The Effects of STW 5-II on Duodenal Mucosa and Symptoms in Functional Dyspepsia

NCT07198243 | Not Yet Recruiting Phase 4

• 2 other identifiers: S701882025-521141-24-00
• Study Type: interventional
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to find out whether a herbal medicine called STW 5-II can help improve gut health and symptoms in adults recently diagnosed with functional dyspepsia (FD)-a condition that causes frequent stomach discomfort, especially after eating. The main questions it aims to answer are: Can STW 5-II reduce certain immune cells (eosinophils) in the gut lining? Can it improve symptoms like severe postprandial fullness, bloating, epigastric pain, and improve quality of life? Researchers will compare STW 5-II to a placebo to see if it helps reduce gut inflammation and ease symptoms. Participants will: Take either STW 5-II or a placebo for 8 weeks Provide small samples of gut tissue (via endoscopy) Answer questions about their symptoms and daily life An optional 4-week treatment with STW 5-II will follow for all participants.

Conditions

Functional Dyspepsia

Outcome Measures

Primary Outcomes (1)

• Difference in duodenal mucosal eosinophil count between baseline and the end of the treatment (week 8) in both arms

  For the primary outcome, the number of eosinophils per square mm tissue will be counted as described by Ceulemans M et al. The numbers of cells will be compared at the end of treatment between both study arms. The baseline values and the delta over time will also be compared between both groups. If necessary, the baseline value can be added as co-variate in the statistical analysis.

  8 weeks

Secondary Outcomes (3)

• The effect of STW 5-II vs. placebo therapy on clinical symptoms

  8 weeks

• The effect of STW 5-II in other immune cells

  8 weeks

• Changes in Mucosal permeability

  8 weeks

Other Outcomes (6)

• The effect of STW 5-II vs. placebo therapy on quality of life

  8 weeks

• The effect of STW 5-II vs. placebo in co-morbidities (depression ) in functional dyspepsia

  8 weeks

• The effect of STW 5-II vs. placebo in co-morbidities (somatization) in functional dyspepsia

  8 weeks

Study Arms (2)

Placebo

PLACEBO COMPARATOR

Functional dyspepsia patients taking the matching placebo for 8 weeks.

Drug: Placebo

STW 5-II

EXPERIMENTAL

Functional dyspepsia patients taking STW 5-II, the active product for the treatment of FD.

Drug: STW 5-II

Interventions

STW 5-II DRUG

STW 5-II is an herbal medicinal product for the symptomatic treatment of functional dyspepsia with main symptoms such as epigastric pain, epigastric burning, postprandial fullness and early satiation, but often also loss of appetite, excessive belching and heartburn. STW5-II consists of six herbal extracts: bitter candy tuft, camomile flower, caraway fruit, melissa leaf, peppermint leaf, and licorice root. STW 5-II will be a solution for oral intake, for the treatment of FD, administered as 20 droplets in liquids, three times daily during 8 weeks. Recommended time of ingestion is just before or with meals. Patients and study staff are blinded for the intervention

STW 5-II

Placebo DRUG

Matching placebo will be a solution for oral intake, administered as 20 droplets in liquids, three times daily during 8 weeks. Recommended time of ingestion is just before or with meals. Patients and study staff are blinded for the intervention.

Placebo

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients ≥18 years newly to be treated with an FD/PDS diagnosis (Rome IV clinical criteria).
• Newly to be treated patients are defined as patients currently not on any ongoing treatment for FD (including OTC medication) for the last 2 weeks. Medications such as PPI or others that may affect GI function and symptom should be stopped prior the trial (min 4 weeks). See list of forbidden medication.
• Male or female using contraception or postmenopausal
• Witnessed written informed consent
• Capable to understand and comply with the study requirements

You may not qualify if:

• Patients ≥18 years newly to be treated with an FD/PDS diagnosis (Rome IV clinical criteria).
• Newly to be treated patients are defined as patients currently not on any ongoing treatment for FD (including OTC medication) for the last 2 weeks. Medications such as PPI or others that may affect GI function and symptom should be stopped prior the trial (min 4 weeks). See list of forbidden medication.
• Male or female using contraception or postmenopausal
• Witnessed written informed consent
• Capable to understand and comply with the study requirements
• Major active somatic or psychiatric condition that may explain dyspeptic symptoms (stable dose of single antidepressant allowed for psychiatric indication, no limitation for other indications) Predominant symptoms of gastro-esophageal reflux disease (GERD) or irritable bowel syndrome (IBS)
• Chronic ppi use. No PPI use for at least the prior 4 weeks before entering the trial- History of major abdominal surgery (except for appendectomy, cholecystectomy or splenectomy)
• History or presence of diabetes mellitus type 1 \& type 2, coeliac disease or inflammatory bowel disease
• Active malignancy
• Known HIV, HBV or HCV infection
• Significant alcohol use (\>10 units/weeks)
• Females pregnant or lactating
• Hypersensitivity against ingredients of STW 5-II or placebo (see annex)
• Abnormal baseline laboratory blood values

Sponsors & Collaborators

• Universitaire Ziekenhuizen KU Leuven: lead

Study Sites (1)

University Hospitals Leuven / UZLeuven

Leuven, 3000, Belgium

Location

Study Officials

• Jan Tack, MD, PhD

  Universitaire Ziekenhuizen KU Leuven

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jan Tack, MD, PhD

CONTACT

+32 16 34 47 75; jan.tack@kuleuven.be

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 18, 2025
• First Posted: September 30, 2025
• Study Start: September 30, 2025
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: September 30, 2025

Record last verified: 2025-07

Locations

BE (1)