A randomized controlled study of convalescent plasma for individuals hospitalized with COVID-19 pneumonia

infected individuals developing severe pneumonia requiring hospitalization. Substantial morbidity and mortality remain for patients with COVID-19 who are hospitalized with pneumonia, and few efficacious therapies exist. Early in the COVID-19 pandemic, convalescent COVID-19 plasma (CCP) was recognized as a potentially promising intervention. Use of convalescent plasma in other infectious diseases (2-5) and previous coronavirus pandemics (6, 7) provided biological plausibility, and early observational studies suggested possible benefit (8-10). In the setting of limited treatments and desperate clinical need, CCP was widely used in hospitalized patients with COVID-19 in the United States via an expanded access program (EAP) or emergency use authorization (EUA; refs. 3, 11) . These mechanisms enabled access to CCP by more than 500,000 hospitalized individuals, with up to 40% of US inpatients with COVID-19 receiving CCP in the fall of 2020 ( 12 ). Observational BACKGROUND. Antibody-based strategies for COVID-19 have shown promise in prevention and treatment of early disease. COVID-19 convalescent plasma (CCP) has been widely used but results from randomized trials supporting its benefit in hospitalized patients with pneumonia are limited. Here, we assess the efficacy of CCP in severely ill, hospitalized adults with COVID-19 pneumonia. METHODS. We performed a randomized control trial (PennCCP2), with 80 adults hospitalized with COVID-19 pneumonia, comparing up to 2 units of locally sourced CCP plus standard care versus standard care alone. The primary efficacy endpoint was comparison of a clinical severity score. Key secondary outcomes include 14-and 28-day mortality, 14-and 28-day maximum 8-point WHO ordinal score (WHO8) score, duration of supplemental oxygenation or mechanical ventilation, respiratory SARS-CoV-2 RNA, and anti-SARS-CoV-2 antibodies. RESULTS. Eighty hospitalized adults with confirmed COVID-19 pneumonia were enrolled at median day 6 of symptoms and day 1 of hospitalization; 60% were anti-SARS-CoV-2 antibody seronegative. Participants had a median of 3 comorbidities, including risk factors for severe COVID-19 and immunosuppression. CCP treatment was safe and conferred significant benefit by clinical severity score (median [MED] and interquartile range ], P = 0.037) and 28-day mortality (n = 10, 26% vs. n = 2, 5%; P = 0.013). All other prespecified outcome measures showed weak evidence toward benefit of CCP. CONCLUSION. Two units of locally sourced CCP administered early in hospitalization to majority seronegative participants conferred a significant benefit in clinical severity score and 28-day mortality. Results suggest CCP may benefit select populations, especially those with comorbidities who are treated early. TRIAL REGISTRATION. ClinicalTrials.gov NCT04397757.