Beginning Radiation Immediately With GammaTile at GBM Excision Versus Standard of Care

NCT07195591 | Recruiting Phase 3 DMC FDA Device

• 1 other identifier: GTM-105
• Study Type: interventional
• Target: 766
• Locations: 1 country
• Sites: 4

Brief Summary

This is a Phase 3 prospective, randomized, superiority, open-label, multi-site study. The overview of this study is as follows:

• A Screening/Baseline Period of 21 days. During this time, patients will be randomized into a 1:2 allocation of Arm A:Arm B.
• A Perioperative/Operative Phase where patients will undergo tumor resection (Arm A) or tumor resection plus GammaTile implantation (Arm B).
• An EBRT Prior to Start Period. This occurs within 10 business days prior to EBRT and Concurrent TMZ Phase.
• An EBRT and Concurrent TMZ Phase, which will begin 30 ±10 days post-surgery. EBRT (30 fractions) and TMZ will be administered up to 5 days a week for 6 weeks in Arm A, and EBRT (20 fractions) and TMZ will be administered for up to 5 days a week for 4 weeks in Arm B. TMZ will be administered at a dose of 75 mg/m2/day orally for each Arm.
• An Adjuvant TMZ Phase, which begins 28 ±7 days following the EBRT and Concurrent TMZ Phase, and is comprised of six 28-day cycles. TMZ (150-200 mg/m2/day orally) will be administered for the first 5 days of each 28-day cycle for each Arm. Tumor treating fields are allowed but are not mandated during this phase. Up to 6 additional cycles (for a total of 12) can be completed at the discretion of the Investigator.
• An Early Discontinuation/Follow-Up Phase will occur 28 ±7 days after completion of Cycle 6 of the Adjuvant TMZ Phase, regardless of the total number of cycles completed or any delays in cycle start. If fewer than six cycles are completed, the first follow-up assessment will occur 28 ±7 days after the last administered dose of adjuvant TMZ. If patient has a qualifying event requiring entrance to Early Discontinuation Phase, the first follow-up assessment will occur as soon as feasible, but within 28 days. For any unscheduled visits, data collected should be documented in the case report form (CRF) and must include, but are not limited to, safety evaluations, survival status, and disease status.

Conditions

Glioblastoma

Keywords

Glioblastoma; Newly Diagnosed; GammaTile; External Beam Radiation Therapy; Temozolomide; Brain; Tumor; Brachytherapy; Radiation Therapy; Surgery; Resection; GBM; BRIDGES; EBRT; TMZ

Outcome Measures

Primary Outcomes (1)

• Overall Survival

  The primary endpoint of the study is OS, defined as the day from surgery to death. Patients who are still alive (or lost to follow-up) at the time of data analysis will be censored at the last time point they were known to be alive.

  Days from surgery to death.

Secondary Outcomes (5)

• Progression Free Survival

  Days from surgery to death or disease progression.

• Time to next unplanned treatment

  Time to next unplanned treatment.

• Performance Status

  24 months.

• Safety Assessment

  Study duration.

• Quality of Life Assessments

  COST-Score duration of study; FACT-Br up to 12 months after randomization.

Study Arms (2)

Maximal safe resection followed by EBRT with concurrent TMZ followed by adjuvant TMZ (Arm A)

ACTIVE COMPARATOR

All patients will undergo tumor resection. Start TMZ (75 mg/m2/day orally) on the first day of EBRT and will be administered concurrently with EBRT, up to 5 days per week, for the 30-fraction course of EBRT for 6 weeks within 30±10 days post-surgery. After EBRT and concurrent TMZ phase, the first cycle begins 28 ±7 days following the last day of the EBRT and Concurrent TMZ Phase. Adjuvant TMZ includes 5 days of TMZ treatment at the start of each 28-day cycle. Additional cycles (up to a maximum of 12), which may be given at the discretion of the Investigator, will be documented, and performed in the same manner as done in the first 6 cycles.

