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Evaluating Aficamten for children with obstructive hypertrophic cardiomyopathy

A Phase 2/3 Multicenter, Randomized, Double-Blind, Placebo-Controlled and Open-Label Extension Trial to Evaluate the Efficacy and Safety of Aficamten in a Pediatric Population With Symptomatic Obstructive Hypertrophic Cardiomyopathy

Phase2; Phase3 Interventional Cytokinetics · NCT06412666

This study is testing a new medication called aficamten to see if it can help children aged 6 to 18 with a heart condition called obstructive hypertrophic cardiomyopathy feel better and stay safe.

Quick facts

PhasePhase2; Phase3
Study typeInterventional
Enrollment55 (estimated)
Ages12 Years to 17 Years
SexAll
SponsorCytokinetics Industry-sponsored
Drugs / interventionstrastuzumab, sunitinib, imatinib, cyclophosphamide
Locations38 sites (Phoenix, Arizona and 37 other locations)
Trial IDNCT06412666 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to assess the efficacy, safety, and pharmacokinetics of aficamten in pediatric patients aged 6 to 18 years with symptomatic obstructive hypertrophic cardiomyopathy (oHCM). The study is structured in three periods: a randomized, double-blind, placebo-controlled treatment phase lasting 12 weeks, followed by an open-label extension for 52 weeks, and a long-term extension for 144 weeks. The trial will involve a staged approach, starting with adolescents and then expanding to younger children based on pharmacodynamic and safety data. Participants will be closely monitored for safety and tolerability throughout the study.

Who should consider this trial

Good fit: Ideal candidates are males and females aged 6 to 18 years with confirmed symptomatic obstructive hypertrophic cardiomyopathy.

Not a fit: Patients with oHCM not of sarcomeric origin or those unable to meet the echocardiographic criteria may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve the management of symptomatic oHCM in pediatric patients.

How similar studies have performed: While there have been studies on hypertrophic cardiomyopathy treatments, this specific approach with aficamten in a pediatric population is novel.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

* Period 1: Treatment Period

  * Males and females between 12 and \< 18 years of age at screening and at Day 1.
  * Body weight ≥ 45 kg for the initial cohort and then body weight ≥ 35 kg after at least 10 participants in the initial cohort have undergone dose titration up to Week 4 without observed events of LVEF \< 50% at the starting dose of 5 mg qd.
  * Core laboratory confirmation of the following oHCM echocardiographic criteria at screening:
* Left ventricular (LV) hypertrophy with nondilated LV chamber in the absence of other cardiac disease.
* LV end-diastolic wall thickness that meets a threshold of:

  * Z-score \> 2.5 in the absence of family history OR
  * Z-score \> 2 in the presence of positive family history or positive genetic test.
* LVEF ≥ 60% AND Valsalva LVOT-G ≥ 50 mmHg.

  * oHCM of sarcomeric origin confirmed by genetic testing or, if unable to confirm by genetic testing, oHCM of sarcomeric origin may be presumed in the absence of history of metabolic disorders, mitochondrial cardiomyopathies, neuromuscular disease, malformation syndromes, infiltrative diseases/inflammation, and endocrine disorders (such as Fabry's disease, Noonan syndrome with left ventricular hypertrophy, and amyloid-cardiomyopathy).
  * New York Heart Association (NYHA) Class ≥ II at screening.
  * Adequate acoustic windows for echocardiography.
  * Participants on beta blockers, verapamil, diltiazem, or disopyramide should have been on stable doses for more than 4 weeks prior to randomization.
* Period 2: Open-Label Extension

  * Completed Period 1. If unable to complete Period 1 due to circumstances not related to compliance or safety, the Medical Monitor may review and determine eligibility.
  * LVEF ≥ 55% after washout.
* Period 3: Long-term Extension • Completed Period 2.

Exclusion Criteria:

* Period 1: Treatment Period

Any of the following criteria will exclude potential participants from the trial:

* Significant valvular heart disease.

  * Moderate or severe valvular aortic stenosis or fixed subaortic obstruction.
  * Mitral regurgitation that is greater than mild in severity and not due to systolic anterior motion of the mitral valve (per judgment of Principal Investigator or designee).
  * Evidence of fixed left-sided obstruction (eg, subaortic membrane, aortic valve stenosis, or coarctation of the aorta).
* History of LV systolic dysfunction (LVEF \< 45%) or stress cardiomyopathy at any time during their clinical course.
* History of congenital heart disease other than oHCM (may be enrolled if not hemodynamically significant in the judgement of the Principal Investigator and study Medical Monitor).
* Has been treated with SRT (surgical myectomy or percutaneous alcohol septal ablation) within the preceding 6 months or has plans for either treatment during the trial period.
* History of paroxysmal or persistent atrial fibrillation or atrial flutter.
* History of syncope, symptomatic ventricular arrhythmia, or sustained ventricular tachyarrhythmia within 3 months prior to screening.
* History or evidence of any other clinically significant disorder, malignancy, active infection, other condition, or disease that, in the opinion of the Principal Investigator (or designee) or the Medical Monitor, would pose a risk to participant safety or interfere with the trial evaluation, procedures, or completion.
* Current or previous use of drugs known to cause cardiomyopathy (eg, anthracyclines, monoclonal antibodies \[trastuzumab\], alkylating agents \[cyclophosphamide\], and tyrosine kinase inhibitors \[sunitinib and imatinib\]).
* Currently participating in another investigational device or drug trial or received an investigational device or drug \< 1 month (or 5 half-lives for drugs, whichever is longer) prior to screening.
* Implantable cardioverter defibrillator (ICD) implantation within 6 weeks of screening or planned ICD implantation during the trial period.
* Has received prior treatment with aficamten or mavacamten.
* Currently listed for heart transplantation or anticipated to be listed for heart transplantation in the next 12 months.

Where this trial is running

Phoenix, Arizona 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 PediatricSymptomatic Obstructive Hypertrophic CardiomyopathyCK-3773274CK-274AficamtenoHCMCEDARCEDAR-HCM
Last reviewed 2026-06-13 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.