GBM Workshop 2021 – Preliminary Results of the Combination of NaviFUS System with Bevacizumab in Patients with Recurrent Glioblastoma
The Focused Ultrasound Foundation partnered with the Society for Neuro-oncology (SNO) and the AANS/CNS Tumor Section to host a virtual workshop on May 19–20, 2021, to convene critical stakeholders – researchers, clinicians, industry, government, and others – on the topic of focused ultrasound for glioblastomas.
Ko-Ting Chen, MD presented data from a clinical trial of the NaviFUS system in combination with bevacizumab. Clinical trials have shown that FUS BBBO can enhance drug delivery in rGBM using different ultrasound systems. Data about FUS BBBO in conjunction with bevacizumab in rGBM are lacking. In a mouse model, FUS significantly enhanced penetration of bevacizumab into the CNS compared with the non-exposed brain. FUS significantly increased median survival time by 135%. In a pilot trial, researchers were able to precisely open the BBB in rGBM patients and suggested a potential immunostimulatory effect by FUS alone.
NaviFUS BBBO combined with bevacizumab will be evaluated in a first-in-human study in patients with rGBM (NCT04446416). The study plans to recruit 10 patients with first recurrence GBM and will be performed in the outpatient setting with a primary endpoint of PFS. Given that >90% of recurrences occur at the margin of resection, the strategy will be for FUS exposure to cover as much of the tumor peripheral region (ROI) as possible. A newer, 2nd generation of array beams were designed to create a larger ROI. To maximize safety, real-time acoustic emission was used with image feedback exposure level control. The NaviFUS system was to be used within 1hr of IV bevacizumab administration. Two patients have been recruited for the study so far. Study results confirmed a larger BBBO up to 2 cm at the target region on contrast-enhanced MR imaging. In patient 1, residual tumor was seen in the frontal lobe. The patient is stable and PFS is 9 months. In patient 4, the recurrent tumor was more extensive in the left temporal parietal region and the beam path was designed to cover these temporal regions. The patient had a PFS of 4 months.
In conclusion, BBBO with the NaviFUS system is feasible to combine with bevacizumab in rGBM as an outpatient procedure, with the goal of repeatedly opening the BBB safely and accurately. A trend of normalizing T2 signal hyperintensity was observed in beam concentrated regions, which might suggest that FUS BBBO has the potential to decrease edema or tumor invasion through enhanced bevacizumab delivery to the treated site (n=2). More data are needed to analyze whether combination of FUS plus bevacizumab offers survival benefit (PFS)
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