Ovarian Cancer Vaccine Development

For the past 30 years, researchers have been looking into the potential of vaccines to treat ovarian cancer. Vaccines are a promising future treatment for ovarian cancer. Although they are still at the clinical trial phase, they may someday be used to prevent the progression of ovarian cancer.

Ovarian cancer affects the ovaries, a pair of small, almond-shaped organs located on either side of your pelvis. It is one of the most common cancers for women, with more than 20,000 new cases each year. It also accounts for more deaths each year than any other female reproductive system cancer.

Ovarian cancer poses treatment challenges. It is difficult to detect and may be at an advanced stage when diagnosed. The overall survival rate after 5 years is less than 50 percent, according to 2019 research. But this varies by stage at diagnosis.

Ovarian cancer vaccines should not be confused with the human papillomavirus (HPV) vaccine, which protects against HPV.

Keep reading to learn about the vaccines currently in development for ovarian cancer, and how they differ from the HPV vaccine.

Dozens of ovarian cancer vaccines are currently at various stages of development. A 2020 review identified 42 published clinical trials on ovarian cancer vaccines. Some of these are described below.

Keep in mind that new drug treatments have to undergo at least three phases of clinical trials before they can be approved for the public by the Food and Drug Administration (FDA).

Dendritic cell vaccines

Dendritic cells (DCs) are a critical part of your immune system. They patrol their surroundings to identify threats, known as antigens. When an antigen — for instance, a cancerous cell — is detected, DCs activate a targeted immune system response to eliminate it.

Dendritic cell vaccines harness the power of DCs to kill tumor cells. The goal is typically to prevent tumor growth, known as maintenance therapy. Researchers are studying most DC vaccines in combination with other treatments, such as chemotherapy.

Studies assessing the use of DC vaccines date back to 2000. According to a 2021 review, the majority of DC vaccine trials conducted to date have not made it past phase 2.

One reason for this is that ovarian cancer tumors have been shown to negatively affect DC function and metabolism, making them less effective. Additional challenges include preparing the vaccines and selecting the right antigens for individual patients.

More technologies, such as personalized antigens, are currently in development. The authors of the 2021 review cited above concluded that, with the use of these technologies, DC vaccines still show potential to slow or stop ovarian cancer tumor growth.

CTA vaccines

Cancer-testis antigens (CTAs) are proteins that are active in the testes. Several tumors, including ovarian cancer, also exhibit active CTAs. CTA vaccines help generate an immune response that targets and disables CTAs.

The clinical trials published to date have focused on the use of a CTA protein called NY-ESO-1. A 2020 review suggests this protein is present in up to 40 percent of people with ovarian cancer. But as of 2020, only four phase 1 clinical trials on CTA vaccines had been published.

The research suggests that CTA vaccination stimulates an immune system response. This response can stabilize tumor growth and prolong survival.

According to another 2020 review, tumors have a number of features that limit the effectiveness of CTA vaccines, including the ability to avoid immune system detection and suppress immune system activity.

The authors suggest using NY-ESO-1 vaccines in combination with other cancer therapies to increase their effectiveness.

A current phase 1 clinical trial is doing just that. It combines an NY-ESO-1 vaccine with nivolumab, an immunotherapy drug. Results are expected in 2023.

Protein- and peptide-based vaccines

These vaccines work in a way similar to both DC and CTA vaccines, targeting other antigens known to play a role in tumor growth. Some of the antigen proteins that have been evaluated in clinical trials include:

  • human epidermal growth factor receptor 2 (HER2)/neu
  • p53
  • WT1
  • folate receptor alpha

Several clinical trials have reported promising results. For instance, the authors of a 2013 phase 2 trial of a WT1 peptide vaccine for gynecological cancers reported no cancer progression in 40 percent of participants.

In addition, a 2018 phase 1 clinical trial of a folate receptor alpha vaccine for breast and ovarian cancer found that all participants were alive 2 years after vaccination.

As of 2022, research focuses on:

  • using multiple proteins in a single vaccine to boost the immune response
  • customizing vaccines to target tumor-specific antigens
  • combining therapies to increase effectiveness

Recombinant viral vaccines

Recombinant viral vaccines use viral vector technology to deliver one or more antigens. In turn, these antigens stimulate an immune response to eliminate cancerous cells.

Between 2006 and 2012, several studies of recombinant viral vaccines for ovarian cancer reported modest results. Some appear not to have made it past the pilot phase.

A more recent 2018 phase 1 trial with 11 participants investigated the effectiveness of a p53 antigen vaccine used in combination with the chemotherapy drug gemcitabine for ovarian cancer.

The authors reported that the immune system response generated by the treatment was associated with longer progression-free survival. However, several people could not complete the study due to gemcitabine side effects.

As of 2022, a phase 2 trial featuring a p53 recombinant viral vaccine and the chemotherapy drug pembrolizumab was actively recruiting participants.

HPV is a common sexually transmitted infection. According to the Centers for Disease Control and Prevention (CDC), 85 percent of people will contract HPV in their lifetime.

HPV doesn’t usually cause noticeable symptoms. But it can lead to health complications over time, including certain cancers.

The HPV vaccine works the same way other vaccines do. It contains a very small amount of the virus, which stimulates your immune system to create antibodies. If you are exposed to HPV later on, your immune system is already prepared to fight the infection.

By preventing an HPV infection, the vaccine also protects against cancers associated with HPV, including:

  • anal cancer
  • cervical cancer
  • mouth cancer
  • penile cancer
  • throat cancer
  • vaginal cancer
  • vulvar cancer

The HPV vaccine can only protect against cancers associated with HPV. The link between HPV and ovarian cancer is unclear, with past studies showing conflicting results.

A 2021 analysis of 29 studies published between 1989 and 2020 estimated the prevalence of HPV in 2,280 people with ovarian cancer. The authors found that the number of people with HPV varied significantly across different studies, with researchers in certain regions more likely to detect a link between HPV and ovarian cancer. They concluded that more high quality studies are needed.

For now, it’s not clear if the HPV vaccine has any potential to prevent ovarian cancer.

According to the CDC, there is no evidence to suggest that the HPV vaccine causes reproductive problems such as primary ovarian insufficiency (POI), infertility, or cancer.

Vaccines undergo rigorous testing both before and after they are made available to the public. Side effects are reported to the Vaccine Adverse Event Reporting System (VAERS).

VAERS received 20 reports of POI following the administration of approximately 90 million HPV vaccines in the United States between 2009 and 2017.

After investigating these reports, the CDC determined that only two had been confirmed by a doctor. The remaining 18 instances were based on unsubstantiated second-hand reports. They concluded that the HPV vaccine is unlikely to cause POI.

The World Health Organization (WHO) also investigated public concerns about the HPV vaccine, POI, and infertility. They concluded that there was no data to support a causal relationship.

Additional studies have reported similar results. For instance, a 2021 cohort study of 996,300 girls and women in Denmark found no evidence to suggest that HPV vaccination causes ovarian failure.

Ovarian cancer is one of the most difficult cancers to detect and treat. Vaccines currently in development may one day be used alongside other treatments to prevent disease progression.

Ovarian cancer vaccines are different from the HPV vaccine. By protecting against an HPV infection, the HPV vaccine prevents the development of reproductive cancers associated with HPV. These include cervical and anal cancers.

If you are seeking treatment for ovarian cancer, you can learn more about ongoing clinical trials at the National Library of Medicine’s Clinical Trials Database.