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NCT Number: NCT07820241

Long-term Immune Persistence of a Bivalent HPV Vaccine in Females From Study 311-HPV-1004

This long-term extension study evaluates the persistence of neutralizing antibody responses to a bivalent human papillomavirus vaccine in females who previously participated in study 311-HPV-1004 (NCT02740777). Participants belonged to one of three vaccination cohorts in the base study: adolescents who received two doses at Months 0 and 6, adolescents who received three doses at Months 0, 2, and 6, and adults who received three doses at Months 0, 2, and 6. No vaccine is administered in the extension study. Blood samples are collected at Months 84, 108, and 132 after the first dose in the base study and tested for HPV-16 and HPV-18 neutralizing antibodies using a high-throughput pseudovirus-based neutralization assay.

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This study is active but is not currently recruiting participants.

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Key information

Conditions

Human Papillomavirus Infection Communicable Diseases DNA Virus Infections Disease Attributes Genital Diseases Infections Papillomavirus Infections Pathologic Processes Pathological Conditions, Signs and Symptoms Sexually Transmitted Diseases Sexually Transmitted Diseases, Viral Tumor Virus Infections Urogenital Diseases Virus Diseases

Age range

16 year–34 year

Sex eligibility

Female

Study type

Observational

Primary location

Hezhou Center for Disease Control and Prevention, Hezhou, Guangxi, China

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Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • The participant, and the participant's legal guardian when applicable, is able to understand the study information and voluntarily sign the informed consent form for the extension study.
  • In the investigator's judgment, the participant is able to comply with protocol requirements, including attending scheduled visits and responding to follow-up telephone contacts.
  • The participant was enrolled in study 311-HPV-1004 and completed blood collection at Day 0 and Months 7, 12, 24, and 36.

Exclusion criteria

  • Receipt of any HPV vaccine other than the study vaccine during study 311-HPV-1004 or between completion of that study and enrollment in this extension study.
  • Use of an investigational or unregistered product, other than the study vaccine, during study 311-HPV-1004 or between completion of that study and enrollment in this extension study.
  • Seropositivity for both HPV-16 and HPV-18 antibodies at baseline in study 311-HPV-1004.
  • Long-term use of immunosuppressive agents or

Treatment and study plan

Bivalent Human Papillomavirus Vaccine (Types 16 and 18, Pichia pastoris)

Biological

Each 0.5 mL dose contained 40 micrograms of HPV-16 L1 virus-like particles and 20 micrograms of HPV-18 L1 virus-like particles adsorbed to aluminum phosphate. The vaccine was administered only in the base study 311-HPV-1004; no study vaccine is administered in 311-HPV-1004-EXTEND.

Primary outcomes

  1. Geometric Mean Titer of HPV-16 Neutralizing Antibodies

    Time frame: Months 84, 108, and 132 after the first dose in the base study

    The geometric mean and two-sided 95% confidence interval of HPV-16 neutralizing antibody titers are summarized separately for each prior-vaccination cohort using the high-throughput pseudovirus-based neutralization assay.

  2. Geometric Mean Titer of HPV-18 Neutralizing Antibodies

    Time frame: Months 84, 108, and 132 after the first dose in the base study

    The geometric mean and two-sided 95% confidence interval of HPV-18 neutralizing antibody titers are summarized separately for each prior-vaccination cohort using the high-throughput pseudovirus-based neutralization assay.

  3. Seropositivity Rate for HPV-16 Neutralizing Antibodies

    Time frame: Months 84, 108, and 132 after the first dose in the base study

    The percentage of participants meeting the assay-defined seropositivity threshold for HPV-16 neutralizing antibodies and its exact two-sided 95% confidence interval are summarized separately for each prior-vaccination cohort.

  4. Seropositivity Rate for HPV-18 Neutralizing Antibodies

    Time frame: Months 84, 108, and 132 after the first dose in the base study

    The percentage of participants meeting the assay-defined seropositivity threshold for HPV-18 neutralizing antibodies and its exact two-sided 95% confidence interval are summarized separately for each prior-vaccination cohort.

Secondary outcomes

  1. Geometric Mean Titer of HPV-16 Neutralizing Antibodies in Stored Serum Samples

    Time frame: Before the first dose on Day 0 and at Months 7, 12, 24, and 36 after the first dose in the base study

    The geometric mean and two-sided 95% confidence interval of HPV-16 neutralizing antibody titers measured using the high-throughput pseudovirus-based neutralization assay are summarized separately for each prior-vaccination cohort using available stored serum samples collected in the base study from participants who subsequently enrolled in the long-term extension study.

  2. Geometric Mean Titer of HPV-18 Neutralizing Antibodies in Stored Serum Samples

    Time frame: Before the first dose on Day 0 and at Months 7, 12, 24, and 36 after the first dose in the base study

    The geometric mean and two-sided 95% confidence interval of HPV-18 neutralizing antibody titers measured using the high-throughput pseudovirus-based neutralization assay are summarized separately for each prior-vaccination cohort using available stored serum samples collected in the base study from participants who subsequently enrolled in the long-term extension study.

  3. Seropositivity Rate for HPV-16 Neutralizing Antibodies in Stored Serum Samples

    Time frame: Before the first dose on Day 0 and at Months 7, 12, 24, and 36 after the first dose in the base study

    The percentage of participants meeting the assay-defined seropositivity threshold for HPV-16 neutralizing antibodies and its exact two-sided 95% confidence interval are summarized separately for each prior-vaccination cohort using available stored serum samples collected in the base study from participants who subsequently enrolled in the long-term extension study.

  4. Seropositivity Rate for HPV-18 Neutralizing Antibodies in Stored Serum Samples

    Time frame: Before the first dose on Day 0 and at Months 7, 12, 24, and 36 after the first dose in the base study

    The percentage of participants meeting the assay-defined seropositivity threshold for HPV-18 neutralizing antibodies and its exact two-sided 95% confidence interval are summarized separately for each prior-vaccination cohort using available stored serum samples collected in the base study from participants who subsequently enrolled in the long-term extension study.

Interested in participating?

Active, not recruiting

This study is active but is not currently recruiting participants.

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Sponsors and collaborators

Lead sponsor

Shanghai Zerun Biotechnology Co.,Ltd

Industry

Collaborators

  • Yuxi Zerun Biotechnology Co., Ltd.

Registry information

Official study title

An Open-label, Long-term Extension Study to Evaluate the Persistence of Immune Responses to a Bivalent Human Papillomavirus Vaccine (Pichia Pastoris) in Healthy Females Who Were Aged 9 to 26 Years at Enrollment in Study 311-HPV-1004

Important dates

Study start
2023
Primary completion
2027
Study completion
2027
First posted
Sep 15, 2026
Registry last updated
Sep 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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