AB&B BIO-TECH-B (02627) has initiated phase I and phase II clinical trials of a recombinant respiratory syncytial virus vaccine (CHO cells) (adjuvant).

AB&B BIO-TECH-B (02627) announced that the group has recently initiated Phase I and Phase II clinical trials for the Group's independently developed recombinant respiratory syncytial virus vaccine (CHO cell) (adjuvant). The company obtained the approval for new drug clinical trials from the China National Medical Products Administration in August 2025. Respiratory syncytial virus (RSV) is a highly infectious RNA virus that is one of the important pathogens causing respiratory infections in infants, elderly people, and immunocompromised individuals. Clinically, it mainly manifests as symptoms of acute respiratory tract infections, with a focus on lower respiratory tract infections. Severe cases can be life-threatening. According to data from the Chinese Center for Disease Control and Prevention, from 2009 to 2019, RSV ranked second among pathogens causing acute respiratory tract infections in adults in China, and first in children. Due to the lack of specific effective treatment drugs in clinical practice, mainly relying on supportive care to address acute infections, vaccination has become the preferred clinical solution for RSV prevention and control. The Group's recombinant respiratory syncytial virus vaccine (CHO cell) (adjuvant) was developed using CHO cells and can express modified pre-F protein. The company has obtained high-yield monoclonal cell lines that can stably express pre-F protein through extensive screening. In preclinical studies by the company, it showed higher levels of pre-F expression, better heat stability, and excellent immunogenicity compared to marketed recombinant RSV vaccines. According to previously disclosed results, the expression level of pre-F protein in marketed recombinant RSV vaccines is between 600mg/L and 800mg/L. In contrast, the pre-F protein produced by the company's high-yield cell lines is approximately 1,000mg/L to 1,500mg/L. Preclinical studies have shown that after being placed at 40C for 14 days, the activity of the company's pre-F protein remains above 95%, while the protein activity of the marketed product decreases to around 50%. Due to its stability, unlike approved products, the company's product is in liquid form rather than freeze-dried form. In preclinical immunogenicity tests conducted in mice, the geometric mean titers of neutralizing antibodies for the company's vaccine under development were significantly higher than for similar products on the market. Good safety was also demonstrated in the company's toxicity studies and tests for systemic allergic reactions.