Serological Diagnostics Regulatory Pathway - May 4th Update

From March 16th, 2020 to May 4th, 2020 FDA allowed antibody-based tests access to market under two pathways during the emergency declaration: Notification (Policy D) and EUA. FDA indicated that EUA application was appropriate for tests seeking a sole diagnosis claim, while notification was appropriate for tests with a qualitative IgG or IgM claim. However, today FDA announced a major policy reversal regarding serological tests.

On May 4th, 2020 FDA published the following piece: Insight into FDA’s Revised Policy on Antibody Tests: Prioritizing Access and Accuracy by Anand Shah, M.D., Deputy Commissioner for Medical and Scientific Affairs, and Jeff Shuren, M.D., Director, Center for Devices and Radiological Health¹. The rationale provided for increased regulatory flexibility early on was to answer critical population-level questions about the prevalence of COVID-19 infections, presence of antibodies, and whether or not they convey immunity. FDA stated that policy D was intended to limit antibody testing to CLIA certified labs with special clinical and technical expertise. However, FDA acknowledged that the risk benefit profile of serological tests brought to market has shifted from where it was in the middle of March. The agency has observed unscrupulous actors marketing fraudulent test kits and making false claims of FDA approval or authorization. FDA noted that they have also observed inaccurate claims that tests can be used at home for diagnosis. 

In response to the shift in benefit risk profile, on May 4th, 2020 FDA re-issued their guidance document, Policy for Coronavirus Disease-2019 Tests During the Public Health Emergency (Revised) Immediately in Effect Guidance for Clinical Laboratories, Commercial Manufacturers, and Food and Drug Administration Staff ². FDA has provided two voluntary EUA templates for antibody tests, one for commercial manufacturers and one for CLIA certified high complexity labs in the guidance document. The guidance contains new requirements for on-market serological tests:

• Commercial manufacturers must submit EUA requests, with their validation data, within 10 business days from the date they notified the FDA of their validation testing or from the date of the revised policy, whichever is later.
• FDA has provided specific performance threshold recommendations for specificity and sensitivity for all serology test developers.
  • Clinical agreement data should use at least 30 antibody positive samples for each immunoglobulin claimed and 75 antibody negative samples from patients test for SARS-COV-2 and confirmed negative. 
  • Data should demonstrate a minimum 90.0% positive percent agreement (PPA) and overall, 95.0% negative percent agreement (NPA) for tests that specifically report IgM and IgG.
  • Data should demonstrate a minimum PPA of 70% for IGM and a minimum PPA of 90% for IgG
• If a claim for fingerstick is desired, FDA recommends evaluating a minimum of 30 positive and 30 negative fingerstick whole blood samples.

The agency has also ramped up its ongoing efforts to shine a light on antibody test performance. FDA launched a serology test umbrella EUA that provides a streamlined pathway to market for certain tests that are independently validated by NCI as part of the partnership between FDA, NIH, CDC, BARDA and NCI³. Serological tests must meet performance and labeling criteria in order to qualify for the umbrella EUA. Tests must demonstrate a minimum of 90.0% positive percent agreement (PPA) and an overall 95.0% negative percent agreement (NPA) and include 30 confirmed SARS-COV-2 antibody positive serum/plasma samples and 80 negative serum/plasma samples. Additionally, 10 of the 80 negative samples must be confirmed to be HIV positive. This new EUA pathway is likely intended to incentivize participation in the independent validation program. Higher participation will allow FDA to identify poorly performing tests and cull them from distribution. FDA has also noted that tests results will be made public.

Since the first policy guidance document was issued, FDA has stressed the limitations of antibody tests. This sentiment continued in today’s announcement. FDA acknowledged 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.” And that “it may be necessary for some individuals to have two serology tests performed to generate reliable results. That is why antibody tests should only be used as part of a well-conceived testing plan and why the results should always be interpreted by appropriate experts.”¹ Today’s policy reversal demonstrates that COVID-19 regulatory landscape is particularly dynamic and highlights the importance of ongoing regulatory intelligence. Novateur Ventures Inc. has highly skilled and knowledgeable regulatory professionals that can help you navigate the constantly changing FDA EUA requirements. 

References:

1. Insight into FDA’s Revised Policy on Antibody Tests: Prioritizing Access and Accuracy
2. Policy for Coronavirus Disease-2019 Tests During the Public Health Emergency (Revised)
3. Serology IVD Umbrella