A Study to Look at the Safety of NNC0363-0845 in Healthy People and People With Type 1 Diabetes

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.