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

We are reporting on a phase IIa study which aimed to determine the intubation rate, survival, viral clearance, and the development of endogenous antibodies in patients with COVID-19 pneumonia treated with convalescent plasma (CCP) containing high levels of neutralizing anti-SARS-CoV-2 antibodies. All 51 treated patients had COVID-19 pneumonia by radiographic and laboratory evaluation. Fresh or frozen CCP from donors with high titers of neutralizing antibodies was administered. The non-mechanically ventilated patients (n=36) had an intubation rate of 13.9% and a day-30 survival of 88.9%. The overall survival for a comparative group based on network data was 72.5% (1625/2241). Patients had rates of negative nasopharyngeal swab on day +10 and +30 of 43.8% and 73% respectively. Patients mechanically ventilated had a day-30 mortality of 46.7%; the mortality for a comparative group based on network data was 71% (369/520). All evaluable patients were found to have neutralizing antibodies on day +3 (n=47), and all but 1 had antibodies on day +30 and +60. The only adverse event was a mild rash. We are concluding that in this study of patients with COVID-19 pneumonia, CCP was safe and conferred transfer of antibodies while preserving endogenous immune response.