Neuronavigation-guided focused ultrasound for transcranial blood-brain barrier opening and immunostimulation in brain tumors

Focused ultrasound (FUS) in the presence of microbubbles can transiently open the blood-brain barrier (BBB) to increase therapeutic agent penetration at the targeted brain site to benefit recurrent glioblastoma (rGBM) treatment. This study is a dose-escalating pilot trial using a device combining neuronavigation and a manually operated frameless FUS system to treat rGBM patients. The safety and feasibility were established, while a dose-dependent BBB-opening effect was observed, which reverted to baseline within 24 hours after treatment. No immunological response was observed clinically under the applied FUS level in humans; however, selecting a higher level in animals resulted in prolonged immunostimulation, as confirmed preclinically by the recruitment of lymphocytes into the tumor microenvironment (TME) in a rat glioma model. Our findings provide preliminary evidence of FUS-induced immune modulation as an additional therapeutic benefit by converting the immunosuppressive TME into an immunostimulatory TME via a higher but safe FUS dosage.

Automated summary

Focused ultrasound (FUS) with microbubbles can transiently open the blood-brain barrier (BBB) to increase therapeutic agent penetration, benefiting recurrent glioblastoma (rGBM) treatment. A pilot trial using a neuronavigation combined with a manually operated frameless FUS system for rGBM patients established safety and feasibility, with dose-dependent BBB-opening effect observed. Additionally, FUS-induced immune modulation was demonstrated to convert the immunosuppressive tumor microenvironment into an immunostimulatory one at a higher but safe dosage.