Clapper, Patti, Schweizer and Mason

Lung cancer, including mesothelioma is the third leading cause of death in the United States.  Advanced stage lung cancer, which is almost always the situation when mesothelioma is diagnosed, is particularly resistant to standard treatments and generally has a poor prognosis.  Alternative treatments for mesothelioma are continually being researched in hopes of finding more effective interventions. 

Mesothelioma acts the same as most types of cancer in that malignant cells are able to proliferate rapidly and are not recognized by the body’s defense system because they look very similar to healthy cells.  Immunotherapy is a type of treatment that employs the body’s own immune system to not only fight tumor growth but also to kill off cancer cells while leaving healthy tissue alone.

Since the 1980’s, researchers have investigated the use of oncolytic viral therapies as a way of fighting cancer.  One such agent is a modified herpes vaccine, such as NV1020, NV1066, and OncoVEX GM-CSF, has shown promise of effectively treating cancer with little side effects. 

The injection of the herpes vaccine has a threefold effect:  one, it multiplies quickly, selectively killing tumor cells but not healthy ones; two, it produces a human protein that activates the body’s natural immune system; and three, it makes a protein that recognizes and attacks tumor cells.  In so doing, the virus inhibits mesothelioma tumor progression within the pleural cavity.  This can be very useful in treating mesotheliomas that are chemo or radiotherapy resistant.

Injection of the virus leads to not only to tumor death but also activation of the immune system by increasing expression of proteins intended to fight off infections and invasions.  Mesothelioma is one type of cancer particularly suitable for viral therapy because tumors are often localized and accessible. 

Clinical trials using oncolytic viruses have shown promising results as a safe, antitumor therapeutic agent with mild side effects compared to other standard modes of therapy.  Five different oncolytic HSV1 viruses are being investigated in clinical trials.  To find out more, speak to your treating oncologist or visit the National Cancer Institute website at http://www.cancer.gov/clinicaltrials.