Extended Bolus for Meals in a Closed-loop System

April 20, 2026 updated by: University of California, San Francisco

Postprandial Glucose Control Using an Extended Bolus for High-fat High Protein Meals in a Closed-loop System in Patients With Type 1 Diabetes

This study aims to evaluate whether the use of an extended bolus will improve glucose control with high-fat high protein meals using a closed-loop system. The new knowledge gained from this study may provide a method to allow for the proper administration of insulin over an extended period to mitigate the risk of prolonged hyperglycemia or early hypoglycemia.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94158
        • University of California San Francisco

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

13 years to 18 years (Child, Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria

  • Age between 13 and 19 years old, A1C > 6% at screening
  • Diagnosed with type 1 diabetes for at least one year
  • Total daily dose (TDD) of insulin ≥ 0.3 units/kg/day
  • Currently using the Control IQ closed-loop system
  • Willing to abide by meal recommendations and study procedures
  • Willing and able to sign the Informed Consent Form (ICF) and/or has a parent or guardian willing and able to sign the ICF
  • Use an Android or Apple smartphone
  • 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
  • Parent/guardian proficient in reading and writing English
  • Live in the United States, with no plans to move outside the United States during the study period

Exclusion Criteria

  • A1C >10%
  • One or more episodes of severe hypoglycemia or DKA requiring ER visit or hospitalization within the past three months
  • Used non-insulin anti-diabetic medication within the last 30 days other than metformin
  • Known history of gastroparesis, seizure disorder, adrenal insufficiency, or ongoing renal or hepatic disease
  • Pregnancy or lactation
  • Untreated or unstable hypothyroidism
  • Currently undergoing cancer treatment or systemic treatment with steroids
  • Untreated or inadequately treated mental illness
  • Current alcohol abuse
  • Current illness that would interfere with participation in the study
  • Delayed gastric emptying or any concurrent conditions that can be associated with delayed gastric emptying or altered digestion; and the use of any medication that affects gastric emptying
  • Celiac Disease

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: High Fat High Protein (HFHP) Meal- extended then standard insulin bolus arm
Subjects will receive extended meal bolus for breakfast on the first day and standard meal bolus on the second day of the study.
Device: Tandem t:slim X2 insulin pump: Extended bolus of insulin then standard bolus of insulin
For a standardized HFHP breakfast, participants will receive an extended meal bolus of insulin on the first morning and a standard meal bolus of insulin on the second morning of the study.
Experimental: High Fat High Protein (HFHP) Meal- standard then extended insulin bolus arm
Subjects will receive standard meal bolus for breakfast on the first day and extended meal bolus on the second day.
Device: Tandem t:slim X2 insulin pump: Standard bolus of insulin then extended bolus of insulin
For a standardized HFHP breakfast, participants will receive a standard bolus of insulin on the first morning and an extended bolus of insulin on the second morning of the study.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Glucose Area Under Curve [AUC]
Time Frame: 0 to 5 hours post-meal onset
Area under the curve between glucose trace and starting glucose (mg/dL* min)
0 to 5 hours post-meal onset

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Percentage of Time Between 70-180 mg/dL
Time Frame: 0 to 5 hours post-meal onset
Percentage of time spent between 70-180 mg/dl based on Continuous Glucose Monitor (CGM) values
0 to 5 hours post-meal onset
Percentage of Time in Hypoglycemic Range (Defined as < 70 mg/dL)
Time Frame: 0 to 5 hours post-meal onset
Percentage of time spent with blood sugar less than 70 mg/dL based on Continuous Glucose Monitor (CGM) values
0 to 5 hours post-meal onset
Average Glucose
Time Frame: 0 to 5 hours post-meal onset
Average glucose value based on Continuous Glucose Monitor (CGM) values
0 to 5 hours post-meal onset
Percentage of Time in Hyperglycemic Range (Defined as ≥180 mg/dL);
Time Frame: 0 to 5 hours post-meal onset
Percentage of time spent with blood sugar higher than 180 mg/dL based on Continuous Glucose Monitor (CGM) values
0 to 5 hours post-meal onset
Insulin Dosage
Time Frame: 0 to 5 hours post-meal onset
Total insulin received during 5 hrs ( manual bolus as well as automated)
0 to 5 hours post-meal onset
Time to Target (110mg/dL)
Time Frame: 0 to 5 hours post-meal onset
Time spent till blood glucose returns to 110mg/dL
0 to 5 hours post-meal onset
Time to Baseline
Time Frame: 0 to 5 hours post-meal onset
Time spent till blood glucose returns to baseline
0 to 5 hours post-meal onset
Time to Peak Glucose
Time Frame: 0 to 5 hours post-meal onset
Time spent till blood glucose reaches the maximum value after meal
0 to 5 hours post-meal onset
Change in Glucose
Time Frame: 0 to 5 hours post-meal onset
The difference between baseline to max glucose value
0 to 5 hours post-meal onset
Peak Glucose Concentration
Time Frame: 0 to 5 hours post-meal onset
Max blood glucose
0 to 5 hours post-meal onset
Percentage of Time Between 70-140 mg/dL
Time Frame: 0 to 5 hours post-meal onset
Percent of glucose readings from CGM system between 70-140 mg/dL per unit of time
0 to 5 hours post-meal onset

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of California, San Francisco

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Laya Ekhlaspour, MD, University of California, San Francisco

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 15, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 19, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 19, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 24, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 8, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 12, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 20, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 58992
  • 5K23DK121942-02 (U.S. NIH Grant/Contract)

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.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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