Treatment of Coronavirus Disease 2019 Patients with Convalescent Plasma Reveals a Signal of Significantly Decreased Mortality

Abstract

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, has spread globally, and proven treatments are limited. Transfusion of convalescent plasma collected from donors who have recovered from COVID-19 is among many approaches being studied as potentially efficacious therapy. We are conducting a prospective, propensity score-matched study assessing the efficacy of COVID-19 convalescent plasma transfusion versus standard of care as treatment for severe and/or critical COVID-19. We present herein the results of an interim analysis of 316 patients enrolled at Houston Methodist hospitals from March 28 to July 6, 2020. Of the 316 transfused patients, 136 met a 28-day outcome and were matched to 251 non-transfused control COVID-19 patients. Matching criteria included age, sex, body mass index, comorbidities, and baseline ventilation requirement 48 hours from admission, and in a second matching analysis, ventilation status at day 0. Variability in the timing of transfusion relative to admission and titer of antibodies of plasma transfused allowed for analysis in specific matched cohorts. The analysis showed a significant reduction (P = 0.047) in mortality within 28 days, specifically in patients transfused within 72 hours of admission with plasma with an anti-spike protein receptor binding domain titer of ≥1:1350. These data suggest that treatment of COVID-19 with high anti-receptor binding domain IgG titer convalescent plasma is efficacious in early-disease patients.

Figure 1

Flowchart of the study population. Propensity score matching was based on patient age (categorical, per 10 years), sex, body mass index (categorical, ±30 kg/m²), diabetes, hypertension, chronic pulmonary disease, chronic kidney disease, hyperlipidemia, and coronary disease, and baseline ventilation status within 48 hours of admission (room air, supplemental oxygen, and mechanical ventilation). After establishing the first propensity score–matched cohort and obtaining day 0 for controls, a second match was run between cases and controls based on the ventilation status at day 0. COVID-19, coronavirus disease 2019.

Figure 2

Kaplan-Meier curves for mortality within 28 days post-day 0 for secondary matched cohorts. A: All secondary matched patients. B: Secondary matched patients transfused within 72 hours of admission. C: Secondary matched patients transfused >72 hours after admission. D: Secondary matched patients transfused within 72 hours of admission with plasma with anti–receptor binding domain IgG titer ≥1:1350.