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)
Erin Dunbar1, David McCracken2, Adam Nowlan3, Kathryn Dusenbery4, Claire Ferreira4, Stuart Lee6, M Sean Peach7, Robert Corns8, Clark Chen5
1Piedmont Physicians Neuro-oncology, 2Piedmont Physicians Neurosurgery, 3Peachtree Radiation Oncology, Piedmont Brain Tumor Center, 4Radiation Oncology, 5Neurosurgery, University of Minnesota, 6Neurosurgery, Vidant Health, 7Radiation Oncology, ECU Health Beaufort Hospital, 8Radiation Oncology, ECU Department of Radiation Oncology
Objective:
To evaluate the safety and feasibility of combining resection with immediate initiation of radiation and subsequent Stupp protocol in newly diagnosed GBM.
Background:
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).
Design/Methods:
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).
Results:
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.
Conclusions:
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.