This research study is testing two types of insulin for adults with type 1 diabetes. Insulin icodec is taken once a week, while insulin glargine is taken every day. Both are combined with another insulin called insulin aspart. The study aims to find out which insulin works better at controlling blood sugar levels. The study lasts about 8.5 months.

• The study involves regular blood sugar checks and insulin injections.
• Participants must have type 1 diabetes for at least one year and use daily insulin.
• Participants cannot join if they are pregnant or have had recent experimental treatments.

This study is important as it may help find a more convenient insulin option for people with type 1 diabetes. If you want to join, you need to be able to follow instructions and measure your blood sugar regularly. Participation involves regular visits and following specific guidelines. You cannot participate if you have allergies to the study treatments or other health issues that may affect safety.