for people ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
completion around
Principal Investigator
by Nicholas Butowski, MD
Headshot of Nicholas Butowski
Nicholas Butowski



The FRONTIER Study is a prospective, interventional, single-arm, multi-center, study to assess the safety and technical feasibility of TheraSphere GBM in patients with recurrent GBM.

Official Title

FRONTIER: A Feasibility Study to Evaluate the Safety of the TheRaSphere GliOblastoma (GBM) Device iN PaTIEnts With Recurrent GBM


Glioblastoma (GBM) is a highly aggressive brain cancer with a grave prognosis, resulting in <7% of patients surviving to five years post-diagnosis. External beam radiotherapy (EBRT) is currently a mainstay treatment for GBM; however, the dose delivered is limited by side effects. The targeted radiotherapy of the TheraSphere GBM Y-90 Glass Microsphere System (TheraSphere GBM) has promising potential to provide GBM patients with reduced side effects compared to external beam radiotherapy as well as a more effective treatment for this catastrophic disease.

The TheraSphere GBM device utilized in the FRONTIER trial is an yttrium-90 (Y-90) glass microsphere therapy for selective internal radiation therapy (endovascular radiotherapy) in recurrent GBM patients. The TheraSphere GBM treatment utilizes intra-arterial delivery and takes advantage of blood flow and direct tumor delivery. Treatment can be delivered by specific placement of a catheter close to the tumor through known angiographic techniques currently utilized by neuro-endovascular or interventional radiology physicians. Angiographic evaluation prior to treatment allows identification of tumor feeding arteries and definition of the treatment volume. TheraSphere GBM could achieve a high tumor response rate based on delivery of a tumor absorbed dose that is not currently possible with EBRT.

In consideration of the potential benefit of a more localized, targeted treatment with a reduced side effect profile compared to other treatment options, and the potential impact on patients' quality of life for this devastating disease, this First-in-Human Early Feasibility Study (EFS) of the TheraSphere GBM Y-90 Glass Microsphere System for the treatment of recurrent GBM is being conducted.


Glioblastoma Multiforme, Recurrent Glioblastoma, Glioblastoma, Recurrence, TheraSphere GBM


You can join if…

Open to people ages 18 years and up

  1. Subject is 18 years or older and has signed and dated the trial informed consent form (ICF)
  2. Life expectancy ≥ 12 weeks
  3. Subject is willing and able to comply with the trial testing, procedures, and follow-up schedule
  4. History of a histologically confirmed diagnosis of glioblastoma per 2021 WHO criteria
  5. Have radiographic evidence of tumor progression/recurrence with measurable disease (≥ 1 cm to ≤ 5cm bidirectional diameters) by contrast-enhancement on MRI, according to RANO criteria
  6. Prior surgery and treatment with combination of radiotherapy and chemotherapy ± Tumor Treating Fields (Optune®)
  7. Prior cranial radiation dose < 66 Gy
  8. WHO performance status ≤ 2
  9. The interval since completion of cranial radiotherapy must be > 6 months, unless there is tissue confirmation of tumor recurrence/progression outside the previous radiation treatment field, in which case the interval since completion of cranial radiation must be at least 12 weeks

    10. Interval since last cytotoxic therapy until presumed date of intervention ≥ 1 cycle or

    ≥ 2 biological half-lives, i.e.

    1. ≥ 4 weeks since last dose of temozolomide
    2. ≥ 6 weeks since last dose of lomustine or other nitrosourea
    3. ≥ 2 weeks since last dose of a small molecule targeted agent (Tyrosine Kinase Inhibitor or similar)
    4. ≥ 12 weeks from last dose of last intravenous bevacizumab infusion, or other antibody-based VEGF therapy
      1. If receiving steroids, patient should be on a stable or decreasing dose equivalent to dexamethasone ≤ 6 mg/d, for at least 7 days prior to registration
        1. Have adequate organ and bone marrow function within 14 days prior to registration, as defined below:
      2. INR ≤ 1.2 (in absence of anticoagulation)
      3. Platelets ≥ 100,000/L
      4. Creatinine ≤1.5 mg/dL
      5. Absolute Neutrophil Count ≥1.5 x 109/L
      6. Hemoglobin ≥9.0 g/dL
        1. Have a negative pregnancy test within 14 days prior to registration on study (for FOCBP, female of child-bearing potential)
        2. Subject is a male or non-pregnant female. If female of child-bearing potential, and if sexually active must be using, or agree to use, a medically acceptable method of birth control as confirmed by the investigator
        3. Angiographic Mapping Inclusion Criteria:
      7. Accessible neurovascular anatomy that allows for safe microcatheter placement (up to two locations) to infuse TheraSphere GBM to treat all of the T1 enhancing component of lesion confirmed by neuro-interventional team.
      8. Total treatment volume is ≤ 150cc in the non-dominant hemisphere and non-eloquent regions as determined by multidisciplinary team. Eloquent regions should be defined as areas of the brain that maintain language, vision, sensory and motor function

