Type 1 DiabetesRocket-BPSNCT05528770
Evaluation of The Postprandial Impact of Automated Priming Bolus for Full Closed Loop Insulin Delivery
A study testing FCL+BPS and FCL in people with Type 1 Diabetes, run by Marc Breton at 1 site in United States.
Trial summary
The purpose of this study is to understand the impact of the automated priming boluses on the safety and feasibility of a new fully automated AP controller. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Type 1 Diabetes
- What is being tested?
- FCL+BPS and FCL
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- 1 siteUnited States
- Study dates
- 20 Oct 2022to 15 Jan 2023
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥18.0 and ≤65 years old at time of consent
- Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least one year
- Currently using insulin for at least six months
- Currently using insulin pump for at least three months
- Using insulin parameters such as carbohydrate ratio and correction factors consistently on their pump in order to dose insulin for meals or corrections
- Current regular exercise (e.g. walk, bike, jog) and be able to participate in a high intensity interval training activity.
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- Access to internet and willingness to upload data during the study as needed
- For females, not currently known to be pregnant or breastfeeding
- 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 childbearing 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.
- Willingness to suspend use of any personal CGM for the duration of the clinical trial once the study CGM is in use
- Willingness to use the UVa closed-loop system throughout study admission
- Willingness to use personal lispro (Humalog) or aspart (Novolog) during the study admission.
- Willingness not to start any new non-insulin glucose-lowering agent during the course of the trial (including metformin/biguanides, GLP-1 receptor agonists, pramlintide, DPP-4 inhibitors, sulfonylureas and naturaceuticals)
- Willingness to eat at least 1 g/kg of carbohydrate per day during the hotel admission
- Willingness to reschedule if placed on oral steroids
- An understanding and willingness to follow the protocol and signed informed consent
- Willingness to follow COVID-19 protocols in place at the time of study.
Who cannot join
- History of diabetic ketoacidosis (DKA) in the 6 months prior to enrollment
- Severe hypoglycemia resulting in seizure or loss of consciousness in the 12 months prior to enrollment
- Pregnancy or intent to become pregnant during the trial
- Currently being treated for a seizure disorder
- Planned surgery during study duration.
- Treatment with meglitinides/sulfonylureas at the time of hotel study.
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- Use of metformin/biguanides, GLP-1 agonists, pramlintide, DPP-4 inhibitors, SGLT-2 inhibitors, or naturaceuticals with a change in dose in the past month.
- Coronary artery disease or heart failure, unless written clearance is received from a cardiologist or personal health care provider allowing clearance for high-intensity interval training and documentation of a negative stress test within the year
- History of cardiac arrhythmia (except for benign premature atrial contractions and benign premature ventricular contractions which are permitted or previous ablation of arrhythmia without recurrence which may be permitted)
- Clinically significant electrocardiogram (ECG) at time of Screening, as interpreted by the study medical physician.
- A known medical condition that in the judgment of the investigator might interfere with the completion of the protocol such as the following examples:
- Inpatient psychiatric treatment in the past 6 months
- Presence of a known adrenal disorder
- Abnormal liver function test results (Transaminase >2 times the upper limit of normal); testing required for subjects taking medications known to affect liver function or with diseases known to affect liver function
- Uncontrolled thyroid disease
- Musculoskeletal or other condition that limits participation in exercise portion of study
- A known medical condition that in the judgment of the investigator might interfere with the completion of the protocol.
- Positive Covid-19 test result
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Virginia Center for Diabetes Technology
Charlottesville, Virginia, 22903
About this study
The purpose of this study is to understand the impact of the automated priming boluses on the safety and feasibility of a new fully automated AP controller.
Read the detailed description
Study participants will be admitted to the hotel for a 4-night study, receiving the two sessions in random order: 1) Fully control loop (FCL) with the bolus priming system (BPS) activated, 2) FCL without the BPS, with a 24-hour washout period in between. During the admission, participants will receive structured meals and have blood glucose control followed to compare time in range 70-180 mg/dL between Controller sessions. After the first 24 hour period on the first FCL approach (BPS vs. no BPS,) that the participant has been randomized to, there will be a 24 hour challenge period before shifting to the other randomized approach; during this session participants will undergo further testing of the control algorithm, including meal challenges and a high-intensity interval training bout.
- Conditions
- Type 1 Diabetes
- Being tested
- FCL+BPS, FCL
- Keywords
- Continuous Glucose Monitor (CGM), Continuous subcutaneous insulin infusion (CSII), Closed Loop Control (CLC), Hybrid Closed Loop (HCL), High-intensity interval training (HIIT), Bolus Priming System (BPS), Fully Automated Closed Loop (FCL), Artificial Pancreas (AP)
- Medical subject headings
- Diabetes Mellitus, Type 1
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
FCL+BPSDevice
Also called Full closed-loop (FCL) with Bolus Priming System
The automated insulin delivery system includes the Bolus Priming System, a software automatically analyzing past continuous glucose monitoring values to trigger priming insulin bolus delivery isn the suspected presence of meal like glycemic disturbances
FCLDevice
Also called Full closed-loop (FCL) without Bolus Priming System
The automated insulin delivery system does not include the Bolus Priming System, and therefore does not automatically command priming boluses.
