Designer immune-cell therapy could shrink deadly brain tumors, early trials show

A new immune cell-based treatment for glioblastoma, the most aggressive type of brain cancer, has shown promise in shrinking tumors in the short-term, according to two early clinical trials. 

The trials tested the safety and effectiveness of a personalized therapy called chimeric antigen receptor (CAR) T-cell therapy. This involves drawing out and genetically manipulating patients' immune cells, known as T cells, to more effectively recognize and attack tumors once they're reintroduced into the body. 

One of the trials, described in a paper published Wednesday (March 13) in the New England Journal of Medicine (NEJM), included three patients with recurrent glioblastoma, meaning their cancer had returned following standard radiation and chemotherapy. T cells from these patients were genetically modified to target two versions of a receptor called epidermal growth factor receptor (EGFR) on the surface of tumor cells. 

In the second trial, published the same day in the journal Nature Medicine, researchers used CAR T cells to target EGFR and an additional tumor-related receptor, called interleukin-13 receptor alpha 2, in six patients with recurrent glioblastoma.  

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Both trials found that CART-cell therapy was safe and reduced tumor size in all nine patients. In the Nature Medicine study, patients saw these reductions within one or two days, while in the NEJM study they saw them after one to five days. One NEJM patient's tumor almost completely regressed five days after a single treatment, while another person's tumor decreased in size by 60.7% after 69 days.

However, these effects didn't necessarily last. Tumors returned for two patients in the NEJM study, within either 72 days or a month after the initial infusion. The other patient showed no signs of tumor recurrence more than 150 days after treatment, although this was the last assessment point of the study so it is uncertain whether this occurred afterward. Some of the reductions seen in the Nature Medicine study have also been sustained for several months, for example up to seven months in one patient.