An interventional study of Hyperbaric Oxygen Therapy (HBOT) in Perianal Crohn Disease, sponsored by Barts & The London NHS Trust. Not yet recruiting at 1 site in United Kingdom. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-13.
Sponsored by Barts & The London NHS Trust · Not applicable, Interventional, and Treatment
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Among 217 studies in Crohn Disease with a site in United Kingdom — 47 open to participants now, 66 under way, 26 of them phase 3. Crohn Disease · United Kingdom.
Among the 217 studies in Crohn Disease with a site in United Kingdom, this one is the 165th largest by planned enrollment of the 171 interventional ones that give a count, is the only one that started in 2027, is one of 32 with no phase, reaches primary completion later than 37 of the 65 other live ones, and was the 217th registered.
1,993 studies on the registry are indexed under Crohn Disease; 478 are open to participants now.
Browse Crohn Disease studies →47 of the 217 studies in Crohn Disease with a site in United Kingdom are open now. Recruiting first, the newest first:
Agomab Spain S.L.U. · Sites in United Kingdom, United States, Serbia
Ages 18+
Agomab Spain S.L.U. · Sites in United Kingdom
Ages 30–65 · Men only · Healthy volunteers
Hoffmann-La Roche · Sites in United Kingdom, United States, Australia and 5 more countries
Ages 2–17
Takeda · Sites in United Kingdom
Ages 18–75
University of Nottingham · Sites in United Kingdom
Ages 16+
A study can be open while its sites in United Kingdom have not opened yet or have stopped. Only those recruiting at a site in United Kingdom →
Of the 353 Crohn Disease studies recruiting now, 154 (44%) set no upper age limit and 144 (41%) stop at 75 or younger; 95 take children under 18; 56 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
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217 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 11 · Phase 2 49 · Phase 3 75 · Phase 4 9
First in 2000; this study’s year is marked. 1 started in 2027.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 10 is below the median of 67 across 1,261 interventional studies indexed under Crohn Disease.
Median enrollment 168 across the 171 interventional studies, 245 across the 46 observational. Of the 135 that completed or were terminated, 75 (56%) have results posted.
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137 of 217 have an industry lead sponsor. The 10 most frequent:
Barts & The London NHS Trust is the lead sponsor of 152 studies on the registry; 22 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
Barts & The London NHS Trust has 3 studies filed under Crohn Disease — fewer than ten, so there is no comparison to draw.
14 of the studies in Crohn Disease with a site in United Kingdom that are under way reach primary completion within a year, 7 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT06063967Phase 3AbbVieA Study to Assess Adverse Events and Change in Disease Activity of Risankizumab Subcutaneous Induction Treatment for Moderately to Severely Active Crohn's Disease. | 2027-03 |
| NCT05347095Phase 3Janssen-Cilag Ltd.A Study of Guselkumab in Participants With Fistulizing, Perianal Crohn's Disease | 2027-03-25 |
| NCT06227910Phase 3TakedaA Study of Vedolizumab With and Without Upadacitinib in Adults With Crohn's Disease | 2027-06-08 |
| NCT03345823Phase 3AbbVieA Maintenance and Long-Term Extension Study of the Efficacy and Safety of Upadacitinib (ABT-494) in Participants With Crohn's Disease Who Completed the Studies M14-431 or M14-433 | 2027-09 |
| NCT04779320Phase 3TakedaA Study of Vedolizumab in Children and Teenagers With Moderate to Severe Crohn's Disease (CD) | 2027-09-13 |
Add all 14 to your calendar (.ics) → With an account.
Among the 217 studies in Crohn Disease with a site in United Kingdom, from their registry updates:
This tab as a report to print or save as PDF → With an account.
Background Perianal fistulae are among the most disabling complications of Crohn's disease, causing significant morbidity, impaired quality of life, and substantial healthcare utilisation. Despite advances in biologic and surgical therapies, many patients experience persistent fistula drainage and fail to achieve durable healing.
Tissue hypoxia is a key regulator of intestinal inflammation and impaired wound healing in inflammatory bowel disease. Hyperbaric oxygen therapy (HBOT) increases tissue oxygenation, promotes angiogenesis, modulates inflammatory pathways, and may enhance fistula healing.
Preliminary studies suggest that HBOT is a safe and effective adjunctive treatment for refractory perianal Crohn's fistulae, with reported clinical response rates of 75-87% and remission rates of 50-60%. However, current evidence is limited by small sample sizes and the absence of prospective studies within UK clinical practice.
Aim To evaluate the preliminary efficacy of HBOT in patients with refractory perianal Crohn's fistulae treated in an outpatient setting.
Methods This prospective pilot study will recruit ten adults with refractory perianal Crohn's fistulae from the Inflammatory Bowel Disease service at Barts Health NHS Trust. Refractory disease will be defined as persistent fistula drainage or failure to heal despite optimised medical therapy and appropriate surgical management. Participants will undergo HBOT 100% oxygen at 2.4 ATA for approximately 90 minutes per session, 40 sessions over 8 weeks. The primary outcome will be overall clinical response, defined as either clinical remission (complete cessation of fistula drainage) or partial response (clinically meaningful reduction in drainage and symptoms). Secondary outcomes will include treatment adherence, safety, tolerability, patient acceptability, and feasibility of recruitment and study completion.
