Scientists and public health officials said Monday they are skeptical convalescent plasma is an effective treatment for patients hospitalized with Covid-19, even after the Food and Drug Administration issued an emergency use authorization for the treatment and President Donald Trump touted it as a "breakthrough."
There are no formally approved drugs or vaccines for the coronavirus. Convalescent plasma is one of several therapies being tested as a potential treatment.
The plasma, taken from patients who have recovered from Covid-19 and developed antibodies against the virus, is infused in sick patients. Scientists hope it helps kick-start the immune system to fight the virus. A study of 35,000 patients posted earlier this month by the Mayo Clinic and sponsored by the National Institutes of Health suggested the plasma may reduce mortality in some hospitalized patients. Though the study had no placebo group to compare the results, making it hard to determine whether the treatment actually worked.
The FDA said Sunday it was granting the emergency use, allowing health-care providers in the U.S. to treat suspected or laboratory-confirmed Covid-19 in hospitalized patients with the disease. The agency said it was reasonable to believe the treatment may be effective in treating Covid-19 patients, and the known and potential benefits outweigh the known and potential risks.
Adequate and well-controlled randomized trials "remain necessary" for a definitive demonstration of effectiveness and "to determine the optimal product attributes and appropriate patient populations for its use," the FDA said in granting emergency use.
"This is a powerful therapy that transfuses very, very strong antibodies from the blood of recovered patients to help patients battling an infection. It's had an incredible rate of success," Trump said Sunday evening at a White House briefing, calling the treatment a "breakthrough." "Today's action will dramatically expand access to this treatment."
Scientists and public health officials have doubts, saying more data from randomized controlled trials, which are considered the "gold standard" in science, is still needed to know whether it is safe and effective. Results from trials have not been conclusive, were relatively small and have provided "very low-quality evidence," according to the World Health Organization.
"We've been tracking this," Dr. Soumya Swaminathan, the WHO's chief scientist, said Monday in Geneva. "We do ongoing meta-analyses and systematic reviews to see where the evidence is shifting or pointing, and at the moment it's still very low-quality evidence. So we recommend that convalescent plasma is still an experimental therapy. It should be evaluated in well-designed, randomized, clinical trials."
She said countries can use it on an emergency basis "if they feel the benefits outweigh the risks, but that's usually done while awaiting the more definitive evidence, which is yet to come."
The FDA has issued emergency use authorization for several coronavirus tests and some drugs. In May, the agency granted antiviral remdesivir the authorization, allowing hospitals and doctors to use the drug on hospitalized Covid-19 patients. Hydroxychloroquine was also granted emergency authorization, but the FDA later removed the designation once the agency found the malaria drug was unlikely to be effective.
Results of the study by the Mayo Clinic that the FDA cited in its authorization of the plasma treatment indicates that patients below age 80 who were not on a respirator and received plasma with a high level of antibodies within three days of diagnosis were about 35% more likely to survive another 30 days compared with patients who received plasma with a low level of antibodies.
The study acknowledged, however, that its findings are limited, particularly because it did not have a placebo comparison.
Dr. Scott Gottlieb, a former FDA commissioner, said the treatment might help patients but it "doesn't look like a home run." He did agree that convalescent plasma "certainly" met the standard for an emergency use approval "in the setting of a public health emergency."
"I think that this could be beneficial. It might be weakly beneficial," Gottlieb said on "Squawk Box." "It doesn't look like a home run, but right now we're looking for singles and doubles. There aren't really going to be any home runs on the horizon until we can get the other therapeutic antibodies on the market and hopefully eventually vaccines and better therapeutics."
Lawrence Gostin, a professor and faculty director of the O'Neill Institute for National and Global Health Law at Georgetown University, is skeptical about the treatment's effectiveness. He also said he was concerned the FDA had been politically pressured to authorize the treatment before data showed whether it was safe and effective. Trump's announcement on Sunday night came on the eve of the start of the Republican National Convention and 10 weeks before the Nov. 3 presidential election.
On Saturday, Trump accused FDA Commissioner Stephen Hahn of delaying enrollment in clinical trials for Covid-19 vaccines or therapeutics because of political motivations.
"The EUA was granted without a published peer review study and rolled out with political fanfare," said Gostin, also the director of the WHO's Collaborating Center on National and Global Health Law. "I'm worried the scientific integrity of FDA may be significantly compromised."
Dr. Jeremy Faust of Boston's Brigham and Women's Hospital and Harvard Medical School blasted the FDA, tweeting that "science lost today" and "politics won."
"Breakthroughs come from randomized controlled trials," he said. "Not cherry picking subsets of existing datasets and finding one promising finding amongst a sea of disappointment."