A Randomized Controlled Study Assessing Convalescent Immunoglobulins vs Convalescent Plasma for Hospitalized Patients With Coronavirus 2019

Background: It is unknown whether convalescent immunoglobulins (cIgGs) are better than convalescent plasma (CP) for patients with coronavirus 2019 (COVID-19).

Methods: In this randomized controlled trial, we assigned high risk COVID-19 patients with ≤10 days of symptoms, to receive cIgGs or CP. The primary endpoint was improvement on day 14 according to the World Health Organization scale. Secondary endpoints were survival on day 14, and improvement, survival, and percent of ventilated patients on day 28, and treatment response in unvaccinated and vaccinated patients.

Results: A total of 319 patients were included: 166 received cIgGs and 153 CP. Median age was 64 to 66 years. A total of 112 patients (67.5%) in the cIgG group and 103 patients (67.3%) in the CP group reached the primary endpoint. Difference between groups was 0.1 (95% confidence interval, -10.1 to 10.4; P = .026), failing to reach noninferiority. More patients receiving cIgG improved by day 28 (136 patients [81.9%] and 108 patients [70.6%], respectively; 95% confidence interval, 1.9-20.7; P < .001; for superiority P = .018). Seventeen patients in the cIgG group (10.2%) and 25 patients (16.3%) in the CP group required mechanical ventilation (P = .136). Sixteen (9.6%) and 23 (15%) patients, respectively, died (P = .172). More unvaccinated patients improved by day 28 in the cIgG group (84.1% vs 66.1%; P = .024), and survival was better in the cIgG group (89.9% vs 77.4%; P = .066).

Conclusions: cIgGs failed to reach the primary noninferiority endpoint on day 14 but was superior to CP on day 28. Survival and improvement by day 28 in unvaccinated patients treated with cIgGs were better. In the face of new variants, cIgGs are a viable option for treating COVID-19.

Trial registration number: My Trials MOH_2021-01-14_009667.