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A Study Testing Atumelnant Compared to Placebo in Adults with Classic Congenital Adrenal Hyperplasia to Reduce Steroid Dose While Controlling Hormones

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 is looking at a condition called classic congenital adrenal hyperplasia, which is a disorder where the adrenal glands do not produce certain hormones properly. People with this condition need to take replacement hormones called glucocorticoids to help their body function normally. The treatment being tested in this study is called atumelnant, which comes in tablet form and is taken by mouth. The study will compare atumelnant with placebo to see which works better. Atumelnant is also known by its code name CRN04894.

The purpose of this study is to find out if atumelnant can help reduce the daily dose of glucocorticoid medication that people with this condition need to take, while still keeping the levels of certain hormones called adrenal androgens under control. The study will measure hormone levels in the blood, including a hormone called androstenedione and another one called 17-hydroxyprogesterone, to see if the treatment is working. The study will also look at how safe atumelnant is and what side effects it might cause.

The study will last for 32 weeks of treatment, and participants will be randomly assigned to receive either atumelnant tablets or placebo tablets. During the study, doctors will regularly check hormone levels in the blood and may adjust the dose of glucocorticoid medication based on these results. Participants will need to continue taking their regular glucocorticoid replacement medication throughout the study, and if they take a medication called fludrocortisone for mineral balance, they will continue that as well. The study will involve multiple visits to the study site for blood tests and health checks to monitor how well the treatment is working and to watch for any problems.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Treatment Period

    This period will last for 32 weeks.

    You will receive either atumelnant or a placebo (an inactive substance that looks like the study medication but contains no active ingredient). The assignment will be random, and neither you nor your doctor will know which one you are receiving.

    Atumelnant is available in two strengths: 80 mg tablets and 120 mg tablets. Both are taken by mouth.

    During this period, your daily dose of glucocorticoid (a type of steroid hormone replacement medication, such as hydrocortisone, prednisolone, prednisone, methylprednisolone, or dexamethasone) may be adjusted. The goal is to reduce the amount of glucocorticoid you take while keeping your hormone levels balanced.

    You will continue taking your regular glucocorticoid medication as prescribed by your doctor throughout the study.

    If you are taking fludrocortisone (a medication to help balance salt and water in your body), you will continue at your current stable dose.

    If you are on estrogen therapy, you will continue at your current stable dose.

  2. Step 2

    Study Visits and Monitoring

    You will have regular visits to the study site throughout the 32-week treatment period.

    At Week 2, your blood will be tested to measure androstenedione (A4), a hormone that is often elevated in people with congenital adrenal hyperplasia.

    At Week 32, your blood will be tested again to measure androstenedione (A4) and 17-hydroxyprogesterone (17-OHP), another hormone related to your condition.

    Blood samples will be taken in the morning, both before and after you take your glucocorticoid dose, to see how well the treatment is working.

    Your doctor will monitor your hormone levels and may adjust your glucocorticoid dose based on the results.

    Your blood sodium and potassium levels will be checked to ensure they remain in the normal range.

  3. Step 3

    Contraception Requirements During the Study

    If you are a female who can become pregnant and engage in sexual intercourse with men, you must use a highly effective method of birth control from the start of the study until at least 2 weeks after your last dose of study medication.

    If you are a male who engages in sexual intercourse with women who can become pregnant, you must use a condom from the start of the study until at least 2 weeks after your last dose of study medication, unless you have had a vasectomy with confirmed absence of sperm.

    If you are a male participant, you must agree not to donate sperm during the study and until at least 2 weeks after your last dose of study medication.

  4. Step 4

    Follow-up Period

    After completing the 32-week treatment period, you will be monitored for at least 2 weeks after your last dose of study medication.

    This follow-up period ensures that any effects of the medication are properly observed after treatment ends.

Who can join the trial?

