Meplazumab, a CD147 antibody, for severe COVID-19: a double-blind, randomized, placebo-controlled, phase 3 clinical trial.

Meplazumab, a humanized CD147 antibody, showed favorable safety and clinical benefits in phase 1 and phase 2/3 seamless clinical studies. Further evaluation of its therapeutic efficacy in patients with severe COVID-19 is needed. In this phase 3 add-on study, we randomized patients with severe COVID-19 in a 1:1 ratio to receive 0.2 mg/kg meplazumab or placebo via intravenous injection, and evaluated efficacy and safety within 56 days. Between February 2023 and November 2023, 108 patients with severe COVID-19 were randomized to two groups, with their baseline characteristics generally balanced. The primary endpoint, 28-day all-cause mortality was 1.96% in the meplazumab group vs 7.69% in the placebo group (P = 0.1703). Supplementary analysis using composite strategy indicated a significant reduction of 28-day all-cause mortality in meplazumab compared to placebo (3.92% vs 15.38%, P = 0.044). Meplazumab also significantly reduced the mortality in smoking subjects on day 28 (P = 0.047) compared to placebo in supplementary analysis. The secondary endpoint, 56-day all-cause mortality, was 1.96% in the meplazumab group and 11.54% in the placebo group (P = 0.048), which was 3.92% and 15.38%, respectively (P = 0.044) by supplementary analysis. Additional secondary endpoints showed potential benefits, including increased hospital discharge rates, improved clinical outcomes, and improved viral nucleotide conversion rate. Meplazumab demonstrated good safety and tolerability, with no grade ≥ 3 TEAEs observed. These promising results indicate that meplazumab reduces mortality and enhances clinical benefits in severe COVID-19 patients with a good safety profile, providing effective and specific therapeutics for severe COVID-19 (the trial was registered at ClinicalTrials.gov (NCT05679479)).