Injection with a modified herpes virus may help melanoma patients achieve anti-cancer responses, according to a recent article published in The Lancet.
Melanoma is a cancer of the skin that usually begins in the form of a mole. The cancer can grow deep into the skin and spread to different parts of the body through blood or lymph vessels. It usually spreads first to lymph nodes that are near the site of cancer origin and when advanced, can spread to organs and other lymph nodes throughout the body. Treatment for advanced melanoma may consist of surgery, radiation, chemotherapy and/or biologic therapy. However, the prognosis for patients diagnosed with this disease is poor, as melanoma typically does not respond well to standard therapies.
A relatively novel concept in biological therapy involves the use of viruses. Viruses can be modified in a laboratory so that they will target cancer cells yet not create deleterious effects on healthy cells. Researchers have been evaluating the use of the herpes simplex virus (HSV) for therapeutic benefit against cancer. HSV can be genetically altered so that the gene within the virus which normally causes infection is rendered inactive, leaving the virus unable to cause a systemic infection. However, the virus is still able to insert itself into a cancer cell. Once inside the cell, the modified HSV continually replicates, ultimately causing the cancer cell to burst.
A small preliminary study involving modified HSV in the treatment of melanoma patients has just been completed. Five patients with advanced melanoma were given injections of HSV directly into the cancer prior to removal. Patients received either one, two or four injections in a given site. All patients had evidence of previous infection with HSV prior to the treatment. All injected cancer sites showed areas of cell death. This is important as it indicated an immune response to the injections, despite the fact that all patients already had HSV. The patient that received 4 injections had a regression in the size of the cancer prior to its removal. All patients tolerated this treatment well.
These results indicate potential for the use of HSV in the treatment of advanced melanoma. Future clinical trials involving treatment combinations involving HSV will further define its role for clinical use. Patients with melanoma may wish to speak with their physician about the risks and benefits of participating in a clinical trial evaluating HSV for treatment against cancer. Two sources of information about ongoing clinical trials include comprehensive, easy-to-use listing services provided by the National Cancer Institute (cancer.gov) and eCancerTrials.com. eCancerTrials.com also provides personalized clinical trial searches on behalf of patients. (The Lancet, Vol 357, No 9255, pp 525-526, 2001)