10 criteria

  • You must be 18 years of age or older but younger than 75 years at the time of signing the consent form
  • You must be willing and able to follow the study procedures and take the study treatment as directed
  • You must have classic congenital adrenal hyperplasia (a condition where the adrenal glands do not make certain hormones properly) caused by 21-hydroxylase deficiency (a specific enzyme problem), confirmed by your doctor
  • Your morning blood test for androstenedione (a hormone called A4) must show one of these patterns: levels above the normal upper limit while taking low doses of glucocorticoid (a steroid hormone medication) equivalent to less than 11 milligrams per square meter of body surface per day in hydrocortisone units, OR normal A4 levels in the upper half of the normal range while taking 15 milligrams per square meter of body surface per day or more of glucocorticoid in hydrocortisone units, OR A4 levels above the normal upper limit while taking 11 milligrams per square meter of body surface per day or more of glucocorticoid in hydrocortisone units
  • You must be on a stable dose of glucocorticoid replacement therapy (such as hydrocortisone, prednisolone, prednisone, methylprednisolone, or dexamethasone) with no dose changes greater than a specific amount within 2 months before joining the study
  • If you are taking fludrocortisone (a medication to replace another hormone called mineralocorticoid), your dose must have been stable for at least 2 months before joining the study, you must not have orthostatic hypotension (dizziness when standing up due to low blood pressure), and your blood sodium and potassium levels must be normal
  • If you are taking estrogen therapy (female hormone treatment) by any method, your dose must have been stable for at least 3 months before joining the study
  • If you are a female who has sexual intercourse with men, you must either be unable to become pregnant because of surgery (removal of the uterus, fallopian tubes, or ovaries), OR agree to use highly effective birth control methods from the start of the study until at least 2 weeks after the last dose of study medication
  • If you are a male who has sexual intercourse with women, you must agree to use a condom when sexually active with a female partner who can become pregnant from the start of the study until at least 2 weeks after the last dose of study medication, OR have had a vasectomy with confirmed absence of sperm, OR agree to remain abstinent throughout the study and until at least 2 weeks after the last dose
  • If you are male, you must agree not to donate sperm during the study and until at least 2 weeks after the last dose of study medication

Who cannot join the trial?

4 criteria

  • The study information provided does not contain specific exclusion criteria details
  • Exclusion criteria are the reasons why a person cannot join this clinical trial, which is a research study that tests new treatments
  • Without detailed exclusion criteria information, it is not possible to list the specific conditions or situations that would prevent participation in this study
  • Typical exclusion criteria in clinical trials may include things like other medical conditions, certain medications being taken, pregnancy status, or previous treatments, but these specific details are not available in the provided study information
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Investigated drugs

Atumelnant is an investigational medication being studied in this trial. It is being tested to see if it can help reduce the amount of daily glucocorticoid (a type of steroid medication) that patients need to take while still keeping their hormone levels under control. This medicine is being compared to a placebo to determine if it is safe and effective for treating adults with classic congenital adrenal hyperplasia, a condition where the adrenal glands do not produce certain hormones properly.

What is already known about the treatment

Atumelnant – Atumelnant is an investigational medication currently being studied in clinical trials for the treatment of classic congenital adrenal hyperplasia, a genetic condition where the adrenal glands cannot produce certain hormones properly. The drug is being tested to see if it can help reduce the amount of glucocorticoid (steroid hormone) medication that patients need to take daily while still keeping their hormone levels under control. Atumelnant works by blocking specific receptors in the body that are involved in the hormonal imbalance seen in this condition, potentially offering a new treatment approach that could minimize the side effects associated with long-term steroid use. The medication is currently in the research phase and is being evaluated for its safety and effectiveness in adult patients through controlled clinical studies.

Investigated diseases

Classic Congenital Adrenal Hyperplasia – Classic Congenital Adrenal Hyperplasia is a genetic disorder that affects the adrenal glands, which are small organs located above the kidneys. The condition occurs when the body cannot produce enough of certain hormones, particularly cortisol, due to enzyme deficiencies. As a result, the adrenal glands become enlarged and produce excessive amounts of male hormones called androgens. This hormonal imbalance begins before birth and continues throughout life if not managed. People with this condition may experience abnormal development of sexual characteristics, growth problems, and difficulties in maintaining proper salt and water balance in the body. The disorder is inherited in an autosomal recessive pattern, meaning both parents must carry the genetic mutation for a child to develop the condition.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-519579-24-00Protocol codeCRN04894-12Estimated enrolment140 patientsSponsorCrinetics Pharmaceuticals Inc.

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