Recently, results from a Phase III clinical trial evaluating the efficacy, safety, and immunogenicity of Cecolin 9, an Escherichia coli-produced nine-valent human papillomavirus (9v HPV) vaccine, were published online in The Lancet Infectious Diseases (DOI: 10.1016/S1473-3099(26)00221-5)[1]. The study showed that Cecolin 9 demonstrated high protective efficacy against 12-month cervical persistent infection associated with five additional high-risk HPV types (HPV 31/33/45/52/58) in adult women, elicited immune responses against HPV 16 and 18 that were non-inferior to those induced by the licensed bivalent HPV vaccine Cecolin, and showed a favorable safety profile, with no serious adverse events considered related to vaccination.

Persistent infection with high-risk HPV types is a well-established cause of cervical cancer and other anogenital and head and neck malignancies. HPV 16 and 18 are associated with approximately 70% of cervical cancer cases, while five additional high-risk types—HPV 31, 33, 45, 52, and 58—account for approximately another 20%. Low-risk HPV 6 and 11 are responsible for around 90% of genital warts. HPV vaccination remains one of the most cost-effective and impactful measures to prevent HPV infection and HPV-related diseases. Clinical trial data and real-world evidence from multiple countries have consistently demonstrated that HPV vaccination can reduce the incidence of high-grade precancerous lesions, cervical cancer, and related disease burden.

Based on the established safety and efficacy of Cecolin, a bivalent HPV vaccine targeting HPV types 16 and 18, the research teams jointly developed Cecolin 9, an iterative vaccine covering HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. To evaluate its efficacy, safety, and immunogenicity in adult women, a multicenter, randomized, double-blind, controlled Phase III clinical trial was initiated in 2019 across multiple study sites in Jiangsu and Sichuan provinces, China.

A total of 9,327 healthy women aged 18–45 years were enrolled and randomly assigned in a 1:1 ratio to the investigational group, receiving the nine-valent vaccine Cecolin 9, or the control group, receiving the bivalent vaccine Cecolin. Participants received three doses of either the nine-valent vaccine Cecolin 9 or the bivalent vaccine Cecolin according to a Day 0, Month 1, and Month 6 immunization schedule. Throughout the study, participants were followed for adverse events after vaccination, pregnancy events, and other safety outcomes. Blood samples were collected from the immunogenicity subgroup at the Lianshui site on Day 0 and at Months 7, 18, 30, 42, 54, 66, and 78 to assess seroconversion rates of serum neutralizing antibodies, antibody levels, and immune persistence against the nine HPV types. Cervical, vulvar, and perianal specimens were collected on Day 0 and at Months 6, 12, 18, 24, 30, 42, 54, 66, and 78 for cytological diagnosis and HPV DNA testing. Participants with abnormal cytology were recalled for colposcopic examination. The publication focuses on the immunogenicity, protective efficacy against persistent infection, and safety of Cecolin 9 in adult women.

For the persistent infection endpoint, efficacy results showed that in the modified intention-to-treat set, Cecolin 9 provided a protective efficacy of 98.2% (95% CI: 89.6–100.0; p<0.0001) against 12-month persistent infection associated with the five additional high-risk HPV types (31/33/45/52/58), defined as positivity for the same HPV type at the same anatomical site in two consecutive samples collected more than 300 days apart. This endpoint occurred in 1 of 4,160 participants in the vaccine group and 55 of 4,166 participants in the control group. For 12-month persistent infection at the cervical site, the protective efficacy of Cecolin 9 was 100% (95% CI: 84.9–100.0; p<0.0001), demonstrating an exceptionally high level of protection. For the additional low-risk HPV types (6/11), the number of persistent infection cases was limited, with a protective efficacy of 100% (95% CI: -429.8–100.0), suggesting a protective trend against infection with these types.

Immunogenicity results showed that in the per-protocol immunogenicity set, the differences of two groups in vaccine-induced neutralizing antibody seroconversion rates for HPV types 16 and 18 were 0.00% (95% CI: -0.49–0.48) and -0.12% (95% CI: -0.67–0.33), respectively, meeting the prespecified non-inferiority criteria. The geometric mean concentration (GMC) ratios also met the prespecified non-inferiority criteria. In addition, during the 36-month observation period, no cervical persistent infection associated with HPV type 16 or 18 occurred in either group, supporting the conclusion that Cecolin 9 provides protection against HPV 16- and 18-related infection and lesions comparable to that of Cecolin. For HPV types 6/11/31/33/45/52/58, Cecolin 9 also demonstrated favorable immunogenicity, with neutralizing antibody seroconversion rates ranging from 99.66% to 100% at Month 7.

