COVID-19 News

BARDA-funded study favors early COVID-19 treatment with convalescent plasma

Hospitalized COVID-19 patients who received convalescent plasma were much less likely to die if they received the treatment within three days of diagnosis than if they received it later, according to researchers running a large national study funded by the Biomedical Advanced Research and Development Authority (BARDA).

The researchers presented their data analysis on August 2 in a webinar for physicians interested in learning about so-called convalescent plasma (transfusions of blood plasma rich with antibodies from recovered patients) with data slides that were reviewed by The Wall Street Journal. The researchers said they saw signs that the treatment might be working in patients who received high levels of antibodies in plasma early in the course of their illness. They based their conclusions on an analysis of about 3,000 patients.

Patients who at three days or less after diagnosis received plasma containing high levels of antibodies against the coronavirus had a mortality rate of 6.6% at seven days after the transfusion. That compared with a mortality rate of 13.3% for patients who got plasma with low levels of antibodies at four days or more after diagnosis. That indicates reduced mortality of about 50%, the researchers said.

At 30 days after transfusion, the mortality rate was reduced by about 36%, investigators reported.

The data haven’t been published in a journal or subjected to peer review. At the webinar presentation, investigators said the conclusions are their own and don’t represent an official government endorsement of efficacy of convalescent plasma.

The sharing of the data comes as the Food and Drug Administration (FDA) is nearing a decision to authorize emergency use of convalescent plasma for treating people infected with the coronavirus. The FDA can’t comment on whether it would take such action, a spokeswoman said.

The data were submitted to the FDA, which is sponsoring an expanded-access program led by the Mayo Clinic in Rochester, Minn. The Mayo Clinic organized the webinar.

The FDA can’t comment on the conclusions of the investigators, a spokeswoman said, adding that, as with other medical products, the FDA is assessing “all of the available evidence that could potentially support the use of convalescent plasma for the management of Covid-19.”

There is a long history of using convalescent plasma to treat people during large viral outbreaks, including the 1918 influenza pandemic and the 2014 Ebola outbreak in West Africa. Many doctors and hospitals are treating hospitalized COVID-19 patients with convalescent plasma under compassionate-use protocols or as part of studies.

The Mayo-led expanded-access program was set up to allow broad and quick access to convalescent plasma, and to ensure the safety of using antibodies from someone who recovered from the coronavirus to improve the immune response of a newly infected individual. Investigators said they initially thought a few thousand people might receive convalescent plasma through the expanded-access program. More than 53,000 COVID-19 patients have received it to date.

As the number of patients in the study multiplied, investigators began to wonder whether they could detect signs it was working, according to Michael Joyner of the Mayo Clinic, the principal investigator of the expanded-access study.

As part of the analysis, the investigators contacted individual blood-collection centers around the country, which retain small amounts of plasma collected from recovered patients. The investigators analyzed the samples and correlated each one to the outcome of individual patients in the study who received them.

Expanded-access studies don’t meet the scientific gold standard of a randomized controlled trial for proving whether a drug or treatment works. Investigators in the Mayo program can’t say with certainty whether the plasma treatment caused the improved outcomes because every patient in the study received it.

Randomized controlled clinical trials of convalescent plasma therapy are under way, including several studies examining its potential effectiveness in outpatient clinics. At present, only hospitalized patients have access to convalescent plasma.

Donald Berry, a professor in the department of biostatistics at the University of Texas MD Anderson Cancer Center, who isn’t involved in the convalescent plasma study and reviewed the slides at the Journal’s request, said the data are promising.

“I agree there is a signal of efficacy,” Dr. Berry said. “It is pointing in the right direction.”

The FDA is conducting additional studies to make sure any early signal of efficacy remains robust, the investigators said.

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