Type 1 Diabetes MellitusCRUMBNCT07455643
Closed-loop Response to Unannounced Mixed and Carbohydrates-rich Breakfasts
A study testing Unannounced meal in people with Type 1 Diabetes Mellitus, run by University of Catania at 1 site in Italy.
Trial summary
The development of advanced hybrid closed-loop (a-HCL) systems represents a significant step toward in improving glucose control and reducing user-dependent variability, especially In pediatric patients. Read more about this study
- Who is it for?
- Ages 11 to 18 years
- Conditions the study is for
- Type 1 Diabetes Mellitus
- What is being tested?
- Unannounced meal
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteItaly
- Study dates
- 20 Apr 2025to 20 May 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 11 to 18 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- Age between 11 and 18 years;
- Type 1 diabetes diagnosed for at least 12 months;
- Use of an A-HCL device for at least 3 months;
- Proficiency in carbohydrate counting.
Who cannot join
- Presence of malabsorption disorders;
- Presence of chronic diabetes complications.
Trial locations and contacts
1 site in 1 country.
Italy1 site
Azienda Ospedaliero Universitaria Policlinico "G.Rodolico - San Marco" - Catania
Catania, Sicily, 95123
About this study
Official title: The CRUMB Study: Closed-loop Response to Unannounced Mixed and Carbohydrates-rich Breakfasts. A Randomized Controlled Crossover Pilot-study in a Cohort of Adolescents With Type 1 Diabetes.
The development of advanced hybrid closed-loop (a-HCL) systems represents a significant step toward in improving glucose control and reducing user-dependent variability, especially In pediatric patients. Systems can automatically deliver correction boluses and modulate insulin delivery based on CGM feedback, thereby compensating for some of the consequences of human error. Current evidence suggests that a-HCL systems can tolerate unannounced carbohydrate loads up to approximately 20 g without compromising time in range (TIR) or safety. However, the metabolic response to larger or compositionally complex meals remains variable and highly dependent on the specific algorithm governing insulin delivery.
Currently a variety of AID are commercially available: all of them present similarities and differences. The Medtronic MiniMed™ 780G uses a proportional-integral-derivative (PID) algorithm, a mathematical model that adjusts in real time insulin delivery rate based on 3 elements obtained from CGM reading values: the difference between the actual value and the chosen glucose target (proportional action), past values (integral action) and the glucose's rate of change (derivative action), In contrast, the Tandem t:slim X2™ with Control-IQ employs a model predictive control (MPC) algorithm, which aims, through a complex mathematical model, to predict glucose trends up to half-an-hour in the future, takin, also, in consideration actual and past glucose values. Despite sharing the same objective, said algorithms have different approaches, the former one being "reactive" and the latter "predictive". Therefore, their difference could result in different performances while facing mixed-nutrient meal or unannounced meals, defined as the consumptions of a meal with any prior insulin administration.
Read more
Pediatric patients represent certainly a unique subgroup in which therapeutic adherence is a relevant issue, due to cognitive, developmental and behavioral factors. Understanding how different AID algorithms respond to unannounced meals in this age group is therefore crucial for optimizing safety and personalization of diabetes management.
This study was designed to evaluate the strengths and limitations of two a-HCL systems, the Medtronic 780G (PID algorithm) and the Tandem t:slim X2 (MPC algorithm), in managing unannounced meals with different macronutrient compositions in children and adolescents with T1D. We also aim to better understand physiological and technological unannounced meal implications as to provide additional insight useful for the development of new fully closed loop algorithms, capable of minimizing glucose excursions and patient's burden.
- Conditions
- Type 1 Diabetes Mellitus
- Being tested
- Unannounced meal
- Keywords
- type 1 diabetes mellitus, automated insulin delivery, unannounced meals, proportional integral derivative control, model predictive control
- 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.
Unannounced mealOther
Participants consumed both the "CHO meal" and the "mixed meal" three times each, without announcing their carbohydrate intake to the device. Consequently, no user-initiated boluses were administered during this period, and all insulin delivery adjustments were determined exclusively by the algorithm.
