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Study of AP31969 compared to placebo to control heart rhythm in patients with atrial fibrillation

Fast replyInvestigationalNo placebo
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What is this trial about?

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

This clinical trial focuses on studying atrial fibrillation, which is an irregular and often rapid heart rhythm condition. The study will evaluate a new medication called AP31969, an experimental antiarrhythmic drug that aims to control heart rhythm. The main purpose is to assess how effectively AP31969 reduces the burden of atrial fibrillation compared to placebo.

The treatment involves taking AP31969 tablets orally for a period of 12 weeks. The medication will be provided as film-coated tablets in various dosage strengths. Some participants will receive the active medication, while others will receive placebo tablets that look identical to the real medication but contain no active substance.

During the study, participants will have their heart rhythm monitored continuously through special recording devices. The study will track how often atrial fibrillation episodes occur and how long they last. Participants will also complete questionnaires about their quality of life and symptoms related to their heart condition.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment and device placement

    You will receive an ECG patch device to measure your heart rhythm and confirm that your atrial fibrillation (irregular heartbeat) occurs between 1% and 90% of the time.

    A loop recorder will be implanted under your skin to continuously monitor your heart rhythm during the study.

  2. Step 2

    Random group assignment

    You will be randomly assigned to receive either AP31969 tablets or placebo tablets (tablets without active medication).

    The tablets in both groups look identical, and you will not know which type you are receiving.

  3. Step 3

    Treatment period

    The treatment period lasts for 12 weeks.

    You will take the assigned tablets by mouth as instructed.

    Your heart rhythm will be continuously monitored through the implanted loop recorder.

  4. Step 4

    Monitoring and assessments

    Your heart rhythm will be specifically analyzed from week 2 to week 12.

    You will complete quality of life questionnaires at the start and at week 12.

    Regular heart measurements (ECG) will be taken to monitor your heart's electrical activity.

    Any side effects will be recorded throughout the study period.

  5. Step 5

    Final assessment

    At week 12, you will have a final evaluation.

    You will complete final questionnaires about your symptoms and quality of life.

    A final ECG measurement will be taken.

    Your overall response to the treatment will be assessed.

Who can join the trial?

11 criteria

  • Must be able and willing to give written permission to participate in the study
  • Must be 18 years of age or older
  • Must have atrial fibrillation confirmed by an ECG (a test that records the heart's electrical activity)
  • Must have a history showing that atrial fibrillation occurs between 1-90% of the time
  • If currently experiencing atrial fibrillation, the episode must have started less than 7 days before screening
  • Must show atrial fibrillation occurring between 1% and 90% of the time when measured with a special heart monitoring patch
  • Must agree not to undergo any heart rhythm treatments outside of the study during the trial period
  • Must be willing to have a loop recorder (a small device that monitors heart rhythm) implanted under the skin
  • For women who can become pregnant and have a male partner: must use reliable birth control and not donate eggs from 4 weeks before starting the study until the follow-up visit
  • For men with female partners who can become pregnant: must use condoms and not donate sperm from screening until the follow-up visit
  • Women must not be pregnant or breastfeeding during the study

Who cannot join the trial?

17 criteria

  • Age below 18 years or above 65 years
  • Pregnancy or breastfeeding
  • History of severe allergic reactions to medications
  • Recent heart surgery (within the last 6 months)
  • Presence of heart valve disease (problems with heart valves)
  • Severe hypertension (high blood pressure that is not controlled with medication)
  • Active bleeding disorders
  • Severe liver disease
  • Severe kidney disease
  • Current participation in other clinical trials
  • Use of medications that could interact with the study drug
  • History of stroke (a condition where blood flow to the brain is interrupted)
  • Untreated thyroid disease (problems with thyroid gland function)
  • Severe heart failure (when heart cannot pump blood effectively)
  • History of drug or alcohol abuse within the past year
  • Mental conditions that could affect ability to follow study procedures
  • Life expectancy less than 1 year due to other medical conditions
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Investigated drugs

AP31969 is an investigational medication being studied for controlling heart rhythm in patients with atrial fibrillation (an irregular heartbeat condition). The medication is being tested to see if it can reduce how often and how long patients experience irregular heart rhythms. This is an experimental drug that is still being researched and does not yet have a common brand name. A placebo (an inactive substance) is also used in this trial as a comparison to measure how well AP31969 works.

What is already known about the treatment

AP31969 - An investigational medication currently in Phase 2 clinical trials for the treatment of atrial fibrillation, which is a type of irregular heart rhythm. This experimental drug is being studied for its potential role in rhythm control for patients with atrial fibrillation, though its specific mechanism of action and administration form are not yet publicly disclosed in the available clinical trial data. As a drug in clinical development, it is being compared to placebo to evaluate its effectiveness in reducing the burden of atrial fibrillation symptoms, but it has not yet received regulatory approval for medical use.

Investigated diseases

Atrial Fibrillation - A heart rhythm disorder where the upper chambers of the heart (atria) beat irregularly and often rapidly, out of coordination with the lower chambers. This condition occurs when the heart's electrical signals become chaotic, causing an irregular heartbeat pattern. The irregular rhythm can cause blood to pool in the heart chambers, which affects how efficiently the heart pumps blood throughout the body. People with atrial fibrillation may experience heart palpitations, shortness of breath, and fatigue. The condition can be persistent, occurring continuously, or paroxysmal, where episodes come and go.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-521377-14-00Protocol codeAP31969-M201Estimated enrolment200 patientsSponsorAcesion Pharma ApS

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).