MANATEE-T1D: Metformin ANd AutomaTEd Insulin Delivery System Effects on Renal Vascular Resistance, Insulin Sensitivity, and Cardiometabolic Function in Youth With Type 1 Diabetes (MANATEE-T1D)

June 10, 2025 updated by: Kalie Tommerdahl
Diabetic kidney disease and cardiovascular disease remain the leading causes of morbidity and mortality in people with type 1 diabetes and are exacerbated with longer duration of diabetes and time outside goal glycemic range. Yet, type 1 diabetes is a complex disease with pathophysiology that extends beyond beta-cell injury and insulin deficiency to include insulin resistance and renal vascular resistance, factors that accelerate cardiovascular disease risk. We have shown that metformin improved peripheral insulin sensitivity and vascular stiffness in youth with type 1 diabetes on multiple daily insulin injections or standard insulin pumps. However, metformin's effect on kidney and endothelial outcomes, and the effects of type 1 diabetes technologies, with or without metformin, on any cardiovascular or kidney outcome, remains unknown. Automated insulin delivery systems combine an insulin pump, continuous glucose monitor, and control algorithm to modulate background insulin delivery and decrease peripheral insulin exposure while improving time in target range and reducing hypoglycemia. We hypothesize that automated insulin delivery systems, particularly when combined with metformin, may modulate renal vascular resistance and insulin sensitivity, thereby impacting cardiometabolic function. MANATEE-T1D is a randomized, double-blind, placebo-controlled trial of 4 months of metformin 2,000 mg daily in 40 youth aged 12-25 years with type 1 diabetes on automated insulin delivery systems vs. 20 control youth with type 1 diabetes on multiple daily injections plus a continuous glucose monitor or an insulin pump in manual mode plus a continuous glucose monitor which will assess for changes in calculated renal vascular resistance and gold standard measures of whole-body and adipose insulin sensitivity, arterial stiffness, and endothelial function.

Study Overview

Status

Status

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

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 (Estimated)

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.
60

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.
  • Phase 1

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.
  • Name: Kalie Tommerdahl, MD
  • Phone Number: (206) 616-9015
  • Email: ktomme@uw.edu

Study Locations

  • United States
    • Colorado
      • Aurora, Colorado, United States, 80045
        • Active, not recruiting
        • Children's Hospital Colorado/University of Colorado Anschutz Medical Campus
    • Washington
      • Seattle, Washington, United States, 98102
        • Recruiting
        • Seattle Children's Hospital
        • Principal Investigator:
          • Kalie Tommerdahl, MD
        • Contact:
          • Kalie Tommerdahl, MD
          • Phone Number: (206) 616-9015
          • Email: ktomme@uw.edu

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

12 years to 21 years (Child, Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • T1D and using an automated insulin delivery system or multiple daily insulin injections/manual insulin pump plus continuous glucose monitor for > 6 months
  • Age 12-25 years
  • Use of an automated insulin delivery system or multiple daily insulin injections plus a continuous glucose monitor or an insulin pump in manual mode plus a continuous glucose monitor for > 6 months
  • Hemoglobin A1c < 11%
  • No recent episodes of diabetic ketoacidosis (DKA) or hyperglycemic hyperosmolar syndrome (HHS) (within 30 days)
  • Pubertal (Tanner stage ≥ 2)
  • Weight > 54 kg and BMI > 5th percentile for age and sex

Exclusion Criteria:

  • Blood pressure > 140/90 mm Hg
  • Hemoglobin < 9 g/dL
  • Estimated glomerular filtration rate < 60 mL/min/1.73 m2 or serum creatinine > 1.2 mg/dL or history of urinary albumin to creatinine ratio ≥ 300mg/g or history of acute kidney injury
  • Use of anti-diabetic agents except insulin, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARB's), diuretics, daily non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin, sulfonamides, procaine, thiazosulfone or probenecid
  • Seafood or iodine allergy
  • Pregnancy or breast feeding for females

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: Parallel Assignment
  • Masking: Double

