PHIL™ Middle Meningeal Artery Embolization for First-Line Treatment of Chronic Subdural Hematoma IDE Trial (PHILFIRST)

May 4, 2026 updated by: Microvention-Terumo, Inc.

PHIL™ (Precipitating Hydrophobic Injectable Liquid) Middle Meningeal Artery Embolization (MMAE) for First-Line Treatment of Chronic Subdural Hematoma (cSDH) IDE Trial (PHILFIRST)

This is a prospective, randomized, controlled, open-label, blinded endpoint (PROBE) clinical investigation in which patients with non-emergent chronic subdural hematoma (cSDH) requiring treatment will be randomized (1:1) to either initial surgical evacuation (Control Arm) or initial MMAE with PHIL™ (investigational arm).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
475

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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 Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 22 years or older
  • Diagnosis of chronic subdural hematoma
  • Subject, or their legally authorized representative provides a signed and dated Informed Consent Form
  • Pre-morbid mRS 0-1
  • cSDH measures ≥ 10 mm in greatest thickness
  • cSDH exerts mass effect upon the subjacent brain
  • Imaging characteristics indicative of chronicity
  • Negative urine pregnancy test for female subjects of child-bearing potential
  • Subject is able and willing to comply with all study protocol requirements, including return to the investigational site for all follow-up visits
  • Subject presents with one or more of the following neurological symptoms: headache/head pressure, cognitive decline, speech difficulty or aphasia, gait impairment or imbalance, focal neurological deficit (weakness, paresthesia or sensory deficit involving of one or more extremities or facial droop), and/or seizure

Exclusion Criteria:

  • Prior ipsilateral craniotomy or burr hole evacuation of cSDH
  • Prior embolization of either MMA
  • Requires (in the opinion of the treating surgeon) full or mini-craniotomy at time of randomization
  • Emergent subdural hematoma evacuation needed
  • cSDH with a focal location
  • cSDH developed due to underlying condition
  • Life expectancy of <1 year
  • Presents with an intracranial mass other than subdural hematoma
  • Presents with a meningioma with mass effect and/or ≥1 cm or currently undergoing radiation therapy for carcinoma or sarcoma of the head or neck region
  • Serum creatinine level > 3.0 mg/dL at time of enrollment and not on dialysis
  • Life-threatening allergy to radiographic contrast (unless treatment for allergy is tolerated or can be managed medically)
  • Currently enrolled in another investigational study protocol that could potentially confound the interpretation of the study endpoints/outcomes
  • Known dangerous anatomic variations leading to increased procedural risk or unsafe access for MMAE
  • Contraindicated for the use of PHIL™ liquid embolic system

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: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Surgical management
Control arm
Procedure: Surgical evacuation
Surgical evacuation of cSDH.
Experimental: PHIL embolic
Treatment arm
Device: PHIL™ (Precipitating Hydrophobic Injectable Liquid)
Embolization of MMA with PHIL.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Primary Safety Endpoint
Time Frame: 90 days post procedure
Incidence of mRS 0-2.
90 days post procedure
Primary Effectiveness Endpoint
Time Frame: 90 days post procedure
Incidence of clinically indicated (as adjudicated by CEC) surgical evacuation of the target cSDH among subjects in the PHIL™ MMAE arm.
90 days post procedure

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Death or major disabling stroke.
Time Frame: 30-, 90-, and 180-days post-index procedure
30-, 90-, and 180-days post-index procedure
The composite of: recurrent or residual chronic subdural hematoma on the target side measuring ≥ 10 mm; retreatment; or major disabling stroke, myocardial infarction, or death from neurologic causes.
Time Frame: 180 days post procedure
180 days post procedure
Resolution of cSDH without retreatment.
Time Frame: 90- and 180-days post procedure
90- and 180-days post procedure
Neurological death
Time Frame: 90- and 180-days post procedure
90- and 180-days post procedure
Change in EQ-5D-5L from baseline
Time Frame: 90- and 180-days post procedure
90- and 180-days post procedure
cSDH-related hospital re-admissions and re-admission days
Time Frame: 90- and 180-days post procedure
90- and 180-days post procedure
Index hospitalization length of stay
Time Frame: post procedure
post procedure
Neurological Events of Interest: minor stroke, major stroke, cSDH expansion, acute cSDH, mRS deterioration of 2 points or greater
Time Frame: 90 days and 180 days post procedure
90 days and 180 days post procedure

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Microvention-Terumo, Inc.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: David Fiorella, Stony Brook University

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 (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 31, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 31, 2030

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
May 31, 2031

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 21, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 4, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 8, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CL1108390

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

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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