EndoFLIP-Guided Initial Management of Esophagogastric Junction Outflow Obstruction (O-FLIP)

November 4, 2026 updated by: Elizabeth Barba, Hospital Clinic of Barcelona

Prospective Evaluation of an Impedance Planimetry-Guided Therapeutic Stratification Algorithm in Patients With Esophagogastric Junction Outflow Obstruction After Endoscopic Assessment: O-FLIP Multicenter Study

Esophagogastric junction outflow obstruction (EGJOO) can make it difficult for food to pass from the esophagus into the stomach. Some people improve without a procedure to treat the obstruction, while others have persistent swallowing difficulties and may need further treatment.

The O-FLIP study tests whether measurements taken during an endoscopy with a tool called EndoFLIP can help doctors choose an initial treatment for adults with EGJOO. The main outcome is improvement in swallowing symptoms three months after initial management. The study will also track how long improvement lasts and how many participants need further treatment over one year.

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.

Detailed Description

O-FLIP is a prospective, multicenter, nonrandomized, single-arm interventional study evaluating an EndoFLIP-guided initial management strategy for esophagogastric junction outflow obstruction (EGJOO). Specialist esophageal motility units in Spain will enroll consecutive adults with clinically relevant dysphagia who meet the study eligibility criteria. Baseline data will include clinical characteristics, symptom scores, and findings from high-resolution manometry, timed barium esophagram, upper gastrointestinal endoscopy, and EndoFLIP panometry.

Participating centers will receive common training and use a standardized protocol for EndoFLIP acquisition and interpretation based on the Dallas Consensus. The treating endoscopist will interpret EndoFLIP findings in real time to guide initial management. The coordinating center will subsequently review coded recordings to assess measurement quality and agreement with the local classification.

Symptoms and scores on the Brief Esophageal Dysphagia Questionnaire (BEDQ) and Eckardt score will be recorded at 1, 3, 6, and 12 months, along with treatment changes, dysphagia recurrence, adverse events, and treatment escalation. Follow-up will start on the date of botulinum toxin administration for participants who receive it and on the date of the index endoscopy for those initially managed conservatively.

The primary analysis will estimate the proportion of participants with clinical response at 3 months in the overall cohort, with a 95% confidence interval. Outcomes will also be summarized by baseline EndoFLIP category. Secondary analyses will assess the durability of response and time to definitive treatment directed at the esophagogastric junction. Among participants who receive botulinum toxin, exploratory analyses will examine baseline clinical and physiological factors associated with an incomplete or transient response and with subsequent definitive treatment. Additional exploratory analyses will examine how baseline timed barium esophagram findings relate to EndoFLIP findings and clinical outcomes.

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.
115

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.
  • Name: Jorge Luis Núñez-Pizarro, MD
  • Phone Number: 3459 +34 932 27 54 00
  • Email: jlnunez@clinic.cat

Study Locations

  • Spain
    • Barcelona
      • Barcelona, Barcelona, Spain, 08036
        • Hospital Clínic de Barcelona
        • Contact:
          • Jorge Luis Nuñez-Pizarro, MD
          • Phone Number: 3459 +34 932 27 54 00
          • Email: jlnunez@clinic.cat
        • Principal Investigator:
          • Jorge Luis Nuñez-Pizarro, MD
        • Sub-Investigator:
          • Isis Karina Araujo, MD, PhD
        • Sub-Investigator:
          • Elizabeth Barba Orozco, MD, PhD
        • Sub-Investigator:
          • Gloria Fernández-Esparrach, MD, PhD
        • Sub-Investigator:
          • Alberto Ezquerra, MD
    • Madrid
      • Madrid, Madrid, Spain, 28041
        • Hospital Universitario 12 de Octubre
        • Contact:
        • Principal Investigator:
          • Isabel Castel de Lucas, MD
      • Madrid, Madrid, Spain, 28040
        • Hospital Clínico San Carlos
        • Contact:
        • Principal Investigator:
          • Constanza Ciriza de los Ríos, MD, PhD
        • Principal Investigator:
          • Ana Zatarain Valles, MD
      • Madrid, Madrid, Spain
        • Hospital de La Princesa
        • Contact:
        • Principal Investigator:
          • Cecilio Santander Vaquero, MD, PhD
    • Majadahonda
      • Madrid, Majadahonda, Spain, 28222
        • Hospital Universitario Puerta de Hierro Majadahonda
        • Contact:
        • Principal Investigator:
          • Rosalia González-Miyar, MD
    • Pamplona
      • Pamplona, Pamplona, Spain, 31008
        • Hospital Universitario de Navarra
        • Contact:
        • Principal Investigator:
          • Fermin Estremera-Arévalo, MD, PhD

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age 18 years or older.
  • Written study-specific informed consent.
  • Clinically relevant dysphagia, defined as a Brief Esophageal Dysphagia Questionnaire (BEDQ) score of at least 8.
  • High-resolution manometry findings consistent with esophagogastric junction outflow obstruction (EGJOO) according to Chicago Classification version 4.0: elevated median integrated relaxation pressure in both the supine and upright positions, evidence of peristalsis, and intrabolus pressure greater than 20 mmHg in at least 20% of supine swallows, without meeting criteria for achalasia. Premature or hypercontractile contractions are permitted when peristalsis is present and criteria for type III achalasia are not met.

