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

September 16, 2026 updated by: GT Medical Technologies, Inc.

Randomized Study of Resection and GammaTile® Followed by Concurrent External Beam Radiation Therapy (EBRT) and Temozolomide (TMZ) and Adjuvant TMZ Versus Standard of Care in Newly Diagnosed Glioblastoma (GBM)

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

766

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Arizona
      • Scottsdale, Arizona, United States, 85251
        • Recruiting
        • HonorHealth Scottsdale Osborn Medical Center
        • Principal Investigator:
          • John Wanebo, MD
        • Contact:
    • Georgia
      • Atlanta, Georgia, United States, 30322
        • Recruiting
        • Emory Winship Cancer Institute
        • Contact:
        • Principal Investigator:
          • Kimberly B. Hoang, MD
    • Maryland
      • Baltimore, Maryland, United States, 21287
        • Recruiting
        • Johns Hopkins University
        • Contact:
        • Principal Investigator:
          • Jordina Rincon-Torroella, MD
    • New Hampshire
      • Lebanon, New Hampshire, United States, 03766
    • New Jersey
      • Neptune City, New Jersey, United States, 07753
        • Recruiting
        • Jersey Shore University Medical Center | Hackensack
        • Principal Investigator:
          • Nitesh Patel, MD
        • Contact:
    • New York
      • Valhalla, New York, United States, 10595
        • Recruiting
        • Westchester Medical Center
        • Principal Investigator:
          • Simon Hanft, MD
        • Contact:
        • Sub-Investigator:
          • Rohil Shekher, MD
    • North Carolina
      • Greenville, North Carolina, United States, 27834
        • Recruiting
        • East Carolina University
        • Principal Investigator:
          • K. Stuart Lee, MD
        • Contact:
    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15212
        • Recruiting
        • Allegheny Health Network
        • Principal Investigator:
          • Matthew Shepard, MD
        • Contact:
    • Rhode Island
      • Providence, Rhode Island, United States, 02903
        • Recruiting
        • Brown University Health
        • Principal Investigator:
          • Clark Chen, MD, PhD
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Major Criteria Includes the Following:

Inclusion Criteria

  • 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.

Exclusion Criteria

  • 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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Maximal safe resection followed by EBRT with concurrent TMZ followed by adjuvant TMZ (Arm A)
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
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
Other Names:
  • EBRT
Drug: Temozolomide
TMZ (Chemotherapy) is used as a first-line treatment, often in combination with radiation therapy after surgical resection of the tumor
Other Names:
  • TMZ
Experimental: Maximal safe resection + GammaTile followed by EBRT with concurrent TMZ then adjuvant TMZ (Arm B)
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.
Radiation: External Beam Radiation Therapy
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
Other Names:
  • EBRT
Drug: Temozolomide
TMZ (Chemotherapy) is used as a first-line treatment, often in combination with radiation therapy after surgical resection of the tumor
Other Names:
  • TMZ
Device: GammaTile®
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

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall Survival
Time Frame: Days from surgery to death.
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 Outcome Measures

Outcome Measure
Measure Description
Time Frame
Progression Free Survival
Time Frame: Days from surgery to death or disease progression.
To compare PFS, defined as days from surgery to death or disease progression, between the 2 study arms based on the most current RANO Resect Group criteria;
Days from surgery to death or disease progression.
Time to next unplanned treatment
Time Frame: Time to next unplanned treatment.
To compare the time to next unplanned treatment per study arm
Time to next unplanned treatment.
Performance Status
Time Frame: 24 months.
To assess the performance status up to 24 months
24 months.
Safety Assessment
Time Frame: Study duration.
To assess the nature, severity, and frequency of AEs between the 2 study arms based on the most current CTCAE criteria
Study duration.
Quality of Life Assessments
Time Frame: COST-Score duration of study; FACT-Br up to 12 months after randomization.
Financial toxicity scale (Comprehensive Score for Financial Toxicity [COST]-score) and functional assessment of cancer therapy - brain (FACT-Br) up to 12 months after randomization.
COST-Score duration of study; FACT-Br up to 12 months after randomization.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

GT Medical Technologies, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

December 10, 2025

Primary Completion (Estimated)

December 1, 2031

Study Completion (Estimated)

December 1, 2031

Study Registration Dates

First Submitted

September 10, 2025

First Submitted That Met QC Criteria

September 19, 2025

First Posted (Actual)

September 26, 2025

Study Record Updates

Last Update Posted (Actual)

September 18, 2026

Last Update Submitted That Met QC Criteria

September 16, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • GTM-105

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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