Experimental immune therapy shows promise against deadly childhood brain cancer

Brain and spinal cord tumors are the deadliest childhood cancers, and treatments for the most aggressive forms often leave families with few options. Now an experimental immune-cell therapy has cleared an important early hurdle, with several children showing no signs of cancer years after receiving the treatment.

In an early-stage clinical trial published last week in Nature Medicine, researchers outline the treatment, called tumor-associated antigen (TAA) T cell therapy, which uses a patient’s own immune cells to target proteins that are commonly expressed by pediatric brain tumors.

Among the children with recurrent brain tumors who participated in the study, three experienced particularly positive outcomes. These three had had aggressive cancers that had progressed despite years of chemotherapy, radiation and other existing treatments. More than two and a half years after receiving the T cell therapy, however, all three were reportedly alive, with no need for further treatment. And the cancer of one of these participants had disappeared completely.

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“This study represents an important step toward developing safer and more effective T cell therapies for children with devastating brain cancers. We were encouraged to see lasting clinical benefit in several patients who otherwise had very few options,” said Catherine Bollard, chief research officer at Children’s National Hospital and a co-senior author of the study, in a press release.

The treatment works by collecting T cells, the immune system’s frontline cancer-fighting cells, from a patient’s blood. Rather than genetically engineering immune cells, as is sometimes done for other therapies, researchers identify T cells in the patient that naturally recognize three proteins that are found in many brain tumors. The researchers then multiply the cells in the laboratory and return them back to the patient in the hope of triggering an immune attack on the cancer.

Such therapies could be especially valuable for brain cancers. Many tumors cannot be completely removed without risking brain regions that control essential functions such as breathing and movement, while the blood-brain barrier makes it difficult for drugs to reach tumors in effective doses.

As a phase 1 clinical trial, the study’s main purpose was to determine a safe dose and identify potential side effects rather than to prove that the treatment works. Overall, the therapy was well tolerated, although two patients experienced serious tumor swelling, and one child with an aggressive brain stem tumor died from complications that investigators determined were related to the treatment at the highest dose tested.

Still, other cancer researchers appeared supportive of the results.

“No one is jumping up and down and saying, ‘This is it,’ just yet,” said Tim Hassall, a pediatric oncologist at Queensland Children’s Hospital in Australia, who was not involved in the study, in an interview with New Scientist. “But it is encouraging, and it’s one step further along in our understanding of how to use cellular therapies to attack brain tumors.”

Much larger trials will be needed to determine whether the therapy truly improves survival rates for these aggressive cancers. But for the children who have already benefited, the impact is difficult to overstate.

“These children are getting to grow up—it’s truly awesome,” said co-senior author and pediatric oncologist Eugene Hwang in the same interview.

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