What Is Cancer Immunotherapy?

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Every time we do something new there are always people who are not prepared to accept it but the fact is that interleukin-2 the very first immunotherapy now, what almost 30 years later has been shown to successfully treat people. The first patient to respond to high dose IL-2 received a lot of publicity at the time.

I just saw her in my office about two months ago and she's now 29 years after having being treated for [xx] ,she had widespread melanoma through her body, it all disappeared and it's still gone 29 years later and we have many patients now that are beyond 20 years and disease free, it's a very likely a curative treatment for patients with metastatic melanoma.

So interleukin-2 is a hormone produced by lymphocytes, it stimulates the immune system non-specifically so when patients develop an immune reaction, their lymphocytes, the immune warriors, the white cells would circulate through the body, when they recognize an antigen they up regulate receptors for IL-2 to, and when you give IL-2 you can expand those cells in the body, that's what an immune response is, an expansion of immune lymphocytes that can attack the given target.

Interleukin-2 appears able to expand the anti-tumor T cells and at least in some patients with melanoma it will cure them. So cancer immunotherapy is a different kind of treatment than the conventional treatments we use at surgery, radiation therapy and chemotherapy. Those are external forces, the use of scalpel, a radiation beam or drugs, and in immunotherapy, we try to attack the cancer by stimulating the body's own immune system to recognize the cancer and reject it.

The immune system is highly specific to recognize things that are non-self that invade the body like viruses, bacteria. Well the immune system of a patient recognizes the cancer as foreign but not foreign enough to reject it. In immunotherapy we manipulate the body's own natural immune system to recognize the cancer more effectively and eliminate it.

We began looking at high dose interleukin-2 therapy for virtually all cancers and it turned out that patients with melanoma and kidney cancer were uniquely responsive. And we spent many years as so many others trying to understand why melanoma is so much more immunogenic than other kinds of cancer.

And we probably understand that now in that melanomas tend to have more mutations than the great majority of other cancers. And the immune system generally acts against cancer by recognizing these mutations. That is DNA changes that result in protein and cancer cells that are not present in normal cells and there are many more of those in melanoma than most other tumors probably except for smoke patients with smoking induced lung cancers.

This is a highly personalized therapy, in other words we identify T-cells, the immune cells in a patient that recognize a unique mutation within that patients cancer that's not present in other cancers. And target it specifically, so it's the most highly personalized treatment one can imagine and we develop a new drug for every patient.

We take their lymphocytes, identify their own lymphocytes that can target the cancer, grow them up to large numbers or genetically engineer those cells to recognize the cancer. So that's just one form of immunotherapy of course we have been developing other immunotherapies to target shared antigens but what has me excited about this new approach is that its potentially the treatment for many different cancer types because especially all cancers contain mutations.