| Study group | Role | What they receive |
|---|---|---|
| Announced meal (AM) | No intervention | Participants followed their usual therapy while consuming both the "CHO meal" and the "mixed meal" three times each. In this phase, the carbohydrate content of each meal was announced to the insulin pump, and pre-meal boluses were delivered as per standard practice. |
| Unannounced meal (UM) | Experimental | Participants consumed the same meals, an equal number of times, without announcing their carbohydrate intake to the device. Consequently, no user-initiated boluses were administered during this period, and all insulin delivery adjustments were determined exclusively by the algorithm. Receives: Other: Unannounced meal |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in blood glucose concentration from pre-meal to two hours post-meal (2h-ΔBG), as measured by CGM in mg/dl
Change in blood glucose concentration from pre-meal to two hours post-meal (2h-ΔBG), as measured by CGM
Measured: from pre-meal to two hours post-meal
Secondary outcomes (8)
Pre- and post-meal four-hour glucose difference (4h-ΔBG), as measured by CGM in mg/dl
Measured: from pre-meal to four hour postprandial
Peak CGM value in mg/dl
Measured: from pre-meal to four hour postprandial
Time to peak CGM value
Measured: from pre-meal to four hour postprandial
Percentage of spent time in range (TIR, 70-180 mg/dL), as measured by CGM
Measured: from pre-meal to four hour postprandial
Percentage of spent time in tight range (TITR, 70-140 mg/dL), as measured by CGM
Measured: from pre-meal to four hour postprandial
Percentage of spent time below range (TBR, < 70 mg/dL), as measured by CGM
Measured: from pre-meal to four hour postprandial
Percentage of spent time above range (TAR, > 180 mg/dL), as measured by CGM
Measured: from pre-meal to four hour postprandial
Percentage of spent time in second-level TAR (> 250 mg/dL), as measured by CGM
Measured: from pre-meal to four hour postprandial
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Mar 2026
- Study start20 Apr 2025
- Primary completion20 May 2025
- Study completion20 May 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Type 1 Diabetes MellitusStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Catania
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Laura Sciacca, University of Catania
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07455643
- Sponsor's protocol ID
- CRUMB Study
- Acronym
- CRUMB
- Status last verified
- Mar 2026
- First submitted
- 23 Feb 2026
- Last updated
- 6 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Lo Presti D, Scire Calabrisotto S, Tomaselli LG, Pezzino G, Frasca F, Baratta R, Sciacca L, Latina C, La Spina N, Galeano F, Oteri V, Tumminia A. The CRUMB study: closed-loop response to unannounced mixed and carbohydrates-rich breakfasts. A randomized controlled crossover pilot-study in a cohort of adolescents with type 1 diabetes. Endocrine. 2026 Jul 10;91(1):222. doi: 10.1007/s12020-026-04705-5.
PubMed 42430041
Study at a glance
From the registry record, last updated by the sponsor on 6 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The CRUMB Study: Closed-loop Response to Unannounced Mixed and Carbohydrates-rich Breakfasts. A Randomized Controlled Crossover Pilot-study in a Cohort of Adolescents With Type 1 Diabetes.
- ClinicalTrials.gov ID
- NCT07455643
- Acronym / sponsor ID
- CRUMB / CRUMB Study
- Conditions
- Type 1 Diabetes Mellitus
- Keywords
- type 1 diabetes mellitus, automated insulin delivery, unannounced meals, proportional integral derivative control, model predictive control
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University of CataniaUniversity, hospital or other
- Study start
- 20 Apr 2025 (actual)
- Primary completion
- 20 May 2025 (actual)
- Study completion
- 20 May 2025 (actual)
- First posted
- 6 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The development of advanced hybrid closed-loop (a-HCL) systems represents a significant step toward in improving glucose control and reducing user-dependent variability, especially In pediatric patients. Systems can automatically deliver correction boluses and modulate insulin delivery based on CGM feedback, thereby compensating for some of the consequences of human error. Current evidence suggests that a-HCL systems can tolerate unannounced carbohydrate loads up to approximately 20 g without compromising time in range (TIR) or safety. However, the metabolic response to larger or compositionally complex meals remains variable and highly dependent on the specific algorithm governing insulin delivery.
Currently a variety of AID are commercially available: all of them present similarities and differences. The Medtronic MiniMed™ 780G uses a proportional-integral-derivative (PID) algorithm, a mathematical model that adjusts in real time insulin delivery rate based on 3 elements obtained from CGM reading values: the difference between the actual value and the chosen glucose target (proportional action), past values (integral action) and the glucose's rate of change (derivative action), In contrast, the Tandem t:slim X2™ with Control-IQ employs a model predictive control (MPC) algorithm, which aims, through a complex mathematical model, to predict glucose trends up to half-an-hour in the future, takin, also, in consideration actual and past glucose values. Despite sharing the same objective, said algorithms have different approaches, the former one being "reactive" and the latter "predictive". Therefore, their difference could result in different performances while facing mixed-nutrient meal or unannounced meals, defined as the consumptions of a meal with any prior insulin administration.
