Jiangsu Recbio Technology Co., Ltd. ("Recbio"), a biopharmaceutical company focusing on the research, development and commercialization of innovative vaccines that can address prevalent diseases with significant burden, today announced preclinical data from its ReCOV a recombinant trimeric NTD and RBD two-component SARS-CoV-2 subunit vaccine adjuvanted with squalene-based adjuvant BFA03. The manuscript was posted online at bioRxiv. According to the paper, ReCOV induced high levels of neutralizing antibodies against SARS-CoV-2 and the circulating variants in mice, rabbits and rhesus macaques. Notably, two-dose immunizations of ReCOV provided complete protection against challenge with SARS-CoV-2 in hACE2 transgenic mice and rhesus macaques，without observable antibody-dependent enhancement of infection.

"We are pleased with these new data showing that ReCOV induced high neutralizing antibodies titers against variants of concern such as the Delta variant,"said Dr. Liu Yong, Chairman and General Manager."Nearly half of the world's population has not been vaccinated, and the coverage rate of COVID-19 vaccine in low-income countries is only 2%. There is still an urgent global demand for more safety, efficacious and accessible new COVID-19 vaccine. Committed to providing the world with a next-generation COVID-19 vaccine with better comprehensive performance, and contributing our corporate strength to an early end to the raging epidemic of Coronavirus."

This study used a variety of assays and showed that after two doses of ReCOV, high levels of neutralizing antibodies were generated against ancestral strain of the virus. Meanwhile, the vaccinated sera also showed cross neutralizing activity against the main VOCs including B.1.1.7(Alpha), B.1.351 (Beta), P.1(Gamma) and B.1.617.2(Delta).

In the CAG-hACE2 transgenic mouse model, ReCOV can protect mice against the lethal infection of SARS-CoV-2 virus. The 14-day survival rate of the vaccine group is 100% while the mortality rate of the placebo group is 100%. After two doses of ReCOV immunization, it has a good protective profile against SARS-CoV-2 virus attack. It can significantly improve clinical symptoms (including malaise, bristling, arched back, drowsiness and body weight reduction), reduce lung damage, reduce lung and brain viral load, and induce high antibody titers .

Importantly, ReCOV induced potent SARS-CoV-2 neutralizing antibodies and potentially protects rhesus macaques from SARS-CoV-2 infection in vaccinated-group. The seroconversion rate of the neutralizing antibodies against the authentic virus was 100% after the first immunization. ReCOV can inhibit the distribution, proliferation and detoxification of the virus in the tissues and organs of the body, and improve the pathology of the lungs.

These results support further clinical development of ReCOV and the vaccine is currently being evaluated in a phase I clinical trial in New Zealand (NCT04818801).

About Recombinant Two-Component COVID-19 Vaccine (ReCOV)

In May 2020, Recbio, together with Jiangsu Provincial Center for Disease Control and Prevention ("Jiangsu CDC") and Taizhou Medical New & High-tech Industrial Development Zone, jointly developed a recombinant two-component COVID-19 vaccine(ReCOV). Under the guidance of Professor Fengcai Zhu from the Jiangsu CDC, the R&D team thoroughly optimized the vaccine using protein engineering and new adjuvant technologies, so that ReCOV has promising safety and strong immunogenicity against SARS-CoV-2 and variants of concern such as Delta. A series of comprehensive advantages such as better cross-protection against emerging variants, easy scale-up of production, cost advantages, worldwide accessibility, good preparation stability, and storage and transportation at room temperature which become a very competitive second-generation new COVID-19 vaccine.

About Recbio

Recbio is an innovative vaccine company founded in 2012. 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, and immunological evaluation 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 scientific 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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Source: Jiangsu Recbio Technology Co., Ltd.