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A study on the long-term effectiveness and safety of nine-valent human papillomavirus vaccine in women aged 16 to 26 years for prevention of cervical cancer

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on diseases and conditions caused by Human Papillomavirus, commonly known as HPV. These include cervical cancer, which is cancer of the cervix (the lower part of the womb), vulvar cancer (cancer of the external female genital organs), vaginal cancer (cancer of the birth canal), anal cancer (cancer of the anus), abnormal cell changes in these areas that can develop before cancer appears, long-lasting HPV infections, and genital warts (small growths in the genital area). The vaccine being studied is Gardasil 9, which protects against nine different types of HPV, specifically types 6, 11, 16, 18, 31, 33, 45, 52, and 58. These HPV types are responsible for causing the cancers and conditions mentioned above.

The purpose of this study is to evaluate how well the vaccine continues to protect women over a long period of time by tracking whether they develop abnormal cervical cell changes or cervical cancer caused by the specific HPV types the vaccine targets. The study also aims to examine the body's immune response to the vaccine over time and to monitor its safety. Additionally, researchers will look at whether the vaccine helps prevent abnormal cell changes and cancers caused by other HPV types not included in the vaccine, as well as cancers of the vulva and vagina.

Women who participated in an earlier study called V503-001 in Denmark, Norway, or Sweden and received either Gardasil 9 or an earlier version of the HPV vaccine will be followed through national health registries in these countries. This means their health information will be collected from official health records over many years without requiring regular study visits. Some participants may be contacted to provide blood samples so researchers can measure the levels of protective substances in their blood against the different HPV types. Tissue samples from any biopsies (small tissue samples taken during medical procedures) will also be analyzed to see if HPV is present and which type it is.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Entry into the extension study

    This study is an extension of a previous study called V503-001. Your participation begins if you were previously enrolled in that study at a site in Denmark, Norway, or Sweden, and you received either the 9vHPV vaccine (a vaccine that protects against 9 types of human papillomavirus) or GARDASIL (another HPV vaccine).

    You will need to agree to allow the study team to follow your health information through national health records, analyze any tissue samples taken during routine medical care, be contacted by the National Registry Study Centers if needed, and provide blood samples for testing.

  2. Step 2

    Passive follow-up through national registries

    Your health will be monitored through existing national health registries in your country. This means the study team will review your medical records without requiring frequent study visits.

    The registries will be checked for any cases of cervical abnormalities (unusual changes in the cells of the cervix), including CIN 2 and CIN 3 (moderate to severe abnormal cell changes that could lead to cancer), adenocarcinoma in situ (early-stage cancer cells that have not spread), and cervical cancer (cancer of the cervix).

    The study will also monitor for other conditions such as vulvar cancer (cancer of the external female genital organs), vaginal cancer (cancer of the vagina), and abnormal cell changes related to specific HPV types.

  3. Step 3

    Analysis of tissue samples

    If you have any tissue samples taken as part of your routine cervical cancer screening or medical care, these samples may be analyzed by the study team.

    The analysis will determine if any abnormal cells or cancers found are related to specific types of HPV, including types 6, 11, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59.

  4. Step 4

    Blood sample collection for immune response testing

    At certain points during the study, you may be asked to provide blood samples.

    These blood samples will be tested to measure the levels of antibodies (proteins that help fight infection) against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58.

    The tests will determine the geometric mean titers (average antibody levels) and seropositivity rates (the percentage of people who have detectable antibodies) to assess how well the vaccine continues to protect against HPV over time.

  5. Step 5

    Contact from National Registry Study Centers

    You may be contacted by the National Registry Study Centers if additional information is needed or if there are updates regarding your participation in the study.

    This contact will be related to the ongoing monitoring of your health through the registries and any additional data collection required.

  6. Step 6

    Long-term follow-up until study completion

    The study is expected to continue until July 2041. During this time, your health information will continue to be monitored through national registries.

    The goal is to assess the long-term effectiveness of the 9vHPV vaccine in preventing cervical abnormalities and cancers caused by HPV.

    No additional vaccine doses will be administered during this extension study. The focus is on observing the long-term protection provided by the vaccine you received in the original study.

Who can join the trial?

6 criteria

  • You must have been enrolled in a previous study called V503-001 at a site in Denmark, Norway, or Sweden, where you received either the 9vHPV vaccine (a vaccine that protects against nine types of human papillomavirus) or GARDASIL (another HPV vaccine)
  • You must be female
  • You must agree to allow researchers to follow your health information through national health records without requiring regular visits
  • You must agree to allow analysis of any tissue samples taken from biopsies (small pieces of tissue removed for testing)
  • You must agree to be contacted by the National Registry Study Centers in the future if needed
  • You must agree to provide blood samples for testing

Who cannot join the trial?

