UPDATE: On Aug. 18, 2021, a study summarizing the conclusion of the C3PO study was published in The New England Journal of Medicine. Researchers found no significant benefit of convalescent plasma for outpatients with early symptoms of COVID-19. A total of 27 patients were enrolled in the study at Oregon Health & Science University among more than 500 enrolled nationwide. See news release from the National Institutes of Health.
Oregon Health & Science University is part of a randomized, controlled clinical trial intended to determine whether convalescent plasma -- the liquid portion of blood collected from patients who have recovered from COVID-19 -- is effective in fighting infection caused by the novel coronavirus.
The study will recruit clinical trial participants who show up at emergency departments with relatively mild symptoms of COVID-19. The goal is to prevent a mild infection, which can be treated at home, from worsening to the point that it results in a patient being hospitalized. Participants must have at least one other factor that presents a risk to their health, such as hypertension or being over age 50.
Convalescent plasma has been tried with varying levels of effectiveness. Led by Stanford University, the new trial is the first to test effectiveness through a randomized controlled trial – the gold standard of clinical research.
Half of participants will be given an injection of convalescent plasma, and half will be given a saline solution with multivitamin as a placebo.
"Despite some of the media attention around convalescent plasma, we don't really know if it works," said Bory Kea, M.D., associate professor of emergency medicine in the OHSU School of Medicine. "There has not been a randomized, controlled trial using this intervention, and that's why we need to do this study."
Nationwide, the trial aims to recruit a total of 600 people with relatively mild symptoms of COVID-19, then test whether convalescent plasma is effective in preventing the disease from progressing to severe illness or death. Roughly 80% of all cases are considered mild, with 5% developing severe forms of the disease. Based on the size of the study, researchers expect they will be able to discern a statistically valid signal of effectiveness.
Aside from the injection, all patients will receive standard treatment.
The antibodies are elicited during infection, which is part of the body's natural immune system mobilized against the novel coronavirus and contained in convalescent plasma. The idea is to supplement each patient's immune response with antibodies donated by people who have successfully fought off the disease.
OHSU is part of a research consortium of emergency departments across the country, which makes it ideally suited to be part of the new trial.
Kea, who is leading the OHSU trial, estimated that OHSU sees about two people a week who fit the criteria for recruitment: Ill enough to have symptoms requiring a visit to the emergency department, but not so sick that they require hospitalization. Nationwide recruitment will occur over the next six to 12 weeks.
Given the lack of proven medications, Kea said the new study could be quite significant.
"Usually we have years to identify effective treatments, and we're doing it all in months," Kea said. "It's pretty amazing to see what we can do when we all put our minds together."
Support for the trial is provided by the National Heart, Lung and Blood Institute of the National Institutes of Health, grant award 1OT2HL156812-01.
The study will recruit patients with mild cases of COVID-19 who also have at least one of the following additional risk factors:
- More than 50 years old
- Hypertension
- Diabetes
- Coronary artery disease
- Chronic lung disease
- Chronic kidney disease
- Immunosuppression
- Sickle cell disease
- Obesity (body mass index greater than 30)
