Celltrion Group announced top-line efficacy and safety data from the global Phase III clinical trial, demonstrating that anti-COVID-19 monoclonal antibody treatment candidate, regdanvimab (CT-P59), met all primary and key secondary endpoints in patients with mild- to- moderate symptoms of COVID-19 (n=1,315). Results showed that CT-P59 significantly reduced the risk of hospitalization or death by 72% for patients at high- risk of progressing to severe COVID-19 up to Day 28, compared to placebo, meeting the primary efficacy endpoint [3.1 vs. 11.1 %, p-value< 0.0001]. CT-P59 also significantly reduced the risk of hospitalization or death by 70% in all patients, meeting the first key secondary endpoint [2.4 vs. 8.0 %, p-value< 0.0001]. The trial also met the other key secondary endpoints, including faster and persistent reduction in symptom duration. Patients treated with CT-P59 (40mg/kg) recovered at least 4.7 days earlier than those in the placebo-treated patients [median 9.3 vs. minimum 14 days, p-value< 0.0001] for patients at high- risk of progressing to severe COVID-19. For all patients treated with CT-P59 (40mg/kg), patients recovered 4.9 days earlier than those in the placebo-treated patients [median 8.4 vs. 13.3 days, p-value< 0.0001]. Top-line results also showed CT-P59 to have a positive safety profile, with no clinically meaningful differences between patients treated with CT-P59 (40mg/kg) and placebo-treated patients. Infusion related reactions were mild and transient, with most patients recovering within 1~3 days. Therapeutic effect of CT-P59 against B.1.351 variant (first identified in South Africa, now classified by the WHO as Beta) was updated through the publication from Biochemical and Biophysical Research Communications. According to the article, in vivo ferret challenge studies demonstrated that a therapeutic dosage of CT-P59 was able to decrease B.1.351 viral load in the upper and lower respiratory tracts, comparable to that observed for the wild type virus. Celltrion plans to release full Phase III data in the coming months and plans to present the data at an oral session at the European Congress of Clinical Microbiology & Infectious Diseases (ECCMID), which will take place online from July 9 to 12 July 2021.