What Is Gene Therapy?
Cancer appears in the body when a human carcinogen, such as asbestos, causes an otherwise healthy cell to divide and disperse abnormally. This abnormal multiplication of cells is a genetic mutation that scientists hope to resolve with the help of gene therapy. Gene therapy replaces the cells with synthetic cells in the hope that they will provide the immune system with enough energy to do its job of defending the body against attack by cancer cells.
Gene therapy is an experimental treatment that has been in its testing phase for several decades, but has not yet been approved by the FDA for exclusive first or second tier treatment. Surgery, radiation and chemotherapy remain the preferred treatment combination for mesothelioma. However, gene therapy can be introduced as an additional, supporting treatment to counteract the defective genes in a cell. Gene therapy has so far proven to aid some patients fighting mesothelioma.
How Does Gene Therapy Work?
Gene therapy is the replacement or addition of mutated genes in a cancerous cell. There are several ways a gene may be affected when it turns into a cancerous cell. The mutated gene could be causing the cell to multiply, it could be suppressing cell advancement, or it could affect the genes that mend other damaged genes.
One type of protein and tumor suppressor gene is BAP1, which acts as a moderator for environmental toxins like asbestos—the only known cause of mesothelioma. Cells with lower levels of BAP1 appear to have a reduced ability for DNA repair once compromised by environmental carcinogens. Doctors feel this is a possible genetic reason why healthy cells in mesothelioma patients become triggered by asbestos and turn into cancer.
By restoring the BAP1 gene through gene therapy, doctors can help patients better defend against mesothelioma cell growth. With gene therapy, patients receive injections of artificial genes into cancerous cells.
While the process is difficult and still being studied, the best practice thus far is to inject new genes into the cell using a vector (an organism that spreads infection). Viruses typically act as gene therapy vectors. They get injected into cells so that they can deliver genetic material and target cancer cells, leaving healthy cells intact so that they can do their job.
Types of Gene Therapy
There are different types of gene therapy that have been tested and used for patients with mesothelioma. These various trials target specific genes so that they can effectively attack cancerous cells. One common approach is the use of gene transfer, which works by injecting foreign substances to trigger effects such as suicide genes (see below).
Angiogenic inhibitors are used to stop the growth of blood cells, which ultimately starves the tumor. Oncolytic viruses are the most common use of gene therapy. They’re used to genetically alter viruses to attack cancerous cells once injected.
Each of these forms of gene therapy act in different ways to aid the fight against mesothelioma.
Some further types of gene therapy and how they work include the following:
- Suicide Gene Therapy: This type of gene therapy is used as a gene transfer, which works to kill mesothelioma cells. This is done by modifying cells to produce enzymes, which triggers what is known as “suicide cells”, and causes the cell to die. One type of suicide gene therapy is called gene-directed enzyme-producing therapy or GDEPT.
- Cytokine Gene Therapy: This type of gene therapy is signaled by cytokines, which act as molecules that signal communication from cell to cell within the immune system. This communication tells cells where to move to attack cancerous areas. Cytokine for gene therapy speeds up this communication to rush those cells to attack the cancer.
- Tumor-Based p53 Gene Therapy: p53 is a tumor-suppressor gene that is one of the genes mutated when cancer is present. Experts believe that targeting this gene specifically to repair it will be a step forwarding in finding a longer lasting treatment for mesothelioma.
Benefits of Gene Therapy for Mesothelioma
The benefits for mesothelioma using gene therapy reflect those of other third-party treatments such as virotherapy. Gene therapy is limited in its ability to fully cure or handle mesothelioma without the help of other treatments. However, one of the benefits of gene therapy is its ability to target cancerous cells specifically, leaving the patient room to fight off the disease using the remaining healthy cells.
Various clinical trials have indicated that the use of gene therapy has shown impressive results. In one trial, 12 patients tolerated the treatment well, experiencing a stable response after just one month of treatment. The median survival rate for these patients was 449 days, or 15 months, with the assistance of gene therapy. It was observed that this treatment boosted pre-existing anti-tumor antibody responses and transitory inflammatory response.
Current and Ongoing Research into Gene Therapy
While the FDA has not approved use of gene therapy for patients with mesothelioma, in August 2017, the FDA approved it as a treatment for certain types of cancer. Specifically, the use of Kymriah gene therapy was approved for pediatric and young adult patients who have been diagnosed with a form of acute lymphoblastic leukemia. Kymriah is the form of treatment used in gene therapy, which genetically modifies cells to treat cancer.
FDA Commissioner, Scott Gottlieb, M.D., said about gene therapy,
“We’re entering a new frontier in medical innovation with the ability to reprogram a patient’s own cells to attack a deadly cancer. New technologies such as gene and cell therapies hold out the potential to transform medicine and create an inflection point in our ability to treat and even cure many intractable illnesses.”
Gene Therapy Side Effects
Gene therapy has been known to cause varying levels of side effects. Typically, these side effects are slight and disappear within 24 to 48 hours.
The most common side effects include flu-like symptoms such as:
- Severe chills (or rigor)
- Changes in blood pressure
Experts have been concerned about the potential side effects of injecting genetic mutations within the body, such as exposing healthy cells to harmful viruses. However, patients have not exhibited these symptoms in clinical trials, and gene therapy remains an asset in treating patients with mesothelioma.
Undergoing Gene Therapy and Other Mesothelioma Treatments
Gene therapy is a promising treatment with the potential to restore hope to patients living with mesothelioma. With its varying abilities and methods at targeting and destroying cancerous cells, it is one of the most prominent treatments in expanding research for mesothelioma.
Clinical trials are currently accepting patients diagnosed with mesothelioma to test out gene therapy treatments. Contact our Patient Advocates today to learn more about the new, emerging mesothelioma treatment.