Cancer vaccine combination therapy shows survival benefit in breast cancer

May 15, 2012

A vaccine that targets cancer cells in combination with the drug letrozole, a standard hormonal therapy against breast cancer, significantly increased survival when tested in mice, a team of UC Davis investigators has found.

The findings will be published today in the journal .

"We found that the vaccine and the hormonal drug were more effective when given together," said Michael DeGregorio, UC Davis professor of hematology and oncology and principal investigator of the study. "This adds critical evidence that with vaccines, which has traditionally been used to prevent , is also a promising new approach to combating cancer."

The vaccine, known as L-BLP25 (Stimuvax), specifically targets Mucin1 (MUC1), an antigen that is expressed in an altered form on cancer cells. When introduced into the body, the vaccine generates an immune response by T-lymphocytes, which then recognize and destroy the . Mice in the study were injected weekly with the vaccine -- or a placebo -- for eight weeks.

In addition to the vaccine or placebo, some mice were treated with either letrozole or , commonly used hormonal therapies against . Both drugs work by blocking the effects of estrogen, which can slow or stop the growth of some types of breast cancer cells that need the hormone to grow. Although the drugs have similar actions, the benefits of the vaccine were greatest in the mice treated with letrozole; in contrast, vaccinated mice given tamoxifen actually fared worse than those given either the vaccine or tamoxifen alone.

"Hormonal drugs affect the immune system in different ways, and apparently the actions of tamoxifen prevent the vaccine from working effectively," said DeGregorio. "This highlights the importance of rigorous testing of different combinations of therapies before using them in patients."

The article, available online, is titled "L-BLP25 vaccine plus letrozole induces a TH1 immune response and has additive antitumor activity in MUC-1 expressing mammary tumors in mice."

Breast cancer is the second-leading cause of cancer death in women in the United States, following lung cancer. Most cases of breast cancer are "estrogen-dependent" and respond to hormonal therapy. For tumors that are independent of hormonal influence, treatment options are limited and would especially benefit from a new treatment strategy such as a vaccine.

The vaccine was found to work best when the tumor burden -- the amount of cancer present -- was low, indicating that the vaccine may one day be best used as a preventative measure for women at high risk of developing breast cancer or for treatment of early disease.

Vaccine therapy is a promising new cancer-fighting strategy; the first therapeutic vaccine for prostate cancer was approved by the U.S. Food and Drug Administration in 2010. Trials with L-BLP25 vaccine are currently under way for lung and pancreatic cancers, whose cells also express altered MUC1, the same tumor-associated antigen found on . The current study is the first known to the authors to demonstrate that a combined with a vaccine provides additive antitumor activity and survival benefit.

"This was a true alliance between academics and industry," added DeGregorio, who noted that trials such as this one are especially expensive because of the number of mice needed and the length of time -- about three and a half years -- required to establish their findings. The study had support from the pharmaceutical company, Merck KGaA Darmstadt Germany.

DeGregorio's group will further test the vaccine with other conventional therapies and determine optimal dosing. Clinical trials in patients with breast cancer are in the planning stages.

Explore further: Mayo Clinic receives FDA approval for ovarian and breast cancer vaccines

Related Stories

Mayo Clinic receives FDA approval for ovarian and breast cancer vaccines

August 17, 2011
Mayo Clinic has received investigational new drug approval from the Food and Drug Administration for two new cancer vaccines that mobilize the body's defense mechanisms to destroy malignant cells. The vaccines are among the ...

Vaccine for metastatic breast, ovarian cancer shows promise

November 8, 2011
Treatment with a recombinant poxviral vaccine showed a positive response in both metastatic breast cancer and ovarian cancer, according to a trial published in Clinical Cancer Research, a journal of the American Association ...

Cancer stem cell vaccine in development shows antitumor effect

April 2, 2012
Scientists may have discovered a new paradigm for immunotherapy against cancer by priming antibodies and T cells with cancer stem cells, according to a study published in Cancer Research, a journal of the American Association ...

Recommended for you

Outdoor light at night linked with increased breast cancer risk in women

August 17, 2017
Women who live in areas with higher levels of outdoor light at night may be at higher risk for breast cancer than those living in areas with lower levels, according to a large long-term study from Harvard T.H. Chan School ...

Scientists develop novel immunotherapy technology for prostate cancer

August 17, 2017
A study led by scientists at The Wistar Institute describes a novel immunotherapeutic strategy for the treatment of cancer based on the use of synthetic DNA to directly encode protective antibodies against a cancer specific ...

Toxic formaldehyde is produced inside our own cells, scientists discover

August 16, 2017
New research has revealed that some of the toxin formaldehyde in our bodies does not come from our environment - it is a by-product of an essential reaction inside our own cells. This could provide new targets for developing ...

Cell cycle-blocking drugs can shrink tumors by enlisting immune system in attack on cancer

August 16, 2017
In the brief time that drugs known as CDK4/6 inhibitors have been approved for the treatment of metastatic breast cancer, doctors have made a startling observation: in certain patients, the drugs—designed to halt cancer ...

Researchers find 'switch' that turns on immune cells' tumor-killing ability

August 16, 2017
Molecular biologists led by Leonid Pobezinsky and his wife and research collaborator Elena Pobezinskaya at the University of Massachusetts Amherst have published results that for the first time show how a microRNA molecule ...

Popular immunotherapy target turns out to have a surprising buddy

August 16, 2017
The majority of current cancer immunotherapies focus on PD-L1. This well studied protein turns out to be controlled by a partner, CMTM6, a previously unexplored molecule that is now suddenly also a potential therapeutic target. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.