Tumor-Infiltrating Lymphocyte therapy

What is tumor-infiltrating lymphocyte (TIL) therapy?

Tumor-infiltrating lymphocyte therapy is a new form of immunotherapy that treats cancerous tumors. Immunotherapy is cancer treatment that helps your immune system identify and fight cancer cells. TIL therapy works by boosting some of your most powerful immune cells: tumor-infiltrating lymphocytes (TILs).

Here’s what makes TILs special.

While you have several immune cell types that patrol your body for threats, TILs invade (infiltrate) tumors directly. TILs learn tumors’ weaknesses and how to best destroy them. The problem is that your immune system doesn’t make enough TILs to fight the tumors.

Tumor-infiltrating lymphocyte therapy works by boosting your TIL count. A surgeon removes your tumor. The TILs are expanded in a lab — growing your attack force by the billions. Then, you get the TILs as an infusion (IV).

Cancers that TIL therapy treats

As of 2024, lifileucel (Amtagvi®) is the first TIL therapy treatment approved by the U.S. Food and Drug Administration (FDA). It treats melanoma that can’t be treated with surgery alone or that has spread (metastatic cancer). If you have this diagnosis, and the cancer hasn’t responded to the standard treatments oncologists prescribe first, you may be a candidate for this treatment.

Healthcare providers are also studying the effectiveness of TIL therapy in treating:

• Breast cancer
• Cervical cancer
• Colon cancer
• Head and neck cancer
• Non-small cell lung cancer

What happens during TIL therapy?

The primary treatment involves getting an infusion of tumor-infiltrating lymphocytes. But there are lots of steps involved before this can happen. It may be helpful to think of treatment as a series of key steps:

• Removal. A surgeon will remove part of the tumor and send it to a lab. You’ll receive anesthesia for the procedure, so you won’t feel any pain. The sample will be about the size of a grape.
• TIL-harvesting and expansion. The lab will harvest TILs from the tumor and make more of them. This should take about five weeks. Then, the lab will send the TILs to your healthcare provider.
• Chemotherapy infusion. You’ll be admitted to the hospital, where you’ll receive regular infusions of chemotherapy for five to seven days. Each infusion lasts about two hours. This treatment makes room in your body for the new TILs you’ll get during the transfusion.
• TIL transfusion. You’ll receive a one-time infusion of TILs. The process takes about two hours.
• Interleukin-2 (IL-2) infusion. For three to five days, you’ll receive infusions of interleukin-2. The process takes about two hours per dose. This immunotherapy treatment activates the TILs to fight the cancer.

You’ll stay in the hospital for a few days after treatment so your care team can monitor your response. For the next several weeks, you’ll stay within driving distance of the hospital while your body adjusts to treatment. That way, you can receive care immediately if you experience side effects that require your provider’s care.

How long will I need this treatment?

TIL therapy is a one-time treatment that takes about 10 weeks from tissue removal to recovery. This includes the waiting period, where the lab prepares the TILs, and your recovery timeline. Your hospital stay will be closer to two weeks.

What are the potential benefits and risks of this treatment?

TIL therapy is a powerful, personalized treatment that targets cancer cells while sparing your healthy cells. This reduces your risk of side effects. Also, it’s long-lasting. The TILs remain in your body for years. The cells keep fighting tumors long after your infusion.

Perhaps most importantly, TIL therapy is helping people whose melanoma was previously untreatable. According to a 2023 study following the effects of TIL treatment at four years, 7 out of 10 people experienced improvements or no cancer progression. Three out of 10 had tumors that got smaller or disappeared.

Still, all steps in the treatment process involve some risk. These include chemotherapy side effects and immunotherapy side effects. The immunotherapy side effects are usually from the IL-2 infusions and not the TIL-infusion. The most common side effects include:

• Diarrhea
• Fatigue
• Fever and chills
• Irregular heartbeat (arrhythmia)
• Low blood pressure
• Nausea and vomiting
• Rash

Although it’s rare, IL-2 therapy can cause a serious complication called capillary leak syndrome. Your healthcare provider will review all potential risks before you start treatment.

How long will it take for me to feel better?

It’ll take about two weeks or more after your last IL-2 infusion before you start feeling better. This is because it will take some time for your body to recover from all the treatments involved in TIL therapy.

Is there anything I can do to make this treatment easier on me?

Your care team will work with you closely during your hospital stay to keep you comfortable. They’ll do regular exams and blood tests to ensure you can receive treatment safely. They’ll give you medications to reduce the risk of side effects and monitor you for complications.

Treatment is an involved process. This is why your providers will go to great lengths to care for you throughout treatment and keep tabs on you during recovery.

When should I call my healthcare provider?

Contact your provider if you experience signs of an infection or unexpected or severe side effects. Don’t second-guess yourself. If something feels “off” after TIL therapy, let your provider know.