Expected Impact This pilot study will generate preliminary efficacy and feasibility data to inform the design, outcome measures, and sample size calculations of a larger clinical trial evaluating HBOT as a novel treatment strategy for refractory perianal Crohn's disease in the United Kingdom.
Hyperbaric Oxygen Therapy for Refractory Perianal Crohn's Disease: A Pilot Feasibility Study Background
Perianal fistulising Crohn's disease (pfCD) affects up to one-third of patients with Crohn's disease and is associated with chronic pain, discharge, recurrent abscess formation, repeated surgery, and impaired quality of life. Despite advances in biologic therapies, long-term fistula healing remains difficult to achieve, particularly in patients with refractory disease.
Hyperbaric oxygen therapy (HBOT) delivers 100% oxygen under increased atmospheric pressure and has demonstrated anti-inflammatory and wound-healing effects through enhanced tissue oxygenation, angiogenesis, and modulation of inflammatory pathways. Previous studies have reported clinical response rates of 75-87% and remission rates of approximately 50-60% in refractory perianal Crohn's disease. The HOT-TOPIC trial demonstrated sustained clinical, biochemical, and radiological improvements at one year, while the AMFIBIO study suggested HBOT may reduce fistula inflammation sufficiently to enable definitive surgical closure.
Despite encouraging results, evidence is limited by small sample sizes, heterogeneous treatment pathways, and lack of UK prospective data. This pilot study aims to evaluate the feasibility, safety, and preliminary efficacy of HBOT in adults with refractory perianal Crohn's disease.
Study Objectives Primary Objective
To evaluate the overall clinical response to HBOT in adults with refractory perianal Crohn's disease.
Overall clinical response is defined as:
Clinical remission (closure of all treated fistula openings with complete absence of drainage), or Partial clinical response (reduction in fistula drainage and improvement in perianal symptoms).
Secondary Objectives Evaluate changes in inflammatory biomarkers (C-reactive protein and faecal calprotectin).
Assess changes in quality of life using the Crohn's Anal Fistula Quality of Life (CAF-QoL) questionnaire.
Assess radiological healing using pelvic MRI and/or transrectal ultrasound. Assess treatment safety and tolerability. Evaluate recruitment, retention, adherence, and feasibility outcomes to inform a future larger trial.
Study Design
This is a prospective, single-centre, open-label pilot interventional study conducted at Barts Health NHS Trust.
Ten adults with refractory perianal Crohn's disease will receive HBOT in addition to standard medical and surgical care.
There is no randomisation or control group owing to the feasibility nature of the study.
Total study duration for each participant will be approximately 34 weeks from enrolment.
Study Population Inclusion Criteria
Participants must:
Be aged 18 years or older. Have a confirmed diagnosis of Crohn's disease. Have active draining perianal fistulae classified as TOpClass 2b or 2c, or a non-healing perineal wound following proctectomy (TOpClass 4).
Have persistent disease despite, intolerance to, or loss of response to optimised medical and/or surgical treatment for at least 3-6 months.
Have a loose draining seton in situ for at least 4 weeks prior to treatment. Have stable medical therapy for at least 6 weeks prior to enrolment. Be willing and able to comply with study procedures. Exclusion Criteria
Participants will be excluded if they have:
Undrained perianal abscesses or collections requiring surgical intervention. Rectovaginal fistulae. Fistulae secondary to malignancy, tuberculosis, or non-Crohn's causes. Anal strictures. Severe active proctitis with deep ulceration. Diverting stoma or ileal pouch-anal anastomosis. Untreated pneumothorax. Severe claustrophobia preventing HBOT. Severe chronic obstructive pulmonary disease with carbon dioxide retention. Uncontrolled seizure disorders. Implanted devices incompatible with hyperbaric treatment. Current pregnancy or planned pregnancy during treatment. Intervention
Participants will receive HBOT in a clinically approved multi-place hyperbaric chamber.
Treatment parameters:
100% medical oxygen. 2.4 atmospheres absolute (ATA). Approximately 90 minutes per session. 40 treatment sessions. Five sessions per week over 8 weeks. Scheduled air breaks during treatment to minimise oxygen toxicity.
Participants will continue standard Crohn's disease treatments during the study.
At approximately week 4, and where clinically appropriate, setons may be removed and definitive closure of the external fistula opening performed according to multidisciplinary team recommendations.
Study Assessments Baseline
Participants will undergo:
Medical history and physical examination. Perianal Disease Activity Index (PDAI). Pelvic MRI and/or transrectal ultrasound. Laboratory testing including CRP and faecal calprotectin. CAF-QoL questionnaire. HBOT medical assessment. Follow-Up Schedule
Week 8
End of HBOT treatment assessment.
Week 16
Primary efficacy assessment. PDAI. Clinical drainage assessment. Evaluation of overall clinical response.
Week 24
Durability assessment. PDAI. MRI pelvis and/or transrectal ultrasound. CRP. Faecal calprotectin. CAF-QoL. Safety review.
