Mesothelioma Treatment with Gene Therapy Remains in Experimental Phase
February 1, 2011
Gene therapy was originally developed to treat genetically inherited diseases, but in the last decade, it has been integrated into the fight against cancer.
Mesothelioma is notoriously resistant to surgery, chemotherapy and radiation, yet gene therapy strives to make the cancerous cells more receptive to traditional treatment. Gene therapy shows promise in the treating the disease, yet further research is required before it is accepted for clinical use.
One form of gene therapy demonstrating potential as a form of mesothelioma treatment uses genetically altered viruses to deliver cytokines to cancerous cells. Cytokines direct the immune system’s efforts, and when delivered to cancerous cells, these proteins may help the immune system attack a mesothelioma tumor.
Another gene therapy procedure with a slightly wider body of research is “suicide gene therapy,” which uses genetic material to make the cancerous cells more receptive to drugs that can inhibit the progression of mesothelioma.
Suicide gene therapy sends a virus into the tumor to alter its genetic code. The virus only infects the mesothelioma cells, leaving the surrounding healthy cells unaffected. Once in the tumor, the gene carried by the virus instructs the cancerous cells to produce a specific protein that will make the tumor susceptible to an otherwise non-toxic drug. A short waiting period will follow the administration of the virus, after which the patient will receive the drug to kill the altered mesothelioma cells.
A clinical trial conducted at the University of Pennsylvania Medical Center measured the effectiveness of suicide gene therapy in 34 patients who received doses of genetically altered Adenovirus. Four of these patients displayed considerable tumor regression, while two others achieved complete regression that lasted more than seven years.
The rapidly dividing nature of cancerous cells poses challenges in infusing every single cell with the virus. This makes obtaining a long-term cure from gene therapy difficult to ensure. While the short term benefits of gene therapy are encouraging, further research must be done before the procedures are approved for widespread public use.
The FDA also requires further investigation of the treatment to address the immune system’s response to the virus used to deliver the gene. Although these viruses are manually altered to remove the harmful genes and insert therapeutic ones, the body may still respond to the virus as it would respond to an infection, causing side effects such as fever and chills. Additional clinical trials are underway to explore these concerns, yet researchers are optimistic that ongoing research for gene therapy will provide the medical world with milestones in mesothelioma treatment.