Cancer vaccine combination therapy shows survival benefit in breast cancer

May 15, 2012, Queen's University Belfast

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

Single blood test screens for eight cancer types

January 18, 2018
Johns Hopkins Kimmel Cancer Center researchers developed a single blood test that screens for eight common cancer types and helps identify the location of the cancer.

Researchers find a way to 'starve' cancer

January 18, 2018
Researchers at Vanderbilt University Medical Center (VUMC) have demonstrated for the first time that it is possible to starve a tumor and stop its growth with a newly discovered small compound that blocks uptake of the vital ...

How cancer metastasis happens: Researchers reveal a key mechanism

January 18, 2018
Cancer metastasis, the migration of cells from a primary tumor to form distant tumors in the body, can be triggered by a chronic leakage of DNA within tumor cells, according to a team led by Weill Cornell Medicine and Memorial ...

Modular gene enhancer promotes leukemia and regulates effectiveness of chemotherapy

January 18, 2018
Every day, billions of new blood cells are generated in the bone marrow. The gene Myc is known to play an important role in this process, and is also known to play a role in cancer. Scientists from the German Cancer Research ...

These foods may up your odds for colon cancer

January 18, 2018
(HealthDay)—Chowing down on red meat, white bread and sugar-laden drinks might increase your long-term risk of colon cancer, a new study suggests.

The pill lowers ovarian cancer risk, even for smokers

January 18, 2018
(HealthDay)—It's known that use of the birth control pill is tied to lower odds for ovarian cancer, but new research shows the benefit extends to smokers or women who are obese.

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.