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Study of the effects of Ibutamoren Mesilate in prepubertal children with growth hormone deficiency

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What is this trial about?

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

This study focuses on children who have not yet reached puberty and are experiencing Growth Hormone Deficiency. This condition occurs when the body does not produce enough of the natural hormone responsible for stimulating growth and development. The purpose of the study is to evaluate the effect of a daily oral medication called LUM 201 on growth rates over a period of 12 months.

Participants in the study will be assigned to receive either LUM 201 in the form of a capsule or a placebo. During the 12-month period, the study will monitor changes in growth and levels of specific substances in the blood, such as IGF-1, which is a hormone that helps the body grow, and IGFBP-3, a protein that carries these growth hormones through the bloodstream. Height and growth patterns will also be tracked throughout the course of the study.

The research process

The trial runs in 2 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Daily medication administration

    An oral capsule is taken once per day for a duration of 12 months.

    The medication provided is either ibutamoren mesylate at a dose of 1.60 mg/kg (milligrams per kilogram of body weight) or a placebo, which is a capsule containing no active medicine.

  2. Step 2

    Monitoring of growth and health

    The growth rate and height are tracked throughout the 12-month period to evaluate the effects of the treatment.

    Changes in igf-1 (a hormone that helps growth), igfbp-3 (a protein related to growth hormones), and height-for-age (height relative to the average for a specific age) are monitored.

Who can join the trial?

14 criteria

  • A parent or legal guardian must provide written informed consent, which is a signed document giving permission to join the study, and the child must also agree to participate if they are old enough to understand.
  • The child must have normal thyroid function, meaning the thyroid gland (which controls energy levels) is working correctly based on blood tests for TSH and free T4.
  • If the child has primary hypothyroidism (a condition where the thyroid gland does not produce enough hormones), they must have had euthyroid status, meaning their hormone levels have been stable and normal, for at least 3 months.
  • The level of IGF-1 (a hormone that helps the body grow) must be at or below a specific standard deviation score (SDS) of -1.0 compared to other children of the same age and sex.
  • During a PEM test (a medical test used to check how much growth hormone the body can produce), the child must show an IGF-1 concentration greater than 30.0 ng/mL and a peak GH response (the highest amount of growth hormone measured) of at least 5.0 ng/mL.
  • The child must be naïve to treatment, meaning they have not previously taken medication for this specific condition.
  • The child must be prepubertal, which means they have not yet entered puberty; this is checked by looking at breast development in girls and testicular volume (the size of the testicles) in boys.
  • The child must have had a low GH response (growth hormone response) of less than 10 ng/mL during two previous GH stimulation tests conducted within the last year.
  • The child must have impaired height, defined as being at least 2.0 standard deviations (SDs) shorter than the average height for their age and sex according to WHO Growth Charts.
  • The child must have a cortisol level (a hormone related to stress and metabolism) of at least 7.0 µg/dL in the morning or at a random time, or they must pass a stimulated cortisol test to prove their body produces enough of this hormone.
  • The child must be at least 3.0 years old and no older than 10.0 years for girls or 11.0 years for boys.
  • The child must have a documented height velocity (the speed at which a child grows) that is below the 25th percentile for their age and sex, based on at least 6 months of growth measurements.
  • The child must have had a BA assessment (a bone age assessment, which uses X-rays to see if bones are growing at the expected rate) showing that their bone age is delayed by at least 12 months compared to their actual age.
  • Girls must have genetic testing to rule out Turner syndrome (a genetic condition affecting growth) and must have a negative result from the SHOX genetic test.

Who cannot join the trial?

