Closed-loop Control of Glucose Levels After Meal Intake in Adults With Type 1 Diabetes

An Open-label, Randomized, Three-way, Cross-over Study to Compare the Efficacy of Closed-loop Operation Combined With Meal-and-carbohydrate-announcement Closed-loop Operation Combined With Meal-announcement, and Conventional Pump Therapy in Regulating Glucose Levels in Adults With Type 1 Diabetes

Closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosage based on the sensor's readings. A dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormones: insulin and glucagon.

The objective of this project is to assess whether a dual-hormone closed-loop strategy would alleviate the burden of carbohydrate counting from patients with type 1 diabetes (T1D) without a significant degradation in post-meal glucose control.

Our primary hypothesis is that meal-announcement strategy (pre-meal CHO-independent bolus) is equivalent to meal-and-carbohydrate-announcement strategy (full CHO-matching bolus) during closed-loop regulation of glucose levels in adults with T1D. Our secondary hypothesis is that closed-loop strategy with meal-announcement strategy (pre-meal CHO-independent bolus) or meal-and-carbohydrate-announcement strategy (full CHO-matching bolus) is better than conventional pump treatment in regulation of glucose levels in adults with T1D.

Closed-loop strategy is composed of three components: glucose sensor to read glucose levels, insulin pump to infuse insulin and a dosing mathematical algorithm to decide on the required insulin dosages based on the sensor's readings. A dual-hormone closed-loop system would regulate glucose levels through the infusion of two hormone: insulin and glucagon.

Each patient will be admitted three times to a clinical research facility. In the meal-and-carbohydrate-announcement visit, patients will eat 3 meals accompanied with a matching insulin bolus (depending on the carbohydrate content of the meal) and glucose levels will be subsequently regulated using dual-hormone closed-loop system. In the meal-announcement visit, patients will eat the 3 same meals but will inject only a partial insulin bolus (not depending on carbohydrate content of the meal) and the remaining needed insulin will be delivered based on glucose sensor excursions as part of closed-loop operation. In the control visit, patients will use conventional pump therapy to regulate glucose levels.

Inclusion Criteria:

• Males and females ≥ 18 years of old.
• Clinical diagnosis of type 1 diabetes for at least one year.
• The subject will have been on insulin pump therapy for at least 3 months.
• Last (less than 3 months) HbA1c ≤ 12%.

Exclusion Criteria:

• Clinically significant microvascular complications: nephropathy (estimated glomerular filtration rate below 40 ml/min), neuropathy (especially diagnosed gastroparesis) or severe proliferative retinopathy as judged by the investigator.
• Recent (< 3 months) acute macrovascular event e.g. acute coronary syndrome or cardiac surgery.
• Ongoing pregnancy.
• Severe hypoglycemic episode within two weeks of screening.
• Medication likely to affect with the interpretation of the results because of their well known impact on gastric emptying: Motilium®, Prandase®, Victoza®, Byetta® and Symlin®.
• Known or suspected allergy to the trial products, meal contents including nuts, peanuts, dairy products or eggs.
• Unusual nutritional habits (e.g. vegetarians)
• Other serious medical illness likely to interfere with study participation or with the ability to complete the trial by the judgment of the investigator.
• Failure to comply with team's recommendations (e.g. not willing to eat snack, not willing to change pump parameters, etc).
• Unreliable carbohydrate counting or lack of insulin to carbohydrate ratios
• Problems with venous access