New Vaccine Destroys Melanoma and Ovarian Cancer Tumors

According to a new study, published in the leading scientific journal Proceedings of the National Academy of Sciences, is showing that a new vaccine/therapy is effective against Melanoma and Ovarian Cancer.

Dr. F. Stephen Hodi, from the Department of Medical Oncology and Cancer Vaccine Center, Dana-Farber Cancer Institute, and Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, led the study.

According to Hodi and colleagues, using fully human anti-CTLA-4 blocking monoclonal antibodies (the new vaccine) to patients with advanced stages of cancer significantly increases the immune response and induces the destruction of tumor in certain patients.

The study focuses on a receptor known as CTLA-4 (for cytotoxic T lymphocyte-associated antigen). CTLA-4 works like a valve, actually a "shut-off" valve for CD4+ T cells. These CD4+ T cells are involved in the immune response of the patient.

The new vaccine is specific for every cancer patient. Tumor cells (from the patient) are removed, and irradiated (to stop growing). After that these tumor cells are infused with a gene that produces a protein called GVAX. Finally, the modified tumor cells (you can call this the vaccine) are injected back into the patient.

What happens after the vaccination is that the GVAX gene causes the body to produce the GVAX protein. This protein is seen as a foreign threat and the immune response acts fully to destroy it.

The study mentioned encouraging results of this procedure. For example, researchers found that a single infusion of anti-CTLA-4 antibodies produced a great deal of tumor destruction in five metastatic melanoma and ovarian cancer patients. Also, tumors in eight of the participants either receded or became stable. Similar good results were obtained for ovarian cancer patients.

Since results from this study are so encouraging, the authors are planning more research. They think that combination therapies of GVAX vaccine with CTLA-4-blocking antibodies could be improved by using other therapeutic agents such as certain compounds that target specific cell components (for example regulatory T cells). A possible candidate is one known as FoxP3+.

Cancer is a term used to designate a broad range of conditions in which cells grow aggressively (grow and divide without respect to normal limits), invade (invade and destroy adjacent tissues), and sometimes spread to other locations in the body (metastasis).

Experts believed that cancer is responsible for around 13% of all deaths. According to the American Cancer Society, more than 7 and a half million people died from cancer during 2007 worldwide.

Sources:

F. Stephen Hodi, Marcus Butler, Darryl A. Oble, Michael V. Seiden, Frank G. Haluska, Andrea Kruse, Suzanne MacRae, Marybeth Nelson, Christine Canning, Israel Lowy, Alan Korman, David Lautz, Sara Russell, Michael T. Jaklitsch, Nikhil Ramaiya, Teresa C. Chen, Donna Neuberg, James P. Allison, Martin C. Mihm, and Glenn Dranoff

Immunologic and clinical effects of antibody blockade of cytotoxic T lymphocyte-associated antigen 4 in previously vaccinated cancer patients

PNAS published February 19, 2008, 10.1073/pnas.0712237105

American Cancer Society