Research in Mice Shows Laser Therapy Can Open Blood-Brain Barrier and Blood-Tumor Barrier
PLYMOUTH, Minn. – Aug. 11, 2020 – Researchers at the Washington University School of Medicine in St. Louis, Mo., led by neurosurgeon Dr. Albert H. Kim, found direct evidence in mice that the focal thermal effect of laser interstitial thermal therapy (LITT) opens the blood-brain barrier (BBB) and blood-tumor barrier (BTB). Their findings, published in Neuro-Oncology Advances and supported in part by Monteris Medical, suggest that this laser therapy – often used to treat cancer in other parts of the body – may overcome a major obstacle to delivering anti-cancer drugs and other therapies directly to the brain.
Glioblastoma (GBM) is the most common malignant primary brain tumor, but most systemic therapies have been unsuccessful in large part due to the highly restrictive nature of the BBB, leading to poor delivery of anti-cancer drugs or immune agents to the tumor-infiltrated brain.
To better understand these challenges, the team developed a brain laser therapy system for mice and utilized two different GBM-bearing mouse models. Their aim was to understand laser therapy’s ability to enable local delivery of small and large molecular size agents through the BBB and BTB over time. Remarkably, the team found molecules as large as human antibodies were able to cross the BBB and BTB for up to 30 days.
The paper further describes a proof of concept application of laser-induced BBB permeability with the tumor-bearing mice. The team determined that mice treated with LITT plus adjuvant doxorubicin “showed substantial accumulation of brain tissue doxorubicin, indicating that laser treatment can increase local BBB permeability to enable entry.” They demonstrated that the combination of laser and adjuvant doxorubicin significantly reduces tumor progression and increases animal survival.
The delivery of larger molecules, relevant for possible immune and other therapies, was similarly enhanced. In the paper, Dr. Kim noted that “laser treatment can greatly increase the amount of immunogloblin that can permeate laser-treated brain and brain tumors. This insight raises the possibility that LITT may increase the delivery and therefore efficacy of therapeutic antibodies currently being used in clinical trials.”
The authors of the study suggest that “combining transient BBB disruption via LITT coupled with adjuvant antibody, biologic, or other pharmaceutical interventions may be considered for the treatment of GBM.”
Glioblastoma is a deadly form of brain cancer that strikes approximately 18,000 people in the United States every year. The average length of survival after diagnosis is 15 months, and only 30 percent of patients survive more than two years.
“Early models are so important in helping us all understand how and why various approaches succeed, deepening our understanding and paving the way for future work,” said Martin J. Emerson, president and chief executive officer of Monteris Medical. “We congratulate Dr. Kim and his collaborative team at Washington University.”
About Monteris® and the NeuroBlate® System
Monteris Medical is a privately held company that develops and markets innovative MRI-guided, laser-based systems to perform minimally invasive brain surgery, commonly referred to as “LITT” (Laser Interstitial Thermal Therapy) or “SLA” (Stereotactic Laser Ablation). Current investors include Versant Ventures, SightLine Partners, Birchview Capital and BDC Capital. The Monteris NeuroBlate System is the only minimally invasive system that enables a robotic interface for the precise and safe delivery of laser energy. The NeuroBlate System is a tool and is not intended to treat any specific disease. Physicians should use their clinical judgment and experience when deciding whether to use NeuroBlate.
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