Clinical and laboratory evaluation of patients with SARS-CoV-2 pneumonia treated with high-titer convalescent plasma

Abstract

Here, we report on a phase IIa study to determine the intubation rate, survival, viral clearance, and development of endogenous Abs in patients with COVID-19 pneumonia treated with convalescent plasma (CCP) containing high levels of neutralizing anti-SARS-CoV-2 Abs. Radiographic and laboratory evaluation confirmed all 51 treated patients had COVID-19 pneumonia. Fresh or frozen CCP from donors with high titers of neutralizing Abs was administered. The nonmechanically ventilated patients (n = 36) had an intubation rate of 13.9% and a 30-day survival rate of 88.9%, and the overall survival rate for a comparative group based on network data was 72.5% (1625/2241). Patients had negative nasopharyngeal swab rates of 43.8% and 73.0% on days 10 and 30, respectively. Patients mechanically ventilated had a day-30 mortality rate of 46.7%; the mortality rate for a comparative group based on network data was 71.0% (369/520). All evaluable patients were found to have neutralizing Abs on day 3 (n = 47), and all but 1 patient had Abs on days 30 and 60. The only adverse event was a mild rash. In this study on patients with COVID-19 disease, we show therapeutic use of CCP was safe and conferred transfer of Abs, while preserving endogenous immune response.

Keywords: COVID-19; Immunotherapy.

Figure 1. Overall survival for patients nonmechanically ventilated (track 2).

BLQ, below limit of quantification; OS, overall survival.

Figure 2. Survival of patients on positive pressure mechanical ventilation (track 3).

Figure 3. Recipients’ neutralizing Ab titers percentage and frequency over time for all patients.

Figure 4. Neutralizing Ab titers percentage and frequency over time for nonimmune or minimally immune patients (≤1:100).