Overview

This study tests how well different doses of the medicine NNC0662-0419 help people living with overweight or obesity. The purpose of the study is to find out if NNC0662-0419 is safe and effective for treating people living with overweight or obesity. There are 2 study treatments in this study, participants will get either NNC0662-0419, the treatment being tested or placebo, a treatment that has no active medicine in it. NNC0662-0419 is a new medicine which cannot be pre-scribed by doctors but has previously been tested in humans.

Eligibility

Inclusion criteria

• Male or female (sex at birth).
• Age at the time of signing the informed consent:
  • For Part A:18-55 years (both inclusive)
  • For Part B and Part C: 18-65 years (both inclusive)
• Body Mass Index (BMI) at screening (overweight should be due to excess adipose tissue, as judged by the investigator):
  • For Part A: 27.0-39.9 kilogram per square meter(kg/m\^2) (both inclusive)
  • For Part B and Part C:
    1. Greater than or equal to (≥) 27.0 kg/m\^2 with the presence of at least one weight-related comorbidity (e.g. hypertension, dyslipidaemia, obstructive sleep apnoea or CV disease), or
    2. Greater than or equal to (≥) 30.0 kg/m\^2
• Considered eligible based on the medical history, physical examination, and the results of vital signs, electrocardiogram and clinical laboratory tests performed during the screening visit, as-judged by the investigator.
• Willingness to obtain a high weight loss (greater than \[\>\] 25 percent \[%\]).

Exclusion criteria:

• Known or suspected hypersensitivity to study intervention(s) or related products.
• Treatment with any compound containing Glucagon-Like Peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) or amylin receptor agonism within 90 days before screening.
• Any condition, unwillingness or inability, which in the investigator's opinion might jeopardise the participant's safety or compliance with the protocol.
• 2nd or 3rd degree atrioventricular-block, prolongation of the QRS complex over 120 millisecond (ms), or of the corrected QT interval by Fridericia (QTcF) calculation over 450 ms (females) or 430 ms (males), or any other clinically significant abnormal ECG results as judged by the investigator, at screening.
• Glycosylated haemoglobin (HbA1c) greater than or equal to (≥) 6.5% (48 millimoles per mole \[mmol/mol\]) at screening.
• History of type 1 or type 2 diabetes mellitus.
• Calcitonin greater than or equal to (≥) 50 nanogram per litre (ng/L) at screening.