Medical milestone: Cell therapy comes to solid tumors

PHILADELPHIA (WPVI) -- For nearly a decade, engineered versions of a person's own disease-fighting cells have saved the lives of many people with blood cancers.

Now, for the first time, they are being used against a solid tumor.

It was a major landmark - Emily Whitehead's leukemia was put in remission by a treatment using her own T-cells to target cancer.

But Dr. Margaret von Mehren, a medical oncologist at Fox Chase Cancer Center, says CAR T-cell therapy hasn't worked with solid tumors.

"Some cancer cells don't have a lot of things that the immune system sees as abnormal," she said.

Synovial sarcoma is one of those.

"These tumors can really present anywhere, oftentimes in the arm or leg, but sometimes we will see them arise in the lung," she said.

The tumor cells not only have fewer proteins on the surface for T-cells to latch onto, but other cells around them hold down any immune response.

In Tecelra, the new FDA-approved treatment, a patient's T-cells are collected, as in CAR T-cell therapy. Then they're genetically engineered and infused back into the patient's body.

But instead of targeting abnormal proteins on the surface of cancer cells, "It allows the T-cells to recognize proteins, or parts of the cells, not only on the cell surface, but can be inside," said Dr. von Mehren.

Tecelra is for patients whose synovial sarcoma has returned after surgery and radiation. And the tumor must have the right cell structure.

"Because this T-cell receptor is targeting a very specific set of protein pieces," Dr. von Mehren said.

Patients must also be healthy enough to wait about six weeks while their personalized treatment is made.

"Or do we need to give them some therapy in between? We call it a bridging therapy," she asks.

Dr. von Mehren says Tecelra is quickly making a difference for these patients.

"More than 70% of them were alive two years later. So that's actually for patients who have metastatic sarcoma. That's a very high number," said Dr. von Mehren.

And she believes Tecelra will open the door to treat other solid tumors with new engineered cell treatments.