TIL Therapy for Melanoma: Magic Bullet? Or?

TIL Therapy also known as the ACT or adoptive cell transfer, is a therapy of great interest to many patients. There are some small trials currently ongoing at the National Cancer Institute and a few other cancer centers. The patients in these trials—most of whom have metastatic disease usually have exhausted other treatment options, although some try it out first time around.

ACT involves removing some of a patient’s own immune-system cells, growing them in the laboratory, and infusing the cultured cells into the patient. The idea is to provide an invading force of immune cells that can attack tumors in a way that the immune system was incapable of doing on its own. The patient must undergo chemotherapy to first deplete the body of the current immune function and then gets high dose IL2 with the infusion of t-cells.

TIL Therapy requires intensive care hospitalization as it can be risky and highly toxic. According to Dr. Keith Flaherty, Director of the Center for Targeted Therapies at Mass General, “the balance of efficacy and safety has not been established to consider the TIL therapy as an option in relation to immunotherapies and Braf inhibitor based therapy. Clinical trials, randomized to other therapies are certainly lacking. It has been unclear whether the TIL therapy will be brought forward for consideration by regulatory agencies.”

The cost at NIH for the TIL therapy is said to be at $500,000 per patient. Funding is taxpayer underwritten. The high cost is due to lack of restrictions on the amount of scans and other procedures that normally health insurance companies would regulate as well as the intense labor it takes and time to go through the therapy. Several new biotech companies are forming around the concept of developing T-cell therapy as a treatment approach and that could lead to approval. There is still a long way to go for this therapy and the type of rigorous dated needed to judge its merits may come in the near future. Other institutions, (Moffitt and MD Anderson) have ACT programs but can’t seem to replicate the success rate of NCI. A major issue is that at the NIH, patients are very carefully selected for TIL to date (young, robust) and that makes it hard to understand if it could be generally relative to the majority of melanoma patients.

I have lost patients to this treatment and that has jaded my outlook. But they just couldn’t come back to a level of wellness to continue their struggle with melanoma after completing TIL. I do know a few patients who have had remarkable recoveries to no evidence of disease and I’m very happy they are doing well. But the numbers aren’t in and as Dr. Flaherty points out, we need to see randomized studies with larger numbers to prove TIL works. The cost may prohibit this from happening for some time.

In the meantime my personal opinion is that TIL is much like IL2, the response is amazing but only in a very small fraction of patients. I question where it may leave a patient once they have failed this therapy and whether they can realize improvement with something else. We have options for once in melanoma therapy and they seem to generate the most success when they have the least toxicity. Our immune system is a fragile entity that needs careful approaches.

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