The International Diabetes Closed Loop (iDCL) Trial: Clinical Acceptance of the Artificial Pancreas (DCLP3 Extension)

Participants in the 6 month primary trial (DCLP3) will be invited to continue in this 3-month
extension study (DCLP3 Extension) following completion of the primary trial. The closed-loop
control (CLC) Intervention Group participants from the primary trial will be randomly
assigned to continue CLC or to switch to Predictive Low-Glucose Suspend (PLGS) therapy with
t:slim X2 with Basal-IQ and Dexcom G6 for 3 months. The Sensor-Augmented Pump (SAP) Control
Group participants from the primary trial will be assigned to CLC using t:slim X2 with
Control-IQ Technology and Dexcom G6 (CGM) for 3 months.

This extension phase has two separate objectives:

Objective 1: Among participants who used CLC in the primary trial: the primary efficacy
outcome for the RCT is time in target range 70-180 mg/dL measured by CGM in CLC group vs.
PLGS group over 3 months. Safety outcomes also will be assessed Objective 2: Among
participants who used SAP in the primary trial: the primary outcome is to obtain additional
safety data. Efficacy also will be assessed as a pre-post within participant analysis

Note: Primary Trial (DCLP3) is NCT03563313

Inclusion Criteria:

1. Successful completion of the original 6-month RCT within the prior 14 days

2. 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 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.

3. For participants <18 years old, living with one or more parent/legal guardian
knowledgeable about emergency procedures for severe hypoglycemia and able to contact
the participant in case of an emergency.

4. Willingness to not use a personal CGM for the duration of the study

5. Investigator has confidence that the participant can successfully operate all study
devices and is capable of adhering to the protocol

6. Willingness to use only lispro (Humalog) or aspart (Novolog), and to use no other
insulin during the study.

7. Willingness not to start any new non-insulin glucose-lowering agent during the course
of the trial

Exclusion Criteria

1. Concurrent use of any non-insulin glucose-lowering agent other than metformin
(including GLP-1 agonists, Symlin, DPP-4 inhibitors, SGLT-2 inhibitors,
sulfonylureas).

2. Hemophilia or any other bleeding disorder

3. A condition, which in the opinion of the investigator or designee, would put the
participant or study at risk

4. Participation in another pharmaceutical or device trial at the time of enrollment or
during the study

5. Employed by, or having immediate family members employed by Tandem Diabetes Care,
Inc., Dexcom, Inc., or TypeZero Technologies, LLC, 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