Mayo Clinic and collaborators have published a preprint that identifies two main signals of efficacy that can inform future clinical trials on plasma therapy on COVID-19 patients. The data are extracted from the Mayo-led national Expanded Access Program (EAP) for convalescent plasma for the treatment of hospitalized patients with COVID-19.
The researchers report in “Effect of Convalescent Plasma on Hospitalized Patients with COVID-19: Initial Three-Month Experience” that the timing of plasma transfusions in a cohort of 35,322 patients were associated with lower mortality. The cohort included a high proportion of critically ill patients, with 52.3% in the intensive care unit (ICU) and 27.5% receiving mechanical ventilation at the time of plasma transfusion. They also report that in a subset of the cohort (3,082 patients), they found lower mortality associated with plasma transfusions that contained higher levels of antibodies against the virus that causes COVID-19. Specifically:
- The seven-day mortality rate was reduced in patients transfused within three days of COVID-19 diagnosis compared with patients transfused four or more days after COVID-19 diagnosis. Similar trends were seen for 30-day mortality rate.
- The use of convalescent plasma with higher antibody levels was associated with reduced seven-day and 30-day mortality.
The overall cohort included a diverse representation of participants by age, gender, weight, race and ethnicity. Study participants included approximately 40% females; 38% Hispanic/Latinos; 19% African American; and 4% Asian. This study includes adult participants enrolled in the U.S. Convalescent Plasma EAP program between April 4 and July 4 who were hospitalized with (or at risk of) severe or life-threatening acute COVID-19 respiratory syndrome.