Tandem Freedom - Feasibility Trial 2

This feasibility study is a prospective, single arm study evaluating the Tandem Freedom system in adults with type 1 diabetes. Existing Control-IQ technology users will use Control-IQ technology at home for a one week run-in, then will use Tandem Freedom in a supervised hotel setting.

Study Overview

• Status: Completed
• Conditions: Diabetes Mellitus, Type 1
• Intervention / Treatment: Device: t:slim X2 insulin pump with Tandem Freedom Algorithm

Detailed Description

After a one week Control-IQ run-in at home, 10 adults who are existing Control-IQ users with type 1 diabetes will use the Tandem Freedom System for 4 nights: 1 day with boluses, and 3 days without boluses, in a supervised hotel setting. Participants will perform exercise challenges. The primary outcome is safety events. CGM time in ranges will also be evaluated.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• New Zealand
  • Christchurch, New Zealand, 8140
    • University of Otago

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age ≥18 years old
• Diagnosis of type 1 diabetes for at least 1 year
• Current Control-IQ user, having been prescribed Control-IQ for at least 3 months
• HbA1c ≤10%, recorded in the last 3 months
• Investigator has confidence that the participant can successfully operate all study devices and is capable of adhering to the protocol, including performing the weekend hotel observed setting portion of the study.
• Willing to use only aspart (novorapid) or lispro (humalog) insulin with the study pump, with no use of long-acting basal insulin injections, or inhaled insulin with the study pump.

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

• For Female: Currently pregnant or planning to become pregnant during the time period of study participation

  1. A negative pregnancy test will be required for all females of child-bearing potential
  2. Counseling on appropriate birth control options will be provided to all females of child-bearing potential
• Concurrent use of any non-insulin glucose-lowering agent, other than metformin (for example, GLP-1 agonists, Symlin, DPP-4 inhibitors, SGLT-2 inhibitors, sulfonylureas).
• Hemophilia or any other bleeding disorder
• Hemoglobinopathy
• History of heart, liver, lung or kidney disease determined by investigator to interfere with the study
• History of allergic reaction to Humalog or Novorapid
• Use of any medications determined by investigator to interfere with study
• Significant chronic kidney disease (which could impact CGM accuracy in investigator's judgment) or hemodialysis
• Concurrent use of any medication that could interfere with the study CGM, such as hydroxyurea
• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Tandem Freedom; After a one week run-in period with Control-IQ technology, participants will use the Tandem Freedom system for one partial day with user initiated mealtime insulin boluses and three days without user initiated mealtime insulin boluses in a supervised hotel setting. Participants will also perform exercise challenges.	Device: t:slim X2 insulin pump with Tandem Freedom Algorithm; t:slim X2 insulin pump with Tandem Freedom System consists of the Tandem t:slim X2 insulin pump and the Freedom algorithm embedded in the pump. Participants will also use the Dexcom G6 continuous glucose monitoring system.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With One or More Severe Hypoglycemia Events	Number of Participants with One or More Severe Hypoglycemia Events (with cognitive impairment such that assistance of another individual is needed for treatment)	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Number of Participants With One or More Diabetic Ketoacidosis Events	Number of Participants with One or More Diabetic Ketoacidosis events	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percent Time <54 mg/dL	CGM measured percent time <54 mg/dL	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Percent Time <70 mg/dL	CGM measured percent time <70 mg/dL	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Percent Time in Range 70 - 180 mg/dL	CGM measured percent time in range 70 - 180 mg/dL	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Percent Time in Range > 180 mg/dL	CGM measured percent time in range > 180 mg/dL	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Percent Time in Range > 250 mg/dL	CGM measured percent time in range > 250 mg/dL	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Percent Time in Range 70 - 140 mg/dL	CGM measured percent time in range 70 - 140 mg/dL	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Glucose Coefficient of Variation (%)	CGM measured Coefficient of Variation (%)	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Glucose Standard Deviation (mg/dL)	CGM measured Standard Deviation (mg/dL)	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)
Median of Mean Glucose (mg/dL)	Median of each participant's mean glucose values (mg/dL)	Control-IQ Run-in Period (7 days), Tandem Freedom (3 days)

Collaborators and Investigators

• Sponsor: Tandem Diabetes Care, Inc.
• Investigators: Study Director: Jordan Pinsker, MD, Tandem Diabetes Care, Inc.

Publications and helpful links

General Publications

• Wilkinson TM, de Bock MI, Meier R, Hurd S, Sasson-Katchalski R, Trahan A, Rueda JR, Sherer N, Stephens M, Meyer B, Gantulga D, Rackow S, D'Souza EW, Briggs P, Corbett JP, Ulrich TR, Pinsker JE. Fully Closed-Loop Insulin Delivery with High-Carbohydrate and High-Fat Meals Using the Tandem Freedom System. J Diabetes Sci Technol. 2025 Nov 14:19322968251389966. doi: 10.1177/19322968251389966. Online ahead of print.

Study record dates

Study Major Dates

• Study Start (Actual): March 24, 2025
• Primary Completion (Actual): April 7, 2025
• Study Completion (Actual): April 7, 2025

Study Registration Dates

• First Submitted: February 13, 2025
• First Submitted That Met QC Criteria: February 13, 2025
• First Posted (Actual): February 19, 2025

Study Record Updates

• Last Update Posted (Actual): May 5, 2026
• Last Update Submitted That Met QC Criteria: April 14, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: T1D; type 1 diabetes; automated insulin delivery; Tandem; t:slim X2
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Autoimmune Diseases; Immune System Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 1; Physiological Effects of Drugs; Hypoglycemic Agents; Insulin
• Other Study ID Numbers: TP-0020402

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes