This study is investigating the safety and tolerability of the new investigational product NNC0363-0845, its concentrations in the blood and its effect on the blood sugar for the treatment of diabetes. The study consists of 3 parts. The first part of the study is conducted in healthy people, while the second part involves people with type 1 diabetes (T1D). Part 3 of this trial involves also people with T1D.

The study will test how NNC0363-0845 is tolerated by the body, how it is taken up in the blood, how long it stays there and how much the blood sugar is lowered. Healthy volunteers will either get NNC0363-0845 or placebo - which treatment is decided by chance. Participants with type 1 diabetes will either get NNC0363-0845 or insulin degludec (Tresiba®), also decided by chance. It is the first time that NNC0363-0845 is tested in humans. Participants will get one dose of NNC0363-0845 or placebo or insulin degludec injected into their left thigh. Participation in the study will last for up to 6 weeks. There will be one Informed Consent visit and 6 clinic visits with the study doctor. Healthy volunteers will have blood sampling to measure blood sugar and the concentration of the investigational product in the blood. Participants with type 1 diabetes will have a clamp experiment where the blood sugar is measured and controlled for up to 42 hours.

For Part 3, the total duration of the trial for each individual is expected to be approximately 3-9 weeks.

Participants cannot be in the study if the study doctor thinks that there are risks for their health. Women can only take part in the study if they are of non-child bearing potential.

Inclusion Criteria:

Part 1 (healthy subjects):

• Male subject or female subject of non-child bearing potential. Non-child bearing potential being defined as surgically sterilised (i.e. documented hysterectomy, bilateral salpingectomy or bilateral oophorectomy) or being postmenopausal (defined as no menses for 12 months without an alternative medical cause) prior to the day of screening.
• Aged 18-55 years (both inclusive) at the time of signing informed consent.
• Considered to be generally healthy 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.

Part 2 and 3 (subjects with type 1 diabetes mellitus):

• Male subject or female subject of non-child bearing potential. Non-child bearing potential being defined as surgically sterilised (i.e. documented hysterectomy, bilateral salpingectomy or bilateral oophorectomy) or being postmenopausal (defined as no menses for 12 months without an alternative medical cause) prior to the day of screening.
• Aged 18-55 years (both inclusive) at the time of signing informed consent.
• Diagnosed with type 1 diabetes mellitus 1 year or more prior to the day of screening.
• Glycated haemoglobin (HbA1c) equal to or below 8.5%.
• Fasting C-peptide below 0.30 nmol/L.
• Considered to be generally healthy (except for type 1 diabetes mellitus and sequelae of diabetes which may only be of mild severity) 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

Exclusion Criteria:

Part 1 (healthy subjects) Part 2 and Part 3 (subjects with type 1 diabetes mellitus):

- Male of reproductive age who or whose partner(s) is not using an adequate contraceptive method (adequate contraceptive measures as required by local regulation or practice). Adequate contraceptive measures include that the male subject uses a condom during intercourse and that the partner practices adequate contraception (risk of pregnancy must be lower than 1%). In addition, subjects must not donate sperm for the duration of the trial.

According to the Novo Nordisk disclosure commitment on novonordisk-trials.com

Sponsor staff involved in the clinical trial is masked according to company standard procedures.