A Multi-Center, Open Label Gene Therapy Study of RP-A501 in Male Patients With Danon Disease

Open to males ages 8 years and up

1. Documentation of a pathogenic or likely pathogenic variant of the LAMP2 gene.
2. Male gender.
3. Age ≥8 years.
4. Evidence of left ventricular hypertrophy with preserved systolic function phenotype as defined by each of the following:
   1. For subjects < 18 years, z-score of the left ventricular posterior wall or interventricular septum at end diastole ≥+ 2, and for subjects ≥18 years, left ventricular posterior wall or interventricular septum at end diastole >13 mm (>12 mm if family history of clinically significant Danon disease),
   2. Left ventricular ejection fraction (LVEF) ≥ 50%.
5. New York Heart Association (NYHA) Class II to III.
6. hsTnI ≥20% above the ULN
7. Ability to comply with study procedures including investigational therapy and follow-up evaluations.

1. Anti-AAV9 neutralizing antibody titer >1:40.
2. Intravenous inotropic, vasodilator, or diuretic therapy within the 30 days prior to enrollment.
3. Presence or requirement for mechanical circulatory support (MCS).
4. Presence or requirement for mechanical ventilation.
5. History of intracardiac thrombosis or arterial thromboembolic events including stroke, transient ischemic attack (TIA), acute coronary syndrome, myocardial infarction or unstable angina.
6. Prior cardiac or other organ (lung, liver, other) transplantation.