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NCT Number: NCT07785843

A Clinical Study of V503 in Chinese Females Who Have Previously Received a Bivalent Human Papillomavirus (HPV) Vaccine (V503-108)

Researchers want to learn if V503 (also called the 9-valent human papillomavirus [9vHPV] vaccine, recombinant) can induce an immune response to HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 in Chinese females who previously received the bivalent HPV (2vHPV) vaccine.

The 9vHPV vaccine protects against diseases caused by 9 types of HPV (6, 11, 16, 18, 31, 33, 45, 52, and 58) and the 2vHPV vaccine protects against diseases caused by 2 types of HPV (16 and 18).

The goals of the trial are to learn:

* If the 9vHPV vaccine can induce an immune response to HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 in participants who received the 2vHPV vaccine * About the safety of the 9vHPV vaccine in prior 2vHPV vaccine recipients

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Key information

Conditions

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

Age range

10 year–45 year

Sex eligibility

Female

Study type

Interventional

Phase

Phase 3

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

The main inclusion criteria include but are not limited to the following:

  • For participants to be enrolled in prior 2vHPV (bivalent human papillomavirus [HPV] vaccine) vaccine groups: has received at least one dose of any one of the three currently marketed 2vHPV vaccines, with the last dose administered at least one year prior to Day 1.
  • For participants to be enrolled in HPV vaccine naïve groups: has never received any HPV vaccine.

Exclusion criteria

The main exclusion criteria include but are not limited to the following:

  • Has known thrombocytopenia or any coagulation disorder that would contraindicate intramuscular injections.
  • Has a history of abnormal Pap test showing low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL) or atypical squamous cells - undetermined significance (ASC-US), atypical squamous cells - cannot exclude HSIL (ASC-H), atypical glandular cells, or biopsy showing CIN, AIS, or cervical cancer.
  • Has a history of external genital wart, vulvar intraepithelial neoplasia (VIN), vaginal intraepithelial neoplasia (VaIN), AIN, vulvar cancer, vaginal cancer, or anal cancer.
  • Has a history of a positive test for HPV (including HPV types not in the vaccine).
  • Is currently immunocompromised or has been diagnosed as having congenital or acquired immunodeficiency, human immunodeficiency virus (HIV) infection, lymphoma, leukemia, systemic lupus erythematosus (SLE), rheumatoid arthritis, juvenile rheumatoid arthritis (JRA), inflammatory bowel disease, or other autoimmune condition.
  • Has a history of splenectomy.
  • Has received, is receiving, or plans to receive the following immunosuppressive therapies: radiation therapy, cyclophosphamide, azathioprine, methotrexate, any chemotherapy, cyclosporin, leflunomide (Arava™), tumor necrosis factor alpha (TNF-α) antagonists, monoclonal antibody therapies (including rituximab [Rituxan™]), intravenous gamma globulin (IVIG), antilymphocyte sera, or other therapy known to interfere with the immune response. With regard to systemic corticosteroids, a participant will be excluded if the participant is currently receiving steroid therapy, has recently (defined as within 2 weeks of enrollment) received such therapy, or has received 2 or more courses of corticosteroids (orally or parenterally) lasting at least 1 week within 12 months prior to enrollment. Participants using inhaled, nasal, or topical corticosteroids are considered eligible for the study.
  • Has received, is receiving, or plans to receive any immune globulin product (including RhoGAM™ [Ortho-Clinical Diagnostics]) or blood derived product other than IVIG.
  • Has participated in an HPV vaccine clinical trial and has received either active agent or placebo.
  • Has received any marketed HPV vaccine other than the 2vHPV vaccines.

Treatment and study plan

V503

Biological

V503 (9-vHPV vaccine [Types 6, 11, 16, 18, 31, 33, 45, 52, and 58]) administered as a 0.5-mL intramuscular (IM) injection on Day 1, Month 2, and Month 6

Other names: 9-valent HPV Vaccine, GARDASIL®9

Placebo

Biological

Saline administered as a 0.5-mL IM injection on Day 1, Month 2, and Month 6

Primary outcomes

  1. Percentage of Participants Who Are Seropositive by Competitive Luminex Immunoassay (cLIA) to HPV Types 6, 11, 31, 33, 45, 52, and 58 (Month 7)

    Time frame: Up to approximately 1 month post vaccination 3 (Up to approximately Month 7)

    The percentage of participants who are seropositive for HPV types 6, 11, 31, 33, 45, 52, and 58 in the Prior 2vHPV Vaccine Recipients Receiving V503 group will be determined using cLIA. Seropositivity is defined as having a titer at or above the prespecified seropositivity cutoff for a given HPV type.

  2. Percentage of Participants Who Experience at Least 1 Solicited Injection-site Adverse Event (AE)

    Time frame: Up to approximately Day 8 post any vaccination

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. AEs such as redness/erythema, swelling, pain, and induration at the injection site are recorded. The percentage of participants who experience 1 or more injection-site AE will be reported.

  3. Percentage of Participants Who Experience at Least 1 Solicited Systemic AE

    Time frame: Up to approximately Day 8 post any vaccination

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. Systemic AEs are those not categorized as injection-site AEs. The percentage of participants who experience 1 or more systemic AE will be reported.

  4. Percentage of Participants Who Experience at Least 1 Serious AE (SAE)

    Time frame: Up to approximately Month 12

    An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. An SAE is an AE that results in death, is life threatening, results in a persistent or significant disability or incapacity, results in or prolongs an existing hospitalization, is a congenital anomaly or birth defect, or is another important medical event. The percentage of participants who experience 1 or more SAEs will be reported.

Secondary outcomes

  1. Percentage of Participants Who Are Seropositive by cLIA to HPV Types 6, 11, 16, 18, 31, 33, 45, 52, and 58

    Time frame: Up to approximately 1 month post vaccination (Up to approximately 7 months)

    The percentage of participants who are seropositive for HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 will be determined using cLIA. Seropositivity is defined as having a titer at or above the prespecified seropositivity cutoff for a given HPV type.

  2. cLIA Geometric Mean Titers (GMTs) for HPV Types 6, 11, 16, 18, 31, 33, 45, 52, and 58

    Time frame: Up to approximately 1 month post vaccination (Up to approximately 7 months)

    Antibodies to HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 will be measured using a cLIA. Antibody titers will be expressed as milli Merck Units/milliliter (mMU/mL).

  3. Difference in Percentage of Participants Who Are Seropositive by cLIA to HPV Types 6, 11, 16, 18, 31, 33, 45, 52, and 58 Between Prior 2vHPV Vaccine Recipients and HPV Vaccine-Naïve Participants

    Time frame: Up to approximately 1 month post vaccination (Up to approximately 7 months)

    The percentage of participants who are seropositive for HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58 will be determined using cLIA. Seropositivity is defined as having a titer at or above the prespecified seropositivity cutoff for a given HPV type. The difference in seropositivity percentages between participants who previously received a 2vHPV vaccine and subsequently receive V503 and participants who were HPV vaccine-naïve and receive V503 will be evaluated.

Sponsors and collaborators

Lead sponsor

Merck Sharp & Dohme LLC

Industry

Registry information

Official study title

A Phase 3 Randomized, Placebo-Controlled, Double-Blind Study to Evaluate the Immunogenicity and Safety of V503 in Chinese Females Aged 10 to 45 Years Who Have Previously Received a Bivalent Human Papillomavirus (HPV) Vaccine

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
Aug 25, 2026
Registry last updated
Aug 25, 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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