5-Year Postoperative Outcomes of Patients Who Completed the CREST Study (CREST-XT)

July 18, 2026 updated by: Iantrek, Inc.

FIVE-YEAR POSTOPERATIVE OUTCOMES IN PATIENTS WITH OPEN-ANGLE GLAUCOMA WHO UNDERWENT BIO-INTERVENTIONAL UVEOSCLERAL OUTFLOW ENHANCEMENT SURGERY: LONG-TERM OBSERVATIONAL FOLLOW-UP FROM THE CREST STUDY (THE CREST-XT STUDY)

This study is designed to collect clinical data at 3, 4, and 5 years postoperatively for participants who completed the CREST Study without having secondary IOP-lowering surgery in the study eye(s).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Enrolling by invitation

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.

Detailed Description

This is a multicenter, prospective, observational study following eligible participants who completed the CREST Study. Participants who consent to participate will have clinical data gathered from annual ophthalmic examinations through 60 months after CycloPen System surgery for analysis of long-term outcomes. As an observational study, examinations at each visit are performed per the investigator's standard of care.

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.
Observational

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.
250

Contacts and Locations

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

Study Locations

  • United States
    • California
      • Newport Beach, California, United States, 92663
        • CREST-XT Site 05
    • Florida
      • Cape Coral, Florida, United States, 33904
        • CREST-XT Site 03
      • DeLand, Florida, United States, 32720
        • CREST-XT Site 10
    • Georgia
      • Atlanta, Georgia, United States, 30342
        • CREST-XT Site 07
    • Maryland
      • Chevy Chase, Maryland, United States, 20815
        • CREST-XT Site 12
      • Rockville, Maryland, United States, 20852
        • CREST-XT Site 13
    • Nevada
      • Las Vegas, Nevada, United States, 89145
        • CREST-XT Site 16
    • Pennsylvania
      • Fort Washington, Pennsylvania, United States, 19034
        • CREST-XT Site 01
    • Tennessee
      • Crossville, Tennessee, United States, 38555
        • CREST-XT Site 04
    • Utah
      • Salt Lake City, Utah, United States, 84132
        • CREST-XT Site 11

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Participants are undergoing treatment for glaucoma at medical clinics located in the United States

Description

Inclusion Criteria:

  1. Diagnosis of open-angle glaucoma (OAG) in the study eye(s), including pigmentary and pseudoexfoliative glaucoma, at the time of CREST enrollment
  2. Completed participation in CREST
  3. Provide signed written consent using the Institutional Review Board (IRB)/Ethics Committee (EC) approved study-specific informed consent form (ICF)
  4. Ability, comprehension, and willingness to follow study instructions

Exclusion Criteria:

  1. Systemic disease that, in the opinion of the Investigator, would put participant's health at risk and/or prevent completion of required study visits
  2. Early termination from CREST
  3. Secondary surgical intervention for long-term IOP control in the study eye(s)

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

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
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.
Bio-reinforced Cyclodialysis in conjunction with cataract surgery
Cataract surgery is performed, then followed by bio-reinforced cyclodialysis using the CycloPen Cyclodialysis System
Procedure: CycloPen Micro-Interventional Cyclodialysis System Post Cataract
After cataract surgery, the CycloPen Micro-Interventional Cyclodialysis System is used to create and cyclodialysis cleft and deliver allograft scleral tissue and/or viscous material to reinforce and maintain the cleft postoperatively.
Bio-reinforced Cyclodialysis alone
Bio-reinforced cyclodialysis is performed using the CycloPen Cyclodialysis System
Procedure: CycloPen Micro-Interventional Cyclodialysis System
The CycloPen Micro-Interventional Cyclodialysis System is used to create and cyclodialysis cleft and deliver allograft scleral tissue and/or viscous material to reinforce and maintain the cleft postoperatively.

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
Mean change in intraocular pressure (IOP)
Time Frame: From before bio-interventional cyclodialysis to 60 months after surgery
Mean change in intraocular pressure (IOP) measured using tonometry
From before bio-interventional cyclodialysis to 60 months after surgery

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Mean change in number of IOP-lowering medications used
Time Frame: From before bio-interventional cyclodialysis to 60 months after surgery
Mean change in the number of IOP-lowering medications used
From before bio-interventional cyclodialysis to 60 months after surgery
Percent change in intraocular pressure (IOP)
Time Frame: From before bio-interventional cyclodialysis to 60 months after surgery
Mean percent change in IOP in comparison with baseline (prior to surgery), while using the same or fewer IOP-lowering medications and without additional IOP-lowering surgical or laser procedures
From before bio-interventional cyclodialysis to 60 months after surgery
Percent of eyes with ≥ 20% decrease in intraocular pressure (IOP)
Time Frame: From before bio-interventional cyclodialysis to 60 months after surgery
Proportion of eyes with postoperative IOP ≥ 20% lower than baseline (prior to surgery), while using the same or fewer IOP-lowering medications and without additional IOP-lowering surgical or laser procedures
From before bio-interventional cyclodialysis to 60 months after surgery

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.
Iantrek, 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.
  • Study Director: Tsontcho Ianchulev, MD, MPH, Iantrek, 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)

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.
September 15, 2025

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.
December 1, 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.
December 1, 2030

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).
December 29, 2025

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.
March 14, 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.
March 18, 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.
July 21, 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.
July 18, 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.
July 1, 2026

More Information

Terms related to this study

Keywords

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.
  • ITR-CYC-042

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

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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