Extended Bolus for Meals in a Closed-loop System

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

Extended Bolus for Meals in a Closed-loop System (NCT05454891) is a Phase 4 interventional studying Type 1 Diabetes, sponsored by University of California, San Francisco. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

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.

What Stage of Research Is This?

Phase 4 studies happen after a treatment has been approved by the FDA. They monitor long-term safety, real-world effectiveness, and any rare side effects that only emerge in larger populations over longer periods. Phase 4 results sometimes lead to label changes, additional warnings, or — rarely — withdrawal of approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

With a target enrollment of 30 participants, this is a small study — typical of early-phase research, rare-disease trials, or pilot studies designed to generate preliminary signal before a larger study is launched.

Who May Be Eligible (Plain English)

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 willing to sign a consent form 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 Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

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

Treatments Being Tested

DRUG

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.

DRUG

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.

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

University of California San Francisco

San Francisco, California, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT05454891), the sponsor (University of California, San Francisco), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT05454891 clinical trial studying?

Who can participate in NCT05454891?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT05454891?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT05454891. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT05454891. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.