29 criteria

  • Any medical or genetic condition (a health problem passed down through families) that could cause short stature or prevent the medicine from working, such as diabetes, idiopathic short stature (shortness of height without a known cause), SHOX-deficiency, chondrodysplasia (a bone growth disorder), or other specific syndromes.
  • Suspected intracranial hypertension, which is a condition involving high pressure inside the skull, confirmed through an eye exam or other tests.
  • High levels of certain liver enzymes, specifically alanine transaminase (ALT), aspartate transaminase (AST), or total bilirubin, which are markers used to check liver health.
  • Having multiple pituitary hormone deficiencies, meaning the pituitary gland (a small gland at the base of the brain) is not producing more than one type of hormone.
  • Previous use of growth factors, such as GH (growth hormone), IGF-1 (insulin-like growth factor 1), or GH secretagogues (medicines that trigger hormone production), unless used briefly for a medical test.
  • Suspicion that the pituitary gland is not working, shown by low results on a GH stimulation test (a test to see how much growth hormone the body can make) within the last 12 months.
  • Malnutrition, which is a lack of proper nutrition required for health, as determined by a doctor.
  • A body weight that is 14.0 kg or less.
  • A BMI (Body Mass Index, a measure of body fat based on height and weight) that is significantly outside the normal range for a child's age and sex.
  • A birth weight that was very low compared to the age of pregnancy (below the 3rd percentile).
  • Taking part in any other study testing new drugs within the 6 months before this study begins.
  • An arm span to height ratio that is much lower than average, which helps rule out bone growth issues like subclinical hypochondroplasia.
  • A known or suspected allergy to the study medicine, a placebo (an inactive substance used for comparison), or any of the excipients (inactive ingredients used to make the medicine).
  • Being unwilling to participate in randomization, which is the process where a child is assigned to a specific group by chance.
  • Taking medications that affect cytochrome P450 (CYP) 3A/4, which are specific proteins in the liver that help break down medicines.
  • Taking medications that are mainly processed by specific liver proteins known as CYP3A/4, 2C8, 2C9, or 2C19.
  • Taking medications that interfere with P-glycoprotein (P-gp) or multidrug and toxin extrusion protein 1, which are proteins that move substances in and out of cells.
  • A history of radiation therapy to the spine, head, or the whole body.
  • A history or presence of malignant disease (cancer) or any evidence of a tumor growing.
  • Psychosocial short stature, which is when growth is affected by emotional or environmental factors.
  • Closed epiphyses, meaning the growth plates at the ends of the bones have finished growing and fused together.
  • A diagnosis of Attention deficit hyperactivity disorder (ADHD), regardless of whether it is being treated.
  • Any medical or genetic condition that a doctor believes would make using the study medicine too risky.
  • Using any medication that could cause short stature or stop the growth medicine from working.
  • Current inflammatory diseases that require systemic corticosteroid treatment (steroid medicine that travels through the whole body) for more than 2 weeks in the last 3 months, or specific high doses of inhaled glucocorticoids (steroid inhalers) within the last year.
  • Using hormone replacement therapy for any condition other than a stable thyroid problem.
  • Any significant abnormalities found on an ECG (an electrical test of the heart) during the screening visit.
  • Any situation that would likely prevent the child from successfully completing the study.
  • Suspected past or present intracranial tumor (a growth inside the skull) confirmed by brain imaging.
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Investigated drugs

Ibutamoren Mesylate is an oral medication being studied to see if it can help increase growth rates in children who do not produce enough growth hormone.

What is already known about the treatment

  • Ibutamoren Mesylate

    This medication is taken by mouth in the form of a capsule. It is currently being studied in advanced clinical trials to treat growth hormone deficiency in children. As a growth hormone secretagogue, it works by stimulating the brain to release more of its own natural growth hormone into the bloodstream.

  • Placebo

    This is an inactive substance administered orally in capsule form once per day. It contains no active medicinal ingredients and is used in clinical studies to provide a comparison against the testing medication. It serves to help researchers determine if the effects seen in participants are truly caused by the drug being studied.

Investigated diseases

Growth Hormone Deficiency - This condition occurs when the pituitary gland does not produce enough growth hormone. This hormone is essential for helping children grow to their expected height. As the condition progresses, an individual may experience a significantly slower rate of physical growth compared to others their age. This can lead to a shorter stature during childhood and adolescence. The lack of sufficient hormone levels affects the body's natural development processes.
Trial detailsLast updated 7 Oct 2026
Age0-17PhasePhase IIITrial ID2025-523820-26-00Protocol codeLUM-201-10Estimated enrolment159 patientsSponsorLumos Pharma Inc.

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