This is a sub-study of Study RM-493-040 (NCT05774756).

The goal of this sub-study is to learn how well Setmelanotide works to improve weight reduction, hunger, and quality of life in patients 4 years of age and older with congenital Hypothalamic Obesity (cHO). To determine how well setmelanotide works and how safe it is, patients with cHO will take a daily injection of either setmelanotide or placebo and complete trial assessments for up to 26 weeks on a therapeutic regimen.

Key Inclusion Criteria:

1. Diagnosis of multiple pituitary hormone deficiency (MPHD), or septo-optic dysplasia (SOD), or optic nerve hypoplasia (ONH), or Childhood-onset combined pituitary hormone deficiency (CPHD), or Pituitary Stalk Interruption Syndrome (PSIS) with at least one pituitary deficiency AND a body mass index (BMI) of ≥30 kg/m2 for patients ≥18 years of age, or BMI ≥95th percentile for age and sex for patients 4 to <18 years
2. Age 4 years and older
3. Weight gain associated with the hypothalamic injury and a BMI of ≥30 kg/m2 for patients ≥18 years of age or BMI ≥95th percentile for age and sex for patients 4 to <18 years of age
4. Agree to use a highly effective form of contraception throughout the study and for 90 days after the study

Key Exclusion Criteria:

1. Diagnosis of Prader-Willi syndrome (PWS) or Rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation, neuroendocrine tumor syndrome (ROHHADNET)
2. Weight loss >2% in the previous 3 months for patients aged ≥18 years or >2% reduction in BMI for patients aged 4 to <18 years
3. Bariatric surgery or procedure within last 2 years
4. Diagnosis of severe psychiatric disorders; any suicidal ideation, attempt or behavior
5. Current, clinically significant pulmonary, cardiac, metabolic, or oncologic disease
6. Significant dermatologic findings relating to melanoma or pre-melanoma skin lesions (excluding non-invasive basal or squamous cell lesion)
7. History or close family history of skin cancer or melanoma
8. Participation in any clinical trial with an investigational drug/device within 3 months prior to the first trial dose
9. Previously enrolled in a clinical trial involving setmelanotide or any previous exposure to setmelanotide
10. Inability to comply with once daily (QD) injection regimen
11. If female, pregnant and/or breastfeeding.
12. If receiving hormone replacement therapy, dose has remained stable for at least 2 months before Screening

Other protocol defined Inclusion/Exclusion criteria may apply.