Most patients miss trials that could apply to them
Finding a glioblastoma clinical trial is different from a general web search. The main registry, ClinicalTrials.gov, lists hundreds of studies in technical language. Eligibility criteria often span several pages. The rules are exact: a single prior treatment or a missing biomarker can eliminate an otherwise fitting trial.
Research in Neuro-Oncology found that only 8 to 11 percent of glioblastoma patients enroll in a clinical trial, even though trials offer access to therapies not yet in standard care. The main barriers: patients don't know trials exist and they struggle to understand what they find.
This guide covers search strategies for three stages - newly diagnosed, mid-treatment, and recurrent disease. It explains how to read eligibility criteria, which molecular markers control access, and whether a trial makes sense for you.
How do you find a glioblastoma clinical trial you actually qualify for?
Use several tools instead of just one registry.
- Start at NCI's glioblastoma clinical trials page, which filters ClinicalTrials.gov to show adult studies currently recruiting.
- Use the National Brain Tumor Society's Clinical Trial Finder. Enter your diagnosis, biomarkers, prior treatment, and location. It ranks matching trials and connects you with a patient navigator.
- Check ABTA's clinical trial resource page for information and links to their trial-matching tool.
- Search ClinicalTrials.gov directly, filtering by status: "Recruiting" and condition: "Glioblastoma." Use the location filter if needed, or leave it open if you can travel.
- Write down the NCT number of trials you're interested in - for example, NCT02977780. This is the best way to refer to a study with your doctor or trial site.
- Show your list to your neuro-oncologist before contacting any trial. They can check your pathology and imaging against eligibility criteria and spot problems you might miss.
What the eligibility criteria section actually tells you
Eligibility splits into two parts: inclusion criteria (what you need) and exclusion criteria (what disqualifies you). Read both before calling a site to save time.
Common inclusion requirements are a confirmed diagnosis by 2021 WHO criteria, specific biomarkers, normal organ function on blood tests, measurable disease on MRI, and an ECOG score of 0, 1, or 2 - explained next.
Common exclusions are prior use of the study drug class, current use of certain medications, and specific health conditions. Pay special attention to bevacizumab. If you've used it before, many trials will exclude you. Research on antiangiogenic exclusion rules found no standard approach across studies, but many trials exclude patients who've received bevacizumab before. Why? Bevacizumab changes how lesions look on MRI, making it hard to measure response. Prior anti-VEGF drugs may also change how your body responds to new agents. If you've had bevacizumab, check this criterion in every trial you consider.
Why your molecular profile is the biggest access gate
Your tumor's molecular profile affects trial access more than almost anything else - age, stage, or treatment. Getting the right tests early is essential - it determines which trials you can enter.
MGMT methylation status matters most for new patients. Trials often divide patients by this marker because it affects how tumors respond to temozolomide, the standard first-line chemotherapy. Trials testing new drugs with or instead of temozolomide usually need MGMT status confirmed before you enroll. About 40 percent of IDH-wildtype glioblastomas carry MGMT promoter methylation, which predicts better responses to chemotherapy.
IDH mutation status separates true glioblastoma (IDH-wildtype, grade 4) from IDH-mutant grade 4 astrocytoma, which was once called secondary GBM. Most GBM trials only enroll IDH-wildtype patients. If your tumor is IDH-mutant, look for astrocytoma or diffuse glioma trials instead of GBM trials.
Other molecular markers like EGFR amplification, PTEN loss, and gene fusions are increasingly used as eligibility criteria in precision-oncology trials. If you've only had basic MGMT and IDH testing, a complete genomic profile may open access to trials your current tests don't qualify you for. If you haven't had complete molecular testing, start there before searching for trials. The article on molecular testing in the first six weeks covers what to request and why delays matter.
What ECOG performance status means for trial access
ECOG status measures how much cancer limits you in daily life, scored from 0 to 4. Most GBM trials require a score of 0, 1, or 2:
- 0: Fully active, no restrictions on any activity.
- 1: Restricted in strenuous activity but ambulatory and able to do light work more than half the day.
- 2: Ambulatory more than 50 percent of waking hours and capable of all self-care, but unable to carry out work activities.
