ABSTRACT
The authors declare no conflict of interest.The effectiveness of neutralizing monoclonal antibodies against emerging variants with spike protein mutations has been limited. Early high-titer convalescent plasma therapy (CPT) tends to be effective and a potential treatment option for COVID-19 outpatient treatment. An open-label, 1:1, randomized controlled trial compared the efficacy of high neutralizing titer CPT with favipiravir (CPT-FPV) versus sotrovimab. The study aimed to evaluate the non-inferiority of CPT-FPV treatment compared to sotrovimab in preventing hospitalization within 14 and 28 days. Among the 136 randomized participants, 68 received CPT-FPV, while 68 received sotrovimab. The study demonstrated that CPT-FPV was non-inferior to sotrovimab in preventing hospitalization within 14 and 28 days. No significant differences between the two treatment arms were observed in emergency room visits, oxygen supplementation, or mortality. Although there were no significant disparities in radiological, virological, or inflammatory marker outcomes, sotrovimab exhibited a more pronounced reduction in IL-6 levels during days 2–5 and lower MCP-1 levels on day 14. High neutralizing titer convalescent plasma and favipiravir demonstrated non-inferior to sotrovimab in preventing hospitalization, emergency room visit, oxygen supplementation, and mortality in mild-to-moderate COVID-19. The evidence may be a choice for treatment for new variants despite the need for further study. (The trial protocol was registered in the Thai clinical trials registry no. 20220319002.)