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A study testing how well zodasiran works and how safe it is for teenagers and adults with homozygous familial hypercholesterolemia

Fast replyInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study examines Homozygous Familial Hypercholesterolemia, a rare inherited condition where the body cannot properly remove cholesterol from the blood, leading to extremely high cholesterol levels from birth. People with this condition have a much higher risk of heart disease at a young age. The study will test a medication called zodasiran, which is also known by its code name ARO-ANG3. This medication works by targeting a specific protein in the body that affects cholesterol levels. Some participants will receive zodasiran while others will receive placebo. All participants will continue taking their regular cholesterol-lowering medications during the study.

The main goal of this study is to find out if zodasiran can reduce low-density lipoprotein cholesterol, commonly called bad cholesterol, compared to placebo in people with this genetic condition. The study will measure cholesterol levels in the blood after participants have not eaten, which is called fasting cholesterol. The researchers will look at various types of fats in the blood, including different forms of cholesterol and other substances that carry fats through the bloodstream.

The study will last approximately 12 months for the main treatment period. Participants will receive the study medication as an injection under the skin using a pre-filled syringe. The maximum dose that may be given is 200 milligrams at one time, with a total maximum dose of 2000 milligrams over the entire treatment period of 24 weeks. During the study, doctors will regularly check cholesterol levels and other measurements to see how well the treatment is working and to monitor for any side effects. The study includes both teenagers aged 12 years and older as well as adults who have been diagnosed with this inherited cholesterol condition.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial screening and baseline assessment

    Your blood will be tested to measure your low-density lipoprotein cholesterol (also called LDL-C, which is a type of cholesterol that can build up in your arteries). For adults, this level should be at least 70 mg/dL. For adolescents aged 12 to under 18 years, this level should be at least 116 mg/dL.

    Your blood will also be tested to check your hemoglobin A1c (a measure of blood sugar control over time), which should be 9.5% or lower.

    Additional blood tests will measure your liver function. Your alanine aminotransferase and aspartate aminotransferase (liver enzymes) should be less than 3 times the upper normal limit. Your total bilirubin (a substance produced when red blood cells break down) should be less than 2 times the upper normal limit.

    Your body weight will be measured and should be at least 35 kg.

    Your diagnosis of homozygous familial hypercholesterolemia (a genetic condition causing very high cholesterol levels) will be confirmed through genetic testing or clinical criteria.

    You should continue taking your current cholesterol-lowering medications at the maximum dose you can tolerate.

  2. Step 2

    Random assignment to treatment group

    You will be randomly assigned to receive either zodasiran (the study medication being tested) or placebo (an inactive substance that looks like the study medication but contains no active ingredient).

    Neither you nor your doctor will know which treatment you are receiving during this phase of the study.

  3. Step 3

    Treatment period with injections

    You will receive injections under your skin (subcutaneous injections) of either zodasiran or placebo.

    The study medication will be given as a solution for injection.

    This treatment period will last for 12 months.

    The specific dosage and frequency of injections will be determined by the study protocol.

  4. Step 4

    Regular monitoring visits during treatment

    Throughout the 12-month treatment period, you will have regular visits where your blood will be tested.

    These tests will measure your fasting LDL-C (cholesterol level after not eating), apolipoprotein B (a protein that carries cholesterol in your blood), non-HDL cholesterol (total cholesterol minus good cholesterol), triglycerides (another type of fat in your blood), total cholesterol, HDL cholesterol (good cholesterol), lipoprotein(a) (another cholesterol-carrying particle), and angiopoietin-like protein 3 (a protein that affects fat levels in your blood).

    Your doctor will monitor how your cholesterol levels change over time compared to your starting levels.

    Your safety will be monitored throughout the treatment period.

  5. Step 5

    Assessment at month 12

    At the end of the 12-month treatment period, your blood will be tested again to measure all cholesterol-related values.

    The main measurement will be the percentage change in your fasting LDL-C from the beginning of the study to month 12.

    Your doctor will assess whether your cholesterol levels meet certain criteria that would qualify you for apheresis (a procedure that removes cholesterol from your blood) according to European Union or United States guidelines.

    Your doctor will also check if your LDL-C level has dropped below 100 mg/dL.

Who can join the trial?

9 criteria

  • You must be at least 12 years old or older
  • You must weigh at least 35 kilograms (about 77 pounds) at the screening visit
  • If you can become pregnant, you must not be pregnant or breastfeeding, and you must not plan to become pregnant during the study
  • You must have Homozygous Familial Hypercholesterolemia, which is a rare inherited condition that causes very high cholesterol levels. This must be confirmed either by a genetic test or by meeting specific clinical criteria including very high cholesterol levels and family history
  • Your LDL cholesterol (a type of cholesterol often called "bad cholesterol") must be at least 70 mg/dL. If you are between 12 and 17 years old, your LDL cholesterol must be at least 116 mg/dL
  • Your HbA1c level (a blood test that shows average blood sugar levels over the past few months) must be 9.5% or lower
  • Your total bilirubin level (a substance produced when red blood cells break down) must be less than 2 times the upper normal limit, unless you have been previously diagnosed with Gilbert's syndrome (a harmless liver condition)
  • Your liver enzyme levels (called ALT and AST, which show how well your liver is working) must be less than 3 times the upper normal limit
  • You must already be taking the maximum dose of cholesterol-lowering medications that you can tolerate as part of your standard care

Who cannot join the trial?

1 criterion

  • No specific exclusion criteria have been provided in the available study information at this time.
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Investigated drugs

Zodasiran is an investigational medication being studied for people with a rare genetic condition called homozygous familial hypercholesterolemia, which causes very high cholesterol levels from birth. This medication works to help lower the amount of bad cholesterol (LDL cholesterol) in the blood. In this study, zodasiran is being compared to a placebo to see how well it works and how safe it is for adolescents and adults with this condition.

A placebo is an inactive substance that looks like the real medication but contains no active treatment. It is used in the study to compare the effects of zodasiran against no treatment, helping researchers understand if the medication truly works.

What is already known about the treatment

Zodasiran – Zodasiran is an investigational medication currently being studied in clinical trials for the treatment of Homozygous Familial Hypercholesterolemia, a rare genetic condition that causes extremely high cholesterol levels from birth. The drug works by using a technology that reduces the production of specific proteins in the liver responsible for controlling cholesterol levels in the blood, specifically targeting low-density lipoprotein cholesterol (LDL-C), often called "bad cholesterol." Zodasiran belongs to a class of medications known as RNA interference therapeutics, which are designed to silence certain genes that contribute to disease. The medication is being tested in adolescents and adults to evaluate whether it can effectively lower dangerous cholesterol levels that put patients at high risk for heart disease and other serious cardiovascular problems.

Investigated diseases

Homozygous Familial Hypercholesterolemia – Homozygous Familial Hypercholesterolemia is a rare inherited disorder that affects the way the body processes cholesterol. People with this condition have two copies of a faulty gene, one from each parent, which severely impairs the body's ability to remove low-density lipoprotein cholesterol from the blood. This results in extremely high levels of cholesterol in the bloodstream from birth or early childhood. The excess cholesterol accumulates in various tissues throughout the body, particularly in the walls of blood vessels and in the skin. Over time, these cholesterol deposits can lead to the narrowing and hardening of arteries at a young age. The condition progresses more rapidly and severely than other forms of high cholesterol due to the complete or near-complete loss of normal cholesterol regulation.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-521792-31-01Protocol codeAROANG3-3001Estimated enrolment61 patientsSponsorArrowhead Pharmaceuticals Inc.

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