Gene Therapy

Radiation and chemotherapy are most commonly used to treat mesothelioma, but other treatments that are in the experimental stages – like gene therapy – are being used more frequently. These therapies are usually administered as part of clinical trials in order to test their effectiveness for cancers like mesothelioma caused by asbestos.

Gene Therapy Information

Gene therapy refers to experimental treatments that are done in an attempt to correct the conditions caused by faulty genes. Genetic techniques are applied that replace the copy of a gene that is defective with a copy that behaves normally. This is generally done by changing a virus so that it has a normal copy of the gene. Using a virus is an ideal method by which to get the genes into the cells since the normal process of a virus is to enter cells and take over the genetic workings to make viral proteins. When a patient is treated with gene therapy, he or she is given a virus that has been changed genetically with a copy of a gene that is normal, but the gene is treated in such a way that it cannot cause an infection. Once inside the body, the virus enters specific cells and makes those cells produce normal proteins rather than proteins that are defective.

Mesothelioma Gene Therapy

While the original point of gene therapy was to treat genetic diseases that are inherited, it is now being used to develop other treatments. In the last 10 years, research in this field has been focused on finding possible treatments for cancer of all kinds. In the case of mesothelioma, gene therapy is aiming to use genetic material to target the cancer cells to make them more susceptible to the drugs used in chemotherapy. One of these gene therapy treatments for mesothelioma that has the most potential is called “suicide gene therapy.” A genetically altered virus is used to attack tumor cells. This virus contains a gene that makes proteins capable of changing a non-toxic drug into one that can kill the tumor cells. When a patient receives this virus, it only infects the tumor cells. Later, the patient is given a drug that is toxic only to cancer cells. There has been some success in clinical trials using suicide gene therapy. According to Clinical Cancer Research, in one such trial involving 21 patients, each was treated with a strain of herpes simplex virus encoded with an adenoviral vector to deliver the tumor-killing proteins. All patients tolerated the treatment well, antibody responses against the tumors were common, and two patients were still alive six and a half years later -- far longer than typical life expectancy for mesothelioma.

Side Effects

It is not uncommon for patients injected with these modified viruses to have the symptoms of an infection like fever and chills. There is the chance of more severe side effects, but the possibility of benefits offset these risks.

Complications

The FDA has not yet approved gene therapy, so the treatment is only available through clinical trials. There are concerns about the way different patient’s immune systems will respond to the virus. If there is a negative response, the treatment will not be as effective. Researchers are also concerned about how difficult it is to get the virus to the cancer cells so that the protein can be produced. Until these two problems are solved, the benefits of gene therapy will be short term. References: