Research Study to Look at Fast-acting Insulin Aspart With the Insulin Pump System 'iLet™' in Adults With Type 1 Diabetes

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 more than or equal to 18 years and less than or equal to 75 years
at the time of signing informed consent

- Diagnosed with type 1 diabetes mellitus more than or equal to 1 year prior to the day
of screening

- Treated with continuous subcutaneous insulin infusion more than or equal to 1 year
prior to the day of screening

- Have a mean total daily dose of insulin more than or equal to 20 units

- Familiar with continuous glucose monitoring as judged by the investigator

- Has someone over 18 years of age who (i) lives with them, (ii) has access to where
they sleep, (iii) is willing to be in the house when the subject is sleeping, and (iv)
is willing to receive calls from the study staff and check the welfare of the study
subject

- Body mass index (BMI) less than or equal to 35.0 kg/m^2 at screening

- Glycated haemoglobin (HbA1c) more than or equal to 6.5% (47 mmol/mol) and less than or
equal to 9% (75 mmol/mol) at screening

- Able and willing to remain in a designated place for the specified duration of the
'in-patient' periods

- Lives within a 120-minute drive away from the central monitoring location (site)

Exclusion Criteria:

- Known or suspected hypersensitivity to trial product(s) or related products

- Previous participation in this trial. Participation is defined as signed informed
consent

- Female who is pregnant, breast-feeding or intends to become pregnant or is of
child-bearing potential and not using an adequate contraceptive method (adequate
contraceptive measures as required by local regulation or practice)

- Participation in any clinical trial of an approved or non-approved investigational
medicinal product within 30 days before screening

- Any disorder, except for conditions associated with diabetes mellitus, which in the
investigator's opinion might jeopardise subject's safety or compliance with the
protocol

- Anticipated initiation or change in concomitant medications known to affect weight or
glucose metabolism during the trial

- Impaired liver function, defined as Alanine Aminotransferase (ALT) more than or equal
to 2.5 times or Bilirubin more than 1.5 times upper normal limit at screening

- Renal impairment measured as estimated Glomerular Filtration Rate (eGFR) value of eGFR
less than 60 ml/min/1.73 m^2

- Any episodes of diabetic ketoacidosis within the past 90 days prior to the day of
screening

- Known hypoglycaemic unawareness as indicated by the Investigator according to Clarke's
questionnaire question 8

- Recurrent severe hypoglycaemic episodes within the last year as judged by the
Investigator

- Any of the following: myocardial infarction, stroke, hospitalization for unstable
angina pectoris or transient ischaemic attack within the past 180 days prior to the
day of screening

- Subjects presently classified as being in New York Heart Association (NYHA) Class IV

- Planned coronary, carotid or peripheral artery revascularisation known on the day of
screening

- Inadequately treated blood pressure defined as Grade 3 hypertension or higher
(systolic more than or equal to 180 mmHg or diastolic more than or equal to 110 mmHg)
at screening

- Unwilling or unable to avoid acetaminophen throughout the trial