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

The purpose of this proposed study is to assess the use of a new feature of the Control-IQ system, MyTDI.

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.

Eligibility Criteria:
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