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Study on Botulinum Toxin Type A Injection for Patients with Inability to Belch Due to Retrograde Cricopharyngeus Dysfunction

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying a condition known as retrograde cricopharyngeus dysfunction, which is commonly associated with the inability to belch. This condition can cause discomfort, such as bloating and nausea, due to trapped air in the digestive system. The study aims to evaluate the effects of a treatment using Botulinum toxin type A, commonly known as Botox, which is injected into the upper esophageal sphincter. This is the muscle at the top of the esophagus that helps control swallowing and belching.

Participants in the study will receive either the Botox injection or a placebo. The purpose of the study is to assess how effective the Botox injection is in reducing the symptoms of difficulty belching. The study will follow participants for a period of 48 weeks, with assessments at various intervals to monitor changes in symptoms and any side effects. The main focus will be on the improvement of symptoms 12 weeks after the treatment, with additional evaluations at 48 weeks.

Throughout the study, participants will be asked to complete questionnaires about their symptoms and overall experience. The study will also monitor the safety of the treatment by recording any adverse events. The goal is to determine if Botox can provide a significant improvement in the quality of life for those suffering from this condition, compared to those receiving a placebo.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes a review of medical history and diagnostic tests to ensure the absence of other throat and esophagus conditions.

    Eligibility criteria include being between 18 and 65 years old, experiencing difficulty belching for at least 6 months, and having typical findings on a specific test called high resolution impedance manometry.

  2. Step 2

    Treatment administration

    The treatment involves an intramuscular injection into the upper esophageal sphincter. This injection contains either botulinum toxin type a (BOTOX) or a placebo (saline solution).

    The purpose of the injection is to assess its effect on symptoms of inability to belch.

  3. Step 3

    Short-term follow-up

    Short-term follow-up occurs at 1, 4, and 12 weeks after the injection. During these visits, questionnaires are used to evaluate any changes in symptoms and overall health quality.

    Safety is assessed by monitoring any adverse events and using a specific questionnaire at 1 and 4 weeks post-procedure.

  4. Step 4

    Primary evaluation

    The primary evaluation takes place 12 weeks after the treatment. The main focus is on the response to the injection, measured by a questionnaire assessing the reduction in symptoms of difficulty belching.

    A successful response is defined as at least a 50% improvement in symptoms.

  5. Step 5

    Long-term follow-up

    Long-term follow-up extends to 48 weeks after the injection. This includes further assessments of symptom improvement, safety, and patient satisfaction.

    Additional exploratory evaluations are conducted, such as changes in associated gastrointestinal symptoms and objective measurements using high resolution impedance manometry at week 20.

  6. Step 6

    Final assessment

    The final assessment at 48 weeks includes a comprehensive evaluation of the treatment's effectiveness and safety.

    The study concludes with a comparison of the results between the BOTOX and placebo groups, focusing on symptom improvement and any adverse events experienced.

Who can join the trial?

6 criteria

  • The participant must provide voluntary written informed consent, or their legally authorized representative must do so, before any screening procedures begin.
  • The participant must use highly effective birth control methods. These methods should have a very low chance of failure (less than 1% per year) when used correctly. Examples include implants, injections, certain birth control pills, some intrauterine devices (IUDs), complete sexual abstinence, or having a partner who has had a vasectomy.
  • The participant must be between 18 and 65 years old.
  • The participant must have an inability to belch that is bothersome enough to consider treatment. This condition must have been present for at least 6 months before joining the study. Additionally, the participant must have:
    • Associated symptoms like abdominal bloating, discomfort or nausea, passing gas, or gurgling noises from the chest or lower neck.
    • No other throat or esophagus problems, as determined by medical history and tests.
    • The participant must have typical findings on a test called high resolution impedance manometry with belch provocation test. This test checks how the esophagus and throat muscles work when gas is present. Typical findings include no relaxation when gas moves back from the stomach, no air clearance through the upper esophageal sphincter (UES), and increased air presence time, which means air gets trapped and causes oscillations.

Who cannot join the trial?

7 criteria

  • Patients who are not experiencing symptoms of inability to belch cannot participate. This means if you can burp normally, you are not eligible.
  • Patients who have any other medical conditions that might interfere with the study or its results are not eligible. This means if you have other health issues that could affect the study, you cannot join.
  • Patients who are under 18 years old cannot participate. This means only adults can join the study.
  • Patients who are pregnant or breastfeeding are not eligible. This means if you are expecting a baby or nursing, you cannot take part in the study.
  • Patients who have had previous treatment with botulinum toxin for any reason are not eligible. Botulinum toxin is a substance used in some medical treatments, and if you've had it before, you cannot join.
  • Patients who are unable to provide informed consent cannot participate. This means if you cannot understand the study and agree to take part, you are not eligible.
  • Patients who are participating in another clinical trial at the same time are not eligible. This means if you are already in another study, you cannot join this one.
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Investigated drugs

Botulinum Toxin is used in this clinical trial to help with a condition where people have trouble belching. The medication is injected into a muscle in the throat called the upper esophageal sphincter. The goal is to see if this injection can improve the symptoms of not being able to belch over a period of 12 weeks.

What is already known about the treatment

Botulinum Toxin – This medication is administered through an injection directly into the upper esophageal sphincter. It is currently being studied in clinical trials for its effectiveness in treating retrograde cricopharyngeus dysfunction, a condition that affects the ability to belch. The main therapeutic indication is to alleviate symptoms associated with this dysfunction. At the molecular level, botulinum toxin works by blocking the release of a neurotransmitter called acetylcholine, which reduces muscle contractions. It is classified pharmacologically as a neurotoxin.

Investigated diseases

Retrograde Cricopharyngeus Dysfunction – This condition involves the malfunction of the cricopharyngeus muscle, which is part of the upper esophageal sphincter. It can lead to difficulties in belching, as the muscle does not relax properly to allow air to escape from the stomach. Individuals with this dysfunction may experience discomfort and bloating due to trapped air. The progression of symptoms can vary, with some people experiencing persistent issues while others may have intermittent symptoms. The condition is not classified as a rare disease, indicating it may be relatively common.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-512546-42-00Protocol code52082Estimated enrolment44 patientsSponsorAlgemeen Ziekenhuis Delta

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