BACKGROUND The evidence for benefit of convalescent plasma for critically ill patients with Covid-19 is inconsistent. We hypothesized that convalescent plasma would improve outcomes for critically ill adult patients with Covid-19.
METHODS In an ongoing adaptive platform trial, critically ill patients with confirmed Covid-19, defined as receiving intensive care-level organ support, were randomized to open-label convalescent plasma or not (i.e., control group). The primary end point was organ support-free days (i.e., days alive and free of ICU-based organ support) up to day 21. The primary analysis was a Bayesian cumulative logistic model with predefined criteria for superiority or futility. An odds ratio greater than 1 represented improved survival, more organ support–free days, or both.
RESULTS The convalescent plasma intervention was stopped after pre-specified criteria for futility were met. At that time, 1084 participants had been randomized to convalescent plasma and 916 to no convalescent plasma (control). The median organ support-free days were 0 (interquartile range, -1 to 16) for the convalescent plasma group and 3 (interquartile range, -1 to 16) days for the control group. The median adjusted odds ratio (OR) was 0.97 (95% credible interval 0.83 to 1.15) and posterior probability of futility (OR < 1.2) was 99.4% for convalescent plasma compared to control. In-hospital mortality was 37.3% (401/1075) in convalescent plasma group, and 38.4% (347/904) in controls. The observed treatment effects were consistent across primary and secondary outcomes.
CONCLUSIONS In critically ill adults with confirmed Covid-19, treatment with convalescent plasma, did not improve clinical outcomes.