Pediatric patients represent certainly a unique subgroup in which therapeutic adherence is a relevant issue, due to cognitive, developmental and behavioral factors. Understanding how different AID algorithms respond to unannounced meals in this age group is therefore crucial for optimizing safety and personalization of diabetes management.
This study was designed to evaluate the strengths and limitations of two a-HCL systems, the Medtronic 780G (PID algorithm) and the Tandem t:slim X2 (MPC algorithm), in managing unannounced meals with different macronutrient compositions in children and adolescents with T1D. We also aim to better understand physiological and technological unannounced meal implications as to provide additional insight useful for the development of new fully closed loop algorithms, capable of minimizing glucose excursions and patient's burden.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Announced meal (AM) | No intervention | –Participants followed their usual therapy while consuming both the "CHO meal" and the "mixed meal" three times each. In this phase, the carbohydrate content of each meal was announced to the insulin pump, and pre-meal boluses were delivered as per standard practice. |
| Unannounced meal (UM) | Experimental | Other: Unannounced mealParticipants consumed the same meals, an equal number of times, without announcing their carbohydrate intake to the device. Consequently, no user-initiated boluses were administered during this period, and all insulin delivery adjustments were determined exclusively by the algorithm. |
Who may qualify
- Ages
- 11 to 18 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (4 listed)
- Age between 11 and 18 years;
- Type 1 diabetes diagnosed for at least 12 months;
- Use of an A-HCL device for at least 3 months;
- Proficiency in carbohydrate counting.
Key exclusion criteria (2 listed)
- Presence of malabsorption disorders;
- Presence of chronic diabetes complications.
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 |
|---|---|---|
| Unannounced mealParticipants consumed both the "CHO meal" and the "mixed meal" three times each, without announcing their carbohydrate intake to the device. Consequently, no user-initiated boluses were administered during this period, and all insulin delivery adjustments were determined exclusively by the algorithm. | Other | Unannounced meal (UM) |
Primary outcome
Change in blood glucose concentration from pre-meal to two hours post-meal (2h-ΔBG), as measured by CGM in mg/dl
Time frame: from pre-meal to two hours post-meal
Change in blood glucose concentration from pre-meal to two hours post-meal (2h-ΔBG), as measured by CGM
8 secondary outcomes
Pre- and post-meal four-hour glucose difference (4h-ΔBG), as measured by CGM in mg/dl
Time frame: from pre-meal to four hour postprandial
Peak CGM value in mg/dl
Time frame: from pre-meal to four hour postprandial
Time to peak CGM value
Time frame: from pre-meal to four hour postprandial
Percentage of spent time in range (TIR, 70-180 mg/dL), as measured by CGM
Time frame: from pre-meal to four hour postprandial
Percentage of spent time in tight range (TITR, 70-140 mg/dL), as measured by CGM
Time frame: from pre-meal to four hour postprandial
Percentage of spent time below range (TBR, < 70 mg/dL), as measured by CGM
Time frame: from pre-meal to four hour postprandial
Percentage of spent time above range (TAR, > 180 mg/dL), as measured by CGM
Time frame: from pre-meal to four hour postprandial
Percentage of spent time in second-level TAR (> 250 mg/dL), as measured by CGM
Time frame: from pre-meal to four hour postprandial
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Mar 2026.
- Derived from this study: PubMed 42430041Lo Presti D, Scire Calabrisotto S, Tomaselli LG, Pezzino G, Frasca F, Baratta R, Sciacca L, Latina C, La Spina N, Galeano F, Oteri V, Tumminia A. The CRUMB study: closed-loop response to unannounced mixed and carbohydrates-rich breakfasts. A randomized controlled crossover pilot-study in a cohort of adolescents with type 1 diabetes. Endocrine. 2026 Jul 10;91(1):222. doi: 10.1007/s12020-026-04705-5.
- Individual participant dataSharing planned: No
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Unannounced meal in people with Type 1 Diabetes Mellitus, run by University of Catania at 1 site in Italy.
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 4 inclusion and 2 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 6 Mar 2026. 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 Italy. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Change in blood glucose concentration from pre-meal to two hours post-meal (2h-ΔBG), as measured by CGM in mg/dl (time frame: from pre-meal to two hours post-meal). 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 NCT07455643, 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 6 Mar 2026.