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Human Papillomavirus Type 18 L1 Protein

This article summarizes several clinical trials investigating the use of Human Papillomavirus (HPV) vaccines containing HPV Type 18 L1 Protein, particularly focusing on the 9-valent HPV vaccine Gardasil 9. These studies aim to evaluate the vaccine’s efficacy, safety, and immunogenicity in various populations and contexts, including extended dosing schedules, immunocompromised individuals, and post-treatment scenarios for HPV-related conditions.

Table of Contents

What is the HPV Type 18 L1 Protein Vaccine?

The Human Papillomavirus (HPV) Type 18 L1 Protein vaccine is a component of the 9-valent HPV vaccine, also known by the brand name Gardasil 9. This vaccine helps protect against infection and disease caused by nine types of HPV, including type 18.[1]

The vaccine contains virus-like particles (VLPs) that mimic the HPV virus but do not cause infection. These VLPs are produced using recombinant DNA technology in yeast cells.[2]

How Does It Work?

When administered, the HPV Type 18 L1 Protein vaccine stimulates the body’s immune system to produce antibodies against HPV type 18. These antibodies help protect against future HPV 18 infections by neutralizing the virus if a person is exposed.[1]

What Does It Treat and Prevent?

The HPV Type 18 L1 Protein vaccine, as part of the 9-valent HPV vaccine, helps prevent:

  • Persistent HPV infections
  • Cervical, vaginal, and vulvar precancers and cancers in females
  • Anal precancers and cancers in both males and females
  • Genital warts in both males and females
  • Head and neck cancers (though this is still being studied)

HPV type 18 is responsible for approximately 20% of cervical cancers worldwide, making it the second most common cancer-causing HPV type after HPV 16.[3]

How Is It Administered?

The vaccine is typically administered as an intramuscular injection. The standard dosing schedule includes:

  • 2 doses for individuals 9-14 years old, given 6-12 months apart
  • 3 doses for individuals 15 years and older, given over 6 months

Some ongoing studies are evaluating extended dosing intervals and different dosing regimens.[1]

Effectiveness

Clinical trials have shown the 9-valent HPV vaccine, which includes the HPV Type 18 L1 Protein, to be highly effective in preventing HPV infections and related diseases. The vaccine induces a strong immune response, with over 99% of vaccinated individuals developing antibodies against the targeted HPV types.[1]

Safety and Side Effects

The HPV vaccine, including the Type 18 L1 Protein component, has been extensively tested and is considered safe. Common side effects may include:

  • Pain, redness, or swelling at the injection site
  • Headache
  • Fever
  • Nausea
  • Dizziness

Serious side effects are rare but can include severe allergic reactions.[4]

Who Should Get Vaccinated?

The HPV vaccine is recommended for:

  • All boys and girls aged 11-12 years (can start as early as 9 years)
  • Teens and young adults up to age 26 who haven’t been vaccinated
  • Some adults aged 27-45 years who haven’t been vaccinated (after discussing with their healthcare provider)

The vaccine is most effective when given before potential exposure to HPV through sexual activity.[5]

Ongoing Research

Several clinical trials are currently underway to further study the HPV vaccine, including the Type 18 L1 Protein component. These studies aim to:

  • Evaluate extended dosing intervals and different dosing regimens[1]
  • Assess the vaccine’s effectiveness in specific populations, such as immunocompromised individuals[2]
  • Study the vaccine’s potential in preventing oral HPV infections[3]
  • Investigate the vaccine’s effectiveness in preventing recurrence of high-grade cervical lesions in women over 45[5]

These ongoing studies will help refine vaccination strategies and potentially expand the vaccine’s uses in the future.

