Control-IQ Technology for High Insulin Users With Type 1 Diabetes (Higher-IQ)

A prospective, single-arm study of 13 weeks of home use of the t:slim X2 insulin pump with Control-IQ technology in individuals with type 1 diabetes who will plan to use at least one basal rate \> 3 units/hr.

The objectives of the study are to assess safety and explore glycemic outcomes with use of an automated insulin dosing (AID) system (t:slim X2 insulin pump with Control-IQ technology v1.5) in adults with type 1 diabetes who will plan to use at least one basal rate \> 3 units/hr. Up to 60 participants may be recruited.

Eligibility Criteria:
Inclusion Criteria:

* Age ≥ 18 years
* Diagnosis of type 1 diabetes for at least 1 year
* Currently using an insulin pump (of any brand) for at least 3 months, and will plan to use at least one basal rate above 3 units/hr with the study pump
* HbA1c \< 10.5%
* Weight ≤ 200 kg
* Residing full-time in the United States, with no anticipated travel outside the United States during the period of study participation.
* Participant has agreed to participate in the study; and has read, understood and signed the informed consent form (ICF); and has agreed to follow all study procedures, including suspending use of any personal CGM for the duration of the clinical trial once the study CGM is in use.
* Willing to use only aspart (novolog) or lispro (humalog) insulin with the study pump, with no use of concentrated insulin above U-100, long-acting basal insulin injections, or inhaled insulin with the study pump.
* Have current glucagon product to treat severe hypoglycemia (injectable or nasal) at home (will provide prescription if they do not have one)
* Willing and able to perform the study exercise and meal challenges.
* Have a care partner, trained in hypoglycemia and hyperglycemia treatment guidelines, present during the challenges and until the next day.
* Investigator has confidence that the participant can successfully operate all study devices and is capable of adhering to the protocol, including ability to respond to alerts and alarms, and to provide basic diabetes self-management.

Exclusion Criteria:

* More than 1 episode of diabetic ketoacidosis (DKA) in the past 6 months
* More than 1 episode of severe hypoglycemia (needing assistance) in the past 6 months
* Inpatient psychiatric treatment in the past 6 months
* History of drug abuse (defined as any illicit drug use) or history of alcohol abuse prior to screening or unwillingness to agree to abstain from illicit drugs throughout the study.
* For Female: Currently pregnant or planning to become pregnant during the time period of study participation
* Use of sulfonylureas, meglitinides or other medications specifically listed in protocol or determined by investigator to interfere with the study
* Unstable dose of SGLT-2 inhibitor, GLP-1 receptor agonist, or DPP-4 inhibitor as listed in the protocol, or starting a new non-insulin glucose lowering or weight loss agent during the trial
* Hemophilia or any other bleeding disorder
* History of heart, liver, lung or kidney disease determined by investigator to interfere with the study
* History of allergic reaction to Humalog or Novolog
* Use of glucocorticoids or other medications determined by investigator to interfere with study
* Abnormal screening electrocardiogram consistent with increased risk during study exercise activities, such as arrhythmia, ischemia, or prolonged QTc interval. Investigator will review all electrocardiograms
* Significant chronic kidney disease (which could impact CGM accuracy in investigator's judgment) or hemodialysis
* History of adrenal insufficiency
* History of abnormal TSH consistent with hypothyroidism or hyperthyroidism that is not appropriately treated
* History of gastroparesis
* A condition, which in the opinion of the investigator or designee, would put the participant or study at risk
* Participation in another pharmaceutical or device trial at the time of enrollment or anticipated for during the time period of study participation
* Employed by, or having immediate family members 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