How Doctors Use Gene Therapy to Treat Cancer

Updated December 10, 2019

Cancer is a terrible disease, a word no one wants to hear from their doctor's lips. However, it's not the automatic death sentence it once was. New treatments like Gene Therapy is giving patients a new lease on life.

Gene therapy adds new genes to the cells of a patient to correct either a missing gene or a malfunctioning one. Medical researchers use a virus to transport genetic materials into cells because that’s the most effective way to deliver genetic cargo. 

This therapy promises to treat a broad spectrum of diseases, like AIDS, hemophilia, diabetes, heart disease, cystic fibrosis, and of course, cancer. Since it is still in an experimental phase, treatment is only available through a clinical trial. 

A New Precision Medicine Drug for Oncology 

In cancer treatment, gene therapy aligns with precision medicine because it allows physicians to select only treatments that match a patient’s genes.

A new drug, Selpercatinib (LOXO-292), tested for more than three years through clinical trials, is an important new advance in precision medicine for oncology.

This drug, developed through a partnership between Lily Oncology and Loxo Oncology, is effective with RET fusion-positive non-small cell lung cancers.

Besides demonstrating positive benefits for patients, the drug is also good news for doctors.

Dr. Nathan Pennell, MD, Ph.D., director of lung cancer medical oncology at Cleveland Clinic, explains, “It’s an incredibly exciting time. Patients are scared when they learn they have an incurable disease. But instead of telling them they may live, on average, less than a year, we hope now to be telling them it will be ‘years’, with an ‘s’ on it. Very soon, we may be treating lung cancer more like a chronic disease, such as hypertension or diabetes.”

Case Study: Sara Whitlock’s Story 

Selpercatinib (LOXO-292) transformed the life of Sara Whitlock, diagnosed with stage 4 lung cancer in 2010. 

Sara developed a 9-year connection with Dr. Pennell. This was something she never imagined possible because when she received her medical diagnosis at age 47, she expected to live less than a year. Yet at 56 years of age, she still talks to her doctor. She also did not expect to see her kids grow up. At the time, her daughters were 8 and 12 years old. Now, she is sending them off to college.

Sara was in the shower when she noticed a knot above her clavicle. It turned out to be stage 4 non-small cell lung cancer. By the time doctors discovered it, the cancer had spread to both her lungs and her abdomen.

In 2010, Dr. Pennell determined she had a common type of lung cancer. But it was only years later that genetic research had advanced enough for him to make a more accurate diagnosis. He then discovered that she had an uncommon genetic condition called a RET-gene fusion, a condition so rare that only 1 to 2% of lung cancer patients have it. 

In 2017, Sara took part in a clinical trial, receiving treatment with the experimental new drug. 

Since Selpercatinib (LOXO-292) is a pill, it’s simple to administer. It also doesn’t have the side effects associated with traditional treatments, such as hair loss and anemia. With the new targeted therapy, none of these distressing symptoms happen.

Today, Sara only visits Dr. Pennell at Cleveland Clinic once a month for a routine visit to replenish her supply of the drug and receive a medical examination.

Her new medication has worked better for her than any of the traditional cancer treatments, and her disease has not progressed in two years. 

How Selpercatinib (LOXO-292) Works 

Patients with RET fusions experience mutations that appear as different varieties of tumors that occur intermittently. In Sara’s case, she experienced tumors in various parts of her body—lungs, brain, abdomen, and bowels—at different times. 

Selpercatinib (LOXO-292) inhibits RET signaling and anticipates resistance mechanisms. Research has shown the drug to be effective for three types of RET fusions: Metastatic RET fusion-positive non-small cell lung cancer, RET-mutant medullary thyroid cancer (MTC), and Advanced RET-fusion-positive thyroid cancer. 

Patients become eligible for treatment if they have made some progress with traditional cancer treatments but then reached a point when they had no more acceptable alternative treatment choices. 

An Emerging Approach in Modern Medicine

Precision medicine provides medical treatment or prevention to patients based on unique individual variables, such as their genes, their environment, and their lifestyle.

While Sara made progress with traditional cancer treatments, she could only progress for a short time before the drug became ineffective or the side effects became intolerable. 

Through advances in gene therapy, Dr. Pennell could identify that she had a rare form of lung cancer, called RET-fusion. Since Sara was eligible for Selpercatinib (LOXO-292), she started clinical trials. The treatment proved highly effective with only mild side effects. She has had no recurring cancer since she began treatments. 

Dr. Pennel fully expects that gene therapy will make it possible for patients with lung cancer to live for many years.