GESTALT (GammaTile Enhanced Stupp Alternative): Feasibility Study of Resection and GammaTile® Followed by Concomitant External Beam Radiation Therapy (EBRT)/Temozolomide (TMZ) and Adjuvant TMZ in Newly Diagnosed Glioblastoma (GBM) (P13-13.001)

Abstract

<h3>Objective:</h3> To evaluate the safety and feasibility of combining resection with immediate initiation of radiation and subsequent Stupp protocol in newly diagnosed GBM. <h3>Background:</h3> GBM is highly proliferative, with rapid early local progression (REP) after surgical resection, prior to the initiation of concurrent EBRT/TZM documented in 25–50% of patients. This high rate of REP supports initiation of an effective postoperative treatment as early as safely possible. FDA cleared GammaTiles (GT)(GT Medical Technologies, Inc, Tempe, AZ) consist of Cesium-131 radiation sources precisely imbedded in bio-resorbable collagen tiles. Intraoperatively tiles are permanently placed to line the at-risk areas of the resection bed achieving an immediate initiation of surgically targeted radiation therapy (STaRT). <h3>Design/Methods:</h3> GESTALT is a single arm 61 patient multi-center trial. Adults with suspected or confirmed GBM consented pre-operatively undergo a maximum safe resection and GT placement. Subjects with confirmed molecular GBM (WHO 2021 criteria) start concurrent EBRT/TMZ beginning 25±4 days post-surgery. Subsequent EBRT (20 fractions, 4 weeks) to low and high-risk PTV takes GT dose into account to a combined biologically equivalent dose of 46 and 60 Gy delivered in 2Gy/fraction, respectively. Adjuvant TMZ (6 cycles) begins 28±7 days after EBRT/TMZ; TTF is allowed. IDH-mutated tumors will be followed for safety. Outcomes include feasibility of incorporating GT without delay of Stupp protocol, consent/attrition rates, safety, OS, progression free survival, local control, functional decline (ECOG-PS) and immune competence (absolute lymphocyte counts). <h3>Results:</h3> The trial opened for enrollment in August of 2022 at 3 sites with 12 additional sites pending (NCT05342883). Clinical results to-date will be presented. <h3>Conclusions:</h3> This is the first trial in newly diagnosed GBM patients combining resection, GT, and the Stupp protocol, and attempts to reduce REP. The outcomes of this trial, if suggestive, will be used as the basis for a subsequent randomized trial. <b>Disclosure:</b> Dr. Dunbar has nothing to disclose. Dr. McCracken has received personal compensation for serving as an employee of GT Medical. Dr. McCracken has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GT Medical. Dr. McCracken has received personal compensation in the range of $500-$4,999 for serving on a Speakers Bureau for GT Medical. Dr. Nowlan has received personal compensation for serving as an employee of GT Medical. Dr. Nowlan has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GT Medical. Kathryn Dusenbery has nothing to disclose. Dr. Ferreira has nothing to disclose. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as a Consultant for GT Medical. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Novocure. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for GT Medical. Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Huff Powell Bailey Law Firm. An immediate family member of Dr. Lee has stock in Remedy Pharmaceuticals. An immediate family member of Dr. Lee has stock in Martin Pharmaceuticals. An immediate family member of Dr. Lee has stock in Critical Diagnostics. An immediate family member of Dr. Lee has stock in Woolsey Pharmaceuticals. An immediate family member of Dr. Lee has stock in Monogram Orthopaedics. An immediate family member of Dr. Lee has stock in Cytonics. An immediate family member of Dr. Lee has stock in 20-20 Gene Systems. Dr. Peach has nothing to disclose. Dr. Corns has nothing to disclose. Clark Chen has nothing to disclose.