A clinical trial investigating the use of coronavirus disease 2019 (COVID-19) convalescent plasma for the treatment of emergency department (ED) patients with mild to moderate symptoms of COVID-19 has been halted, according to the National Institutes of Health (NIH).

The trial (ClinicalTrials.gov: NCT04355767), which was launched in August 2020, compared the efficacy and safety of convalescent plasma to placebo in adults who were admitted to the emergency department with mild to moderate COVID-19 symptoms that were present for a week or less. The trial enrolled 511 adult participants across 47 hospital emergency departments in the United States who had at least 1 risk factor for severe COVID-19 (eg, obesity, hypertension, diabetes, heart disease or chronic lung disease). 

The primary end point was the number of participants with disease progression defined as a need to seek further emergency or urgent care, hospitalization, or death within 15 days of entering the trial.

The decision to discontinue the study was made following a second planned interim analysis on February 25, 2021. Findings of the analysis showed no significant difference in outcomes between the 2 groups. An independent data and safety monitoring board determined that “while the convalescent plasma intervention caused no harm, it was unlikely to benefit this group of patients,” A decision was made thereafter by the National Heart, Lung, and Blood Institute to stop enrolling new patients into the study.

Based on these findings, the investigators concluded that, “Even if enrollment continued, this trial was highly unlikely to demonstrate that COVID-19 convalescent plasma prevents progression from mild to severe illness in at-risk emergency department non-hospitalized participants.”


NIH halts trial of COVID-19 convalescent plasma in emergency department patients with mild symptoms. [press release]. Bethesda, MD: National Institutes of Health; March 2, 2021.