What are the challenges in creating a vaccine for cancer?

Although vaccines have been effective in preventing viral infections, researchers have not found ways to stimulate those cells in the body that recognize cancer. Steven Rosenberg, MD, shares how adoptive T-cell therapy is an effective treatment.

Transcript

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We haven't found ways to stimulate those very rare cells that are in the body that are recognizing the cancer.

00:06

And so although it's a promising approach that's been used effectively to prevent viral infections,

00:12

but we haven't been able to develop vaccines that will actually stimulate t cells that will eliminate or reduce

00:20

cancers that already exist.

00:29

Now, the third form of immunotherapy is called adoptive t-cell therapy or adoptive cellular therapy.

00:36

In that therapy, we identify the exact immune lymphocytes, the immune warriors of the body that can recognize a cancer.

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We take them out of the body. We either educate them or genetically engineer them so that they can recognize the cancer.

00:52

And then we return them under conditions that allow them to work. That is, we have to first eliminate

00:59

the body's natural immune system to make room for the new cells we give. And when we do that, we can see response rates

01:07

in patients with melanoma that are higher than any other kind of cancer treatment. In one trial, we had 72% of our patients

01:15

with metastatic melanoma undergo objective regressions. And 40% of those had complete durable regressions ongoing

01:23

beyond five years. And we have some beyond 10 years. Now, this therapy has been used in patients with melanoma

01:30

quite effectively. It's an experimental treatment. But we've developed ways to genetically engineer lymphocytes, that is, take out normal lymphocytes

01:38

and put in receptors that can recognize a cancer. And we first reported that in 2010 as a treatment for patients

01:46

with lymphomas targeting a CD19 molecule, not a mutation but a normal molecule that's on b cells

01:53

but that's also expressed in over 90% of lymphomas and leukemias. And so you can genetically engineer a lymphocyte

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for patients that have advanced refractory lymphomas or leukemias and give them back.

02:07

And they can then cause regressions and often complete regressions. In the first patient ever treated this way, in 2010,

02:15

one of our patients here at the NCI, is still progression-free now five years later. So one can use a patient's natural cells

02:23

or you can genetically engineer them to attack the cancer. [AUDIO LOGO]