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Government ends research of plasma for COVID-19
The federal government discontinued a research trial of convalescent plasma for COVID-19 saying the blood product from recovered patients doesn’t prevent at-risk people visiting emergency rooms from getting sicker.
Convalescent plasma has been used widely to treat patients with COVID-19. The Food and Drug Administration authorized the emergency use of convalescent plasma last summer for hospitalized patients, though it said further research would be needed to confirm whether immune cells in a recovered person’s blood would help the next patient fight off the virus.
A trial run by the National Institutes of Health was stopped early Tuesday, because an independent group of reviewers determined it was not providing benefit to COVID-19 patients treated and released from emergency rooms.
“We do not see any sign that convalescent plasma had a benefit” in ER patients at risk for more serious disease, said Simone Glynn, program scientist for the trial.
Plasma from recovered patients contains antibodies or proteins generated by the immune system to fight disease. In some conditions, such as the flu, antibodies from a recovered patient are believed to help someone who has been infected.
For COVID-19, convalescent plasma “just doesn’t look like it’s providing any significant impact on things that count: mortality and hospitalization,” said Daniel Griffin, an infectious disease specialist at ProHEALTH Care in New York.
In science, a treatment’s effectiveness is ideally determined by a series of studies that show whether it did or didn’t work and in what context. Griffin said the majority of studies he’s seen found convalescent plasma ineffective.
There are more than 180 trials underway for convalescent plasma in COVID-19, including one led by Vanderbilt University in Nashville, Tennessee, using plasma in early hospitalized patients, and two at Johns Hopkins University in Baltimore looking at whether convalescent plasma reduces the risk of developing symptoms for people exposed to the virus that causes COVID-19 and whether it can be useful for those visiting doctors’ offices for COVID-19.
Dr. R. Scott Wright helped run a large convalescent plasma trial last summer out of the Mayo Clinic that concluded plasma can be helpful. The study of more than 100,000 patients, all of whom received some form of convalescent plasma, found there were 7.3% fewer deaths among patients who received plasma with high levels of antibodies than among patients who received plasma with few antibodies.
The Mayo Clinic study did not include a placebo group, so technically, it did not meet the gold standard for clinical trials, but it effectively did, Wright said, because getting plasma with low levels of antibodies is akin to receiving a placebo.
Wright criticized the new federal study as too small to provide any conclusive evidence of convalescent plasma’s effectiveness.
“We know it takes more than 1,000 patients to show a benefit of effectiveness,” Wright said. The government’s trials have involved too few patients and haven’t enough potential COVID-19 treatments, he said.
The federal trial, dubbed the Clinical Trial of COVID-19 Convalescent Plasma of Outpatients (C3PO), was done at 47 hospital emergency departments and had enrolled 511 participants out of its goal of 900. Planning for the trial began in April and enrollment in August.
An independent group of reviewers determined it was not providing benefit to COVID-19 patients.
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