Study Focus Key Population Main Objectives Primary Endpoints
Extended dosing intervals Boys and girls 9-14 years, women 16-26 years Evaluate safety and immunogenicity of 2-dose vs 3-dose regimens Antibody GMTs at 4 weeks post-last dose
Immunocompromised patients Children and adolescents 9-18 years Assess immunogenicity in immunocompromised individuals Seroconversion rates at 7 and 12 months
Oral HPV prevention Adult males 20-45 years Evaluate efficacy against oral persistent HPV infection Incidence of HPV16/18/31/33/45/52/58-related oral persistent infection
Post-treatment vaccination Women with vulvar HSIL Assess efficacy in preventing HSIL recurrence Clinical recurrence rate of vulvar HSIL within 24 months
Vaccination after cervical lesions Women over 45 years Evaluate HPV clearance after treatment and vaccination HPV-negative status within 24 months of initial positive test

FAQ

  • What is the main purpose of these HPV vaccine clinical trials? The main purpose of these clinical trials is to evaluate the efficacy, safety, and immunogenicity of HPV vaccines, particularly the 9-valent vaccine Gardasil 9, in different populations and scenarios. This includes testing extended dosing schedules, assessing effectiveness in immunocompromised individuals, and studying its use after treatment for HPV-related conditions.
  • Who are the target populations for these HPV vaccine studies? The target populations vary across studies but include boys and girls aged 9-14, young women aged 16-26, men who have sex with men (MSM) aged 19-26, immunocompromised children and adolescents, adult males aged 20-45, women treated for vulvar high-grade squamous intraepithelial lesions (HSIL), and women over 45 treated for high-grade cervical lesions.
  • What are some of the key outcomes being measured in these trials? Key outcomes being measured include antibody responses to HPV types, incidence of HPV infections and related diseases, vaccine safety and tolerability, seroconversion rates, and in some cases, quality of life and cost-effectiveness of vaccination.
  • How long do these clinical trials typically last? The duration of these trials varies, but many extend from 6 months to several years. Some studies include long-term follow-up periods of up to 5 or 10 years to assess the vaccine's long-term effectiveness and safety.
  • Are there any special considerations for participants in these HPV vaccine trials? Yes, there are several special considerations. These may include age restrictions, sexual history requirements, exclusion of those with certain medical conditions or prior HPV vaccinations, and specific timing of vaccinations in relation to other treatments or procedures. Some trials also have restrictions related to pregnancy or plans for pregnancy during the study period.

Ongoing Clinical Trials on Human Papillomavirus Type 18 L1 Protein

  • Study on HPV Vaccine Timing for Patients After Stem Cell Transplantation Using Gardasil 9

    Recruiting

    2 1 1 1
    Investigated diseases:
    Investigated drugs:
    Sweden

Glossary

  • HPV (Human Papillomavirus): A group of viruses that can cause various types of cancer and genital warts. There are many types of HPV, and some are targeted by vaccines to prevent infection.
  • Gardasil 9: A 9-valent HPV vaccine that protects against nine types of HPV (6, 11, 16, 18, 31, 33, 45, 52, and 58). It is used in many of the clinical trials discussed.
  • Immunogenicity: The ability of a substance, such as a vaccine, to provoke an immune response in the body.
  • Seroconversion: The development of detectable antibodies in the blood directed against an infectious agent, indicating a response to vaccination or infection.
  • HSIL (High-grade Squamous Intraepithelial Lesion): A precancerous condition found in the cervix or vulva, often caused by persistent HPV infection.
  • Conisation: A surgical procedure to remove a cone-shaped piece of tissue from the cervix, often used to treat cervical HSIL.
  • Colposcopy: A medical procedure to closely examine the cervix, vagina, and vulva for signs of disease.
  • Geometric Mean Titers (GMT): A measure of the average concentration of antibodies in the blood, often used to assess vaccine response.
  • Adverse Event (AE): Any unfavorable and unintended sign, symptom, or disease temporarily associated with the use of a medical treatment or procedure.
  • cLIA (Competitive Luminex Immunoassay): A laboratory test used to measure antibody levels in response to HPV vaccination.

References

  1. http://clinicaltrials.eu/trial-id/2022-500256-37-00
  2. http://clinicaltrials.eu/trial-id/2022-501413-31-00
  3. http://clinicaltrials.eu/trial-id/2022-501974-21-00
  4. http://clinicaltrials.eu/trial-id/2022-502224-49-00
  5. http://clinicaltrials.eu/trial/study-on-hpv-vaccine-after-treatment-for-high-grade-cervical-lesions-in-women-over-45/