Convalescent plasma for preventing critical illness in COVID-19: A phase 2 trial and immune profile

Abstract

Rationale: The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an unprecedented event requiring rapid adaptation to changing clinical circumstances. Convalescent immune plasma (CIP) is a promising treatment that can be mobilized rapidly in a pandemic setting.

Objectives: We tested whether administration of SARS-CoV-2 CIP at hospital admission could reduce the rate of ICU transfer or 28 day mortality.

Methods: In a single-arm phase II study, patients >18 years-old with respiratory symptoms documented with COVID-19 infection who were admitted to a non-ICU bed were administered two units of CIP within 72 hours of admission. Detection of respiratory tract SARS-CoV-2 by polymerase chain reaction and circulating anti-SARS-CoV-2 antibody titers were measured before and at time points after CIP transfusion.

Measurements and main results: Twenty-nine patients were transfused CIP and forty-eight contemporaneous controls were identified with comparable baseline characteristics. Levels of anti-SARS-CoV-2 IgG, IgM, and IgA anti-spike, anti-receptor-binding domain, and anti-nucleocapsid significantly increased from baseline to post-transfusion for all proteins tested. In patients transfused with CIP, the rate of ICU transfer was 13.8% compared to 27.1% for controls with a hazard ratio 0.506 (95% CI 0.165-1.554), and 28-day mortality was 6.9% compared to 10.4% for controls, hazard ratio 0.640 (95% CI 0.124-3.298).

Conclusions: Transfusion of high-titer CIP to patients early after admission with COVID-19 respiratory disease was associated with reduced ICU transfer and 28-day mortality but was not statistically significant. Follow up randomized trials may inform the use of CIP for COVID-19 or future coronavirus pandemics.