Safety of Artificial Pancreas Therapy in Preschoolers, Age 2-6

A single-arm, multi-center, clinical study to assess the safety profile of the Tandem t:slim X2 with Control-IQ system in children with T1D aged 2-6 years old under free living condition

This clinical trial aims to demonstrate the safety of the Closed-Loop Control (CLC), also known as Artificial Pancreas (AP) named t:slim X2 with Control-IQ Technology and assess usability in a supervised setting for the treatment of type 1 diabetes (T1D) in young children (2-6 years old).

Eligibility Criteria:
Inclusion Criteria:

1. Age ≥ 2 and \< 6 years old at the time of consent
2. Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least 3 months and using insulin at the time of enrollment
3. Use of an insulin pump in the past 3 months
4. Use of Dexcom G6 for at least 11 out of the last 14 days
5. Parent/guardian(s) have familiarity with and use of carbohydrate ratios for meal boluses
6. Living with one or more parent/guardian knowledgeable about emergency procedures for severe hypoglycemia and able to contact emergency services and study staff
7. At least one parent/guardian is willing to stay with the child during the hotel/house portion of the study on the dates selected by the study team
8. Investigator has confidence that the parent/guardian(s) can successfully operate all study devices and is capable of adhering to the protocol
9. Willingness to switch to lispro (Humalog) or aspart (Novolog) if not already, and to use no other insulin besides lispro (Humalog) or aspart (Novolog) during the study
10. Total daily insulin dose (TDD) of at least 5 U/day
11. Willingness not to start any new non-insulin glucose-lowering agent during the course of the trial
12. Child participant and parent/guardian(s) willingness to participate in all training sessions as directed by study staff
13. Willingness to discontinue non-Tandem t:slim insulin pumps during the entire study
14. Willingness to wear a Dexcom G6 sensor during the entire study
15. An understanding and willingness to follow the protocol and sign informed consent

Exclusion Criteria:

1. Hypoglycemia induced seizure or loss of consciousness in the past 3 months
2. Diabetes Ketoacidosis in the past 3 months
3. Use of diluted insulin
4. Concurrent use of any non-insulin glucose-lowering agent
5. Hemophilia or any other bleeding disorder
6. A condition, which in the opinion of the investigator or designee, would put the participant or study at risk. These conditions may include:

   * Acute illness at the time of the enrollment visit (fever of 101 or higher, vomiting, diarrhea)
   * Addison's disease
   * Diagnosed at less than 1 year of age without positive antibodies
   * Decreased renal function
   * Cystic fibrosis
   * Other chronic conditions, such as an underlying seizure disorder
7. Participation in another pharmaceutical or device trial at the time of enrollment or during the study.
8. Having a family member(s) employed by Tandem Diabetes Care, Inc. or having a direct supervisor at place of employment who is also directly involved in conducting the clinical trial (as a study investigator, coordinator, etc.); or having a first-degree relative who is directly involved in conducting the clinical trial.