TIL (tumor-infiltrating lymphocyte) therapy is a type of cellular immunotherapy that has been used to treat head and neck squamous cell carcinoma, melanoma, lung cancer, genitourinary cancers and a growing list of other malignancies. Cellular immunotherapy leverages components of the patient’s immune system to seek out and attack specific cancer cells.

What are TILs?

Before discussing how TIL therapy works, it may be helpful to first explain exactly what TILs are. As noted above, TILs are a type of lymphocyte which is an immune cell that is made in the bone marrow and found within the blood and lymph tissue. There are two main types of lymphocytes: B lymphocytes (which produce antibodies) and T lymphocytes (which help destroy tumor cells and control immune responses). TILs move from the blood into tumors, where they can recognize and destroy cancer cells.

How does TIL therapy for cancer work?

TIL therapy uses unaltered tumor cells to destroy the tumor itself. In TIL therapy, TILs are grown directly from the tissue removed during a surgical resection. They are then grown to very large numbers in a laboratory with interleukin-2 (IL-2), a protein that promotes rapid TIL growth, This process typically takes four to six weeks, which means that patients will qualify for TIL therapy only if their tumor is stable enough to withstand that waiting period. 

Once successfully grown to billions in number, the TILs are infused back into the patient, where they actively attack cancer cells while leaving healthy cells alone. As with most other cellular immunotherapy approaches, a one-week course of chemotherapy is required before the TIL infusion to make space for the TIL to expand in the patient. 

Unlike many other forms of cancer treatment that require ongoing care, TIL therapy is generally performed only one time. However, if a patient previously benefited from TIL therapy and he or she once again needs to undergo treatment, then TIL therapy may be performed a second time.

Does TIL therapy cause any side effects?

The side effects that develop shortly after the TIL infusion are usually relatively minor—especially when compared to the side effects associated with many other cancer treatments—and may include:

• Fever
• Chills
• Shortness of breath

The vast majority of the side effects associated with TIL therapy are not from the TIL themselves but rather from the other medications (chemotherapy, IL-2) used as a part of the regimen. Once the blood counts have recovered and the IL-2 doses are stopped, the chance of a new adverse event occurring is low.

TIL therapy vs. CAR T-cell therapy

TIL therapy and CAR T-cell therapy are both forms of T-cell transfer therapy (also known as adoptive cell therapy, adoptive immunotherapy and immune cell therapy). T-cell transfer therapy is a type of immunotherapy that is aimed at strengthening a patient’s immune cells so that they’re better able to destroy cancer cells.

Both TIL therapy and CAR T-cell therapy involve collecting a patient’s immune cells but TIL are grown directly from a tumor whereas CAR-T cells are modified from normal T-cells found in the blood. In both cases, the cells are grown to large numbers in a laboratory and then returning the cells to the patient’s body via an intravenous catheter. While the cells are growing in the laboratory, the patient may undergo chemotherapy and/or radiation therapy. 

There are two primary differences between TIL and CAR-T therapy. First, the TIL product is polyclonal, meaning that there are many different T-cell clones in the product which can attack a wide variety of different tumor antigens. Second, TIL are not genetically modified whereas CAR-T cell therapy involves genetic modification of normal T-cells to attack a single antigen target on tumor cells.

TIL therapy at Moffitt Cancer Center

Moffitt Cancer Center is helping revolutionize the way cancers are treated through TIL therapy and many other innovative treatments. With established physician-scientists and clinicians, our center is actively exploring cellular immunotherapies by spearheading ambitious research initiatives and a groundbreaking clinical trial program. Thanks in part to our dedication to improving patient outcomes and quality of life through research, Moffitt is designated by the National Cancer Institute as a Comprehensive Cancer Center. We are the only Florida-based cancer center to hold this distinction.

While TIL therapy originally began as an advance against melanoma, the scientists at Moffitt have translated it for lung cancer, one of the world’s most deadly malignancies for which treatment research has remained underfunded. We also have treated patients with cervical cancer, head and neck squamous cell carcinoma, and sarcoma with TIL therapy. As a national leader in immunotherapies, we’re doubling down on cell therapy exploration to treat more solid tumors and improve the effectiveness of TIL therapy. By continuing to support the development of new options, we're reducing mortality rates and offering hope to cancer patients who previously had none.

Medically reviewed by John Mullinax, MD

If you would like to learn about Moffitt’s approach to cellular immunotherapy, treatment options for your specific type of cancer or whether or not you are a candidate for TIL therapy, contact us at 1-888-663-3488 or complete a new patient registration form online. We make advanced cancer treatment accessible by providing clinical and supportive care services in one location and responding to potential patients’ inquiries as soon as possible.