| Study group | Role | What they receive |
|---|---|---|
| Full closed-loop (FCL) with Bolus Priming System (BPS) followed by FCL without BPS | Active comparator | Two separate 24-hour periods during where fully closed loop (FCL) control is used with \& without the Bolus Priming system (BPS) active (BPS is designed to recognize meal ingestion \& deliver a quick priming dose of insulin prior to extreme blood sugar excursions.) These will be separated by a 24-hour challenge period which will involve further meal \& exercise challenges. During these 24-hour periods, participants will be followed for the experimental meals as part of the Study Controller Sessions to compare blood glucose control with \& without the BPS. The study meals \& activities will be standardized between study sessions.
During a washout period, we will test the RocketAP system in FCL with further challenges:
* A session of high-intensity interval training
* A high-carbohydrate, high-fat meal
* Ingestion of a bolus of simple sugar Receives: Device: FCL+BPS; Device: FCL |
| Full closed-loop (FCL) without Bolus Priming System (BPS) followed by FCL with BPS | Active comparator | Two separate 24-hour periods during where fully closed loop (FCL) control is used with \& without the Bolus Priming system (BPS) active (BPS is designed to recognize meal ingestion \& deliver a quick priming dose of insulin prior to extreme blood sugar excursions.) These will be separated by a 24-hour challenge period which will involve further meal \& exercise challenges. During these 24-hour periods, participants will be followed for the experimental meals as part of the Study Controller Sessions to compare blood glucose control with \& without the BPS. The study meals \& activities will be standardized between study sessions.
During a washout period, we will test the RocketAP system in FCL with further challenges:
* A session of high-intensity interval training
* A high-carbohydrate, high-fat meal
* Ingestion of a bolus of simple sugar Receives: Device: FCL+BPS; Device: FCL |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in Daytime Percent Time-in-range
Percentage of CGM values falling between 70 and 180 mg/dL during daytime (6am to midnight)
Measured: 18 hours
Secondary outcomes (3)
Difference in Overall Percent Time-in-range
Percentage of CGM values falling between 70 and 180 mg/dL
Measured: 24 hours
Difference in Daytime Percent Time-below-range
Percentage of CGM values falling below 70mg/dL during daytime (6am to midnight)
Measured: 18 hours
Difference in Overall Percent Time-below-range
Percentage of CGM values falling below 70mg/dL
Measured: 24 hours
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Sep 2022
- Study start20 Oct 2022
- Primary completion13 Jan 2023
- Study completion15 Jan 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Type 1 DiabetesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Participants will be randomized to the order that they experience the use of the Bolus Priming System (BPS) in fully automated closed loop (FCL) (for 24 hours each, with a 24-hour challenge period in between): 1) with the BPS active, 2) BPS inactive.
- Masking
- None (open label)
- Enrolment
- 15 participants (actual)
Sponsor and investigators
- Lead sponsor
- Marc Breton
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Marc Breton, University of Virginia
- Investigators
- Sue Brown, MD, Principal investigator, University of Virginia Center for Diabetes Technology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05528770
- Sponsor's protocol ID
- 220261
- Other IDs
- R01DK129553
- Acronym
- Rocket-BPS
- Status last verified
- Aug 2025
- First submitted
- 29 Aug 2022
- Last updated
- 8 Sep 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
Publications
Moscoso-Vasquez M, Colmegna P, Barnett C, Fuller M, Koravi CLK, Brown SA, DeBoer MD, Breton MD. Evaluation of an Automated Priming Bolus for Improving Prandial Glucose Control in Full Closed Loop Delivery. Diabetes Technol Ther. 2025 Feb;27(2):93-100. doi: 10.1089/dia.2024.0315. Epub 2024 Nov 6.
PubMed 39501832
Study at a glance
From the registry record, last updated by the sponsor on 8 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of The Postprandial Impact of Automated Priming Bolus for Full Closed Loop Insulin Delivery
- ClinicalTrials.gov ID
- NCT05528770
- Acronym / sponsor ID
- Rocket-BPS / 220261
- Conditions
- Type 1 Diabetes
- Keywords
- Continuous Glucose Monitor (CGM), Continuous subcutaneous insulin infusion (CSII), Closed Loop Control (CLC), Hybrid Closed Loop (HCL), High-intensity interval training (HIIT), Bolus Priming System (BPS), Fully Automated Closed Loop (FCL), Artificial Pancreas (AP)
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 15 participants (actual)
- Lead sponsor
- Marc BretonUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 20 Oct 2022 (actual)
- Primary completion
- 13 Jan 2023 (actual)
- Study completion
- 15 Jan 2023 (actual)
- First posted
- 6 Sep 2022 (actual)
- Results
- Posted 9 Jul 2024
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to understand the impact of the automated priming boluses on the safety and feasibility of a new fully automated AP controller.
