“It is proven to reduce mortality by 35 percent. It’s a tremendous number,” Trump said at the press conference. “Based on this data, the FDA has made the determination the treatment is safe and very effective.” That last part isn’t actually true yet—without large-scale randomized controlled trials, which haven’t happened yet, no one actually knows that for sure. Yet the agency has issued what’s called an Emergency Use Authorization, not quite an approval of the treatment but still giving the all-clear to physicians who want to administer the frothy, yellow liquid.
Based on the president’s comments and those of FDA head Stephen Hahn and HHS director Alex Azar, the data that tipped plasma into getting this Emergency Use Authorization came from a nationwide program to give people wider access to convalescent plasma, led by researchers at the Mayo Clinic. That program was not a large, randomized, controlled clinical trial, which is typically the standard for determining whether a treatment is safe and effective. That “expanded access program” did publish some outcomes in a preprint two weeks ago. It still hasn’t been peer-reviewed, but the researchers did keep track of the levels of antibodies, disease-fighting molecules, in the plasma administered to 35,000 people. It turned out that those people who received plasma earlier, and with the highest levels of antibodies, did have an increased survival rate. But the 35 percent number wasn’t for everyone who got plasma, just a specific statistical slice of the tens of thousands who received plasma sooner and with higher antibody levels. And even though the people who set up the expanded access program wanted to run concurrent randomized, controlled trials, that’s not what this was.
The timing of the announcement makes the whole thing even weirder. The president, who during this week’s Republican National Convention will presumably accept his party’s nomination to run for a second term, is under increasing pressure to show some progress in the fight against Covid-19—a disease from which nearly 175,000 Americans have died, with little sign of abatement. The only randomized trials that have published data on plasma so far have been small and, while promising, inconclusive.
Technically, that’s fine for an EUA. The criteria for issuing one really just demand reasonable safety and the possibility of usefulness. The agency still maintains that it’ll take actual randomized trials to make convalescent plasma into standard care. And it’s not clear that the authorization does anything that the expanded-access program wasn’t already doing, making sure anyone who wanted plasma could get it.
“It’s sufficient for an Emergency Use Authorization in the sense that most EUAs make no claim of benefit. They simply authorize utilization during the emergency, and when the emergency is over they are automatically canceled,” says Peter Bach, director of the Center for Health Policy and Outcomes at Memorial Sloan Kettering Cancer Center. “That said, this is one of the more frustrating examples, where we have had every opportunity to do proper randomized trials on convalescent plasma. The sole excuse offered back in February and March was, ‘We don’t have time,’ and it’s now nearly September.”