FDA chief Hahn walks back plasma claims, but his correction still missed the mark, experts say

With the emergency use authorization (EUA) for convalescent plasma to treat COVID-19, the FDA and Commissioner Stephen Hahn, M.D., touched off a controversy—particularly about his presentation of the evidence and the political pressure from the White House.

Now, Hahn is defending the agency's move even as criticism continues and lawmakers express concern over the agency’s independence.

In a series of tweets late Monday, Hahn said the decision was made by “career scientists” at the agency “based on data submitted a few weeks ago.” Still, the timing was less than ideal, as the day before the announcement, President Donald Trump had accused the FDA of harboring “deep state” employees who are seeking to hurt the administration’s response to the pandemic.

At the plasma press briefing on Sunday, Hahn falsely said that the treatment is associated with a “35% improvement in survival.” In a tweet Monday, he corrected himself, saying the data so far show a “relative risk reduction not an absolute risk reduction.” That didn’t satisfy some experts, including physicians Eric Topol, M.D., and Adam Gaffney, M.D., who said the claims are still inaccurate.

In authorizing convalescent plasma, the FDA cited data from a single-arm observational study. The survival figure was apparently a comparison of benefit for patients who received plasma with a high dose of antibodies versus a low dose. That's not sufficient evidence to claim a survival benefit, experts said.

Following Sunday's EUA, former FDA Commissioners Scott Gottlieb, M.D., and Robert Califf, M.D., said the agency's move was legal, but they stressed the importance of the agency resisting political pressure and clearly presenting its data.

The evidence supports an EUA, “but we need better studies to confirm preliminary findings," Gottlieb said on Twitter. In authorizing the treatment for hospitalized patients, the FDA concluded the benefits are likely to outweigh risks. Still, the agency admits controlled trials are needed. 

That doesn't match with what was said at the press briefing Sunday. Trump called plasma a "historic breakthrough," and officials repeated the 35% improvement in survival figure at least 7 times, according to a White House transcript. Hahn's Monday tweet came more than 24 hours after those statements.

"We dream, in drug development, of something like a 35% mortality reduction," HHS secretary Alex Azar said at the event. "This is a major advance in the treatment of patients. This is a major advance."

RELATED: FDA's emergency nod for convalescent plasma sparks questions of whether it's bowing to Trump 

All of the developments have some lawmakers worried. In a letter to Hahn Monday, leaders of the House Committee on Energy and Commerce said they’re “gravely concerned” about recent statements from Trump and other officials directed at the FDA. 

After Trump's "deep state" allegation, White House Chief of Staff Mark Meadows doubled down, reportedly saying that “sometimes you have to make them feel the heat if they don’t see the light.”

“As FDA Commissioner, it is your responsibility to lead and defend the agency, yet when the President and his Chief of Staff accused the FDA of being part of the 'deep state' you remained silent,” Reps. Frank Pallone, D-New Jersey; Anna Eshoo, D-California; and Diana DeGette, D-Colorado, wrote to Hahn. 

It’s not a one-off episode either, the lawmakers argued. Instead, it’s the latest instance of “science being politicized” during the U.S. pandemic response. For evidence, the lawmakers pointed to hydroxychloroquine saga, criticism of National Institute of Allergy and Infectious Diseases chief Anthony Fauci, M.D., and the administration's sidelining of the Centers for Disease Control and Prevention in favor of the White House coronavirus task force.

RELATED: Is the 'deep state' running the FDA? Trump tweet sparks pushback amid COVID-19 fight 

In their letter, the lawmawkers asked Hahn for information about the FDA’s safeguards to defend against political pressure and detailed info about future vaccine reviews, asking him to respond by Sept. 4.

Hahn told Reuters Monday he hasn’t seen any evidence of a “deep state” at the agency. The plasma EUA was based on scientific evidence, he said, adding that the agency would require potential COVID-19 vaccines to be safe and effective before they are given to Americans.