Detailed description
Study participants will be admitted to the hotel for a 4-night study, receiving the two sessions in random order: 1) Fully control loop (FCL) with the bolus priming system (BPS) activated, 2) FCL without the BPS, with a 24-hour washout period in between. During the admission, participants will receive structured meals and have blood glucose control followed to compare time in range 70-180 mg/dL between Controller sessions. After the first 24 hour period on the first FCL approach (BPS vs. no BPS,) that the participant has been randomized to, there will be a 24 hour challenge period before shifting to the other randomized approach; during this session participants will undergo further testing of the control algorithm, including meal challenges and a high-intensity interval training bout.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Participants will be randomized to the order that they experience the use of the Bolus Priming System (BPS) in fully automated closed loop (FCL) (for 24 hours each, with a 24-hour challenge period in between): 1) with the BPS active, 2) BPS inactive.
| Arm | Type | Receives |
|---|---|---|
| Full closed-loop (FCL) with Bolus Priming System (BPS) followed by FCL without BPS | Active comparator | Device: FCL+BPS, Device: FCLTwo separate 24-hour periods during where fully closed loop (FCL) control is used with \& without the Bolus Priming system (BPS) active (BPS is designed to recognize meal ingestion \& deliver a quick priming dose of insulin prior to extreme blood sugar excursions.) These will be separated by a 24-hour challenge period which will involve further meal \& exercise challenges. During these 24-hour periods, participants will be followed for the experimental meals as part of the Study Controller Sessions to compare blood glucose control with \& without the BPS. The study meals \& activities will be standardized between study sessions. During a washout period, we will test the RocketAP system in FCL with further challenges: * A session of high-intensity interval training * A high-carbohydrate, high-fat meal * Ingestion of a bolus of simple sugar |
| Full closed-loop (FCL) without Bolus Priming System (BPS) followed by FCL with BPS | Active comparator | Device: FCL+BPS, Device: FCLTwo separate 24-hour periods during where fully closed loop (FCL) control is used with \& without the Bolus Priming system (BPS) active (BPS is designed to recognize meal ingestion \& deliver a quick priming dose of insulin prior to extreme blood sugar excursions.) These will be separated by a 24-hour challenge period which will involve further meal \& exercise challenges. During these 24-hour periods, participants will be followed for the experimental meals as part of the Study Controller Sessions to compare blood glucose control with \& without the BPS. The study meals \& activities will be standardized between study sessions. During a washout period, we will test the RocketAP system in FCL with further challenges: * A session of high-intensity interval training * A high-carbohydrate, high-fat meal * Ingestion of a bolus of simple sugar |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (17 listed)
- Age ≥18.0 and ≤65 years old at time of consent
- Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least one year
- Currently using insulin for at least six months
- Currently using insulin pump for at least three months
- Using insulin parameters such as carbohydrate ratio and correction factors consistently on their pump in order to dose insulin for meals or corrections
Key exclusion criteria (18 listed)
- History of diabetic ketoacidosis (DKA) in the 6 months prior to enrollment
- Severe hypoglycemia resulting in seizure or loss of consciousness in the 12 months prior to enrollment
- Pregnancy or intent to become pregnant during the trial
- Currently being treated for a seizure disorder
- Planned surgery during study duration.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| FCL+BPSAlso: Full closed-loop (FCL) with Bolus Priming SystemThe automated insulin delivery system includes the Bolus Priming System, a software automatically analyzing past continuous glucose monitoring values to trigger priming insulin bolus delivery isn the suspected presence of meal like glycemic disturbances | Device | Full closed-loop (FCL) with Bolus Priming System (BPS) followed by FCL without BPS, Full closed-loop (FCL) without Bolus Priming System (BPS) followed by FCL with BPS |
| FCLAlso: Full closed-loop (FCL) without Bolus Priming SystemThe automated insulin delivery system does not include the Bolus Priming System, and therefore does not automatically command priming boluses. | Device | Full closed-loop (FCL) with Bolus Priming System (BPS) followed by FCL without BPS, Full closed-loop (FCL) without Bolus Priming System (BPS) followed by FCL with BPS |
Primary outcome
Difference in Daytime Percent Time-in-range
Time frame: 18 hours
Percentage of CGM values falling between 70 and 180 mg/dL during daytime (6am to midnight)
3 secondary outcomes
Difference in Overall Percent Time-in-range
Time frame: 24 hours
Difference in Daytime Percent Time-below-range
Time frame: 18 hours
Difference in Overall Percent Time-below-range
Time frame: 24 hours
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Sep 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publication: PubMed 39501832Moscoso-Vasquez M, Colmegna P, Barnett C, Fuller M, Koravi CLK, Brown SA, DeBoer MD, Breton MD. Evaluation of an Automated Priming Bolus for Improving Prandial Glucose Control in Full Closed Loop Delivery. Diabetes Technol Ther. 2025 Feb;27(2):93-100. doi: 10.1089/dia.2024.0315. Epub 2024 Nov 6.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Sue Brown, MD principal investigator
University of Virginia Center for Diabetes Technology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing FCL+BPS and FCL in people with Type 1 Diabetes, run by Marc Breton at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 17 inclusion and 18 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 8 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 9 Jul 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in Daytime Percent Time-in-range (time frame: 18 hours). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05528770, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Sep 2025.