Gene Therapy: Pioneering Cancer Care

Gene therapy either reduces or alters the toxic proteins in a cell or introduces new proteins to help the patient’s immune system recognize and destroy a disease. Here is a list of the main types of gene therapies currently used in clinical trials:

• Gene Addition: Inserting a new and healthy copy of a gene into a targeted cell to produce more proteins
• Gene Correction: Using gene-editing technology to remove or replace parts of an abnormal gene
• Gene Silencing: Preventing the production of a diseased protein
• Reprogramming: Adding new genes to a cell to change the characteristics of the damaged genes
• Cell Elimination: Destroying malignant (cancerous) cells and inhibiting the excessive growth of benign (non-cancerous) cells

Gene therapy modifies a person’s genetic information to treat disease. The treatment uses a carrier, called a “vector,” to deliver new genetic material to a diseased gene. Viruses are the most common vectors because they are uniquely capable of infecting cells and transferring genes. The viruses are disarmed and therefore not harmful but do carry low risks. Recently, researchers have discovered how to use microscopic particles for delivery, instead of the viral vectors, which eliminates risks associated with the use of the virus.

Depending on the cancer and the type of therapy, the vector can be injected or introduced intravenously into the patient’s tissue, or a sample of the patient’s cells can be removed and exposed to the vector in a lab before being returned.

CAR T-cell therapy is one of the first FDA-approved gene therapies available. A type of immunotherapy called adoptive cell therapy, CAR T-cell therapy alters a patient’s T cells to turn them into killer cells that attack cancerous tumors.

This treatment is offered through clinical trials at MD Anderson for patients with adult non-Hodgkin’s lymphoma or childhood acute lymphoblastic leukemia who have not responded to standard treatment. The next phase of clinical trials involves working to expand the types of cancer CAR T-cell therapy can treat.

“Eventually, the hope is that CAR T-cell therapy could replace chemotherapy and stem cell transplants altogether,” said Sattva Neelapu, M.D, an oncologist in the Department of Lymphoma and Myeloma at MD Anderson. “CAR T-cell therapy is a living drug, and its benefits can last for many years. Since the cells can persist in the body long-term, they will still recognize and attack cancer cells if and when there’s a relapse.”

Researchers at MD Anderson are working on developing more gene therapies and making them available through their world-renowned clinical trials program. Trials are currently exploring new techniques for the expansion of viral and nonviral vectors as well as the types of cancers that can be treated.

Gene therapies bring potential benefits.

• Treatments are more precise than chemotherapy or radiation
• Gene therapies can be used in combination with other cancer treatments to enhance their effectiveness.
  
• Patients do not have to undergo surgery
• They provide new opportunities for patients with rare cancers that don’t respond to other types of treatment
• There is a reduced chance of relapse as the modified cells remain in the body long-term and can identify and attack cancerous cells for many years

Cancer patients who participate in gene therapy clinical trials receive advanced, frontline treatment. However, because a healthy gene cannot be directly inserted into a diseased cell, there are risks of using a virus as a carrier.

• The virus could regain its ability to cause infection
• Complications could arise because of the highly intricate insertion process

Before a gene therapy treatment is made available to patients, it has already gone through an extensive testing process. At MD Anderson, safety is a top priority, and all gene therapy clinical trials must first be approved by the Institutional Review Board. In 2011, MD Anderson initiated an ongoing open clinical trial to study the long-term safety and impact of gene therapy.

“The goal of our research is to develop drugs that can be more effective at killing cancer cells and less toxic for patients,” said MD Anderson researcher Jack A. Roth, M.D., who led the first tumor suppressor gene therapy clinical trial approved by the FDA and the National Institutes of Health. Dr. Roth and his team at MD Andersonalso initiated the first clinical trial using nanoparticles to systematically deliver genes to cancers, and were the first to identify and characterize a number of tumor suppressor genes for lung cancer treatment.

Yes, gene therapy can be combined with other forms of cancer treatment, including surgery, radiation and chemotherapy.

MD Anderson is home to the most distinguished and extensive clinical trials program in the world, and clinical trials are an essential part of our mission to end cancer. Request an appointment online or call 1-855-761-9064.