Convalescent Plasma as Adjunctive Therapy for Hospitalized Patients with COVID-19: The Co-CLARITY Trial.

Background And Objective: Convalescent plasma therapy (CPT) may reduce the risk of disease progression among patients with COVID-19. This study was undertaken to evaluate the efficacy and safety of CPT in preventing ICU admission among hospitalized COVID-19 patients.

Methods: In this open-label randomized controlled trial, we randomly assigned hospitalized adult patients with COVID-19 in a 1:1 ratio to receive convalescent plasma as an adjunct to standard of care or standard of care alone. The primary endpoint was ICU admission within first 28 days of enrolment. Primary safety endpoints include rapid deterioration of respiratory or clinical status within four hours of convalescent plasma transfusion and cumulative incidence of serious adverse events during the study period including transfusion-related acute lung injury (TRALI), transfusion-associated circulatory overload (TACO), severe allergic reactions, and transfusion-related infections.

Results: A total of 22 patients were assigned to receive convalescent plasma as an adjunct to standard of care and 22 to receive standard of care alone. The median time from onset of COVID-19 symptoms to study enrolment was eight days (IQR, 4 to 10). Two patients (9.1%) in the CPT group and one patient (4.5%) in the control group were admitted to the ICU. The primary outcome measure, ICU admission, was not different between the two groups (q-value >0.9). No patient who received convalescent plasma had rapid deterioration of respiratory/clinical status within four hours of transfusion and none developed TRALI, TACO, anaphylaxis, severe allergic reactions, or transfusion-related infections. There was also no significant difference in the secondary outcomes of 28-day mortality (two patients in the CPT group and none in the control group, q-value >0.90), dialysis-free days, vasopressor-free days, and ICU-free days.

Conclusions: Among hospitalized COVID-19 patients, no significant differences were observed in the need for ICU admission between patients given CPT as adjunct to standard of care and those who received standard of care alone. Interpretation is limited by early termination of the trial which may have been underpowered to detect a clinically important difference.