A Study of t:Slim X2 With Control-IQ Technology (DCLP5)
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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT03844789 |
Recruitment Status :
Completed
First Posted : February 18, 2019
Last Update Posted : December 7, 2020
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Condition or disease | Intervention/treatment | Phase |
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Type 1 Diabetes Mellitus | Device: t:slim X2 with Control-IQ Technology & Dexcom G6 CGM Device: Control Group | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 101 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Other |
Official Title: | The International Diabetes Closed Loop (iDCL) Trial: Clinical Acceptance of the Artificial Pancreas in Pediatrics: A Study of t:Slim X2 With Control-IQ Technology |
Actual Study Start Date : | June 6, 2019 |
Actual Primary Completion Date : | December 20, 2019 |
Actual Study Completion Date : | March 20, 2020 |

Arm | Intervention/treatment |
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Experimental: Closed Loop Control (CLC)
Eligible participants not currently using an insulin pump and Dexcom G4, G5 or Dexcom G6 CGM with minimum data requirements will initiate a run-in phase of 2 to 4 weeks that will be customized based on whether the participant is already a pump or CGM user. Participants who skip or successfully complete the run-in will be randomly assigned 3:1 to the use of closed-loop control (CLC group) system using Tandem Control-IQ Technology & Dexcom G6 CGM vs Control Group for 16 weeks. Participants randomized to the closed loop control (CLC) arm will use the t:slim X2 with Control-IQ Technology & Dexcom G6 CGM for 16 weeks. All participants will be provided the option of continue using the t:slim X2 with Control-IQ system in a 12 week Extension Phase.
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Device: t:slim X2 with Control-IQ Technology & Dexcom G6 CGM
Eligible participants will be use the t:slim X2 with Control-IQ Technology & Dexcom G6 CGM technology for 16 weeks during the main study. All participants will be provided the option of continue using the t:slim X2 with Control-IQ system in a 12 week Extension Phase. This arm to be uset:slim X2 with Control-IQ Technology & Dexcom G6 CGM
Other Name: Experimental |
Active Comparator: Control Group
Eligible participants not currently using an insulin pump and Dexcom G4, G5 or Dexcom G6 CGM with minimum data requirements will initiate a run-in phase of 2 to 4 weeks that will be customized based on whether the participant is already a pump or CGM user. Participants who skip or successfully complete the run-in will be randomly assigned 3:1 to the use of closed-loop control (CLC group) system using Tandem t:slim X2 with Control-IQ Technology vs Control Group for 16 weeks. All participants will be provided the option of using t:slim X2 with Control-IQ system in a 12 week Extension Phase.
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Device: Control Group
Eligible participants will be use the study Dexcom G6 CGM for 16 weeks during the main study. All participants will be provided the option of using the t:slim X2 with Control-IQ system in a 12 week Extension Phase.
Other Name: Control |
- Time in range in main study [ Time Frame: 16 weeks ]The primary outcome for the first phase is % time in target range 70-180 mg/dL measured by CGM in CLC group vs. Control Group.
- CGM-measured % above 180 mg/dL [main study] [ Time Frame: 16 weeks ]Percent
- CGM-measured mean glucose [main study] [ Time Frame: 16 weeks ]mg/dL
- HbA1c at 16 weeks [main study] [ Time Frame: 16 weeks ]Percent
- CGM-measured % below 70 mg/dL [main study] [ Time Frame: 16 weeks ]Percent
- CGM-measured % below 54 mg/dL [main study] [ Time Frame: 16 weeks ]Percent
- CGM-measured % above 250 mg/dL [main study] [ Time Frame: 16 weeks ]Percent
- Glucose variability measured with the coefficient of variation (CV) [main study] [ Time Frame: 16 weeks ]Coefficient of variation- CGM measured
- CGM-measured % above 180 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent
- CGM-measured mean glucose [extension study] [ Time Frame: 12 weeks ]mg/dL
- HbA1c at 28 weeks [extension study] [ Time Frame: 12 weeks ]Percent
- CGM-measured % below 70 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent
- CGM-measured % below 54 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent
- CGM-measured % above 250 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent
- Glucose variability measured with the coefficient of variation (CV) [extension study] [ Time Frame: 12 weeks ]Coefficient of variation- CGM measured
- % in range 70-140 mg/dL [main study] [ Time Frame: 16 weeks ]Percent - CGM measured
- glucose variability measured with the standard deviation (SD) [main study] [ Time Frame: 16 weeks ]Standard Deviation- CGM measured
- % <60 mg/dL [main study] [ Time Frame: 16 weeks ]Percent- CGM measured
- Low blood glucose index [main study] [ Time Frame: 16 weeks ]index- CGM measured
- Hypoglycemia events (defined as at least 15 consecutive minutes <70 mg\dL) [main study] [ Time Frame: 16 weeks ]mg/dL- CGM measured
- % >300 mg/dL [main study] [ Time Frame: 16 weeks ]Percent- CGM measured
- High blood glucose index [main study] [ Time Frame: 16 weeks ]index- CGM measured