Scores of 3 or 4 exclude you from most trials. This makes sense. Trials are designed to show the drug's effect clearly, and in very sick patients, disease drives outcomes more than the drug does. If your score is borderline, ask your oncologist to document it. Sometimes better steroid doses, seizure control, or addressing fatigue can improve your score enough to qualify. It's worth trying before you give up on a trial.
How to evaluate a specific trial once you find one you may qualify for
Qualifying for a trial doesn't mean it's the right choice. Think carefully about these factors.
Phase of the trial. Phase 1 trials test safety and dose, not whether the drug works. They're for patients who've used all standard options or want an experimental drug they can't access elsewhere. Phase 2 trials check if a treatment works and find the right dose. Phase 3 trials compare a new treatment to standard care and give the best data on benefits and risks.
The control arm. Many phase 3 trials randomize you to the experimental drug or to standard care. Ask the trial site if any group gets a placebo instead of real treatment. Most current GBM trials use real treatment in the control arm, but ask to be sure. The National Brain Tumor Society's guide on brain tumor trials covers this clearly. Read it before you contact a trial site.
Practical logistics. How many in-person visits are needed? Can you do some monitoring remotely or nearby? Some trials pay for extra scans, travel, or lodging. Ask the coordinator about costs before you decide.
What if the drug stops working. Some trials limit what drugs you can use while enrolled. Ask before you sign up - this matters when you're deciding.
Site experience. A center that's enrolled many patients in a specific trial is better at managing its side effects and monitoring. Ask the coordinator how many patients the site has treated on this trial.
Questions to ask the trial team before you consent
A good trial team answers these questions directly. If a coordinator is evasive, that tells you something about how the site works.
- Why do you think this drug might help GBM?
- What side effects have been observed so far, and how are they managed?
- Will I continue standard treatments alongside the trial drug, or does enrollment replace them?
- How often will imaging be required, and at which location?
- If I need to withdraw from the trial, what is the process and how does it affect my ongoing care?
- Does the trial cover any costs related to extra visits, tests, or travel?
- Who do I contact if I experience a side effect between scheduled visits?
Recurrent GBM and trials: why the calculation changes
At recurrence, clinical trials often become your main way to get experimental therapies. Options after first recurrence are limited. CAR-T therapies, oncolytic viral therapies, and newer checkpoint inhibitors are mostly available only through trials. At recurrence, the risk-benefit tradeoff changes. A phase 1 trial with uncertain results may be reasonable when choices are few. At first or second recurrence, the recurrent glioblastoma salvage options guide covers all available treatments and where trials fit in. The immunotherapy for recurrent glioblastoma guide explains which molecular features determine if you qualify for checkpoint inhibitors and CAR-T therapies - useful when evaluating these trials.
If your team doesn't mention trials at recurrence, ask about them. If you're unsure which trials might fit your profile, the Art of Healing Cancer team can map precision-oncology options and relevant trials to your specific pathology and imaging. You can request a review from them to explore your options.
International patients: how trial access works across borders
Most trials require in-person visits at a registered site. For patients outside the US or Western Europe, this is a real barrier - but you can sometimes work around it.
- Some trials have sites in the Middle East, South Asia, or Southeast Asia. Use the location filter on ClinicalTrials.gov to find trials near you.
- Expanded access programs (also called compassionate use) let patients access experimental drugs outside of trials when they have no other choices. This requires a separate application through the drug maker or your country's health authority.
- Some centers accept international patients who travel for required visits, with remote follow-up in between. How often you need to travel varies by trial.
If you're seeking international options, collect your records first - it speeds every conversation. The glioblastoma second opinion checklist shows which reports and scans reviewers and trial sites will ask for.
When to talk to your doctor
Show any trial you're interested in to your neuro-oncologist before contacting the site. They can check eligibility against your pathology and imaging, spot conflicts with your treatment, and help you contact the trial team if it's a good fit. If your team doesn't have trial experience or isn't connected to research, ask for a referral to a neuro-oncology center with a trials unit or get a second opinion at a specialist center.
To find trials that match your molecular profile and imaging, the Glioblastoma Center team can review your reports and map matching options. You can upload your reports and request a remote review from them.
This article is for general information and is not a substitute for medical advice. Always consult your oncologist or care team about your specific situation.