V503-108: See if the 9-valent HPV vaccine boosts protection in Chinese women who already got the bivalent HPV vaccine
Official 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
Run by Merck Sharp & Dohme LLC · NCT07785843 · Data updated 2026-11-12
In Chinese women who previously received the bivalent HPV vaccine, this study tests whether the 9-valent HPV vaccine (V503) can trigger an immune response to additional HPV types.
Quick facts
| Phase | Phase 3 |
|---|---|
| Study type | Interventional |
| Ages | 10 Years to 45 Years |
| Sex | Women only |
| Enrollment | 930 (estimated) |
| Sponsor | Merck Sharp & Dohme LLC Industry-sponsored |
| Drugs / interventions | rituximab, chemotherapy, radiation, methotrexate, cyclophosphamide |
| Locations | 1 site (Taizhou, Zhejiang) |
| Status | Recruiting |
| Started | October 10, 2026 |
| Main results expected | December 18, 2027 |
| Study ends | December 22, 2028 |
| Registry record updated | October 22, 2026 |
| Trial ID | NCT07785843 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Women in China who previously received the bivalent HPV vaccine and are at least one year past their last 2vHPV dose, or women with no prior HPV vaccination.
✕Probably not a fit
Participants who do not show an adequate immune response or who experience adverse safety signals may not benefit.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This Phase 3, randomized, controlled trial evaluates the immune response and safety of V503 compared with placebo in Chinese females who previously received a bivalent HPV vaccine. Participants are enrolled into groups based on prior 2vHPV vaccination status or HPV vaccine naivety and receive V503 or placebo. The study measures immunogenicity to nine HPV types (6, 11, 16, 18, 31, 33, 45, 52, 58) and monitors safety outcomes. Enrolled individuals include those who completed prior 2vHPV vaccination at least one year before Day 1 or those with no HPV vaccine history, with specific exclusions for thrombocytopenia or certain cervical abnormalities. Lead sponsor is Merck Sharp & Dohme LLC, with the Yuhuan Center for Disease Control and Prevention as the site in Taizhou, Zhejiang.
Why it matters
Potential benefit: If successful, the vaccine could provide broader protection against HPV infections and related diseases for people who previously received a different HPV vaccine.
How similar studies have gone: Previous HPV vaccine studies have shown immunogenicity with 9vHPV; this study explores cross-type boosting in a prior-2vHPV population, which is somewhat novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
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.
Where it's running
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Yuhuan Center for Disease Control and Prevention ( Site 0001)
Taizhou, Zhejiang, China Recruiting
Study contacts
- Study coordinator: Toll Free Number
- Email: Trialsites@msd.com
- Phone: 1-888-577-8839
Similar studies
Other studies for the same condition or treatment. Recruiting studies are listed first.
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Reducing HPV‑16/18 infectivity and transmission after Gardasil‑9 vaccination in HPV‑positive women
This trial will try to see if three doses of Gardasil‑9 given to women with HPV‑16 and/or HPV‑18 reduce how infectious the virus is and lower the chance of passing it to partners.
How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.