- % in range 70-180 mg/dL improvement from baseline to 16 weeks ≥5% [main study] [ Time Frame: 16 weeks ]Percent- CGM measured
- % in range 70-180 mg/dL improvement from baseline to 16 weeks ≥10% [main study] [ Time Frame: 16 weeks ]Percent- CGM measured
- HbA1c < 7.0% at 16 weeks [main study] [ Time Frame: 16 weeks ]Percent - HbA1c
- HbA1c <7.5% at 16 weeks [main study] [ Time Frame: 16 weeks ]Percent - HbA1c
- HbA1c improvement from baseline to 16 weeks >0.5% [main study] [ Time Frame: 16 weeks ]Percent - HbA1c
- HbA1c improvement from baseline to 16 weeks >1.0% [main study] [ Time Frame: 16 weeks ]Percent - HbA1c
- HbA1c relative improvement from baseline to 16 weeks >10% [main study] [ Time Frame: 16 weeks ]Percent - HbA1c
- HbA1c improvement from baseline to 16 weeks >1.0% or HbA1c <7.0% [main study] [ Time Frame: 16 weeks ]Percent - HbA1c
- Questionnaire - Fear of Hypoglycemia Survey (HFS-II) - total score, 2 subscales and 4 factor scores: 1- Behavior (avoidance and maintain high BG), 2- Worry (helplessness and social consequences) [main study] [ Time Frame: 16 weeks ]Questionnaire
- Questionnaire - Clarke Hypoglycemia Awareness Scores [main study] [ Time Frame: 16 weeks ]Questionnaire
- Questionnaire - Problem Areas in Diabetes Survey (PAID) [main study] [ Time Frame: 16 weeks ]Questionnaire
- Questionnaire - INSPIRE survey scores [main study] [ Time Frame: 16 weeks ]Questionnaire
- Questionnaire - PedsQL Diabetes Module - total score and 5 subscales: 1- Diabetes, 2 - Treatment I, 3 - Treatment II, 4 - Worry, 5 - Communication [main study] [ Time Frame: 16 weeks ]Questionnaire
- Questionnaire - Pittsburgh Sleep Quality Index (Parent only) [main study] [ Time Frame: 16 weeks ]Questionnaire
- Questionnaire - System Usability Scale (SUS) [main study] [ Time Frame: 16 weeks ]Questionnaire
- Insulin - Total daily insulin (units/kg) [main study] [ Time Frame: 16 weeks ]units/kg
- Insulin - Basal: bolus insulin ratio [main study] [ Time Frame: 16 weeks ]bolus insulin ratio
- Weight and Body Mass Index (BMI) [main study] [ Time Frame: 16 weeks ]Weight and BMI
- Time in range in extension study [ Time Frame: 12 weeks ]The primary outcome for the extension phase is improving % time in range 70-180 mg/dL by CGM when Control Group transitions to t:slim X2 with Control-IQ compared with the same group during the Main Phase.
- % in range 70-140 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent - CGM measured
- glucose variability measured with the standard deviation (SD) [extension study] [ Time Frame: 12 weeks ]Standard Deviation- CGM measured
- % <60 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent- CGM measured
- Low blood glucose index [extension study] [ Time Frame: 12 weeks ]index- CGM measured
- Hypoglycemia events (defined as at least 15 consecutive minutes <70 mg\dL) [extension study] [ Time Frame: 12 weeks ]mg/dL- CGM measured
- % >300 mg/dL [extension study] [ Time Frame: 12 weeks ]Percent- CGM measured
- High blood glucose index [extension study] [ Time Frame: 12 weeks ]index- CGM measured
- % in range 70-180 mg/dL improvement from 16 weeks to 28 weeks ≥5% [extension study] [ Time Frame: 12 weeks ]Percent- CGM measured
- % in range 70-180 mg/dL improvement from 16 weeks to 28 weeks ≥10% [extension study] [ Time Frame: 12 weeks ]Percent- CGM measured
- HbA1c < 7.0% at 28 weeks [extension study] [ Time Frame: 12 weeks ]Percent - HbA1c
- HbA1c <7.5% at 28 weeks [extension study] [ Time Frame: 12 weeks ]Percent - HbA1c
- HbA1c improvement from 16 weeks to 28 weeks >0.5% [extension study] [ Time Frame: 12 weeks ]Percent - HbA1c
- HbA1c improvement from 16 weeks to 28 weeks >1.0% [extension study] [ Time Frame: 12 weeks ]Percent - HbA1c
- HbA1c relative improvement from 16 weeks to 28 weeks >10% [extension study] [ Time Frame: 12 weeks ]Percent - HbA1c
- HbA1c improvement from 16 weeks to 28 weeks >1.0% or HbA1c <7.0% [extension study] [ Time Frame: 12 weeks ]Percent - HbA1c
- Questionnaire - Fear of Hypoglycemia Survey (HFS-II) - total score, 2 subscales and 4 factor scores: 1- Behavior (avoidance and maintain high BG), 2- Worry (helplessness and social consequences) [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Questionnaire - Clarke Hypoglycemia Awareness Scores [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Questionnaire - Problem Areas in Diabetes Survey (PAID) [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Questionnaire - INSPIRE survey scores [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Questionnaire - PedsQL Diabetes Module - total score and 5 subscales: 1- Diabetes, 2 - Treatment I, 3 - Treatment II, 4 - Worry, 5 - Communication [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Questionnaire - Pittsburgh Sleep Quality Index (Parent only) [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Questionnaire - System Usability Scale (SUS) [extension study] [ Time Frame: 12 weeks ]Questionnaire
- Insulin - Total daily insulin (units/kg) [extension study] [ Time Frame: 12 weeks ]units/kg
- Insulin - Basal: bolus insulin ratio [extension study] [ Time Frame: 12 weeks ]bolus insulin ratio
- Weight and Body Mass Index (BMI) [extension study] [ Time Frame: 12 weeks ]Weight and BMI

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 6 Years to 13 Years (Child) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least one year and using insulin for at least 6 months
- Familiarity and use of a carbohydrate ratio for meal boluses.
