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Lerodalcibep for Heterozygous Familial Hypercholesterolemia in Children and Adolescents 6 to 17 Years Old

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What is this trial about?

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

This study is being done in children and adolescents with Heterozygous Familial Hypercholesterolemia, a condition passed down in families that causes very high cholesterol levels from a young age. The study is testing lerodalcibep, a medicine given as a monthly injection under the skin, to see whether it can lower LDL-C, often called “bad cholesterol,” more than placebo when used together with a stable diet and oral cholesterol-lowering medicine.

The study lasts about 24 weeks. Participants are assigned by chance to receive either lerodalcibep or placebo, and neither the family nor the study team knows which one is given during the study. The medicine is given once a month, and study visits are spread over the treatment period. Doctors also check general health, growth, and development, and watch for side effects and other safety concerns.

The main purpose of the study is to find out whether lerodalcibep is safe and effective for lowering LDL-C in children and adolescents with this inherited cholesterol disorder. Other blood fats and some body changes related to growth and hormones are also followed during the study.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Study start and first treatment day

    day 1 begins the trial after joining the study. you receive either lerodalcibep or a placebo in a pre-filled pen as a subcutaneous injection, which means an injection under the skin.

    The dose of lerodalcibep is 300 mg. the placebo matches the study medicine in appearance but does not contain the active substance.

    On day 1, the study measures ldl-c (low-density lipoprotein cholesterol, the type of cholesterol often called bad cholesterol), pcsk9 (a blood protein linked to cholesterol levels), and adas (antidrug antibodies, which are antibodies the body may make against a medicine) in participants receiving lerodalcibep.

  2. Step 2

    Monthly dosing period

    After day 1, treatment continues with monthly dosing of lerodalcibep 300 mg or matching placebo.

    The planned treatment period lasts until week 24.

    During this period, you continue the assigned injection schedule as directed by the study plan.

  3. Step 3

    Follow-up study visits during treatment

    Study visits take place at weeks 4, 8, 12, 16, 20, 22, and 24.

    At these visits, the study checks changes in ldl-c and other blood fats, including tc (total cholesterol), hdl-c (high-density lipoprotein cholesterol, often called good cholesterol), non-hdl-c, vldl-c (very-low-density lipoprotein cholesterol), and tg (triglycerides, a type of fat in the blood).

    The study also measures apob and lp(a) at weeks 12, 22, and 24.

    For participants receiving lerodalcibep, the study measures pcsk9 and drug levels at week 12, week 22, and week 24. pcsk9 is a blood protein related to cholesterol control, and drug levels show how much of the medicine is in the blood.

    Some extra blood samples may be taken at weeks 4, 8, 12, 16, and 20 if needed for ada testing or for checking medicine levels.

    For participants receiving placebo, samples are stored.

  4. Step 4

    Safety and growth checks throughout the trial

    Throughout the study, the trial checks safety with blood tests, urine tests, heart tracing tests, physical examinations, and vital signs. vital signs include basic body measurements such as pulse and blood pressure.

    The study watches for side effects, serious side effects, reactions related to treatment, side effects that lead to stopping treatment, cardiovascular events, and death from any cause.

    The safety blood tests include checks of liver function, blood sugar, long-term blood sugar, and muscle enzymes. liver-related tests include alanine transaminase, aspartate transaminase, total bilirubin, and alkaline phosphatase.

    The study also follows growth and development by checking height, weight, bmi (body mass index, a number based on height and weight), tanner staging (a scale that describes physical development during puberty), and hormone levels such as estradiol, testosterone, dehydroepiandrosterone, fsh (follicle-stimulating hormone), lh (luteinizing hormone), acth (adrenocorticotropic hormone), and cortisol.

    The study also checks for isrs (injection-site reactions, which are reactions where the injection is given).

  5. Step 5

    Week 24 assessment and end of planned treatment

    At week 24, the study measures the main outcome: the change in ldl-c compared with placebo.

    The study also measures ldl-c by different calculation methods, including hopkins, friedewald, and preparative ultracentrifugation. these are different ways of estimating or measuring cholesterol in the blood.

    The study checks whether your ldl-c reaches the pediatric target of less than 3.5 mmol/L.

    For participants receiving lerodalcibep, adas and drug levels are measured at week 24. if treatment ends early, the same assessments may be done at early termination.

