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Study on the Safety and Effectiveness of Crinecerfont for Adults with Classic Congenital Adrenal Hyperplasia

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What is this trial about?

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

This clinical trial is focused on studying a condition known as Classic Congenital Adrenal Hyperplasia (CAH). This is a genetic disorder that affects the adrenal glands, which are responsible for producing important hormones. The study is testing a new treatment called Crinecerfont, also known by its code name NBI-74788. This medication is being compared to a placebo to see how effective it is in managing the symptoms of CAH.

The purpose of the study is to evaluate how well Crinecerfont works in reducing the need for other medications called glucocorticoids, which are often used to treat CAH. The study will also look at how Crinecerfont affects hormone levels in the body and its overall safety. Participants will take the medication in capsule form, twice a day, for a period of time. The study will start with a four-week treatment period, followed by additional assessments to monitor changes in hormone levels and any side effects.

Throughout the study, researchers will collect information on how Crinecerfont affects the body, including its impact on hormone levels and any potential side effects. The study aims to provide a better understanding of how this new treatment can help manage Classic Congenital Adrenal Hyperplasia and improve the quality of life for those affected by this 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 treatment phase

    The study begins with a randomized, double-blind, placebo-controlled phase. Participants receive either Crinecerfont (NBI-74788) or a placebo.

    The medication is administered in the form of oral capsules. The dosage for Crinecerfont is 100 mg taken twice daily.

    This phase aims to evaluate the reduction in daily glucocorticoid dosage while maintaining control over adrenal androgens.

  2. Step 2

    Evaluation period

    After an initial 4-week treatment period, the study evaluates the reduction in adrenal steroid levels.

    The effect of Crinecerfont on clinical endpoints related to high glucocorticoid dosing is assessed.

    Plasma concentrations of Crinecerfont and its metabolites are measured to ensure safety and tolerability.

  3. Step 3

    Adjustment phase

    Participants who have not reduced their glucocorticoid dose by Month 12 may be evaluated for an alternate dosing regimen of Crinecerfont.

    The goal is to achieve a reduction in glucocorticoid daily dose to physiologic levels by Week 24.

  4. Step 4

    Open-label treatment

    Following the double-blind phase, participants may enter an open-label treatment phase where all receive Crinecerfont.

    This phase continues to monitor safety, efficacy, and any changes in health markers such as weight and fat mass.

  5. Step 5

    Final assessment

    The study concludes with a final assessment of the primary and secondary endpoints.

    The primary endpoint is the percent change from baseline in glucocorticoid daily dose at Week 24.

    Secondary endpoints include changes in serum androstenedione, HOMA-IR, weight, and fat mass.

Who can join the trial?

6 criteria

  • Subjects must provide written informed consent. This means you agree to participate in the study and understand what it involves.
  • Be a female or male at least 18 years of age.
  • Have a medically confirmed diagnosis of classic 21-hydroxylase deficiency. This is a specific type of condition related to the adrenal glands.
  • Be on a stable, supraphysiologic glucocorticoid dose regimen that has been stable for at least 1 month prior to screening. This means you are taking a higher than normal dose of a specific medication for at least a month before the study starts.
  • If treated with fludrocortisone, the dose should be stable for at least 1 month prior to screening. During screening, your plasma renin activity (PRA) should not be greater than the upper limit of normal (ULN) on your usual salt intake. If PRA is higher than normal, your blood pressure should be over 100 mmHg, without a drop in blood pressure when standing up, and your blood sodium and potassium levels should be normal.
  • Female subjects of childbearing potential with fertile male partners must agree to use contraception consistently from screening until the final study visit or 30 days after the last dose of study drug, whichever is longer. This means using birth control to prevent pregnancy during the study and for a short time after.

Who cannot join the trial?

7 criteria

  • Patients who are not diagnosed with Classic Congenital Adrenal Hyperplasia (CAH) cannot participate. This is a condition where the body has trouble making certain hormones.
  • Patients who are unable to reduce their daily glucocorticoid dosage while maintaining control of adrenal androgens are excluded. Glucocorticoids are a type of steroid medication, and adrenal androgens are hormones produced by the adrenal glands.
  • Patients who cannot reduce adrenal steroid levels after an initial 4-week treatment period are not eligible. Adrenal steroids are hormones produced by the adrenal glands.
  • Patients who have not reduced their glucocorticoid dose by Month 12 are excluded.
  • Patients who are not within the specified age range for the study cannot participate. The study includes specific age groups.
  • Both male and female patients are eligible, but those who do not meet gender criteria are excluded.
  • Patients who are part of a vulnerable population, which may include groups like children or those with certain disabilities, are not eligible.
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Investigated drugs

Crinecerfont (NBI-74788) is a medication being studied for its potential to help adults with Classic Congenital Adrenal Hyperplasia. This condition affects the adrenal glands, which produce important hormones. The trial is testing if Crinecerfont can reduce the need for other medications called glucocorticoids, which are often used to manage this condition. The study also looks at how well Crinecerfont can control hormone levels and its overall safety for patients.

What is already known about the treatment

Crinecerfont – Crinecerfont is administered orally in the form of tablets, typically taken twice daily. It is currently being studied in clinical trials for its potential use in treating Classic Congenital Adrenal Hyperplasia (CAH). The main therapeutic indication for Crinecerfont is to help reduce the need for glucocorticoid medication while maintaining control over adrenal androgens. At the molecular level, Crinecerfont works by modulating the activity of certain receptors involved in adrenal steroid production, helping to balance hormone levels. It is classified pharmacologically as a corticotropin-releasing factor receptor antagonist.

Investigated diseases

Classic Congenital Adrenal Hyperplasia (CAH) – This is a genetic disorder affecting the adrenal glands, which are responsible for producing certain hormones. In CAH, the body lacks an enzyme needed to make cortisol, a hormone crucial for stress response, blood pressure, and other vital functions. As a result, the adrenal glands produce excess androgens, which are male sex hormones. This hormonal imbalance can lead to early signs of puberty in children and affect growth and development. Symptoms may include ambiguous genitalia in newborns, rapid growth during childhood, and early or excessive hair growth. The condition is present from birth and requires lifelong management.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-509171-16-00Protocol codeNBI-74788-CAH3003Estimated enrolment182 patientsSponsorNeurocrine Biosciences Inc.

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