Outcome Measures Primary Endpoint
Overall clinical response at Week 16.
Clinical remission is defined as complete closure of all treated fistula openings with absence of drainage.
Radiological remission is defined by:
Absence of fluid signal within the fistula tract. Fibrotic replacement of the tract. Absence of contrast enhancement indicating no active inflammation.
Partial response is defined as improvement in fistula drainage and symptoms without complete remission.
Secondary Endpoints Clinical remission rate. Change in PDAI score. MRI evidence of fistula healing. Change in modified Van Assche score and/or PEACE score where applicable. Change in CRP. Change in faecal calprotectin. Change in CAF-QoL score. Treatment completion rate. Participant retention rate. Recruitment rate. Safety and adverse events. Feasibility Outcomes
Pre-specified success criteria include:
Recruitment of at least 8 of 10 planned participants. Completion of at least 75% of scheduled HBOT sessions. Retention at Week 34 of at least 80%. No unexpected serious HBOT-related adverse events.
These outcomes will inform the design of a future larger prospective trial.
Statistical Analysis
As a pilot study, analyses will be exploratory and descriptive.
Baseline characteristics will be summarised using means and standard deviations, or medians and interquartile ranges where appropriate.
Clinical response and remission rates will be reported as proportions with 95% confidence intervals.
Changes in continuous outcomes, including PDAI, CRP, faecal calprotectin, MRI scores, and quality-of-life measures, will be analysed using paired statistical tests according to data distribution.
Effect size estimates and variability measures will be generated to support sample-size calculations for future studies.
Missing data will not be imputed and will be reported descriptively.
Safety Monitoring
HBOT has an established safety profile and is widely used in approved clinical indications.
Potential adverse events include:
Middle-ear barotrauma. Sinus discomfort. Transient myopia. Claustrophobia. Oxygen toxicity (rare). Hypoglycaemia in susceptible individuals.
Participants will undergo standard hyperbaric medicine screening before enrolment and will be monitored throughout treatment by experienced hyperbaric medicine clinicians.
Adverse events will be recorded and reported in accordance with Good Clinical Practice, sponsor requirements, and Health Research Authority guidance.
No independent Data Monitoring Committee has been established for this pilot study. Safety oversight will be provided through the study investigators, sponsor processes, and routine adverse event reporting procedures.
Expected Outcomes
This study aims to provide preliminary estimates of treatment effect, feasibility, and safety for HBOT in refractory perianal Crohn's disease within UK clinical practice.
Findings will support:
Development of a future multicentre prospective trial. Improved understanding of clinical and radiological healing following HBOT. Generation of UK feasibility and safety data. Future peer-reviewed publications and conference presentations.
This pilot study will contribute important evidence regarding the role of HBOT as an adjunctive treatment for refractory perianal Crohn's disease.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
perianal fistulising disease despite conventional and/or advanced medical therapy, as determined by the treating clinician.
Stable Crohn's disease medical therapy for at least 4 weeks prior to enrolment. Able and willing to undergo hyperbaric oxygen therapy. Able to provide written .
Exclusion Criteria:
Age \<18 years. Inability or unwillingness to provide . to hyperbaric oxygen therapy, including untreated pneumothorax.
Severe claustrophobia not manageable within the hyperbaric chamber. Pregnancy or breastfeeding. Active requiring treatment. Requirement for major surgery during the HBOT treatment period. Inability to comply with the study procedures or complete the HBOT treatment course.
Any medical condition that, in the opinion of the investigator, would make participation unsafe or interfere with study assessments
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Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Single experimental arm including patients with refractory Crohn's disease fistulae. Patients will receive hyperbaric oxygen therapy (HBOT) in addition to standard medical care. HBOT consists of 40 treatment sessions delivered over approximately 8 weeks, with participants breathing 100% oxygen at 2.4 atmospheres absolute (ATA) for approximately 90 minutes per session in a multiplace hyperbaric chamber
Device: Hyperbaric Oxygen Therapy (HBOT)
Participants with refractory perianal Crohn's disease fistulae will receive hyperbaric oxygen therapy (HBOT) in addition to standard medical care. HBOT consists of 40 treatment sessions delivered over approximately 8 weeks, with participants breathing 100% oxygen at 2.4 atmospheres absolute (ATA) for approximately 90 minutes per session in a multiplace hyperbaric chamber
Clinical Response of Perianal Crohn's Disease Fistulae
Clinical response defined as a ≥50% reduction from baseline in the number of draining perianal fistulae, assessed by gentle finger compression.
Time frame: 16 weeks
Plan to share: No — De-identified individual participant data may be made available upon reasonable request to the study sponsor, subject to approval, data protection requirements, and appropriate data sharing agreements.
Start is estimated for Jul 2027; primary completion for Apr 2028, 9 months later.
Of 288 non-industry interventional studies with no phase under Crohn Disease, half reached primary completion within 46 months of starting (the median), counting those still running; a quarter within 22 and three quarters within 67. This study's planned 9 months is below that.
Counting every sponsor, half of 300 studies reached it within 45 months; a quarter within 21 and three quarters within 65.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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Barts & The London NHS Trust →