    The planned treatment phase ends after the week 24 visit.

  6. Step 6

    Study period dates

    The study is planned to begin on 2026-07-27 and end on 2027-12-31.

Who can join the trial?

18 criteria

  • Written informed consent must be signed before any study-specific procedure starts. For children, this also includes assent, which means the child agrees to take part in a way that matches their age and understanding.
  • The patient must be a boy or girl who is 6 to 17 years old at the first screening visit.
  • The patient must weigh more than 18 kg (about 40 lb).
  • The patient must have a BMI (body mass index, a number based on height and weight) of more than 17 and less than 42 kg/m².
  • The patient must have a diagnosis of definite or probable heterozygous familial hypercholesterolemia, based on accepted clinical criteria or genetic testing.
  • At the screening visit or after any required treatment pause, the patient must have an LDL-C level of 130 mg/dL or higher. LDL-C means “bad cholesterol,” the type that can build up in blood vessels.
  • At the same time, the patient must have triglycerides below 400 mg/dL. Triglycerides are a type of fat in the blood.
  • The patient must be on a stable diet and taking oral cholesterol-lowering medicine for at least 6 weeks. Oral medicine means medicine taken by mouth.
  • Allowed cholesterol-lowering medicines include statins, ezetimibe, and bile-acid sequestrants, alone or in combination. Statins are medicines that lower cholesterol, ezetimibe helps reduce cholesterol absorption, and bile-acid sequestrants help remove cholesterol from the body.
  • The patient must not be taking certain excluded oral medicines, including mipomersen, lomitapide, or gemfibrozil.
  • If the patient has been taking a PCSK9 monoclonal antibody medicine, there must be a washout period of at least 8 weeks after the last dose. A washout period means enough time must pass after stopping a medicine so it is no longer affecting the body.
  • If the patient has been taking a PCSK9 siRNA inhibitor, there must be a washout period of 360 days after the last dose.
  • Girls who can become pregnant must use a highly effective birth control method during the study and until 60 days after the last dose, if sexually active.
  • Girls who can become pregnant must have a negative urine pregnancy test during the study and at the last screening visit.
  • Girls who can become pregnant must not donate eggs during the study drug period or for 90 days after the last dose.
  • Boys must either be unable to father a child because of surgery, or agree to use birth control until 90 days after the last dose.
  • Acceptable birth control for boys includes a male or female condom with spermicide, or having a female partner who is sterile or uses an effective birth control method such as a diaphragm, cervical cap, intrauterine device (IUD), birth control pills, a birth control implant, or a birth control injection.
  • Boys must not donate sperm until 90 days after the last dose of the study drug.

Who cannot join the trial?

