One of the most important medical advances in recent decades is that doctors can now use patients’ immune systems to fight cancer. Immunotherapy is the name for this type of treatment.
In most forms of immunotherapy, drugs boost your immune system so it can attack cancer cells. Now, doctors can also use your own immune cells to fight cancer. Scientists call this form of immunotherapy adoptive cell transfer or adoptive cellular therapy.
First, doctors harvest a specific type of cell from your body. The type they choose depends on what form of cancer you have. Then they grow the cells in a lab, so they can select the ones that are best able to fight the type of tumor you have. When they have enough of these cells, doctors infuse them back into your body.
Once back in the body, the cells continue to multiply while attacking cancer cells.
Exploring TIL Therapy
One type of adoptive cell transfer uses the patient’s lymphocytes. These white blood cells help fight infection. They also eliminate damaged cells.
As cancers grow, lymphocytes identify the tumor as abnormal. The lymphocytes try to enter the tumor cells. Doctors refer to these lymphocytes as tumor-infiltrating lymphocytes, or TILs.
Udai Kammula, MD, Director of UPMC’s Solid Tumor Cell Therapy Program, explains that tumors can prevent TILs from doing their job. “The tumor is really quite a formidable foe,” he says. “Tumors have developed unique strategies to either evade these cells or in some cases just starve them or kill them.”
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But when TILs grow in the lab away from the tumor, they multiply rapidly. Doctors start with a small sample of the patient’s tumor, sliced up into small fragments. They include cell nutrients to help the TILs grow. The doctors select the TILs that show the most antitumor activity.
After several weeks, the TILs grow to about 100 billion cells. Dr. Kammula says the cells are “highly activated and hungry,” ready to return to the patient’s body.
Rebooting the Immune System
While the TILs are growing, doctors give a specific chemotherapy designed to knock out the patient’s immune system. “If your computer has a virus, sometimes the best thing to do is to wipe the hard drive clean and start over,” Dr. Kammula says. “Reboot the immune system, is what I tell patients.”
Once the chemotherapy suppresses the immune system, the patient receives an intravenous infusion of their TILs. “We literally can see these tumors shrinking before the patient leaves the hospital at the end of a week.” Dr. Kammula says.
In clinical trials, TIL therapy has a response rate of more than 50% in patients with cutaneous melanoma. These same trials show a long-term complete response rate of about 25%. This provides a great deal of hope to patients whose traditional therapies have failed.
What’s Ahead for TIL Therapy
Based on these results, Dr. Kammula’s team is developing TIL therapy for other hard-to-treat cancers. These include:
- Pancreatic cancer.
- Mesothelioma, a rare form of lung cancer.
- Uveal melanoma, a rare cancer of the eye.
And they’re seeing encouraging results.
Dr. Kammula credits TILs’ ability to attack hard-to-reach tumors for the successes so far.
“When you put living, breathing cells like TILs into the bloodstream, they go wherever blood goes,” he says. “We’ve not seen an obstacle, even with tumors in a tiny nook or crevasse.”
These advantages are particularly important when treating solid tumors that have spread. “These are exactly the types of cancers that have been so hard to cure with conventional therapies,” he explains.
Dr. Kammula remains optimistic about TIL therapy. “Every single day I come to work is an exciting day,” he says. “As I tell the people in the lab, we’re doing things that no one has ever done before.”
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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.