A Phase 2 interventional study of RP-A501 in Danon Disease, sponsored by Rocket Pharmaceuticals Inc.. Recruiting at 6 sites in 4 countries. Open to male participants aged 8 Years and older. Per ClinicalTrials.gov, last updated 2026-10-06.
Sponsored by Rocket Pharmaceuticals Inc. · Phase 2, Interventional, and Treatment
This is a single arm Phase 2 trial to evaluate the efficacy and safety of RP-A501, a recombinant adeno-associated virus serotype 9 (rAAV9) vector containing the human lysosome-associated membrane protein 2 isoform B (LAMP2B) transgene, in male patients with Danon disease.
RP-A501-0123 is a Phase 2 global, multi-center, single arm, open-label, single dose trial in males with Danon disease. The study is designed to assess the efficacy and safety of a single intravenous dose of RP-A501 in treating the cardiomyopathy associated with Danon disease.
RP-A501-0123 will enroll subjects ≥ 8 years of age with a pathogenic or likely pathogenic LAMP2 variant. The trial will include a total of 5 years of follow-up after administration of RP-A501.
363 studies on the registry are indexed under Cardiomyopathy, Hypertrophic; 116 are open to participants now.
This study's planned enrollment of 18 is below the median of 60 across 180 interventional studies indexed under Cardiomyopathy, Hypertrophic.
Browse Cardiomyopathy, Hypertrophic studies →Rocket Pharmaceuticals Inc. is the lead sponsor of 19 studies on the registry; 7 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The criteria were revised on the registry on Oct 6, 2026. See what changed
Key Inclusion Criteria:
Evidence of left ventricular hypertrophy with preserved systolic function phenotype as defined by each of the following:
Key Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A single intravenous infusion of RP-A501 in cohorts of subjects with a confirmed diagnosis of Danon disease.
Genetic: RP-A501
RP-A501 is a gene therapy product consisting of an rAAV9 capsid containing the human LAMP2B transgene which will be administered as a single IV infusion. Dose of RP-A501: Cohorts 1, 2 \& 3 = 6.7 x10\^13 genome copies (GC)/kg; Cohort 4 = 3.8 x10\^13 GC/kg. An immunomodulation regimen is initiated before RP-A501 administration to reduce the risk of gene therapy-related complications. The regimen includes rituximab or a biosimilar, administered in two doses for Cohorts 1-3 and three doses for Cohort 4, along with sirolimus and corticosteroids. Pegcetacoplan was incorporated into the immunomodulation regimen for Cohort 3 but excluded in Cohort 4.
Evaluation of Efficacy: Improvement as assessed via primary endpoint comprised of LAMP2 myocardial tissue expression and left ventricular mass index (LVMI)
Myocardial tissue expression of LAMP2 protein improved from baseline to ≥ Grade 1 (by IHC), AND, ≥ 10% decrease in LVMI from baseline.
Time frame: 12 months post-infusion
Evaluation of efficacy via components of the primary endpoint - LAMP2
Myocardial tissue expression of LAMP2 protein improved from baseline to ≥ Grade 1 (by IHC)
Time frame: 12 months post infusion
Evaluation of efficacy via components of the primary endpoint - Left Ventricular Mass Index (LVMI)
≥ 10% decrease in LVMI from baseline
Time frame: 12 months post infusion
Evaluation of efficacy via biomarker evidence of myocardial injury - High Sensitivity Troponin I (hsTnI)
≥ 20% decrease in hsTnI from baseline
Time frame: 12 months post infusion
Evaluation of efficacy via biomarker evidence of myocardial injury - N-Terminal Prohormone of Brain Natriuretic Peptide (NT-proBNP)
≥ 20% decrease in NT-proBNP from baseline
Time frame: 12 months post infusion
Evaluation of efficacy via Quality of Life
Change in KCCQ-12 Overall Score from baseline
Time frame: 12 months post infusion
Evaluation of efficacy via heart failure symptoms
Change in NYHA class from baseline
Time frame: 12 months post infusion
Evaluation of efficacy via assessment of event-free survival
1. Event free survival with events defined as death, heart transplant, mechanical circulatory support (MCS) or heart failure hospitalization 2. Incidence of death, heart transplant, MCS, or heart failure hospitalization
Time frame: From infusion to 60 months post infusion
Evaluation of safety
Incidence, severity and duration of treatment emergent safety events.
Time frame: From infusion to 60 months post infusion
Started Sep 2023 (actual). Primary completion is estimated for Jun 2028, 57 months after the start.
Of 20 phase 2 interventional studies under Cardiomyopathy, Hypertrophic, half reached primary completion within 36 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 43. This study's planned 57 months is above that.
Since we started tracking on Sep 25, 2026, the dates moved once, on Oct 6, 2026: primary completion Apr 2028 → Jun 2028 and completion Apr 2032 → Jun 2032.
Earlier changes are on the record history on ClinicalTrials.gov ↗
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Rocket Pharmaceuticals Inc.