Safety and Efficacy of Initializing the Control-IQ Artificial Pancreas System Using Total Daily Insulin

This trial aims to demonstrate the safety and feasibility of using MyTDI to determine insulin
parameters on the Closed Loop Control (CLC) Artificial Pancreas (AP) system t:slim X2 with
Control-IQ technology for use both at ski camp and at home in adolescent patients with type 1
diabetes.

Once deemed eligible, participants and their parent(s) will be trained on the use of the
Tandem t:slim X2 insulin pump with Control-IQ technology and the study Dexcom G6 system.
Participants will then use the this study equipment with their home insulin parameters at
home for at home for 5 days. Participants will then come to the ski resort to participate in
a 72-hour ski admission. Upon arrival, each participant will be randomized to either the
using the Control-IQ system with their usual insulin parameters during the ski study and the
at-home 5 days at home study or using the MyTDI insulin parameters during the ski study and
the at-home 5 days at home study. Study duration for each participant will require 5 study
visits over about 2 weeks.

Inclusion Criteria:

- Criteria for documented hyperglycemia (at least 1 must be met):

- Clinical diagnosis of type 1 diabetes (C-peptide levels and antibody
determinations are not required)

- Diagnosis of type 1 diabetes is based on the investigator's judgement

- Criteria for requiring insulin at diagnosis (both criteria must be met):

- Daily insulin therapy for ≥ 6 months

- Insulin pump therapy for ≥ 3 months

- Age 12-18 years

- Currently using no insulins other than one of the following rapid-acting insulins at
the time of enrollment: insulin lispro (Humalog), insulin aspart (Novolog), or insulin
glulisine (Apidra). If using glulisine, subject must be willing to switch to lispro or
aspart.

- Treatment with any non-insulin glucose-lowering agent (including GLP-1 agonists,
Symlin, DPP-4 inhibitors, SGLT-2 inhibitors, biguanides, sulfonylureas, and
naturaceuticals) is permitted if stable on current dose for at least 1 month.

- Willingness to wear a continuous glucose sensor and physiological monitor for the
duration of the study.

- For females, not pregnant or breastfeeding. Female subjects who are sexually active
should agree to use birth control during the study.

- Total daily insulin dose (TDD) at least 10 U/day.

Exclusion Criteria:

- Diabetic ketoacidosis in the past 6 months

- Hypoglycemic seizure or loss of consciousness in the past 6 months

- History of seizure disorder

- History of any heart disease including coronary artery disease, heart failure, or
arrhythmias

- History of altitude sickness

- Chronic pulmonary conditions that could impair oxygenation

- Cystic fibrosis

- Current use of oral glucocorticoids, beta-blockers or other medications, which in the
judgement of the investigator, would be a contraindication to participation in the
study.

- History of ongoing renal disease (other than microalbuminuria).

- Subjects requiring intermediate or long-acting insulin (such as NPH, Detemir, or
Glargine).

- Pregnancy

- Presence of a febrile illness within 24 hours of the Ski Admission

- Medical or psychiatric conditions that in the judgement of the investigator might
interfere with the completion of the protocol such as:

- Inpatient psychiatric treatment in the past 6 months

- Uncontrolled adrenal insufficiency

- Alcohol abuse