OS07.3.A Phase 1/2 clinical trial of blood-brain barrier opening with the SonoCloud-9 implantable ultrasound device in recurrent glioblastoma patients receiving IV carboplatin

Background

Low intensity pulsed ultrasound (LIPU) in combination with microbubbles is a promising approach for brain drug delivery. A phase 1/2 clinical study (NCT03744026) was initiated to demonstrate the safety and efficacy of blood-brain barrier (BBB) disruption over a large volume using an implantable ultrasound system (SonoCloud-9) in patients with recurrent glioblastoma receiving carboplatin chemotherapy.

Material and Methods

The SonoCloud-9 device (Carthera, Paris, France) was placed at the end of tumor resection and replaced the bone flap. The device was activated 9-14 days after surgery for a duration of 270 seconds every 4 weeks until progression or treatment completion, concomitantly with IV DEFINITY microbubbles (10 μl/kg, Lantheus, Billerica, US). The Phase 1 cohort consisted of an escalation of BBB disruption volume by activation of 3 (n=3), 6 (n=3), then 9 (n=3) emitters of the device. Dose limiting toxicity (DLT) was assessed during the first 2 weeks after the 1st sonication. A subsequent expansion cohort consisted of patients treated with 9 emitters in which the primary endpoint was assessment of BBB opening on MRI using gadolinium (<1 hr after sonication). All patients received carboplatin either after (n=21) or before (n=12) device activation to disrupt the BBB. In addition, a sub-study was performed to investigate carboplatin concentration enhancement in the peritumoral region with sonication at time of device implantation.

Results

Study accrual is complete with 38 patients enrolled and 33 patients having been implanted and received at least one sonication+carboplatin. A total of 101 sonications were performed (range=1-10 sonication sessions/patient). No DLTs were observed. A total of 14 SAEs were observed including five events considered as possibly treatment related. BBB disruption was confirmed by gadolinium enhancement after sonication. In an analysis of 60 treatments in 27 patients that had all nine emitters active, 90% of activated emitters led to BBB opening in gray and/or white matter with good repeatability of BBB opening. In 3 patients who underwent intraoperative sonication and carboplatin administration, a 7.58-fold increase in brain/plasma drug levels was demonstrated. Updated and mature outcome results will be presented.

Conclusion

These results confirm the safety and feasibility of repeated BBB disruption using an implantable ultrasound system. LIPU substantially increases drug levels in the peritumoral brain.

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

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.

The I-CreI meganuclease and its engineered derivatives: applications from cell modification to gene therapy

Meganucleases (MNs) are highly specific enzymes that can induce homologous recombination in different types of cells, including mammalian cells. Consequently, these enzymes are used as scaffolds for the development of custom gene-targeting tools for gene therapy or cell-line development. Over the past 15 years, the high resolution X-ray structures of several MNs from the LAGLIDADG family have improved our understanding of their protein-DNA interaction and mechanism of DNA cleavage. By developing and utilizing high-throughput screening methods to test a large number of variant-target combinations, we have been able to re-engineer scores of I-CreI derivatives into custom enzymes that target a specific DNA sequence of interest. Such customized MNs, along with wild-type ones, have allowed for exploring a large range of biotechnological applications, including protein-expression cell-line development, genetically modified plants and animals and therapeutic applications such as targeted gene therapy as well as a novel class of antivirals.