CONVALESCENT PLASMA for OUTPATIENTS with EARLY COVID-19: A RANDOMIZED TRIAL

ABSTRACT

Background: Trials on convalescent plasma (CP) for hospitalized patients with COVID-19 have not demonstrated clear benefits. However, data on outpatients with early symptoms are limited. We studied if treatment with CP reduces disease burden of outpatients treated in the first 7 days of symptoms. Methods: Two double blind randomized trials (NCT04621123, NCT04589949) were merged. Pooling of data started when <20% of their predefined sample size had been recruited. A Bayesian adaptive individual patient data meta-analysis was implemented. Analyses were done with Bayesian proportional odds and logistic models, where odds ratios(OR)<1.0 indicate a favorable outcome for CP. A DSMB monitored the accumulating data for efficacy. Patients aged ≥50, diagnosed with COVID-19 and symptomatic for ≤7days were eligible for participation. The intervention was one unit (200-300mL) of CP with a predefined minimum level of antibodies. The two primary endpoints were (a) a 5-point disease severity scale (fully recovered by day 7 or not, hospital or ICU admission and death) and (b) a composite of hospitalization or death. Secondary endpoints were efficacy in patients with ≤5days of symptoms and time to full symptom resolution. Results: Of 797 patients included, 390 received CP and 392 placebo. They had a median age of 58, 1 comorbidity, symptoms for 5 days and 93% tested negative for SARS-CoV-2 S-protein IgG antibodies. 74 patients were hospitalized, 6 required mechanical ventilation and 3 died. The OR of CP for an improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311). The OR for hospitalization or death was 0.919 (CI 0.592-1.416). The effect of CP on hospital admission or death was largest in patients with ≤5days of symptoms (OR 0.658, 95% CI 0.394-1.085). CP did not decrease the time to full symptom resolution (p=0.62). Conclusion: Treatment with CP of outpatients in the first 7 days of symptoms did not improve outcome of COVID-19. The possible beneficial effect in patients with ≤5days of symptoms requires further study.