Your body’s immune system plays an important role in fighting off disease. But sometimes it is not strong enough on its own.
Immunotherapy can help boost the body’s natural defenses and enhance the immune response to fight off different diseases, including cancer.
One experimental type of cancer immunotherapy is tumor-infiltrating lymphocyte (TIL) infusion therapy. It uses the cancer-fighting T cells from a patient’s own tumor to create a treatment to eliminate the cancer.
“The fundamental goal of TIL therapy is to utilize the immune cells that come from the patient as a means to fight their cancer,” says Udai Kammula, MD, FACS, director, Solid Tumor Cell Therapy Program, UPMC Hillman Cancer Center.
Find out more about TIL therapy and how it works at UPMC.
What Are TILs?
TILs, or tumor-infiltrating lymphocytes, are the specialized T cells from the immune system that are found in tumors.
When activated, TILs have the ability to recognize and kill cancer cells. But cancer can suppress TILs.
In TIL therapy, a form of immunotherapy, doctors remove a tumor from a patient, identify the fighter T cells, grow them in a lab, then infuse them back into the patient to fight the cancer.
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Who Can Get TIL Therapy?
TIL therapy is not currently approved as a standard treatment for any specific forms of cancer. But it is being tested on many different types in clinical trials.
“We’re using it for a dozen different cancers to see the response, but it’s purely experimental,” says Dr. Kammula.
“We’re exploring a variety of cancers. We tend to think that cancers that have a good response to other immune therapies are a good start. But we’ve had good results treating patients with very atypical cancers that don’t have any precedent of responding.”
To be a candidate for TIL therapy, a patient has to meet certain criteria:
- They must have metastatic cancer, or cancer that has spread in the body
- Their tumor must be large enough to be removed surgically and provide enough tissue to grow the cells
Also, a patient cannot be in the late stages of cancer since the TIL therapy process takes about a month, says Dr. Kammula.
How Does TIL Therapy Work at UPMC?
TIL therapy begins with an extensive consultation to see if the patient is a candidate.
If doctors decide to move forward with TIL therapy, the first step is surgery to remove the tumor.
After the tumor is removed, it is taken to the lab where it is dissected to find the most potent tumor-fighting cells. Interleukin-2 (IL-2), a naturally occurring protein that promotes TIL growth, is then added to those cells.
Some growth is typically seen within a week. In two weeks, there is usually enough for a sample to test the potency of the cells.
“We believe that the key to successful therapy is that the T cells have the capability to attack the tumor,” says Dr. Kammula. “If the T cells don’t have favorable properties in the laboratory, they typically don’t work after infusion. So there’s a vetting process.”
If the cells are determined to be favorable, it takes another two weeks for the cells numbers to grow to several billion. The T cells are then infused back into the patient.
Before receiving the T cells, patients go through a chemotherapy regimen. The chemotherapy temporarily wipes out their existing immune system to make it more likely for the new T cells to work.
“What we’re doing is shutting down their immune system for about a week,” says Dr. Kammula. “Then we infuse a whole new immune system with the TIL cells.”
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Risks and Benefits of TIL Therapy
The odds that the T cells will be favorable and TIL therapy will be successful depend on the type of cancer you have, among other factors. The therapy has shown good results against skin melanoma and other cancers, although it is not yet approved as a standard treatment for any type of cancer.
Doctors are still studying the overall effects of TIL therapy, so its full benefits are not yet known.
There are risks to this treatment. While TILs don’t typically cause severe side effects, patients can have side effects from the chemotherapy regimen they undergo before the T cells are infused back into the body. Because of the possibility of side effects, patients likely will undergo chemotherapy on an inpatient basis. And patients at high risk for severe chemotherapy side effects may not be candidates for TIL therapy.
“It requires two and a half weeks in the hospital, and patients do feel weak for about four weeks afterward. But by the second month, they do feel close to normal,” says Dr. Kammula.
The Future of TIL Therapy
TIL therapy continues to be evaluated on a clinical trial basis for a variety of cancers.
Scientists also are using their findings from TIL therapy as an entryway into using other forms of immunotherapy, cell therapy, and gene therapy.
“In my mind, the future of cell therapy is really to make a more consistent and available product for all patients with cancer,” says Dr. Kammula.
UPMC Hillman Cancer Center provides world-class cancer care, from diagnosis to treatment, to help you in your cancer battle. We are the only comprehensive cancer center in our region, as designated by the National Cancer Institute. We have more than 70 locations throughout Pennsylvania, Ohio, New York, and Maryland, with more than 200 oncologists. Our internationally renowned research team is striving to find new advances in prevention, detection, and treatment.