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Therapy shrank tumors in 62% of patients in small trial

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Result was not lasting beyond a few months for most

patients

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"We're on the right track," scientist says

By Julie Steenhuysen

CHICAGO, June 1 (Reuters) - A Gilead Sciences ( GILD )-backed

therapy made with a patient's own white blood cells shrank

tumors in 62% of patients with recurrent glioblastoma, a rare

event for a fatal brain cancer with few treatment options,

researchers reported on Sunday.

The study, presented at the American Society of Clinical

Oncology meeting in Chicago and published in Nature Medicine, is

the latest among several efforts testing next-generation

chimeric antigen receptor T-cell or CAR-T treatments, a type of

immunotherapy in which patients' immune cells are engineered to

recognize and kill cancer cells.

The work, from researchers at the University of Pennsylvania

and Gilead's Kite cell therapy unit, tested a dual

CAR-T treatment in an effort to overcome the defenses of

glioblastoma, the most common brain tumor in adults.

CAR-T therapy is already used to treat blood cancers

including leukemia, lymphoma and multiple myeloma, and those

treatments typically only take aim at one target on the tumor.

But solid tumors such as glioblastoma tend to have multiple

subpopulations of tumor cells, suggesting that treatments will

need more than one target to succeed, said University of

Pennsylvania researcher Dr. Stephen Bagley, who led the study.

For the treatment, which is injected directly into spinal

fluid, the team selected EGFR, which is found in 50% to 60% of

all glioblastoma tumors, and a second target called

interleukin-13 receptor alpha 2, found in an estimated 75% of

glioblastoma tumors.

Typically, advanced glioblastoma patients whose cancers

return after initial treatment with surgery, radiation and

chemotherapy live six to 10 months.

Interim results of just six patients were published in March

2024 in Nature Medicine. The current study now includes 18

patients treated with the experimental therapy after their

tumors returned following standard treatment.

Of these, only 13 had a measurable tumor at the time the

cells were introduced, and of those, eight, or 62%, had their

tumors shrink, Bagley said.

"That was pretty remarkable to us because historically for

recurrent glioblastoma tumors, we usually don't see anything

shrink them."

Several patients lived 12 months or longer, and in one

patient, the disease remained stable for 16 months. But so far,

the benefit is largely temporary, with many patients relapsing

two to three months later.

Most patients experienced fevers and neurotoxicity such as

lethargy or confusion for two or three days after the cells are

injected, but the side effects were manageable, Bagley said.

Cindy Perettie, executive vice president of Gilead's Kite

cell therapy unit, said she is encouraged by the 62% response.

"What we didn't see that we wanted to in a majority of the

patients was persistence," she said.

Kite is working to develop a third target that will allow

the drug to remain in the brain longer. "We will be putting that

construct into the clinic sometime next year," she said.

Meanwhile, the team wants to test the therapy in 12 patients

with newly diagnosed disease. "We know patients in the frontline

setting are going to be healthier," she said, and the hope is to

see more persistent results.

Demand for the trial has been great. Perettie estimates

there are 10 times as many patients seeking enrollment for every

open slot, and some doctors are referring patients from as far

away as Hawaii.

"Today, there's only one approved therapy outside of

radiation, so for these patients, this is really exciting to see

any kind of response," she said.

Kite hopes to expand to three or four centers with its

triple-target version of the product.

"I think we're on the right track," Bagley said, adding that

he believes there will be longer-lasting treatments in the next

few years.