What Is Blood Plasma Treatment, and Why Did FDA Stop Emergency Use Authorization for Coronavirus?

Among the numerous approaches being tested as a treatment for infection with the novel coronavirus is blood plasma therapy, which the Food and Drug Administration (FDA) was just about to authorize for emergency use before federal health officials intervened.

According to The New York Times, the FDA was preparing to issue an emergency use authorization (EUA) last week, which would have allowed the doctors to administer the therapy as a COVID-19 treatment in certain situations without it having gone through the usual approval process.

During public health emergencies the FDA Commissioner may allow unapproved medical products or unapproved uses of approved medical products to be used in an emergency to diagnose, treat, or prevent serious or life-threatening diseases or conditions "when there are no adequate, approved, and available alternatives," according to the agency.

However, top federal health officials, including Dr. Francis Collins, director of the National Institutes of Health, and Dr. Anthony Fauci, the government's top infectious disease expert, stepped in to prevent the agency issuing the EUA, arguing that emerging data regarding the efficacy of blood plasma therapy against COVID-19 was not strong enough yet, two senior administration officials told the Times.

The therapy involves taking plasma—the pale, liquid portion of blood with all the white blood cells, red blood cells and platelets removed—from people who have recovered from COVID-19 and infusing it into patients who are currently suffering from the disease, according to Sarah Caddy from the University of Cambridge in the U.K. writing for the Conversation.

Blood plasma in patients who have recovered from the disease is rich in antibodies—proteins that fight off specific infections. The idea of the therapy is that transferring these antibodies, which bind to the novel coronavirus, will offer immediate, albeit temporary, protection.

There are some potential risks with this approach. For example, the person receiving the plasma may experience mild side effects, such as fever or allergic reactions. Furthermore, there is the potential to transmit blood-borne infections although blood-screening can minimize this risk.

So far, evidence suggests that plasma therapy—which has long been used to treat other diseases—is safe as a treatment for COVID-19. However, scientists still do not know whether it is effective in combating the infection, something that is currently being investigated in several clinical trials.

The top health officials urged the FDA to hold off on issuing the EUA for plasma blood therapy after reviewing recent data from the largest study of its kind in the country, run by the Mayo Clinic, that has given plasma infusions to more than 66,000 COVID-19 patients.

They concluded that the evidence from the study so far was to weak to justify an EUA at this point, although one still could be issued in the coming weeks as more evidence is examined, H. Clifford Lane, clinical director at the National Institute of Allergy and Infectious Diseases, told the Times.

"The three of us are pretty aligned on the importance of robust data through randomized control trials, and that a pandemic does not change that," Dr. Lane told the Times, referring to himself, Collins and Fauci.

Randomized controlled trials are the gold standard of drug testing, however, the most recent set of data from the Mayo Clinic trial—collected from around 35,000 patients—did not include a control group that were given a placebo rather than the plasma therapy. This means that definitive conclusions about the effectiveness of the drug are difficult to draw from the results at this point.

The FDA has already issued one EUA during the COVID-19 pandemic for the anti-malaria drugs hydroxychloroquine and chloroquine, however, this was later withdrawn after evidence from large studies emerged indicating that the medications were not effective against hospitalized coronavirus patients.