A Study to Assess the Efficacy, Safety and Pharmacokinetics of Debio 4326 in Pediatric Participants Receiving Gonadotropin-Releasing Hormone Agonist Therapy for Central Precocious Puberty

Open to people ages 5-8

1. Diagnosis of central precocious puberty and currently receiving GnRHa therapy.
2. Onset of development of sex characteristics (i.e., breast development in girls or testicular enlargement in boys according to the Tanner method) before the age of 8 years in girls and 9 years in boys.
3. Initially, only participants aged (a) 5 to 8 years inclusive (i.e., <9 years) are eligible. The Sponsor will determine based on the recommendation of the DMC following the interim analysis whether participants aged 2 to 4 years inclusive (i.e., <5 years) and/or 9 to 10 years inclusive (i.e., <11 years) may be recruited.
4. Participant to receive at least 1 year of GnRHa therapy from study treatment start.
5. Start of initial GnRHa therapy no later than 18 months after onset of the first signs of Central precocious puberty (CPP).
6. Difference between bone age (Greulich and Pyle method) and chronological age of ≥1 year based on historical values at the initiation of the GnRHa therapy.
7. Pubertal-type LH response following a GnRH/GnRHa stimulation test, or random non-stimulated serum (if considered local standard of care), based on historical values prior to the initiation of GnRHa therapy.
8. Clinical evidence of puberty, defined as Tanner Staging ≥2 for breast development for girls and testicular volume ≥4 mL (cc) for boys, prior to the initiation of GnRHa therapy.

1. Gonadotropin-independent (peripheral) precocious puberty: gonadotropin-independent gonadal or adrenal sex steroid secretion.
2. Non-progressing, isolated premature thelarche prior to the initial GnRHa therapy.
3. Presence of an unstable intracranial tumor or an intracranial tumor potentially requiring neurosurgery or cerebral irradiation. Participants with hamartomas not requiring surgery are eligible.
4. Any other condition or chronic illness possibly interfering with growth (e.g., renal failure, diabetes, moderate to severe scoliosis, previously treated intracranial tumor).
5. Other than GnRHa therapy, any ongoing treatment with a potential effect on serum levels of gonadotropins or sex steroids, or possibly interfering with growth.
6. Prior or current therapy with medroxyprogesterone acetate, growth hormone, or Insulin-like growth factor-1 (IGF-1).
7. Diagnosis of short stature, i.e., more than 2.25 standard deviations (SD) below the mean height-for-age.
8. Known history of seizures, epilepsy, and/or central nervous system disorders that may have been associated with seizures or convulsions.
9. Prior (within 2 months of study treatment start) or current use of medications that have been associated with seizures or convulsions.
10. Use of anticoagulants (heparin or coumarin derivatives).