BrainChild-01 Will Evaluate CAR T Cells in Pediatric CNS Tumors

Researchers at the Seattle Children’s Hospital have initiated enrollment in the BrainChild-01 trial, which is designed to test chimeric antigen receptor (CAR) T-cell therapy in children and young adults with relapsed/refractory brain and central nervous system (CNS) tumors. Intriguingly, the modified CAR T cells will not be infused intravenously—rather, the cells will be injected either directly at the site of tumor resection or into the ventricular system of the CNS.

According to the National Brain Tumor Society, about 28,000 US children are living with a brain tumor and about 4610 new cases of childhood and adolescent primary malignant and nonmalignant brain and CNS tumors are expected to be diagnosed in 2018. Brain tumors surpass leukemia as the leading cause of cancer-related deaths among children and adolescents.

Direct infusion of CAR T cells into the resected tumor cavity in the brain is also being evaluated in adult patients. Speaking at the recent annual meeting of the American Society of Clinical Oncology, Amy B. Heimberger, MD, professor, Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, told the audience that the process helps overcome the lack of T-cell infiltration in the tumor. Multiple intracranial infusions of IL13Rα2 CAR T cells in the resected tumor cavity of a patient with recurrent multifocal glioblastoma, as well as in the ventricular system, resulted in a regression of intracranial and spinal tumors in that patient. The response was sustained for 7.5 months.

The phase 1 BrainChild-01 study expects to recruit 26 patients with recurrent or refractory HER2-positive CNS tumors who will be treated with autologous CD4 and CD8 T cells transduced to express a HER2-specific CAR and EGFRt. Children with HER2-positive tumors that have relapsed or are refractory to prior treatment, and who meet the trial’s inclusion criteria, will undergo apheresis. The collected T cells will then be genetically modified to target them to HER2-expression tumor cells, and the modified cells will be administered through an indwelling catheter in 2 phases:

• A weekly dose for 3 weeks followed by a week off and an examination period
• Weekly dose for 3 weeks

Following evaluation of treatment impact, including magnetic resonance imaging, patients can receive 6 more courses of infusion if there are T cells available and if patients have not had adverse effects.

Primary outcomes that the study plans to measure include safety and feasibility of administering the CAR T-cell infusion directly into the tumor cavity.

Secondary study objectives include examining the distribution of CAR T cells in the cerebrospinal fluid, their diffusion into the blood stream, and, if possible, monitoring HER2 expression in the tumors at diagnosis versus at recurrence.

BrainChild-01, as the trial is named, will initially leave out patients diagnosed with diffuse intrinsic pontine gliomas, or DIPG tumors, which are highly aggressive tumors found at the base of the brain. However, Seattle Children’s Hospital plans to include children needing treatment for DIPG tumors in future BrainChild trials.