Mayo finds convalescent plasma safe for diverse patients with COVID-19

Mayo Clinic researchers and collaborators have found investigational convalescent plasma to be safe following transfusion in a diverse group of 20,000 patients. The findings — from the Food and Drug Administration’s Expanded Access Program for COVID-19 — are reported in Mayo Clinic Proceedings.

The safety report assessed the seven days following transfusion for hospitalized patients between April 3 and June 11 who were deemed at risk of progressing to a severe or life-threatening condition. Almost 40% of the patients were women; 20% African Americans; nearly 35% Hispanic and 5% Asian. Seven-day mortality rates declined to 8.6 % compared to 12% in a previous safety study of the first 5,000 transfused patients. Serious adverse events continued to be less than 1%.

“Our efforts to understand convalescent plasma continue,” says Michael Joyner, M.D. (ANES ’92) principal investigator of the EAP at Mayo Clinic and lead author of the article. “We’re optimistic but must remain objective as we assess increasing amounts of data.”

This expanded safety report reveals a decline in mortality which appears contemporary with the more rapid availability of plasma for use, but the authors caution that this alone does not provide any evidence on effectiveness of convalescent plasma for treating COVID-19. Given the accelerating use of the therapy, research is now broadening its focus to determine indicators of efficacy. At this time, convalescent plasma therapy is the only antibody-based therapy for COVID-19.

“The 7,000-plus physicians who are part of the program have done an exceptional job of offering convalescent plasma to a diverse group of patients, enrolling women as 40% of the participants as well as significant numbers of patients who are of African American, Asian or Hispanic ethnicity,” says Mayo Clinic researcher DeLisa Fairweather, Ph.D. (CV ’18) “We hope recruitment of minority subjects continues to increase given the disproportionate burden these communities have faced with COVID-19.”

The researchers say that while the mortality rate has decreased, the patients in the latter part of this study were less critically ill. They also say the decrease may be in part due to improved medical care based on increased knowledge during the pandemic and that more of the patients received the plasma earlier in their hospital treatment. They note that there was no system in place for delivering convalescent plasma in March, and now there is sufficient donation to meet most of the demand. Also, as donors came forward more rapidly, it was more likely their plasma contained neutralizing antibodies.

Physicians at any institution in the U.S. who are treating hospitalized patients with COVID-19 can register their patients’ information at uscovidplasma.org.

Patients who have recovered from COVID-19 and are seeking to donate plasma should contact the national resource sharing network for a nearby blood donation center location. Mayo Clinic, groups including Vitalant, America’s Blood Centers and many others within the larger commercial and non-commercial blood-banking community are working with physicians to collect and distribute donor plasma to hospitalized patients with severe or life-threatening COVID-19.

The study was supported by a contract with the U.S. Health and Human Services, Biomedical Advanced Research and Development Authority; multiple grants from the National Institutes of Health; Natural Sciences and Engineering Research Council of Canada; the Schwab Charitable Fund; United Health Group; the National Basketball Association; Millennium Pharmaceuticals; Octapharma USA, Inc.; and Mayo Clinic.

The convalescent plasma program at Mayo Clinic grew from a national initiative of physicians and investigators from 10 institutions that self-organized to investigate the use of convalescent plasma during the COVID-19 pandemic. These institutions include Mayo Clinic, Johns Hopkins University, Washington University, Einstein Medical Center, Icahn School of Medicine at Mount Sinai, Michigan State University and many other academic medical centers and government agencies seeking to establish a national program to modify the course of the disease.

Mayo Clinic is committed to advancing research so patients are able to benefit from new discoveries as quickly as possible. Mayo’s goal is to rapidly discover and apply scientific advances that will defeat this deadly disease.