- Age ≥ 6 and ≤ 13 years old
- Weight ≥25 kg and ≤140 kg
- For females, not currently known to be pregnant If female and sexually active, must agree to use a form of contraception to prevent pregnancy while a participant in the study. A negative serum or urine pregnancy test will be required for all females of child-bearing potential. Participants who become pregnant will be discontinued from the study. Also, participants who during the study develop and express the intention to become pregnant within the timespan of the study will be discontinued.
- Living with one or more parent/legal guardian knowledgeable about emergency procedures for severe hypoglycemia and able to contact emergency services and study staff.
- Willingness to suspend use of any personal closed loop system that they use at home for the duration of the clinical trial once the study CGM is in use
- Investigator has confidence that the participant can successfully operate all study devices and is capable of adhering to the protocol
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Willingness to switch to lispro (Humalog) or aspart (Novolog) if not using already, and to use no other insulin besides lispro (Humalog) or aspart (Novolog) during the study for participants using to t:slim X2. This includes:
- Participants randomized to Control IQ
- Participants on the SC group on MDI treatment that will be provided a Tandem pump to switch to CSII
- Participates that are already in Continuous Subcutaneous Insulin Infusion (CSII) randomized to SC during the extension phase when transition to Control IQ
- Total daily insulin dose (TDD) at least 10 U/day
- Willingness not to start any new non-insulin glucose-lowering agent during the course of the trial
- Participant and parent(s)/guardian(s) willingness to participate in all training sessions as directed by study staff.
Exclusion Criteria:
- Concurrent use of any non-insulin glucose-lowering agent other than metformin (including glucagon-like peptide [GLP-1] agonists, Symlin, dipeptidyl peptidase 4 [DPP-4] inhibitors, sodium-glucose cotransporter-2 (SGLT2) inhibitors, sulfonylureas).
- Hemophilia or any other bleeding disorder
- A condition, which in the opinion of the investigator or designee, would put the participant or study at risk (specified on the study procedure manual)
- Participation in another pharmaceutical or device trial at the time of enrollment or during the study
- 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

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03844789
United States, California | |
Stanford University | |
Stanford, California, United States, 94304 | |
United States, Colorado | |
Barbara Davis Center, University of Colorado | |
Aurora, Colorado, United States, 80045 | |
United States, Connecticut | |
Yale University | |
New Haven, Connecticut, United States, 06511 | |
United States, Virginia | |
UVA Center for Diabetes Technology | |
Charlottesville, Virginia, United States, 22903 |
Principal Investigator: | Melissa J Schoelwer, MD | University of Virginia |
Documents provided by University of Virginia:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | University of Virginia |
ClinicalTrials.gov Identifier: | NCT03844789 |
Other Study ID Numbers: |
DCLP5 |
First Posted: | February 18, 2019 Key Record Dates |
Last Update Posted: | December 7, 2020 |
Last Verified: | November 2020 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Will follow the NIH Data Sharing Policy and Implementation Guidance on sharing research resources for research purposes to qualified individuals within the scientific community. |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) Informed Consent Form (ICF) |
Time Frame: | Generally, data will be made available after the primary publications of each study. |
Access Criteria: | The Data Sharing Agreements will be formulated by the Steering Committee in collaboration with the NIH Project Scientist Program Official. In addition, under special arrangements, complete data sets will be provided to industry partners who would use the data for regulatory clearance (PMA - pre-market approval) of the tested artificial pancreas system. This will be done in response to the specific requirements of RFA-DK-14-024 for this project to "…generate data able to satisfy safety and efficacy requirements by regulatory agencies regarding the clinical testing of artificial pancreas device systems" in the target population of people with type 1 diabetes. |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | Yes |
Device Product Not Approved or Cleared by U.S. FDA: | Yes |
Artificial Pancreas (AP) Control-IQ System Insulin Pump |
Closed Loop Control (CLC) Continuous Glucose Monitor (CGM) Multiple Daily Injections (MDI) |
Diabetes Mellitus, Type 1 Diabetes Mellitus Glucose Metabolism Disorders Metabolic Diseases |
Endocrine System Diseases Autoimmune Diseases Immune System Diseases |