P05.05 Safety and feasibility of temporary blood-brain barrier disruption with the SonoCloud-1/3 implantable ultrasound device in recurrent glioblastoma

Abstract

Abstract BACKGROUND The blood-brain barrier (BBB) limits penetration of drug therapies to the brain and may account for the limited effectiveness of chemotherapies in patients with primary brain cancer. An implantable ultrasound (US) device, SonoCloud, was developed to temporarily disrupt the BBB in patients with recurrent glioblastoma (rGBM) prior to carboplatin chemotherapy administration to enhance brain drug concentrations. BBB disruption was investigated with a single emitter device, SonoCloud-1 (SC1) and a three-emitter device, SonoCloud-3 (SC3) in a safety and feasibility study in rGBM patients at the Hôpitaux Universitaires La Pitié Salpêtrière in Paris, France (NCT02253212). MATERIAL AND METHODS The SC1 implant consisted of a 1 MHz, 10-mm diameter ultrasound transducer encapsulated in a biocompatible housing while the SC3 consisted of (3) separate SC1 emitters implanted in a triangular pattern to disrupt the BBB over a 3x larger volume. Patients were implanted with the SonoCloud device during tumor debulking or in a dedicated surgical procedure. The devices were activated monthly by connecting the device to an external generator via a transdermal needle. Intravenous injection of SonoVue® microbubbles was performed with device activation to temporarily disrupt the BBB. Magnetic resonance imaging (MRI) was performed after sonications with gadolinium contrast to verify BBB disruption followed by carboplatin infusion at AUC4-6. Patients received treatments until disease progression. RESULTS Between 2014 and 2016, 21 patients were registered for the study and implanted with the SC1; 19 patients received at least one sonication. Six additional patients were implanted and received sonications with the SC3. A total of 89 US sessions were performed to disrupt the BBB - 65 with the SC1 and 24 with the SC3. Treatment-related adverse events observed were transient and manageable. No carboplatin-related neurotoxicity was observed. SC1 patients with no or poor BBB disruption (n=8) visible on MRI had a median progression-free survival (PFS) of 2.73 months, and a median overall survival (OS) of 8.64 months. SC1 patients with clear BBB disruption (n=11) had a median PFS of 4.11 months, and a median OS of 12.94 months. The SC3 device was as well-tolerated as the SC1 device, with SC3 patients receiving between 1–12 monthly sonications. CONCLUSION These results provide the first safety data on the effects of disrupting the BBB in rGBM patients prior to carboplatin chemotherapy using an implantable low intensity pulsed ultrasound device on enlarged areas of brain. This study has now been completed. A new safety study with a larger device, SonoCloud-9, that covers the tumor and surrounding infiltrative regions, has started in France in early 2019 (NCT03744026). Work supported by CarThera and APHP.