A promising new treatment for recurrent pediatric brain cancer

This shows brains
CAR T cells are a form of immunotherapy involving engineering of T cells, a type of immune cell that fights cancer. Image is in the public domain.

Summary: Administering medulloblastoma specific CAR T cells into the cerebrospinal fluid was more effective than administering via the blood.

Source: Baylor College of Medicine

Two pediatric 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 Baylor College of Medicine, Texas Children’s Hospital and the Hospital for Sick Children (SickKids) 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 pediatric 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. These studied guided 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.

About this neuroscience research article

Source:
Baylor College of Medicine
Media Contacts:
Molly Chiu – Baylor College of Medicine
Image Source:
The image is in the public domain.

Original Research: Closed access
“Locoregional delivery of CAR T cells to the cerebrospinal fluid for treatment of metastatic medulloblastoma and ependymoma”. by Laura K. Donovan, Alberto Delaidelli, Sujith K. Joseph, Kevin Bielamowicz, Kristen Fousek, Borja L. Holgado, Alex Manno, Dilakshan Srikanthan, Ahmed Z. Gad, Randy Van Ommeren, David Przelicki, Cory Richman, Vijay Ramaswamy, Craig Daniels, Jonelle G. Pallota, Tajana Douglas, Alyssa C. M. Joynt, Joonas Haapasalo, Carolina Nor, Maria C. Vladoiu, Claudia M. Kuzan-Fischer, Livia Garzia, Stephen C. Mack, Srinidhi Varadharajan, Matthew L. Baker, Liam Hendrikse, Michelle Ly, Kaitlin Kharas, Polina Balin, Xiaochong Wu, Lei Qin, Ning Huang, Ana Guerreiro Stucklin, A. Sorana Morrissy, Florence M. G. Cavalli, Betty Luu, Raul Suarez, Pasqualino De Antonellis, Antony Michealraj, Avesta Rastan, Meenakshi Hegde, Martin Komosa, Olga Sirbu, Sachin A. Kumar, Zied Abdullaev, Claudia C. Faria, Stephen Yip, Juliette Hukin, Uri Tabori, Cynthia Hawkins, Ken Aldape, Mads Daugaard, John M. Maris, Poul H. Sorensen, Nabil Ahmed & Michael D. Taylor.
Nature Medicine doi:10.1038/s41591-020-0827-2

Abstract

Locoregional delivery of CAR T cells to the cerebrospinal fluid for treatment of metastatic medulloblastoma and ependymoma

Recurrent medulloblastoma and ependymoma are universally lethal, with no approved targeted therapies and few candidates presently under clinical evaluation. Nearly all recurrent medulloblastomas and posterior fossa group A (PFA) ependymomas are located adjacent to and bathed by the cerebrospinal fluid, presenting an opportunity for locoregional therapy, bypassing the blood–brain barrier. We identify three cell-surface targets, EPHA2, HER2 and interleukin 13 receptor α2, expressed on medulloblastomas and ependymomas, but not expressed in the normal developing brain. We validate intrathecal delivery of EPHA2, HER2 and interleukin 13 receptor α2 chimeric antigen receptor T cells as an effective treatment for primary, metastatic and recurrent group 3 medulloblastoma and PFA ependymoma xenografts in mouse models. Finally, we demonstrate that administration of these chimeric antigen receptor T cells into the cerebrospinal fluid, alone or in combination with azacytidine, is a highly effective therapy for multiple metastatic mouse models of group 3 medulloblastoma and PFA ependymoma, thereby providing a rationale for clinical trials of these approaches in humans.

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