The Food and Drug Administration is reducing its authorization to use convalescent blood plasma for Covid-19 patients in an effort to guide physicians who have experienced a confusing pile of data on the effectiveness of therapy.
The agency said late Thursday that the permit, a controversial issue since it was first issued in August last year, will be reviewed to limit the use of plasma in early-hospitalized patients and inpatients with a condition that affects their ability to produce antibodies. Patients will be allowed to receive only plasma that contains high concentrations of antibodies.
“The upgrade is designed so that convalescent plasma can be best used for those who will benefit,” said Peter Marks, director of the FDA’s Center for Biological Evaluation and Research. “It is used somewhat more without discrimination.”
Dr. Claudia Cohn, medical director of AABB, an organization representing the transfusion-medicine community, said the group intends to issue interim recommendations on convalescent plasma later this month. “There are so many studies that have come to different conclusions,” she said. “It’s not clean, it’s not black and white.”
Dr. Marks said the FDA made its decision after evaluating the results of several recent studies. Some have shown benefits from convalescent plasma, the fluid that contains antibodies derived from the blood of people who have recovered from Covid-19. Others showed no benefit.
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Two convalescent plasma clinical trials for hospitalized patients were closed last month after investigators said there appeared to be no benefit. Three studies involving inpatients recently reported some plasma benefits, but only when given to patients shortly after admission. Another study showed that elderly patients who received plasma shortly after they had symptoms were less likely to develop serious illnesses.
Arturo Casadevall, president of molecular microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health, called the FDA’s decision a “step forward.” He said, “For the first time in the United States, doctors will have guidance on when to use it and how to use it” of convalescent plasma.
Dr. Casadevall is the co-founder of the Covid-19 Convalescent Plasma Project, which helped organize a nationwide study with extensive access to convalescent plasma, which began in April last year.
Despite conflicting findings, convalescent plasma remains in demand – in part because there are few effective treatments for Covid-19 and many people remain unvaccinated. Since the FDA issued the emergency permit in August last year, the blood industry has distributed an average of about 20,600 units of convalescent plasma per week to hospitals across the country, according to the American Red Cross.
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The FDA’s previous decision to authorize convalescent plasma for patients hospitalized with Covid-19 was largely based on the results of an agency-sponsored extended access program, through which more than 72,000 patients received plasma. For a study published last month in the New England Journal of Medicine, researchers analyzed data from 3,000 of these patients and reported an apparent survival benefit among hospitalized patients who did not receive mechanical ventilation, who received plasma containing concentrations. large amounts of antibodies.
But many scientists have expressed skepticism about the finding, saying that extended access studies do not have the scientific rigor of traditional studies because they do not have a control group to compare any apparent effect.
The FDA’s Dr. Marks said the convalescent plasma clearance “could have been handled much better.” It had to do with the sense of urgency that everyone feels. I can’t blame anyone for feeling a sense of urgency. “
Dr. Marks also said the data could be confusing. Each unit of convalescent plasma is unique, reflecting the immune response of the recovered patient who donated it. It took time to find out the best way to measure antibodies in a unit, he added.
The United States is not the only government trying to establish reliable guidelines for the use of convalescent plasma. In Argentina, a study of outpatients in the elderly, published last month in the New England Journal of Medicine, contributed to current recommendations to treat elderly patients with Covid-19 at the onset of the disease. “Plasma supplies are not endless, and public health officials invariably face difficult decisions,” said study co-author Dr. Fernando Polack of the Infant Foundation in Buenos Aires. In any of these decisions, data-based guidelines are needed and are the best way for clinicians to feel comfortable when dealing with individual cases.
Donors donating blood and plasma to a donation center in Brooklyn, NY
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Natalie Keyssar for The Wall Street Journal
Louis M. Katz, medical director of the Mississippi Valley Regional Blood Center in Davenport, Iowa, which supplies blood products to more than 120 hospitals, said there is little evidence to support the use of convalescent plasma in hospitalized patients. “I think there is data that works early,” he said. “As you move on to increasingly sick people, the evidence becomes thinner and thinner.”
In an editorial in the New England Journal of Medicine on the US Open Access Study, Dr. Katz said that convalescent plasma should only be used in patients at the beginning of the disease. The problem with this suggestion, he added later, is that the FDA’s emergency authorization still only covers hospitalized patients, who tend to go to the hospital when they’ve been sick for a long time.
Treatment of patients with Covid-19 who are just beginning to show symptoms presents its own challenges. Logistically, it is very difficult to treat patients earlier, said Dr. Katz. “It’s hard to transfuse a lot of plasma into outpatients.”
Dr. Marks said an extensive study by the National Institutes of Health is underway to test convalescent plasma in people with Covid-19 who are sick enough to come to the emergency room but are not hospitalized. as well as other randomized controlled trials. plasma in outpatients. “Until we have this data, we will keep the authorization for hospitalized patients,” he said. “We will refine it again, if necessary. This is a limited resource. ”
Write to Amy Dockser Marcus at [email protected]
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