This was a long-term extension trial to study the safety and tolerability of continued setmelanotide treatment in participants who had completed a previous clinical trial on treatment with setmelanotide for obesity associated with genetic defects upstream of the Melanocortin-4 (MC4) receptor in the leptin-melanocortin pathway.

The primary objectives of this extension trial were to explore the long-term safety and tolerability of setmelanotide for up to 7 years or until drug was otherwise available through authorized use. Participants entered this protocol immediately upon completion of their index protocol such that dosing of setmelanotide continued without gaps in therapy.

Key Inclusion Criteria:

1. Participants aged 2 or older (or aged >2 years as per local regulations) who had completed participation in a previous setmelanotide trial and demonstrated adequate safety and meaningful clinical benefit (efficacy)
2. Participant and/or parent or guardian was able to communicate with the investigator, understand and sign the written informed consent/assent, and comply with the trial requirements
3. Agree to use a highly effective form of contraception throughout the trial

Key Exclusion Criteria:

1. Pregnant and/or breastfeeding women
2. Significant dermatologic findings relating to melanoma or pre-melanoma skin lesions (excluding non-invasive basal or squamous cell lesion)
3. Current, clinically significant disease
4. Documented diagnosis of schizophrenia, bipolar disorder, personality disorder, major depressive disorder, or other psychiatric disorder(s)
5. Suicidal ideation, attempt or behavior
6. History of significant liver disease
7. Moderate to severe renal dysfunction as defined by a glomerular filtration rate (GFR)<30 milliliters per minute (mL/min).
8. History or close family history of melanoma or participant history of oculocutaneous albinism

Other protocol defined Inclusion/Exclusion criteria may apply.