23 criteria

  • Use of mipomersen or lomitapide within 6 months before screening, or use of gemfibrozil within 6 weeks before the screening visit. These are medicines that lower blood fats.
  • Having had LDL apheresis or plasma apheresis within 2 months before Day 1. Apheresis is a procedure that removes certain parts of the blood.
  • A documented history of homozygous familial hypercholesterolemia, including true homozygous disease, compound heterozygous disease, or combined heterozygous disease. These are more severe inherited forms of high cholesterol.
  • Any past or current medical condition, or an acute or unstable illness, that may make the person unsafe for the study or affect the study results. This includes significant lung, blood, stomach or bowel, hormone, immune system, skin, nerve, or mental health problems, unless the study doctor feels it is still suitable.
  • Females who can become pregnant and are sexually active if they are not using, or do not want to use, a highly effective form of birth control during the study and for 60 days after the last dose. This also includes females who are pregnant, breastfeeding, or have a positive pregnancy test at screening.
  • Moderate to severe kidney problems, defined as an estimated glomerular filtration rate below 30 mL/min/1.73m². This is a measure of how well the kidneys are filtering blood.
  • Active liver disease or liver dysfunction, such as cirrhosis, alcoholic liver disease, hepatitis B, hepatitis C, autoimmune hepatitis, liver failure, liver cancer, or a past liver transplant. Also excluded if AST or ALT is more than 2.5 times the upper normal limit for age. AST and ALT are liver enzymes that can rise when the liver is injured.
  • Uncontrolled thyroid disease, meaning hyperthyroidism or hypothyroidism not well controlled at screening. Hyperthyroidism means the thyroid is too active, and hypothyroidism means it is not active enough. If thyroid medicine has not been stable for at least 3 months, the person may be excluded.
  • Uncontrolled type 1 or type 2 diabetes, defined as fasting glucose above 200 mg/dL and HbA1c above 9%. HbA1c is a blood test that shows average blood sugar over about 3 months.
  • Uncontrolled serious heart rhythm problems, such as sustained ventricular tachycardia, frequent non-sustained ventricular tachycardia, ventricular fibrillation, wide-complex tachycardia, atrial fibrillation with rapid response, or severe second- or third-degree atrioventricular block. These are dangerous abnormal heartbeats.
  • Having had a heart attack, unstable chest pain, coronary angioplasty or stent procedure, coronary artery bypass surgery, implantable cardioverter defibrillator or biventricular pacemaker placement, aortic valve surgery, or stroke within 3 months before enrollment.
  • Planned heart surgery or a planned procedure to improve blood flow to the heart, called revascularization.
  • Severe heart failure, meaning New York Heart Association class III or IV, or a last known left ventricular ejection fraction below 30% within the past 12 months. Ejection fraction is the percentage of blood the heart pumps out with each beat.
  • High blood pressure that is not controlled, defined as treated blood pressure at or above the 95th percentile for age and sex.
  • Participation in another investigational device or drug study, or not enough time since ending another such study, or current use of another experimental treatment. This includes treatments such as PCSK9, ANGPTL3, Lp(a) siRNA, or locked nucleic acid lowering agents within 12 months before screening.
  • Unexplained creatine kinase (CK) level more than 5 times the upper normal limit, unless it is thought to be caused by exercise or unusual activity and one repeat test is allowed. CK is a blood test that can rise with muscle injury.
  • Not being able to attend the required study visits or procedures.
  • A history within 6 months before screening of prescription drug abuse, illegal drug use, or alcohol abuse.
  • Donating or losing more than 500 mL of blood or plasma within 30 days before Day 1.
  • Receiving a blood transfusion within 4 weeks before randomization, or having a known HIV infection. HIV is a virus that affects the immune system.
  • Previous treatment with lerodalcibep or any adnectin product.
  • Any other finding that the study doctor thinks could affect safety or make it hard to take part in the study.
  • Being an employee of the investigator or study site, or being a family member of study staff.
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Investigated drugs

Lerodalcibep is the study medicine being tested in this trial. It is given as an injection under the skin using a pre-filled pen. The trial is looking at whether it can lower “bad” cholesterol (LDL-C) in children and teenagers with inherited high cholesterol who are already following a stable diet and taking regular cholesterol-lowering medicine by mouth.

What is already known about the treatment

  • Lerodalcibep

    Lerodalcibep is given as a solution for injection in a pre-filled pen and is injected under the skin, usually by a healthcare provider or trained caregiver. It is an investigational medicine, meaning it is still being studied in medical trials and is not yet widely established in routine medical practice. It is being developed to lower LDL cholesterol, or “bad” cholesterol, in children and adolescents with heterozygous familial hypercholesterolemia, a condition that causes very high cholesterol from birth. Lerodalcibep is a PCSK9 inhibitor, which means it blocks a protein that normally reduces the liver’s ability to remove LDL cholesterol from the blood, helping the body clear more cholesterol and lower blood levels.

  • Placebo

    The placebo is a matching solution for injection in a pre-filled pen or injector and is given in the same way as the study medicine, by injection under the skin. It has no active drug and is used in clinical trials to compare results fairly against the real treatment. A placebo does not treat heterozygous familial hypercholesterolemia, but it helps researchers see whether lerodalcibep truly lowers LDL cholesterol and is safe. Because it contains no active substance, it has no pharmacological class or mechanism of action in the body.

Investigated diseases

Heterozygous Familial Hypercholesterolemia - A genetic disorder that causes high levels of low-density lipoprotein cholesterol, often beginning in childhood. It happens because the body does not clear LDL cholesterol from the blood normally. Cholesterol levels stay elevated over time and may rise further as the person grows. This condition usually develops gradually and can be present even when a person follows a healthy diet.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IIITrial ID2025-524214-28-00Protocol codeLIB003-008Estimated enrolment150 patientsSponsorLib Therapeutics LLC

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