FDA OKs Use of Convalescent Plasma for COVID-19
“A 35% improvement in survival is a pretty substantial clinical benefit. What that means is—and if the data continue to pan out—[of] 100 people who are sick with COVID-19, 35 would have been saved because of the admission of plasma,” Hahn said.
But in a press release from the FDA last night Hahn was more circumspect.
“We’re encouraged by the early promising data that we’ve seen about convalescent plasma. The data from studies conducted this year shows that plasma from patients who’ve recovered from COVID-19 has the potential to help treat those who are suffering from the effects of getting this terrible virus,” said Hahn. “At the same time, we will continue to work with researchers to continue randomized clinical trials to study the safety and effectiveness of convalescent plasma in treating patients infected with the novel coronavirus.”
Pressure to Approve?
Hahn’s press conference enthusiasm, according to the Washington Post, could be a sign he was buckling to political pressure from Trump, who tweeted over the weekend that the “deep state” was at work at the FDA, slowing down vaccine and treatment developments until after the presidential election.
Hahn’s interpretation of the 35% reduction in mortality was widely disputed by scientists on Twitter, who used the same data from the Mayo Clinic to show that 3.2 people out of 100—not 35—would be saved by the administration of convalescent plasma. The difference is in relative versus absolute risk, with 35% being the percent improvement but, because the rate of those seeing improvement was so low—8.7% to 11.9%—the absolute reduction is much smaller.
Also, even for that small absolute improvement, the plasma would need to be administered within 3 days versus 7, according to the Mayo data [to be precise: the Mayo Clinic study, which has not yet been peer-reviewed or published, involved 35,000 patients. There was no placebo group, and the patients who did better also received many more doses of anti-biotics relative to the patients who did worse. Patients who received transfusions of convalescent plasma within three days of diagnosis demonstrated a seven-day death rate of 8.7%. Patients who received plasma after four or more days had a mortality rate of 11.9%. This was deemed statistically significant].
Thomas File, MD, the president of the Infectious Disease Society of America (IDSA) also issued a cautious statement on the FDA’s announcement.
“While the data to date show some positive signals that convalescent plasma can be helpful in treating individuals with COVID-19, especially if given early in the trajectory of disease, we lack the randomized controlled trial data we need to better understand its utility in COVID-19 treatment,” File said.
“For this reason, IDSA supports the continued collection of data in randomized clinical trials to better understand the benefits of convalescent plasma treatment before authorizing its wider use in patients with COVID-19.”
Stephanie Soucheray is a news reporter for CIDRAP News.This article is published courtesy of the University of Minnesota’s Center for Infectious Diseases Research and Policy (CIDRAP).
