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By Joshua Mansour, M.D.
Will Anti-vaccinators also be against these new breakthrough vaccines that can improve odds for a type of cancer once thought to be a death sentence?
With the continued outbreak in measles and other illnesses that were once thought to be essentially eradicated with the concurrent use of vaccines it is interesting enough that vaccines again have made yet another improvement, this time to treat cancer. Will this be something that anti-vaccine individuals would turn down if now their life now depended on it?
Pancreatic cancer is many times not diagnosed until it has metastasized and by then is many times uncurbable. Initial symptoms are many times vague, therefore mistake it for a simple illness. That is until this cancer spreads beyond the pancreas, this organ that is located deep in the abdomen.
Dr. Elizabeth M. Jaffee an international leader in immune-based therapy and Co-Director of the Cancer Immunology Program and the Gastrointestinal Cancers Program at Johns Hopkins and the Sidney Kimmel Comprehensive Cancer Center has focused recently on the development of vaccines that overcome immune tolerance to cancers. She has focused on testing a pancreatic cancer vaccine in patients who are eligible for complete surgical resection but are at high risk for disease recurrence. The initial studies have demonstrated the safety of the vaccine and identified a dose that allows for activation of the immune system. Thus far it has been associated with improved disease-free survival.
In addition to the vaccines mentioned above oncolytic virotherapy has been an emerging treatment, with major institutions investing research and time into finetuning this therapy. There has been a wide array of viruses that have been used, including measles, polio, herpes, and the adenovirus.
MD Anderson has genetically modified the adenovirus, which can cause the common cold, to help treat Glioblastoma Multiforme, a very aggressive brain tumor. Malignant gliomas are both the most common and most lethal type of central nervous system tumors, with glioblastoma being the most aggressive subtype. The current standard of care involves a combination therapy that consists of surgery, radiation, and chemotherapy. Even with this treatment, these tumors remain incredibly fatal. After second-line therapy, there is currently no standard of care.
Duke University has used an oncolytic virus to treat Glioblastoma Multiforme. In this manner, a live genetically modified polio virus is imparted in the brain tumor via a catheter. The adapted virus, without the part that causes the viral disease, can then penetrate the cancer cells and surmount an immune response to attack the cancer cells. The rate of overall survival of patient's treated with this at 24 months was 21 percent compared to 4 percent in the general population group.
Another instance where a different virus is being used is with Talimogene Laherparepvec (also known as TVEC), which is used to treat melanoma and is currently FDA approved. It is a herpes virus that is genetically engineered to help shrink the tumor and then activate the immune system to continue to recognize and destroy cancer cells. Similar to the others, the herpes virus also has the ability to invade the cancer cells. However, this treatment differs from the others previously mentioned, as this oncolytic virus is genetically engineered to include granulocyte-macrophage colony-stimulating factor to help draw immune cells to the tumor. This can further enhance the response of our immune system to fight these once unrecognizable cells.
The measles vaccine, used to prevent measles, contains a weakened but live version of the measles virus and causes your immune system to produce antibodies against the virus without causing you to contract the illness. In this manner, if you are exposed to measles, these developed antibodies will work to protect you from the disease.
In a different manner, Mayo clinic has used a large dose of measles virus for treatment of multiple myeloma after patients failed multiple lines of conventional therapy. The dose used for this vaccine contains about 100 billion units, enough to inoculate approximately 10 million people. While some of the previously mentioned treatments will inject an oncolytic viral therapy locally, in this particular case the engineered measles virus was injected intravenously in order to help treat metastatic disease instead of localized disease.
Above, there are several methods described in which vaccines and viruses are being used to treat cancer. Some of these are in the investigational phases and others are FDA approved. These treatments have been described as immune therapy, viral oncolytic treatment, or "cancer vaccines", even when referring to the same mechanism. A person who favors one type of "name" versus the other may choose the one that they find suitable to their personal beliefs. Whichever you choose though, there is no denying that these vaccines can be used to help fight cancer.
Dr. Joshua Mansour is a board-certified hematologist/oncologist working and in the field of hematopoietic stem cell transplantation and cellular immunotherapy in Stanford, California. Recently he has managed to have over 10 recent abstracts and over 10 recent manuscripts published in esteemed journals and given countless presentations at conferences and other institutions. He has helped design and implement clinical studies to evaluate current treatment plans, collaborated on grant proposals, and lead multi-institutional retrospective studies that have been published.
