Clapper, Patti, Schweizer and Mason

Malignant mesothelioma (MM) is a cancer of the lining of the lungs, heart or intestines and is known to be resistant to conventional therapies. Standard treatment usually includes one or more of:

 

To date, the majority of mesothelioma patients respond poorly to frontline treatments. Mesothelioma prognosis is usually poor, with a median survival time of 6-9 months from time of diagnosis. Because no treatment method has proven to be effective, there are ongoing clinical trials that are exploring therapeutic potential with alternative therapies and drugs. One such line of study is investigating the viability and effectiveness of gene therapy. 

 

Gene therapy, sometimes also referred to as molecular therapy, aims to replace or repair defective genes in targeted mesothelioma cancer cells. By injecting genes into the pleural space that is infected with tumors, the proliferation or spreading of cancerous cells can be stopped or slowed. The idea is to replace the genes in cancer cells with healthy genes. Most gene therapies use either different vector systems and/or different transgenes.

 

In technical terms, several strategies used in clinical trials have included:

 

Two recent studies were conducted in the United States, each with a different strategy. The first was to inject a virus into the pleural space in the chest where mesothelioma had developed.  In this Phase I clinical trial, none of the patients had received any prior chemotherapy. The injection involved the expression of a herpes simplex virus gene (Ad-HSVtk) or interferon-b gene. The study showed successful gene transfer into the mesothelioma tumors in the majority of patients with minimal side effects. Three of the 25 evaluable patients survived more than five years, which is extremely rare with mesothelioma cancer. More research is needed to clearly demonstrate and validate clinical benefits and hopefully further investigations will lead to more successful therapeutic interventions.

 

The second study conducted in pilot and Phase I trials involved injecting a virus expressing the interleukin – 2 (IL-2) gene. The experimental results showed promise that this method could lead to tumor cell death and prolonged survival as well, although more study must take place to validate clinical responsiveness and effectiveness.  

 

Current clinical trial results show that gene therapy may be a viable therapeutic approach to treating mesothelioma. Further research is warranted as studies have shown improvement in symptoms of mesothelioma as well as survival times. 

 

If you have been diagnosed with mesothelioma and are interested in participating in a current mesothelioma gene therapy trial, consult with your oncologist or visit the National Cancer Institute website for information about what may be available in your area.