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.
Active Comparator: Metformin plus automated insulin delivery system
Some participants with type 1 diabetes using an automated insulin delivery system will be randomized to receive treatment with metformin and will undergo RPF (Aminohippurate Sodium Injections 20%), GFR (Iohexol Inj 300 MG/ML), and insulin sensitivity (hyperinsulinemic-euglycemic clamp) assessments, in addition to assessments of cardiovascular and endothelial function.
Drug: Metformin Hcl 1000Mg Tab
Agent used to modify insulin sensitivity
Other Names:
  • Glucophage
  • Glumetza
  • Fortamet
  • Riomet
Drug: Aminohippurate Sodium 20 % Injection
Diagnostic aid/agent used to measure renal plasma flow and calculate renal vascular resistance
Other Names:
  • Para-aminohippurate
  • Aminohippuric acid
  • Sodium 4-amino hippurate (PAH) injection 20% (2g/10 mL)
Drug: Iohexol 300 Mg/mL Injectable Solution
Diagnostic aid/agent used to measure glomerular filtration rate
Other Names:
  • Omnipaque 300
Placebo Comparator: Placebo plus automated insulin delivery system
Some participants with type 1 diabetes using an automated insulin delivery system will be randomized to receive treatment with a placebo pill which is identical in appearance to the metformin pill and will undergo RPF (Aminohippurate Sodium Injections 20%), GFR (Iohexol Inj 300 MG/ML), and insulin sensitivity (hyperinsulinemic-euglycemic clamp) assessments, in addition to assessments of cardiovascular and endothelial function.
Drug: Aminohippurate Sodium 20 % Injection
Diagnostic aid/agent used to measure renal plasma flow and calculate renal vascular resistance
Other Names:
  • Para-aminohippurate
  • Aminohippuric acid
  • Sodium 4-amino hippurate (PAH) injection 20% (2g/10 mL)
Drug: Iohexol 300 Mg/mL Injectable Solution
Diagnostic aid/agent used to measure glomerular filtration rate
Other Names:
  • Omnipaque 300
Drug: Placebo
Identical to Metformin Hcl 1000Mg Tab but without metabolic effects
Other: Multiple daily insulin injections or manual insulin pump plus continuous glucose monitor
Participants with type 1 diabetes using multiple daily injections or an insulin pump in manual mode plus a continuous glucose monitor will not be randomized to receive medication treatment but will undergo RPF (Aminohippurate Sodium Injections 20%), GFR (Iohexol Inj 300 MG/ML), and insulin sensitivity (hyperinsulinemic-euglycemic clamp) assessments, in addition to assessments of cardiovascular and endothelial function.
Drug: Aminohippurate Sodium 20 % Injection
Diagnostic aid/agent used to measure renal plasma flow and calculate renal vascular resistance
Other Names:
  • Para-aminohippurate
  • Aminohippuric acid
  • Sodium 4-amino hippurate (PAH) injection 20% (2g/10 mL)
Drug: Iohexol 300 Mg/mL Injectable Solution
Diagnostic aid/agent used to measure glomerular filtration rate
Other Names:
  • Omnipaque 300

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
Renal vascular resistance
Time Frame: 4 months
Renal plasma flow will be measured by para-aminohippurate clearance and used to calculate renal vascular resistance
4 months
Glomerular filtration rate
Time Frame: 4 months
Measured by iohexol clearance
4 months

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
Arterial stiffness
Time Frame: 4 months
Measured by SphygmoCor
4 months
Insulin sensitivity
Time Frame: 4 months
Measured by hyperinsulinemic-euglycemic clamp
4 months

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.
Kalie Tommerdahl

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.
University of Colorado, Denver
National Heart, Lung, and Blood Institute (NHLBI)

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 1, 2022

Primary Completion (Estimated)

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.
March 1, 2027

Study Completion (Estimated)

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.
July 31, 2027

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).
September 13, 2021

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.
September 22, 2021

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.
October 4, 2021

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.
June 13, 2025

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.
June 10, 2025

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.
June 1, 2025

More Information

Terms related to this study

Keywords

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.
  • 21-3483
  • K23HL159292 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

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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Drug Interventions

Conditions

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