MINNEAPOLIS -- Preliminary research by Mayo Clinic shows that high-dose plasma therapy is correlated with fewer deaths in patients with severe COVID-19.
A 10 percentage point difference in deaths was found when comparing hospitalized COVID-19 patients who received donor plasma with high concentrations of virus-fighting antibodies compared with those who received lower concentrations, Mayo reported.
The findings are good news in the fight against a global pandemic with few proven treatments and an infectious disease that as of Wednesday had caused 57,779 known infections and 1,629 deaths in the state, according to the Minnesota Department of Health.
"I'm just grateful as an American and a doctor that we are seeing some potential benefit, because our patients and our country need some help with COVID," said Dr. R. Scott Wright, who is coordinating Mayo's national COVID-19 convalescent plasma program.
Mayo launched the program with support from the U.S. Food and Drug Administration this spring to provide plasma from donors who have recovered from COVID-19 as an experimental therapy at smaller or nonacademic hospitals that otherwise wouldn't have access to it.
More than 2,700 sites have registered and more than 56,000 patients with COVID-19 have already received plasma infusions, according to the program's website.
The preliminary results are based on samples of donor plasma sent to Mayo and clinic results from 3,000 COVID-19 patients. A key finding was that plasma was associated with fewer deaths when administered in three or fewer days of the patients' COVID-19 diagnoses.
Among patients who received the therapy this quickly, the death rate after seven days was 6.6% in those who received plasma with high antibody concentrations but 15.4% in those who received low concentrations. That gap persisted 30 days after treatment -- with a death rate of 17.6% in the high concentration group and 27.6% in the low concentration group.
The results come loaded with caveats, including that the Mayo Clinic hadn't intended them for public review yet. They were presented to the FDA as the agency considers whether to grant an emergency use authorization for broader use of convalescent plasma in COVID-19 patients with severe and potentially fatal cases. Mayo then presented the data in a webinar for clinicians this weekend that was leaked to the media.
The observational design of the program also means that there was no comparison group of patients who didn't receive plasma, and no way to know for sure if patients benefited from the plasma or any other type of treatment that they received for COVID-19.