AB&B BIO-TECH-B (02627) announced that its self-developed recombinant respiratory syncytial virus vaccine (CHO cell) with adjuvant has received Investigational New Drug (IND) approval from China's Center for Drug Evaluation (CDE) under the National Medical Products Administration. Additionally, the IND application for this vaccine has also been approved by the U.S. Food and Drug Administration (FDA).

Respiratory syncytial virus (RSV), a highly contagious RNA virus, represents one of the major pathogens causing respiratory tract infections in infants, elderly individuals, and immunocompromised patients. Clinically, it primarily manifests as acute respiratory tract infection symptoms, predominantly affecting the lower respiratory tract. Severe cases can be life-threatening. According to data from China's Center for Disease Control and Prevention, from 2009 to 2019 in China, RSV ranked second among pathogens causing acute respiratory tract infections in adults and first in children.

Given the current lack of specific therapeutic drugs in clinical practice, with treatment mainly relying on supportive care for acute infections, vaccination has become the preferred clinical solution for RSV prevention and control.

The company's recombinant respiratory syncytial virus vaccine (CHO cell) with adjuvant is developed using CHO cells and can express modified pre-F protein. Through extensive screening, the company has obtained high-yield monoclonal cell lines capable of stably expressing pre-F protein. In the company's preclinical studies, it demonstrated higher pre-F expression levels, better thermal stability, and superior immunogenicity compared to marketed recombinant RSV vaccines.

According to previously published results, marketed recombinant RSV vaccines have pre-F protein expression levels between 600mg/L and 800mg/L. In comparison, the company's high-yield cell lines produce pre-F protein at approximately 1,000mg/L to 1,500mg/L. Preclinical studies showed that after 14 days at 40°C, the company's pre-F protein retained activity above 95%, while marketed products saw protein activity decrease to around 50%.

Due to its stability, unlike approved products, the company's product uses a liquid formulation rather than a lyophilized formulation. In preclinical immunogenicity trials conducted in mice, the company's investigational vaccine showed significantly higher neutralizing antibody geometric mean titers compared to marketed similar products. The vaccine also demonstrated good safety profiles in the company's toxicity studies and active systemic anaphylaxis tests.