In terms of safety, adverse reactions following Cecolin 9 vaccination were generally mild, and most resolved spontaneously within a short period. No vaccine-related serious adverse events were reported during the trial, supporting a favorable safety profile.

This study provides important confirmatory evidence for the clinical value of Cecolin 9. The results show that Cecolin 9 is a 9-valent HPV vaccine with a favorable safety profile, clear immunogenicity, and high protective efficacy against vaccine-targeted HPV types. Based on robust scientific evidence and rigorous regulatory review, Cecolin 9 was officially approved in China in 2025, providing strong support for expanding access to high-valency HPV vaccines and advancing cervical cancer prevention.

An accompanying commentary in The Lancet Infectious Diseases was authored by Professor Punnee Pitisuttithum[2], a member of the WHO Strategic Advisory Group of Experts on Immunization, and Professor Rakesh Aggarwal. The commentary noted that Cecolin 9’s efficacy against 12-month persistent infection associated with the five additional high-risk HPV types represents an important milestone in nine-valent HPV vaccine development. It also stated that the bivalent HPV vaccine Cecolin has contributed to HPV vaccine supply in low- and middle-income countries, and that advancing regulatory approvals outside China and WHO prequalification for Cecolin 9 will be important for broader global public health use.

The publication comes as global efforts to accelerate cervical cancer elimination continue to advance. In November 2025, China formally introduced HPV vaccination into its National Immunization Programme, marking an important step toward broader prevention coverage. In June 2026, Cecolin 9 submitted its prequalification application to the World Health Organization, further advancing the path for a China-developed high-valency HPV vaccine to support broader global public health needs.

About the Study

The study, titled Efficacy, safety, and immunogenicity of an Escherichia coli-produced nine-valent human papillomavirus vaccine: a multicentre, double-blind, randomised, controlled, phase 3 trial, was published in The Lancet Infectious Diseases. The study was conducted by research teams from Xiamen University, Jiangsu Provincial Center for Disease Control and Prevention, Sichuan Provincial Center for Disease Control and Prevention, the Cancer Hospital of the Chinese Academy of Medical Sciences, the National Institutes for Food and Drug Control, Xiamen Innovax Biotech Co., Ltd., and other collaborating institutions.

About Cecolin 9

Launched in China in 2025, Cecolin 9 is a next-generation 9-valent HPV vaccine jointly developed by IX and Xiamen University. Building on the global use of Cecolin, the bivalent HPV vaccine, Cecolin 9 further expands coverage across nine HPV types associated with cervical cancer and other HPV-related diseases. Results from the Phase III confirmatory clinical trial showed that Cecolin 9 demonstrated favorable immunogenicity and safety, as well as high protective efficacy against persistent infection associated with vaccine-targeted HPV types. A previous head-to-head clinical study also showed that Cecolin 9 induced type-specific immune responses comparable to those induced by another licensed 9-valent HPV vaccine. As an important expansion of IX’s HPV vaccine portfolio, Cecolin 9 provides a new high-quality option for cervical cancer prevention and control.

About IX

Founded in 2005, Xiamen Innovax Biotech Co., Ltd. (IX) is a wholly owned subsidiary of Beijing Wantai Biological Pharmacy Enterprise Co., Ltd. (Wantai BioPharm, Stock Code: 603392.SH) and serves as the vaccine business headquarters of Wantai BioPharm. IX focuses on the research, development, manufacturing, and commercialization of innovative human vaccines. Built on its E. coli-derived VLP expression technology platform, IX has launched innovative vaccines including Hecolin, Cecolin, and Cecolin 9. IX is committed to helping meet public health needs with high-quality, affordable, and reliable vaccines.

References

1.Pan HX, Bi ZF, Jing YL, et al. Efficacy, safety, and immunogenicity of an Escherichia coli-produced nine-valent human papillomavirus vaccine: a multicentre, double-blind, randomised, controlled, phase 3 trial. The Lancet Infectious Diseases. Published online June 30, 2026. doi:10.1016/S1473-3099(26)00221-5.

2.Pitisuttithum P, Aggarwal R. Nine-valent human papillomavirus vaccine: implications for cervical elimination. The Lancet Infectious Diseases. Published online June 30, 2026. doi:10.1016/S1473-3099(26)00256-2.