Exclusion Criteria:

  • Prior surgery or treatment directed at the esophagogastric junction, including botulinum toxin injection, pneumatic dilation, peroral endoscopic myotomy (POEM), Heller myotomy, or fundoplication.
  • Current opioid use unless opioids can be discontinued for at least 1 week before enrollment.
  • Hiatal hernia larger than 3 cm, peptic stricture, esophageal rings, esophagogastric malignancy, or any other mechanical cause of dysphagia. This includes a mechanical cause detected during the index endoscopy before EndoFLIP.
  • Eosinophilic esophagitis.
  • Systemic or infectious disease that significantly affects esophageal motility, such as systemic sclerosis or Chagas disease.
  • Inability to complete the planned clinical follow-up.

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

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.
Experimental: EndoFLIP-Guided Clinical-Care Strategy

All participants will follow a standardized management algorithm based on esophagogastric junction (EGJ) opening on EndoFLIP panometry. Reduced opening will lead to botulinum toxin type A injection during the same endoscopy. Inconclusive or normal opening will lead to initial conservative management, which may include observation, proton pump inhibitors, neuromodulators, or calcium channel blockers at the treating physician's discretion.
Diagnostic test: EndoFLIP Panometry

EndoFLIP panometry will be performed during the index upper gastrointestinal endoscopy after mechanical causes of dysphagia have been excluded. The treating endoscopist will classify EGJ opening in real time according to standardized Dallas Consensus criteria. Coded recordings will subsequently undergo central review to assess measurement quality and agreement with the local classification.

Other Names:
  • Functional Lumen Imaging Probe
  • Impedance Planimetry
  • FLIP Panometry
Drug: Botulinum Toxin Type A (BOTOX) Injection

Botulinum toxin type A will be injected endoscopically into the lower esophageal sphincter in participants with reduced EGJ opening. The treating physician will be responsible for prescribing and administering the injection as part of the EndoFLIP-guided management strategy.

Other Names:
  • BOTOX

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
Proportion of Participants With Clinical Response at 3 Months
Time Frame: 3 months after botulinum toxin administration or, for participants initially managed conservatively, 3 months after the index endoscopy.

Proportion of participants in the overall cohort with at least a 50% reduction from baseline in the Brief Esophageal Dysphagia Questionnaire (BEDQ) total score. BEDQ scores range from 0 to 40, with higher scores indicating more severe dysphagia.
3 months after botulinum toxin administration or, for participants initially managed conservatively, 3 months after the index endoscopy.

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
Measure Description
Time Frame
Clinical Response During Follow-up
Time Frame: Months 1, 6, and 12.

Proportion of participants with at least a 50% reduction from baseline in BEDQ total score.
Months 1, 6, and 12.
Change From Baseline in BEDQ Score
Time Frame: Baseline and months 1, 3, 6, and 12.

Change in BEDQ total score from baseline. Scores range from 0 to 40, with higher scores indicating more severe dysphagia.
Baseline and months 1, 3, 6, and 12.
Change From Baseline in Eckardt Score
Time Frame: Baseline and months 1, 3, 6, and 12.

Change in Eckardt symptom score from baseline. Scores range from 0 to 12, with higher scores indicating greater symptom burden.
Baseline and months 1, 3, 6, and 12.
Sustained Clinical Response
Time Frame: Months 3 through 12.

Proportion of participants with a clinical response at month 3 who maintain at least a 50% reduction from baseline in BEDQ score through month 12 without recurrence.
Months 3 through 12.
Dysphagia Recurrence After Clinical Response
Time Frame: From the first documented response through month 12.

Proportion of participants with a previously documented clinical response who subsequently have a BEDQ reduction of less than 50% from baseline.
From the first documented response through month 12.
Proportion of Participants Receiving Definitive EGJ-Directed Treatment
Time Frame: Through month 12.

Proportion of participants who undergo pneumatic dilation, peroral endoscopic myotomy, or Heller myotomy after initial management, and time from the start of follow-up to the first such treatment.
Through month 12.
Adverse Events Related to Procedures or Treatment
Time Frame: From the index endoscopy through month 12.

Proportion of participants with at least one adverse event associated with endoscopy, EndoFLIP, or treatment. Event severity will be reported using the AGREE classification, from grade I to V
From the index endoscopy through month 12.
Agreement Between Local and Central EndoFLIP Classification
Time Frame: Index endoscopy, with subsequent central review of the same recording.

Agreement on EGJ opening category (reduced, inconclusive, or normal), quantified using Cohen's kappa with a 95% confidence interval.
Index endoscopy, with subsequent central review of the same recording.

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.
Hospital Clinic of Barcelona

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Institut d'Investigacions Biomèdiques August Pi i Sunyer

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: Jorge Luis Núñez-Pizarro, MD, Hospital Clinic of Barcelona

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 7, 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.
March 6, 2029

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 6, 2029

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).
November 4, 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.
November 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.
November 10, 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.
November 10, 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.
November 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.
November 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.
  • HCB/2026/1095

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

There is no plan to make individual participant data available to researchers outside the study team. Coded EndoFLIP recordings without direct participant identifiers will be transferred from participating sites to the coordinating center for central review as part of the study. The code key will remain at the originating site.

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.

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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