A Gene Therapy Study for Homozygous Familial Hypercholesterolemia (HoFH)

AAV8-mediated Low Density Lipoprotein Receptor (LDLR) Gene Replacement in Subjects With Homozygous Familial Hypercholesterolemia (HoFH)

This first-in-human study is intended to evaluate the safety and preliminary effectiveness of AAV (Adeno-associated virus)-based liver-directed gene therapy in the treatment of adults with Homozygous Familial Hypercholesterolemia (HoFH).

Homozygous Familial Hypercholesterolemia (HoFH) is a rare genetic metabolic disorder characterized by absent or severely reduced capacity to catabolize circulating LDL (Low density lipoprotein) particles by the hepatic LDL receptor. As a consequence, HoFH subjects present abnormal total plasma cholesterol (LDL-C) levels, resulting in severe atherosclerosis often leading to early onset of cardiovascular disease. Early initiation of aggressive treatment for these patients is therefore essential. Unfortunately, despite existing therapies, treated LDL-C (Low density lipoprotein cholesterol) levels could remain well above acceptable levels. Thus, the functional replacement of the defective LDLR via AAV-based liver-directed gene therapy may be a viable approach to treat this disease and improve response to current lipid-lowering treatments. This first-in-human study is intended to evaluate the safety of this gene therapy investigational product and assess preliminary evidence of efficacy using plasma LDL-C levels as a surrogate biomarker for human LDLR transgene expression.

Subjects may be asked to participate in an optional kinetics study to assess the metabolic mechanism by which LDL-C is reduced.

Inclusion Criteria:

• Male or female ≥ 18 years of age.
• Untreated and/or treated LDL-C levels and clinical presentation consistent with the diagnosis of homozygous FH (Familial hypercholesterolemia)
• Molecularly defined LDLR mutations at both LDLR alleles.
• A baseline serum AAV8 NAb (Neutralizing antibody) titer ≤ 1:10.

Exclusion Criteria

• Unwilling to wash out of the following lipid lowering therapies for the pre-specified time period:

  1. niacin > 250 mg/day: within 6 weeks of baseline
  2. fibrates: within 4 weeks of baseline
  3. lomitapide: within 8 weeks of baseline
  4. mipomersen: within 24 weeks of baseline

• History of cirrhosis or chronic liver disease based on documented histological evaluation or non-invasive imaging or testing.

• Abnormal liver function tests (LFTs) at screening (AST (Aspartate aminotransferase) or ALT (Alanine aminotransferase) > 2 × upper limit of normal (ULN) and/or Total Bilirubin of > 1.5 × ULN