Radiation: External Beam Radiation Therapy; Drug: Temozolomide

Maximal safe resection + GammaTile followed by EBRT with concurrent TMZ then adjuvant TMZ (Arm B)

EXPERIMENTAL

All patients will undergo tumor resection + GammaTile implantation. Start TMZ (75 mg/m2/day orally) on the first day of EBRT and will be administered concurrently with EBRT, up to 5 days per week, for the 20-fraction course of EBRT for 4 weeks within 30±10 days post-surgery. After EBRT and concurrent TMZ phase, the first cycle begins 28 ±7 days following the last day of the EBRT and Concurrent TMZ Phase. Adjuvant TMZ includes 5 days of TMZ treatment at the start of each 28-day cycle. Additional cycles (up to a maximum of 12), which may be given at the discretion of the Investigator, will be documented, and performed in the same manner as done in the first 6 cycles.

Device: GammaTile®; Radiation: External Beam Radiation Therapy; Drug: Temozolomide

Interventions

GammaTile® DEVICE

GammaTiles are a U.S. FDA-cleared, surgically targeted radiation therapy for patients with certain brain tumors. GammaTile consists of bioresorbable collagen tiles embedded with Cesium-131 (Cs-131) radioactive seeds

Maximal safe resection + GammaTile followed by EBRT with concurrent TMZ then adjuvant TMZ (Arm B)

External Beam Radiation Therapy RADIATION

External beam radiation therapy (EBRT) is a type of radiation therapy that is standard of care. EBRT uses a machine outside the body to deliver high-energy beams of radiation to cancerous areas within the body

Also known as: EBRT

Maximal safe resection + GammaTile followed by EBRT with concurrent TMZ then adjuvant TMZ (Arm B); Maximal safe resection followed by EBRT with concurrent TMZ followed by adjuvant TMZ (Arm A)

Temozolomide DRUG

TMZ (Chemotherapy) is used as a first-line treatment, often in combination with radiation therapy after surgical resection of the tumor

Also known as: TMZ

Maximal safe resection + GammaTile followed by EBRT with concurrent TMZ then adjuvant TMZ (Arm B); Maximal safe resection followed by EBRT with concurrent TMZ followed by adjuvant TMZ (Arm A)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients must be ≥18 years of age.
• Have radiographic suspicion of newly diagnosed glioblastoma (GBM).
• o If final pathology reports IDH mutant glioma, then the patients found to have an IDH mutation will be followed for safety and QoL measures but will not be included in the primary and secondary comparative survival and efficacy analyses.
• Are medically and surgically appropriate for resection.
• Have an estimated Karnofsky Performance Scale (KPS) score of ≥70.
• Are able to receive standard of care treatment.

You may not qualify if:

• A previous biopsy diagnosis other than IDH wild-type GBM.
• Have contraindications to TMZ, magnetic resonance imaging, gadolinium, or non-contrast computed tomography.
• Have multi-focal enhancing tumors that cannot be encompassed in one operative field.

Sponsors & Collaborators

• GT Medical Technologies, Inc.: lead

Study Sites (4)

HonorHealth Scottsdale Osborn Medical Center

Scottsdale, Arizona, 85251, United States

RECRUITING

HMH Jersey Shore University Medical Center

Neptune City, New Jersey, 07753, United States

RECRUITING

Westchester Medical Center

Valhalla, New York, 10595, United States

RECRUITING

Brown University Health

Providence, Rhode Island, 02903, United States

RECRUITING

MeSH Terms

Conditions

Glioblastoma; Neoplasms

Interventions

Temozolomide

Condition Hierarchy (Ancestors)

Astrocytoma; Glioma; Neoplasms, Neuroepithelial; Neuroectodermal Tumors; Neoplasms, Germ Cell and Embryonal; Neoplasms by Histologic Type; Neoplasms, Glandular and Epithelial; Neoplasms, Nerve Tissue

Intervention Hierarchy (Ancestors)

Dacarbazine; Triazenes; Organic Chemicals; Imidazoles; Azoles; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds

Central Study Contacts

Kimberly Johnson

CONTACT

(833)662-0044; kjohnson@gammatile.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 10, 2025
• First Posted: September 26, 2025
• Study Start: December 10, 2025
• Primary Completion (Estimated): December 1, 2031
• Study Completion (Estimated): December 1, 2031
• Last Updated: April 30, 2026

Record last verified: 2026-04

Locations

US (4)