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About SickKids

April 27, 2020

A promising new treatment for recurrent paediatric brain cancer

TORONTO – Two paediatric brain cancers that are challenging to treat if they recur, medulloblastoma and ependymoma, are the target of a clinical trial using a new type of therapy. A multi-institutional, international team led by researchers at The Hospital for Sick Children (SickKids) and Baylor College of Medicine, Texas Children’s Hospital has developed a novel approach that delivers appropriately-targeted chimeric antigen receptor (CAR) T cell therapy directly into the cerebrospinal fluid that surrounds the tumor.

The researchers report in the journal Nature Medicine that this approach was effective in treating these cancers in mouse models of human disease. The findings support further clinical studies to evaluate this strategy to treat paediatric brain cancers, the most common cause of cancer death in childhood. Indeed, a first-in-child clinical trial currently is recruiting patients at Texas Children’s Hospital and Baylor College of Medicine to test the safety and anti-tumor efficacy of this approach (Clinicaltrials.gov identifier: NCT02442297).

“Recurrences of medulloblastoma and ependymoma can be disseminated throughout the lining of the brain and spinal cord, which are bathed in cerebrospinal fluid. This location offers the opportunity to deliver therapies into the cerebrospinal fluid compartment and could provide a better chance for the therapy to reach and eliminate the tumor than administering it through the blood stream,” said co-corresponding author Dr. Nabil Ahmed, Associate Professor of Pediatrics and Immunology, Section of Hematology-Oncology at Baylor and Texas Children’s Hospital.

“The vast majority of children with recurrent metastatic medulloblastoma or ependymoma currently have a deadly prognosis, so it is very exciting to think we have identified a novel approach to treat this underserved patient population,” said co-corresponding author Dr. Michael Taylor, Neurosurgeon, Senior Scientist in the Developmental and Stem Cell Biology program, Garron Family Chair in Cancer Research at SickKids, and professor in the Departments of Surgery and Laboratory Medicine and Pathobiology at the University of Toronto.

This project was led by Dr. Laura Donovan, Post-Doctoral Fellow in the Developmental and Stem Cell Biology program at SickKids, who performed in-depth molecular studies of the target profile of recurrent medulloblastoma and ependymoma to guide the design of CAR T cells engineered by Ahmed and colleagues at Baylor’s Center for Cell and Gene Therapy and Texas Children’s Hospital to target the most appropriate cancer molecules.

CAR T cells are a form of immunotherapy involving engineering of T cells, a type of immune cell that fights cancer. The researchers genetically engineered CAR T cells to recognize specific molecules on the surface of the tumor cells. When these CAR T cells encounter the tumor, they can fight it more effectively. CAR T cells have been impressively effective for patients with certain types of leukemia and are FDA-approved for this disease.

In mouse model studies, CAR T cells were administered into the cerebrospinal fluid around the tumor or into the blood stream of mice harboring multiple patient-derived medulloblastoma and ependymoma tumors. The tumor size and animal survival were studied for about 200 days.

The results showed that administering tumor-specific CAR T cells into the cerebrospinal fluid was more effective than administering them via the blood.

“As opposed to delivery through the blood, cerebrospinal fluid delivery overcomes the blood-brain barrier and also offers the advantage of minimizing exposure of other tissues of the body to the CAR T cells and, consequently, potential side effects,” Donovan said.

In some of their experiments, the researchers combined CAR T cells with an approved cancer medication called azacytidine. The results showed that combining immunotherapy with azacytidine was significantly more effective than either treatment alone.

“This work was possible thanks to the concerted collaboration of our Pediatric Cancer Dream Team supported by Stand Up to Cancer (SU2C) St. Baldrick’s Foundation Translational Research Grant, which brought together scientists studying tumor genomics and tumor immunotherapy around the world to enable the design of more effective therapies for children with incurable and hard to treat cancers,” Ahmed said.

For a complete list of all the contributors, their affiliations and financial support for this project, visit the publication.

About The Hospital for Sick Children (SickKids)

The Hospital for Sick Children (SickKids) is recognized as one of the world’s foremost paediatric health-care institutions and is Canada’s leading centre dedicated to advancing children’s health through the integration of patient care, research and education. Founded in 1875 and affiliated with the University of Toronto, SickKids is one of Canada’s most research-intensive hospitals and has generated discoveries that have helped children globally. Its mission is to provide the best in complex and specialized family-centred care; pioneer scientific and clinical advancements; share expertise; foster an academic environment that nurtures health-care professionals; and champion an accessible, comprehensive and sustainable child health system. SickKids is a founding member of Kids Health Alliance, a network of partners working to create a high quality, consistent and coordinated approach to pediatric health care that is centred around children, youth and their families. SickKids is proud of its vision for Healthier Children. A Better World.

About Baylor College of Medicine

Baylor College of Medicine (www.bcm.edu) in Houston is recognized as health sciences university and is known for excellence in education, research and patient care. It is the only private medical school in the greater southwest and is ranked 22nd among medical schools for research and 4th for primary care by U.S. News & World Report. Baylor is listed 20th among all U.S. medical schools for National Institutes of Health funding and No. 1 in Texas. Located in the Texas Medical Center, Baylor has affiliations with seven teaching hospitals and jointly owns and operates Baylor St. Luke’s Medical Center, part of CHI St. Luke’s Health. Currently, Baylor has more than 3,000 trainees in medical, graduate, nurse anesthesia, physician assistant, orthotics and genetic counseling as well as residents and postdoctoral fellows.

Media contacts

Molly Chiu
Baylor College of Medicine
713-798-4710
Molly.Chiu2@bcm.edu
https://www.bcm.edu/news

Jessamine Luck
The Hospital for Sick Children (SickKids)
416-813-7654 ext. 201436
jessamine.luck@sickkids.ca