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AP31969 versus placebo to control heart rhythm in people with atrial fibrillation

Clinical Randomised Phase 2 Trial of AP31969 Versus Placebo for Rhythm Control of Atrial Fibrillation

Phase 2 Interventional Acesion Pharma · NCT07267949

This trial tests whether taking oral AP31969 twice daily at several doses can lower AF burden compared with a placebo in adults with paroxysmal or persistent atrial fibrillation.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment200 (estimated)
Ages18 Years and up
SexAll
SponsorAcesion Pharma Industry-sponsored
Locations38 sites (Plovdiv, PD and 37 other locations)
Trial IDNCT07267949 on ClinicalTrials.gov

What this trial studies

This is a randomized, double-arm Phase 2 trial comparing multiple oral doses of AP31969 to placebo over a 12-week treatment period with a 30-day follow-up. Participants will be implanted with a loop recorder to continuously measure AF burden and will attend scheduled visits for ECGs, blood and urine tests, and safety monitoring. Eligible adults must have documented paroxysmal or persistent AF with an expected AF burden between 1% and 90% at screening and agree to avoid other rhythm-control interventions during the trial. Doses being tested include 100 mg, 200 mg, 350 mg (and a later 500 mg cohort may be added), all given twice daily.

Who should consider this trial

Good fit: Adults with documented paroxysmal or persistent AF who have an AF burden between 1% and 90%, are willing to have a loop recorder implanted, and agree to avoid non-trial rhythm-control treatments during participation.

Not a fit: People with very low AF burden (<1%), recent major cardiac events, prior extensive AF ablation (other than PVI), or who cannot avoid other rhythm-control interventions are unlikely to benefit from or be eligible for this trial.

Why it matters

Potential benefit: If successful, AP31969 could reduce the frequency or duration of AF episodes and lower overall AF burden, potentially improving symptoms and reducing need for other rhythm-control procedures.

How similar studies have performed: SK channel inhibition is a relatively novel approach for AF with supportive preclinical and early-phase data, but larger clinical proof of effectiveness is still limited.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Willing and able to provide written informed consent.
* Age 18 or older.
* ECG documented diagnosis of paroxysmal or persistent AF.
* AF history at screening indicating an expected AF burden of 1-90%, i.e., at least 1 self-terminating AF episode within 4 months prior to the screening visit.
* AF burden of ≥ 1% and ≤ 90% assessed with an ECG patch device during the screening period prior to the randomisation visit.
* Investigator and participant agreement to avoid non-trial related rhythm control intervention for the duration of the trial, including:

  * Antiarrhythmic drug class I and/or III (including amiodarone)
  * Electrical or pharmacological cardioversion
  * AF ablation procedure
* Willing to have a loop recorder implanted.

Exclusion Criteria:

* Prior AF ablation procedure other than pulmonary vein isolation (PVI) only.
* Any of the following events within 4 weeks prior to the screening visit: Myocardial infarction, Unstable angina pectoris, Stroke or transient, ischaemic attack, Percutaneous coronary intervention (PCI), Coronary artery bypass graft (CABG), Peripheral revascularisation procedure.
* Cardiac pacing device e.g. pacemaker and cardiac resynchronization therapy device with atrial or ventricular pacing for \> 5% of the time or existing implantable loop recorder.
* Heart failure, New York Heart Association class III (3) or IV (4).
* Left ventricular ejection fraction \< 40% based on imaging (e.g. echocardiography) performed within 6 months prior to or during the screening visit.
* Clinically significant valvular heart disease, including severe aortic stenosis, severe mitral regurgitation and/or severe mitral stenosis, in the opinion of the investigator.
* QTc (Fridericia, QTcF) interval \> 450 ms for males and \> 470 ms for females at screening.
* eGFR \<60 mL/min /1.73 m² based on creatine and CKD-EPI formula
* Use of antiarrhythmic drug class I and/or III within 7 days or, for amiodarone, within 3 months prior to the screening visit.

Where this trial is running

Plovdiv, PD and 37 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Atrial FibrillationAP31969SK channel inhibitor
Last reviewed 2026-06-10 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.