What is Glioblastoma (GBM)?

Glioblastoma (GBM) is the most aggressive form of brain cancer, characterized by rapid growth and spread. Treatment is notoriously difficult, and recurrence is almost unavoidable. Understanding how the tumor responds to treatment, however, remains a meaningful challenge.

The Challenge of Monitoring Treatment Response

Traditional imaging techniques frequently enough fail to accurately reflect the complex changes happening within a GBM tumor during treatment. This makes it difficult for clinicians to determine if a therapy is truly working, or if adjustments are needed. Obtaining tumor tissue for analysis is also challenging due to the risks associated with brain biopsies and the inherent complexity of these tumors.

“Getting tissue from GBM patients is difficult because the brain is sensitive, the procedures are risky, and the tumors themselves are complex and change over time. But studying the cancerous tissue itself is also the best way to understand how the tumor reacts to treatment.”

E. Antonio Chiocca, MD, PhD, executive director of the Center for Tumors of the Nervous System at the mass General Brigham Cancer Institute

Serial Biopsies: A Window into the Tumor Microenvironment

Researchers from the Accelerating GBM therapies Through Serial Biopsies TeamLab conducted a study involving over 100 scientists and clinicians. They collected 96 tumor samples over four months from two patients participating in a clinical trial of CAN-3110, an oncolytic virus immunotherapy. this approach allowed them to track changes within the tumor over time, revealing when the treatment was activating the immune system – even when imaging showed no visible changes.

The study highlights the importance of analyzing the tumor’s microenvironment. Serial biopsies provide a dynamic view of this environment, capturing changes in immune cell infiltration, gene expression, and other key indicators of treatment response.

CAN-3110: An Oncolytic Virus Immunotherapy

CAN-3110 is a novel immunotherapy that utilizes an oncolytic virus. Oncolytic viruses are engineered to selectively infect and destroy cancer cells. In the case of CAN-3110, the virus is designed to stimulate an immune response against the tumor, further enhancing its effectiveness.

The study demonstrated that serial biopsies could detect the activation of the immune system in response to CAN-3110,even when traditional imaging methods failed to show a clear response. This suggests that biopsies can serve as a valuable tool for monitoring the effectiveness of this and other immunotherapies.

Implications and Future directions

This research underscores the potential of serial biopsies to improve the management of GBM. By providing a more accurate assessment of treatment response, biopsies can help clinicians personalize therapy and optimize outcomes for patients. Further research is needed to refine biopsy protocols,identify biomarkers that predict immunotherapy response,and develop less invasive methods for monitoring the tumor microenvironment.