5 criteria

  • The study does not list specific exclusion criteria in the provided information
  • If you are a male, you cannot participate in this study as it only includes female participants
  • If you were not a participant in the previous study called Protocol V503-001, you cannot join this study
  • If you do not live in the Nordic region, you may not be eligible for this study
  • If you did not receive the 9vHPV vaccine (a vaccine that protects against nine types of human papillomavirus) in the previous study, you cannot participate
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Investigated drugs

9vHPV vaccine is a vaccine that helps protect against nine types of human papillomavirus (HPV). HPV is a common virus that can cause cervical cancer and other problems. This vaccine works by teaching your immune system to recognize and fight these specific types of HPV before you are exposed to them. In this study, researchers are following women who received this vaccine to see how well it continues to protect them over a long period of time against abnormal cell changes in the cervix and cervical cancer.

What is already known about the treatment

9vHPV vaccine – This is a preventive vaccine given as an injection to protect against nine types of Human Papillomavirus (HPV), which can cause cervical, vulvar, vaginal, and anal cancers, as well as genital warts. The vaccine works by introducing virus-like particles that train the immune system to recognize and fight off HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 before actual infection occurs. It is approved for use in females aged 9 years and older and is currently being studied in long-term clinical trials to monitor its continued effectiveness in preventing precancerous changes and cancers in women who were vaccinated between ages 16 and 26. The vaccine belongs to the class of immunological agents and works by stimulating the body's natural defense system to produce antibodies that provide protection against these specific HPV strains.

Investigated diseases

  • Cervical Intraepithelial Neoplasia Grade 2

    This is a condition where abnormal cells are found in the tissues of the cervix. The cells show moderate changes in their size, shape, and number when examined under a microscope. This condition is caused by persistent infection with certain types of Human Papillomavirus. The abnormal cells are present in about two-thirds of the thickness of the cervical tissue lining. Without intervention, these cellular changes may progress to more severe abnormalities over time. This condition is considered a precancerous lesion of the cervix.

  • Cervical Intraepithelial Neoplasia Grade 3

    This condition involves abnormal cells found in the cervical tissue that show severe changes. The cellular abnormalities affect more than two-thirds of the thickness of the cervical lining. It is caused by persistent infection with certain types of Human Papillomavirus. The cells appear significantly different from normal cells in their appearance and organization. This represents a more advanced precancerous condition than lower grades of cervical abnormalities. The abnormal cells remain within the surface layer and have not yet invaded deeper tissues.

  • Adenocarcinoma In Situ of the Cervix

    This is a condition where abnormal glandular cells are found in the cervical tissue. These cells show cancerous features but remain confined to the inner lining of the cervix without spreading deeper. It typically develops in the glandular cells that produce mucus in the cervical canal. The condition is often caused by persistent infection with certain types of Human Papillomavirus. The abnormal cells have not invaded the surrounding tissue or spread beyond their original location. This is considered a precancerous condition affecting the glandular cells of the cervix.

  • Cervical Cancer

    This is a disease where cancerous cells form in the tissues of the cervix. It typically develops slowly over time, often beginning with precancerous changes in the cervical cells. Most cases are caused by persistent infection with certain types of Human Papillomavirus. The cancer cells can invade deeper into the cervical tissue and potentially spread to nearby areas. As the disease progresses, the cancerous cells may grow into surrounding tissues and organs. This cancer primarily affects the lower part of the uterus that connects to the vagina.

  • Vulvar Cancer

    This is a disease where cancerous cells develop in the tissues of the vulva, which is the outer part of the female genital area. The cancer most commonly forms on the inner edges of the outer lips of the vulva. Some cases are associated with persistent infection with certain types of Human Papillomavirus. The disease typically develops slowly, sometimes over many years. Cancerous cells can grow into deeper layers of tissue and potentially spread to nearby areas. This type of cancer can occur at any age but is more common in older women.

  • Vaginal Cancer

    This is a disease where cancerous cells form in the tissues of the vagina. It is a relatively uncommon type of cancer that can occur at various locations along the vaginal canal. Some cases are linked to persistent infection with certain types of Human Papillomavirus. The cancer typically begins in the cells lining the surface of the vagina. As it progresses, the cancerous cells can grow deeper into the vaginal wall. The disease may spread to nearby tissues and organs if it continues to develop.

Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-508683-30-00Protocol codeV503-021Estimated enrolment2 220 patientsSponsorMerck Sharp & Dohme LLC

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