Examining gut microbiome effects in glioblastoma patients undergoing treatment

THERApeutic Outcomes Related to Gut microBIOME in Glioblastoma (GBM) Patients Receiving Chemo-radiation: A Prospective Observational Study

Observational Ottawa Hospital Research Institute · NCT05326334

This study is trying to see if changes in gut bacteria can affect how well treatment works for adults with newly diagnosed glioblastoma who are getting chemotherapy and radiation.

Quick facts

Study typeObservational
Enrollment20 (estimated)
Ages18 Years and up
SexAll
SponsorOttawa Hospital Research Institute Academic / other
Drugs / interventionsradiation, chemotherapy, immunotherapy
Locations1 site (Ottawa, Ontario)
Trial IDNCT05326334 on ClinicalTrials.gov

What this trial studies

This observational study aims to assess the feasibility of collecting and analyzing stool samples from adults with newly diagnosed glioblastoma multiforme (GBM) who are undergoing chemoradiation. Participants will provide stool samples at four different time points during their treatment and complete a diet diary and health-related quality of life questionnaires. The study seeks to correlate changes in gut microbiome composition with patient survival outcomes and the occurrence of radiation necrosis. The ultimate goal is to determine if gut microbiome diversity can influence treatment outcomes in GBM patients.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with newly diagnosed WHO grade 4 glioblastoma who have undergone significant tumor resection and plan to receive chemoradiation.

Not a fit: Patients with metastatic cancer or those receiving additional systemic therapies that could confound results may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved understanding of how gut microbiome influences treatment outcomes in glioblastoma patients.

How similar studies have performed: While the specific approach of correlating gut microbiome with GBM outcomes is novel, similar studies in other cancers have shown promising results.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Patients with newly diagnosed WHO grade 4 glioblastoma, IDH-1 R132H wild type
* Maximum safe resection (≥70% of initial tumor volume resected)
* Age ≥ 18
* Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 or ECOG 2 if on ≤ 8 mg/day of dexamethasone (or bioequivalent)
* Plan to receive 60 Gy / 30 fractions of radiation with temozolomide within 12 weeks of surgery
* Patient or substitute decision maker able to provide written informed consent

Exclusion Criteria:

* Metastatic cancer or secondary cancer that could affect interpretation of primary and secondary study outcomes
* Receiving additional systemic therapy / clinical intervention for glioblastoma that would prevent a uniform treatment cohort with temozolomide and radiation x 6 weeks followed by adjuvant temozolomide 150-200 mg/m2 on days 1-5 every 28 days for up to 6 cycles.\*
* Inability to collect study stool samples
* Any diagnosis or medical condition, physical and / or psychological, that the investigator feels precludes the patient from participation in the study.

  * If there is a new standard of care treatment for newly diagnosed GBM before the first patient is enrolled (e.g., Optune Tumor Treating Fields), then we will allow all patients on this study to adopt the new standard of care therapy. To allow for maximum patient accrual, if patient chooses to enroll on an open label randomized therapeutic study whereby the control arm involves only the standard of care treatment, then patients enrolled in the control arm could be eligible for this study at the discretion of the investigator.

Where this trial is running

Ottawa, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Glioblastoma, IDH-wildtypeGut microbiomeGlioblastoma multiforme
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.