New weekly shot aims to curb obesity in rare genetic disorders

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Key Inclusion Criteria: Parts A and B: * Male and female subjects in good health aged 18-55 years of age at Screening. * Body mass index (BMI) ≥30 kg/m2. * Subjects who are medically healthy with normal or clinically insignificant screening results. * Subjects must use a highly effective form of contraception and follow the study contraception requirements. * Ability to communicate well with the Investigator, understand and comply with the requirements of the trial, and understand English and sign the written informed consent. Part C: * Male and female patients with HO, aged 12-65 years of age at Screening. * Patient has documented evidence of acquired HO defined as: * Diagnosis of craniopharyngioma or other brain lesion affecting the hypothalamic region and has undergone surgery, or chemotherapy, or radiation therapy involving the hypothalamus at least 6 months before Screening, OR * Documented injury to the hypothalamus at least 6 months before Screening for which surgery/radiation is not indicated. * Weight gain associated with the hypothalamic injury either before or following therapy (surgery and/or following chemotherapy or radiotherapy), and a BMI of ≥30 kg/m2 for patients ≥18 years of age or BMI ≥95th percentile for age and sex for patients 12 to \<18 years of age. * Patients must use a highly effective form of contraception and follow the study contraception requirements. * Ability to communicate with the Investigator, understand and comply with the requirements of the trial, and understand and sign the written informed consent and assent (for patients aged \<18 years), and informed consent for a parent or guardian of any patient \<18. Part D: * Confirmed diagnosis of PWS as determined by the Investigator at the time of Screening. * Age ≥12 to 65, inclusive, at the time of signing Informed Consent and/or Assent. * BMI ≥30 kg/m2 for patients ≥18 years of age or BMI ≥95th Percentile for age and sex for patients \<18 years of age based on the US CDC criteria. * Able to meet contraception requirements. Key Exclusion Criteria: Parts A and B * Any clinically significant abnormalities on screening laboratories or physical examination as determined by the Investigator. * Active or history of any significant medical condition such as and including renal, hepatic, pulmonary, gastrointestinal, cardiovascular, genitourinary, endocrine, immunologic, metabolic, neurologic or hematological disease. * Obesity due to genetic, syndromic, or endocrine etiologies. * History of renal transplant, end stage renal disease. * Diagnosis of severe psychiatric disorders. * Current, clinically significant pulmonary, cardiac, metabolic, or oncologic disease considered severe enough to interfere with the trial and/or confound the results. * Cigarette smoking or dependence on caffeine, alcohol or drugs; unable or unwilling to abstain completely from caffeine, alcohol and related substances for 24 hours prior to and after study visits. * History of recent surgery (within 60 days of Screening). * Participation in any clinical trial with an investigational drug/device within 3 months or 5 half-lives, whichever is longer, prior to the first trial dose. * Pregnant and/or breastfeeding or desiring to become pregnant during this trial. Part C * Diagnosis of Prader-Willi syndrome (PWS) or Rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation, neuroendocrine tumor syndrome (ROHHADNET). * Weight loss \>2% in the previous 3 months for patients aged ≥18 years or \>2% reduction in BMI for patients aged 12 to \<18 years and/or anti-obesity medications for the treatment of obesity. * Bariatric surgery or procedure within the last 2 years. * Diagnosis of severe psychiatric disorders; any suicidal ideation, attempt or behavior. * Current, clinically significant pulmonary, cardiac, metabolic, or oncologic disease considered severe enough to interfere with the trial and/or confound the results. * History of renal transplant, end stage renal disease. * Participation in any clinical trial with an investigational drug/device within 3 months or 5 half-lives, whichever is longer, prior to the first trial dose, or previous participation in a trial with setmelanotide. * Pregnant and/or breastfeeding or desiring to become pregnant during this trial. * Obesity attributable to other genetic or syndromic conditions (eg, PPL \[pro-opiomelanocortin (POMC), proprotein convertase subtilisin/kexin type 1 (PCSK1), leptin receptor (LEPR), collectively\], Bardet-Biedl syndrome \[BBS\]) prior to the hypothalamic injury. Part D * Weight loss \>2% in the previous 3 months for patients aged ≥18 years or \>2% reduction in BMI for patients aged 12 to \<18 years or therapies for the treatment of obesity or hyperphagia. * Metabolic and bariatric surgery (MBS) or procedure within last 6 months. * Diagnosis of severe psychiatric disorders; any suicidal ideation, attempt or behavior. * Current, clinically significant pulmonary, cardiac, metabolic, or oncologic disease considered severe enough to interfere with the trial and/or confound the results. * Pregnant and/or breastfeeding or desiring to become pregnant during this trial. Other protocol defined Inclusion/Exclusion criteria may apply.