The ultimate T1D treatment tool is a closed-loop glucose control system, i.e. a fully automated system for intensive insulin treatment. Such system will ease the burden of constant treatment decision-making and at the same time it has the potential to safely intensify insulin therapy such that more patients can reach treatment goals. Currently, no off-the-shelf closed-loop system exists but research efforts in this field have been intensified and resulted in great progress in recent years. Most closed-loop systems consist of an insulin pump, a CGM, and a control algorithm residing on a mobile computer that continuously (every 5-15 min) computes the optimal insulin dosage from the CGM values. For daytime blood glucose control, however, we believe that the system needs to be further advanced. Consequently, we have extended our single-hormone closed-loop system such that it now includes a second pump for glucagon delivery and correspondingly we have further developed our control algorithm to compute both insulin and glucagon dosages.

We hypothesize that we have developed a safe and effective dual-hormone closed-loop system for patients with type 1 diabetes and that this system is superior to single-hormone closed-loop therapy. The aims of this two-phase project are to 1) demonstrate proof-of-concept and 2) to compare dual-hormone with single-hormone closed-loop glucose control.

Inclusion Criteria:

• T1D ≥ 2 years
• Insulin pump therapy with rapid-acting analog insulin ≥ 1 year
• HbA1c ≤ 8.5% (69 mmol/mol)
• Ability and willingness to comply with all protocol procedures

Exclusion Criteria:

• Pregnancy or nursing
• Plan to become pregnant or sexually active and not using adequate contraceptive methods (sterilization, intrauterine device, contraceptive pill, patch or injection)
• Hypoglycemia unawareness (self-reported lack of hypoglycemia symptoms when blood glucose is < 3.0 mmol/l)
• Use of anti-diabetic medicine (other than insulin), corticosteroids or other drugs affecting glucose metabolism during or within 30 days prior to study participation
• History of coronary artery disease or congestive heart failure
• Abnormal ECG suggestive of coronary artery disease and increased risk of malignant arrhythmia
• Allergy to glucagon or lactose
• Pheochromocytoma
• Other concomitant medical or psychological condition that according to the investigator's assessment makes the patient unsuitable for study participation