Lovaxin C Vaccine to Combat a Female Cancer
A Cervical Cancer Vaccine Based on Immunotherapy is Showing Promise
Apr 2, 2009
The American Cancer Society estimates that about 11,070 cases of invasive cervical cancer will be diagnosed in the United States. About 3870 women will die. All women are at risk for cervical cancer, but most often it is found in women older than 20 years of age. Cervical cancer is the easiest female cancer to prevent because a preventive vaccine and a screening test are available. It is also highly curable when found and treated early.
Lovaxin C-Vaccine Treatment
For those who have been diagnosed with cervical cancer, a new vaccine called Lovaxin C is currently being developed. Lovaxin C is a Listeria Monocytogenes cancer vaccine. It enables the body to fight cancer tumors by producing tumor-specific antigens that the immune system would not recognize as its own and attack. The Lovaxin C will be effective against Human Papilloma Virus causing cancers which include cervical, head and neck cancer. Listeria is an environmental bacteria and humans routinely ingest it, suggesting that we already have an immune relationship with it.
"It generates a very, very strong immune response in humans. It serves to clear the bugs usually without us ever knowing we've been exposed", says Dr. John Rothman, PhD., Executive Vice President of Science and Operations at Advaxis.
How Lovaxin C Works
The Lovaxin C vaccine is an altered (weakened) form of Listeria that has been modified to secrete a tumor-specific antigen. It then fuses with another fragment of a Listeria protein (adjuvent), stimulating the immune system. This activates the body's own Killer T-Cells (scavengers that seek out foreign antigens to destroy) and Helper T-Cells (cells that release chemicals that activate the immune system to produce antibodies against the antigen).
Results of Early Studies of Lovaxin C
The vaccine is still in the earliest study phase. However, it is showing promise to be safe and effective. The phase I study participants are those who have tried and failed first line therapies such as surgery, chemotherapy, and radiation. Of the 13 study participants, seven had tumor reductions of 30%, three had a tumor reduction of 20%, one had a 33% tumor reduction and two had tumors that disappeared completely. According to Dr. Rothman, by stimulating and reconstituting an active immune response, cancer becomes more of a chronic disease than a fatal disease.
"One of the hallmarks of an effective immunotherapy in late stage disease is that often the tumors don't go away and in many cases they don't even diminish measurably, but survival is increased", says Dr. Rothman. Exact availability of the vaccine can't be determined at this time, but the hope is the near future.
A Word About Immunity
Immunity is the body's internal protective mechanism that is activated by being exposed to a disease antigen. There are many types of immunity but following are most prominent:
- Active Immunity is developed in the body when it comes in contact with a particular substance that has the ability to make us immune. For example if we get the mumps, then we become immune and usually don't get them again.
- Cell-Mediated immunity develops when an antigen (foreign invader) and white blood cells such as Helper T-Cells and Killer T-Cells interact. This type defends against bacteria, viruses and fungi, and malignant cells.
- Passive immunity is acquired in utero when antibodies from the mother pass into the placenta and through breast milk.
Sources:
Interview with Dr. Rothman of Advaxis
Handbook Of Medical-Surgical Nursing, by Springhouse Corporation, 1994
