Update: A breast cancer vaccine for people with an inherited BRCA1, BRCA2 or PALB2 mutation

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What is this update about?

Researchers are studying a new vaccine to see if it lowers the chance of developing breast cancer in people who have a high risk due to an inherited mutation. The study will also determine whether the vaccine reduces the risk for recurrence in people diagnosed with early-stage triple-negative breast cancer who are at high risk for recurrence.

In this study update from the 2023 San Antonio Breast Cancer Symposium, researchers found that the vaccine triggers the immune system to recognize a protein found on some breast cancer cells. However, the research is in its early phases and scientists do not yet know how well the vaccine lowers the risk for breast cancer in high-risk people or prevents recurrence in people who have already been diagnosed.

This is the latest update on this vaccine. In May 2021, we originally published an XRAY review of a press release announcing the opening of the initial research study for people diagnosed with triple-negative breast cancer. In January 2023, we published an update highlighting how the research study was being expanded to include people at high risk for breast cancer.

Why is this new update important?

Researchers want to know if the vaccine can prevent breast cancer or breast cancer recurrence, but it is not yet known if the vaccine works. Early results show that this new breast cancer vaccine is safe and well tolerated.

The trial was initially open to people with non-metastatic triple-negative breast cancer (TNBC).

Two new groups of people can now enroll in the trial:

• People at high risk of developing breast cancer due to an inherited mutation in BRCA1, BRCA2 or PALB2 and are planning risk-reducing mastectomies.
• People with breast cancer who are taking an immunotherapy drug called Keytruda (pembrolizumab) and still have breast cancer after chemotherapy. 

How does the vaccine work?

Your immune system can defend against cancer. A cancer vaccine can help your immune system find and fight cancer.

Researchers are studying a vaccine that trains the immune system to kill cells that make a protein called alpha-lactalbumin. This protein is found on breast cells during late pregnancy and lactation. Once a person is no longer pregnant or lactating, the protein is no longer made. However, breast cancer cells, particularly TNBC cells, also produce alpha-lactalbumin.

Study findings

Study participants with TNBC received a total of three vaccinations, one every two weeks. Over 10 weeks, researchers looked at how well participants tolerated the vaccine and how well it triggered an immune response.

Early results show that:

• Researchers were able to identify the dose that triggers the best immune response.
  • All participants had an immune response. regardless of the dose they were given.
    • A strong immune response was seen in 12 of 16 (75%) participants. 
• The vaccine is safe and well tolerated.
  • No significant side effects were seen at this dose level, other than irritation at the site of injection.

What does this mean for me?

If you have an inherited  BRCA1, BRCA2 or PALB2 mutation and have never had breast cancer, you may qualify for this study. You may also qualify if you have been diagnosed with stage 2 or stage 3 TNBC or if you have remaining disease after completing neoadjuvant chemotherapy (chemotherapy given before surgery) and you are currently taking Keytruda.

The study is enrolling patients only in Cleveland, Ohio, so individuals outside of the area would need to travel to participate. Researchers are in the planning stages of larger studies using this vaccine. As this research continues, participation may be expanded to more cancer centers. If you are interested in participating, speak with your doctor and contact the study team listed on clinicaltrials.gov to see if you qualify for enrollment.

It is not known when this vaccine might be available to the public. Even if the research is successful, availability will likely take several more years. If the vaccine proves to be effective and is approved for breast cancer prevention, people who are breastfeeding or plan to breastfeed in the future would not be eligible to receive it.

Reference

Johnson J, Rhoades E, Levengood H, et.al. Phase I Trial of an alpha-lactalbumin vaccine in high risk operable triple-negative breast cancer (TNBC) and patients at high genetic risk for TNBC. Poster PO2-17-12  presented at the San Antonio Breast Cancer Symposium, December 5-9, 2023.

Disclosure: FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.

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posted 1/31/24