A Research Study to Investigate How Well NNC0165-1875 in Combination With Semaglutide Works in People With Obesity

A Research Study to Investigate How Well NNC0165-1875 in Combination With Semaglutide Works in People With Obesity

Investigation of Efficacy and Safety of NNC0165-1875 as add-on to Semaglutide for Weight Management in Subjects With Obesity

The study is looking at a new medicine to help people lose weight. In this study participants will either get semaglutide and NNC0165-1875 or semaglutide and a "dummy" medicine (placebo). Which treatment participants get is decided by chance. Participants will get 2 injections per week, on the same day. Participants will have to take the study medicine by use of a pre-filled pen. A pen is a medical tool with a needle used for injections under the skin. The study doctor or staff will show participants how. The study will last for about 26 weeks. Participants will have 17 visits at the clinic with the study doctor. At 4 of the clinic visits participants cannot eat and drink (water is allowed until 2 hours prior to the visit) for 8 hours before the visit.Women: Women cannot take part if pregnant, breast-feeding or plan to become pregnant during the study period. Women who are able to become pregnant can participate if they agree to use contraception during the study.

Part 1: is a 16-week study were one group of participants will receive two doses of NNC0165-1875 a week, in combination with one injection dose of semaglutide a week. The other group will receive a placebo. Part 2: is a 40-week study were one group of participants will receive one dose of NNC0165 a week, in combination with one injection dose of semaglutide a week. The other group will receive a placebo.

NNC0165-1875 will be co-escalated once-weekly subcutaneously with semaglutide every 2 weeks for the first 4 weeks, and every 4 weeks for the next 8 weeks until final target dose levels are reached.

NNC0165-1875 placebo will be co-escalated subcutaneously once-weekly with semaglutide every 2 weeks for the first 4 weeks, and every 4 weeks for the next 8 weeks until final target dose levels are reached.

NNC0165-1875 will be co-escalated subcutaneously once-weekly with semaglutide every 2 weeks for the first 4 weeks, and every 4 weeks for the next 8 weeks until final target dose levels are reached.

NNC0165-1875 placebo will be co-escalated subcutaneously once-weekly with semaglutide every 2 weeks for the first 4 weeks, and every 4 weeks for the next 8 weeks until final target dose levels are reached.

Inclusion Criteria: Informed consent obtained before any trial-related activities. Trial-related activities are any procedures that are carried out as part of the trial, including activities to determine suitability for the trial. Male or female, age above or equal to 18 years at the time of signing informed consent. BMI 30.0-45.0 kg/m^2 (both inclusive) at the screening visit. Exclusion Criteria: HbA1c greater than or equal to 48 mmol/mol (6.5%) as measured by a central laboratory at screening. History of type 1 or type 2 diabetes mellitus. Treatment with glucose-lowering agent(s) within 90 days before screening.