Study Shows Laser Ablation May Enhance Immunotherapy Response in Brain Tumors

A new randomized prospective study suggests that laser interstitial thermal therapy (LITT) using Monteris Medical’s NeuroBlate may enhance the efficacy of the immunotherapy drug pembrolizumab (Keytruda) for patients with recurrent, high-grade brain tumors.  

Published in Nature Communications, the conclusions were drawn from a Phase 1/randomized Phase 2b clinical trial led by investigators at Washington University, the University of Florida, and the University of Southern California. The study evaluated the combination of NeuroBlate LITT followed by pembrolizumab. 

High-grade astrocytomas, including glioblastoma (GBM), remain among the most aggressive and treatment-resistant brain tumors. Immune checkpoint inhibitors, such as pembrolizumab, have historically had a limited benefit in these patients due to blood-brain barrier (BBB) impermeability and tumor characteristics that evade the body’s immune response, among other factors.

This study suggests that thermal ablation—heat generated by laser energy—delivered by NeuroBlate induces BBB disruption and activates an immune response, thereby enhancing pembrolizumab’s therapeutic effect.

“What we’re seeing in this trial is that NeuroBlate may be doing more than cytoreducing the tumor—it appears to prime the immune system in ways that make pembrolizumab more effective at delivering real clinical benefit,” said Dr. David Tran, lead author and division chief, neuro-oncology, and co-director of the University of Southern California Brain Tumor Center in Los Angeles. “This opens the door to continue studying new treatment strategies for patients who currently have very limited options.”

In the full study analysis, patients who received NeuroBlate followed by pembrolizumab demonstrated improved overall survival by more than three-fold compared with those who received surgery or biopsy followed by the same therapy. The combined approach was also found to be safe and well-tolerated.

“Monteris has invested for more than a decade in pioneering the use of NeuroBlate for brain tumors and drug-resistant epilepsy, and we are proud that our technology continues to play a central role in advancing minimally invasive neurosurgery,” Monteris Medical President/CEO Martin J. Emerson stated. “This new clinical evidence suggests that NeuroBlate may also serve as a powerful enabler of treatments like immunotherapy. We are honored to support the innovators and institutions pushing this field forward and, most importantly, to help bring new hope to patients and their families.”

Monteris Medical develops and markets MR‑guided laser ablation systems that enable minimally invasive, robotically controlled brain surgery—often referred to as laser ablation, LITT (laser interstitial thermal therapy) or SLA (stereotactic laser ablation). The company’s NeuroBlate System is designed for adults and children aged two and older and uses laser technology to precisely destroy abnormal brain tissue, including certain brain tumors and specific areas of the brain that cause seizures due to epilepsy. NeuroBlate is the only LITT platform with a robotic interface that supports the targeted, safe delivery of laser energy and is supported by published prospective clinical data. Multicenter studies on NeuroBlate show that patients typically experience short hospital stays, low rates of complications, improved quality of life, and outcomes comparable to open surgical resection.