirus. (A different kind of test, a molecular test, is used to diagnose a current COVID-19 infection.)
“Serological assays are needed and should be widely available, accurate, rapid, and low cost,” the American Enterprise Institute wrote in a March 29 report on reopening the economy. “Such assays have already been developed by researchers, but they have not yet been fully validated and are not available at scale.”
In the less than two months since the FDA implemented that policy, two issues came up that worried the FDA enough to rethink that policy: a lack of insight into test validation data and fraudulent marketing claims by “unscrupulous actors.”
“Flexibility never meant we would allow fraud,” the FDA said Monday.
Test makers now have 10 business days following a FDA notification to submit their validation results. This way, “the FDA is able to examine data on the test’s performance and make a formal determination of whether to authorize it for emergency use.”
“The tests [were] being marketed without the submission of validation data, and (consequently) relatively low sensitivity and specificity in many cases,” Stifel analysts wrote May 4. “This is highly sub-optimal, as the low prevalence of the disease means that even good tests with specificity rates of 99+% will still yield a large number of false positives — much less tests with rates in the high 80’s or low/mid 90’s.”
Antibody tests aren’t perfect, even by the FDA’s standards. The regulator noted that all antibody tests can produce false results, based on their “inherent limitations.” In some cases, at least two antibody tests may need to be performed for one patient.
The Abbott test, for example, has 100% IgG sensitivity and 99.6% specificity, while PerkinElmer’s test has 90% IgG sensitivity and 100% specificity. Researchers are usually looking for one of two antibodies: immunoglobulin M (IgM) and immunoglobulin G (IgG).
Large corporations, in particular, are eager to have employees return to work and have talked up the potential of serological testing to investors during this earnings season.
“I’m excited to hear about the Roche antibody test this morning, and we can all go back to work if we know that half the country’s already been exposed and won’t get it,” Barry Sternlicht, CEO of the Starwood Property Trust Inc. /zigman2/quotes/202642684/composite STWD -4.21% told investors on Monday, according to a FactSet transcript of the earnings call.
“Much more of the focus right now has shifted to testing as governments around the world are trying to figure out — and states are trying to figure out — how to bring people back to work,” Stryker Corp. /zigman2/quotes/207664662/composite SYK -1.94% CEO Kevin Lobo said on Friday. “So that’s the big focus right now, on testing.
SL Green Realty Corp. /zigman2/quotes/208985878/composite SLG -4.66% , a real-estate investment trust, is considering antibody tests and vaccination stations. “Will be surrounding our lobby with the necessary support to understand exactly how everything should flow through,” COO Edward Piccinich said April 23.
Shares of test manufacturers have largely gone up in recent months. Year-to-date, Abbott’s stock is up 7.1%, and shares of Roche have gained 8.0%. (Both companies are also making diagnostics tests for COVID-19, and Roche is testing its Actemra as a potential treatment for severely ill patients.) PerkinElmer shares, however, have dropped 6.3%. The Health Care Select Sector SPDR Fund /zigman2/quotes/205918244/composite XLV -0.87% is down 3.5%.