In the pipeline: preventive vaccine against breast cancer

June 7, 2010 by  
Filed under CANCER

Could this be the vaccine we have been waiting for? Researchers at Cleveland Clinic announced last week that we may be closer to having a vaccine to fight breast cancer that previously thought. The researchers have developed a vaccine that was tested and shown to be effective in mice. The next step is to test the vaccine in clinical trials, e.g. in humans.

According to Vincent Tuohy, Ph.D., the study’s principal investigator and an immunologist in Cleveland Clinic’s Lerner Research Institute Department of Immunology:

“We believe that this vaccine will someday be used to prevent breast cancer in adult women in the same way that vaccines prevent polio and measles in children. If it works in humans the way it works in mice, this will be monumental. We could eliminate breast cancer.”

There are two main types of vaccines: preventive vaccines and therapeutic vaccines. Preventive vaccines are those that we are most familiar with – the childhood inoculations such as MMR and DPT, as well as adult vaccines against yellow fellow and hepatitis. These vaccines start up the immune system to produce that antibodies for certain antigens, thus protecting the recipient from certain diseases. Therapeutic vaccines (also called treatment vaccines), on the other hand, are the new kid in the block. They work not a preventive measure but as treatment of an already existing condition.  The vaccine is designed to boost the immune system to better fight or control an ongoing infection or disease. Currently, there are many therapeutic vaccines against cancer being developed and tested.

There are currently two preventive vaccines targeting some types of cancer. According to the US-based National Cancer Institute:

“The U.S. Food and Drug Administration (FDA) has approved two types of cancer preventive vaccines: A vaccine against the hepatitis B virus, which can cause liver cancer in chronically infected people, and a vaccine against human papillomavirus types 16 and 18, which are responsible for about 70 percent of all cases of cervical cancer.”

The Cleveland Clinic prototype is the first of its kind preventive vaccine for breast cancer. The vaccine is made from the antigen and has been shown to prevent the development of breast cancer tumors in mice as well as slow down the growth of existing tumors. The mice tested were genetically engineered to be prone to breast cancer, thus representing a high-risk population. All these mice did not develop breast cancer. The α-lactalbumin antigen targets breast cancer cell without damaging healthy breast tissue. The vaccine will be tested in women as early as next year, targeting women over 40 years old, the age where breast cancer risk starts to increase and the likelihood of pregnancy is low.

Soon: a vaccine against prostate cancer?

February 23, 2010 by  
Filed under CANCER

What does the small pox virus has to do with prostate cancer? Well, scientists are using relatives of the deadly virus to develop a vaccine that holds lots of promise for patients with advanced prostate cancer. The vaccine Prostvac-VF is still in the testing stage and is a ground-breaking project of BN ImmunoTherapeutics, a division of Danish biotech firm Bavarian Nordic.

In the clinical trial development program of Prostvac-VF, the vaccine the vaccine was tested in 125 male patients with advanced prostate cancer that was resistant to most cancer drugs. The study conducted with the help of researchers at the Dana-Farber Cancer Institute and Harvard Medical School in Boston.

The results of the trial was very promising, with patients treated with the vaccine having extended survival of 8 months or more compared to those who did not receive the vaccine. According to researcher Dr. Philip Kantoff:

The average survival for these men is two years…At three years, 30 percent of the men who got the vaccine were still alive.”

Prostvac is one of therapeutic vaccines currently in the development stage Therapeutic vaccines are used to treat diseases that have been diagnosed and are therefore different from prophylactic vaccines which prevent diseases.

Prostvac was developed from genetically-engineered cowpox virus and fowlpox viruses which are related to the small pox virus. The viruses were weakened and genetically engineered to carry irregular versions of the prostate specific antigen (PSA), which are produced only by prostate cells. In addition, the vaccine also induces the production of “three costimulatory molecules that spur the immune system to a more vigorous attack on tumor cells.”

The results of the study have been published in the Journal of Clinical Oncology. The authors concluded that immunotherapy with Prostvac-VF was well tolerated and associated with a 44% reduction in the death rate and an 8.5-month improvement in median overall survival rate in patients with metastatic castration-resistant prostate cancer. However, larger studies needed to confirm these findings.

Dr. Kantoff continues:

“Although this study is relatively small, it offers encouraging evidence of a clinically meaningful benefit from this vaccine approach.”

A trial that intends to include about 600 patients is in the planning.

There is a large economic potential for an effective prostate vaccine. Prostate cancer is a leading cause of mortality among American men, ranking second only to lung cancer as cancer killer. 2009 statistics from the American Cancer Society give 192,000 diagnosed cases 27,000 deaths. Financial analysts foresee a billion-dollar market for such a vaccine.

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NOTE: The contents in this blog are for informational purposes only, and should not be construed as medical advice, diagnosis, treatment or a substitute for professional care. Always seek the advice of your physician or other qualified health professional before making changes to any existing treatment or program. Some of the information presented in this blog may already be out of date.