Real-world effectiveness of an intranasal spray A8G6 antibody cocktail in the post-exposure prophylaxis of COVID-19.

Previously, we identified an antibody combination A8G6 that showed promising efficacy in COVID-19 animal models and favorable safety profile in preclinical models as well as in a first-in-human trial. To evaluate the real-word efficacy of A8G6 neutralizing antibody nasal spray in post-exposure prophylaxis of COVID-19, an open-label, non-randomized, two-arm, blank-controlled, investigator-initiated trial was conducted in Chongqing, China (the register number: ChiCTR2200066416). High-risk healthy participants (18-65 years) within 72 h after close contact to COVID-19 patients were recruited and received a three-dose (1.4 mg/dose) A8G6 treatment daily or no treatment (blank control) for 7 consecutive days. SARS-CoV-2 infection occurred in 151/340 (44.4%) subjects in the blank control group and 12/173 (6.9%) subjects in the A8G6 treatment group. The prevention efficacy of the A8G6 treatment within 72 h exposure was calculated to be 84.4% (95% CI: 74.4-90.4%). Moreover, compared to the blank-control group, the time from the SARS-CoV-2 negative to the positive COVID-19 conversion was significantly longer in the AG86 treatment group (mean time: 3.4 days vs 2.6 days, p = 0.019). In the secondary end-point analysis, the A8G6 nasal treatment had no effects on the viral load at baseline SARS-CoV-2 RT-PCR positivity and the time of the negative COVID-19 conversion. Finally, except for 5 participants (3.1%) with general adverse effects, we did not observe any severe adverse effects related to the A8G6 treatment. In this study, the intranasal spray AG86 antibody cocktail showed potent efficacy for prevention of SARS-CoV-2 infection in close contacts of COVID-19 patients.