You CAN'T join if...

  1. Have bilateral gadolinium enhancing disease, tumor located in the posterior fossa, tumor involving critical subcortical structures (thalamus/hypothalamus, midbrain, brainstem, corticospinal tract, internal capsule, cerebral peduncle), tumor approximating or invading the brainstem and/or optic chiasma, leptomeningeal disease, or extracranial metastatic disease
  2. Have received more than 1 course of prior cranial radiotherapy (EBRT)
  3. Have received radiosurgery, brachytherapy, or hypofractionated radiotherapy
  4. Have received more than 2 systemic treatment protocols (lines of treatment), not including maintenance temozolomide
  5. Have received prior intra-arterial cerebral infusion therapy
  6. Have received more than 2 surgical GBM-related procedures
  7. Have received prior thoracic radiation therapy
  8. Are at increased risk of wound dehiscence by the discretion of the investigators (e.g. brain surgery within the last 3 months, poor skin condition, and/or previously infected surgical field or any other condition that is of increased infectious risk in the opinion of the neurosurgeon)
  9. Have uncontrolled epilepsy

    10. Have severe and/or insufficiently controlled intercurrent illness; patients with the

    following are not eligible:

    1. Hypertension grade 3 or higher without adequate control on medications
    2. Symptomatic or unstable cardiac disease, known to have right-to-left shunts, or severe pulmonary hypertension (pulmonary artery pressure > 90 mmHg)
    3. Pulmonary insufficiency (arterial oxygen pressure (Pa,O2) of < 60 mmHg, or oxygen saturation (Sa,O2) of < 90%) as measured by fingertip pulse oximeter
    4. Ongoing or active bacterial or viral infection requiring systemic treatment (including HIV)
    5. Pneumonitis
    6. Psychiatric illness/social situations that would limit compliance with study requirements
    7. Peripheral Neuropathy ≥ grade 1
    8. Any other illness or condition that the treating investigator feels would interfere with study compliance or would compromise the patient's safety, study endpoints or longevity
      1. Are currently pregnant or breast feeding (unless patient agrees to stop breastfeeding)
      2. Patients with a history of an active other malignancy within 1 year prior to registration. NOTE: Exceptions to this requirement include adequately treated non-melanoma skin cancer or lentigo maligna or carcinoma in situ without evidence of disease, or recurrent glioblastoma
        1. Patients with a history of ischemic cerebral disease and/or at risk of cerebral herniation
        2. Medical contraindication to undergo contrast-enhanced magnetic resonance imaging (MRI)
        3. Known history of hypersensitivity reactions to iodinated and/or gadolinium-based contrast
        4. Subject has received any other investigational agents within 4 weeks of treatment, or is currently participating, or plans to participate in, another investigational trial that may confound the results of this trial (unless written approval is received from the Boston Scientific study team)
        5. Angiographic Mapping Exclusion Criteria: Patients with significant vascular disease, significant AV shunting, or anatomic tortuosity on MR/CT Angiogram precluding safe or feasible vascular access or an eloquent high-risk vascular distribution of the treatment plan


  • UCSF accepting new patients
    San Francisco California 94143 United States
  • Northwestern Univerity accepting new patients
    Chicago Illinois 60611 United States

Lead Scientist at UCSF

  • Nicholas Butowski, MD
    Dr. Nicholas Butowski is a neuro-oncologist who specializes in brain tumors, neuroimaging, cognitive and rehabilitative neurology, and complementary therapies for neurological disorders. He is director of clinical services in neuro-oncology and a researcher at the Brain Tumor Center.


accepting new patients
Start Date
Completion Date
Boston Scientific Corporation
Phase 1 research study
Study Type
Expecting 12 study participants
Last Updated