Superior Neutralizing Antibody Titer Levels Against Omicron BF.7 And BA.2.75 Of The Company's Two-Component Recombinant COVID-19 Vaccine ReCOV As Compared To International Mainstream mRNA Vaccine

TAIZHOU,China,Dec. 26,2022 --Jiangsu Recbio Technology Co.,Ltd. (the "Company",together with its subsidiaries,the "Group") is pleased to announce that positive results were achieved for its sequential booster vaccination Phase II study of the recombinant two-component COVID-19 vaccine ReCOV in the Philippines. This clinical study aims to compare the immunogenicity and safety profile of ReCOV and Pfizer's mRNA vaccine COMIRNATY®as booster vaccination among subjects who have completed primary vaccination of inactivated vaccines. The results showed that neutralizing antibody titer levels against Omicron BF.7 and BA.2.75 induced by sequential vaccination of ReCOV were significantly better than those of the mRNA vaccine group (with significant differences statistically).

The main strain of the current outbreak in Beijing is Omicron BF.7. As a variant of Omicron,BF.7 has a stronger immune escape ability,faster infection rate,and stronger concealment. Therefore,vaccination of vaccines with better efficacy is key to ending the epidemic.

1. Statistically superior neutralizing antibody titer levels against Omicron BF.7 compared to the mRNA vaccine. Upon 14 days after booster vaccination,the seroconversion rate (SCR) of neutralizing antibody against Omicron BF.7 of the ReCOV group and the mRNA vaccine group were 91.1% and 88.4%,respectively,and the SCR of the ReCOV group was higher than that of the mRNA vaccine group . At the same time,the geometric mean titers (GMT) of neutralizing antibodies in the ReCOV group and the mRNA vaccine group were 6,549.1 and 4,529.6,and the GMT in the ReCOV group was significantly higher than that in the mRNA vaccine group (P value < 0.001). In addition,the neutralizing antibody level induced by the ReCOV group increased by 30.8 times compared with the baseline,which was significantly higher than that of the mRNA vaccine (22.7 times). In the ReCOV group,the neutralizing antibody against Omicron BF.7 was only 2.5 times lower than that of the original strain,showing excellent cross-neutralization effect.

2. Statistically superior neutralizing antibody titer levels against Omicron BA.2.75 compared to the mRNA vaccine. Upon 14 days after booster vaccination,the SCR of neutralizing antibody against Omicron BA.2.75 of the ReCOV group and the mRNA vaccine group were 92.1% and 88.4%,and the SCR value of the ReCOV group was higher than that of the mRNA vaccine group. At the same time,the neutralizing antibody GMT of the ReCOV group and the mRNA vaccine group were 6,268.3 and 4,676.3,and the GMT of the ReCOV group was significantly higher than that of the mRNA vaccine group (P value = 0.003). In addition,the neutralizing antibody induced by the ReCOV group increased by 27.3 times compared with the baseline,which was significantly higher than that of the mRNA vaccine (21.5 times). In the ReCOV group,the neutralizing antibody against Omicron BA.2.75 was only 2.6 times lower than that of the original strain,showing excellent cross-neutralization effect.

ReCOV is a recombinant COVID-19 vaccine being developed by the Company with its technology platforms including the novel adjuvant,protein engineering and immunological evaluation platforms,and the adjuvant used therein is the self-developed novel adjuvant BFA03. It has a variety of comprehensive advantages,including favourable neutralizing effect and immune persistence,overall positive safety profile,potential growth in production scale,low production cost,preparation stability,and ability to be stored and transported at room temperature. The Company has completed the construction of ReCOV manufacturing facility and preparation for commercial production,and has obtained the relevant vaccine production license issued by the regulatory authorities in China,which is fully prepared for commercialization in China.

About Recbio

Founded in 2012,Recbio is an innovative vaccine company. With the vision of "Become the Leader of Innovative Vaccine in the Future," Recbio takes "Protect Human Health with Best-in-Class Vaccines" as its mission. It has established three major cutting-edge technology platforms including novel adjuvants platform,protein engineering platform,immunological evaluation platform and mRNA vaccine platform. Recbio has a high-value vaccine portfolio consisted of HPV vaccine candidates,COVID-19 vaccine candidates,shingles vaccine candidates,influenza vaccine candidates,adults TB vaccine candidates etc. The core management team has more than 20 years of experience in the development and commercialization of innovative vaccines. For more information,please visit https://www.recbio.cn/.

Forward-looking statements

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