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Trial · Interventional

RecruitingPhase 2Registry data

Acute Metabolic Effects of Tirzepatide in Type 1 Diabetes

Short name TIRTLE2

NCTNCT06820281 (opens ClinicalTrials.gov in a new tab)Other idU1111-1316-2752
Open at ClinicalTrials.govAsk about this trial

Overview

Status
Recruiting
Phase
Phase 2
Enrollment
44 participants (estimated)
Sponsor
Victor Chang Cardiac Research Institute · Other gov
Design
Randomized · Quadruple masking
Countries
1 country

Australia

Start
7 Jul 2026
Primary completion
31 Dec 2027 (estimated)
Completion
31 Dec 2027 (estimated)
First posted
11 Feb 2025
Last update posted
16 Sept 2026
Conditions
Type 1 Diabetes Mellitus

Timeline

1 trial · 1 ongoing

  • Completed
  • Ongoing
  • Not yet recruiting
  • Stopped
  • Estimated dates (est.)
  • Results posted
202620272028
  1. Ph 2

    TIRTLE2

    NCT06820281

    7 Jul 2026 to est. 31 Dec 2027

Registry summary

Text and fields below are the sponsor's entries at ClinicalTrials.gov, shown as posted.

This study will examine the effects of Tirzepatide (TZP), a glucagon-like peptide 1 (GLP1) - gastric inhibitory peptide (GIP) co-agonist, on metabolism in type 1 diabetes (T1D). Research participants with T1D will undergo measures of insulin sensitivity, and hormone levels post-meal, post-hypoglycemia and during the overnight period. These measures will be performed prior to, and after 6 weeks of treatment with TZP or placebo.

Interventions

  • Tirzepatide 2.5mg weeklyDrug
  • Placebo injection (normal saline)Drug

Arms2

  • Experimental

    Tirzepatide 2.5mg weekly

    Administered subcutaneously.

  • Placebo comparator

    Placebo

    Administered subcutaneously.

Primary outcomes1

Outcomes the sponsor listed as primary.

  1. Whole-body insulin sensitivity

    Time frame · 6 weeks

    Registry description

    Change in insulin sensitivity from baseline, assessed using the hyperinsulinemic-euglycemic clamp (60 mU/m2/min)

Secondary outcomes(16)

  1. Prandial glucagon secretion

    Time frame · 6 weeks

    Registry description

    Change from baseline glucagon area under the curve (AUC) during mixed meal tolerance test (MMTT)

  2. Glucagon response to hypoglycemia

    Time frame · 6 weeks

    Registry description

    Change from baseline glucagon AUC after glucose nadir as measured during the hyperinsulinemic hypoglycemic clamp

  3. % Time level 2 hypoglycemia

    Time frame · 6 weeks

    Registry description

    Change from baseline % time level 2 hypoglycemia (defined by glucose \< 54 mg/dL \[\<3.0 mmol/L\]) as measured by continuous glucose monitoring

  4. % Time level 1 hypoglycemia

    Time frame · 6 weeks

    Registry description

    Change from baseline % time level 1 hypoglycemia (defined by glucose \< 70 mg/dL \[3.9 mmol/L\] and ≥ 54 mg/dL \[3.0 mmol/L\]) as measured by continuous glucose monitoring

  5. Resting energy expenditure (REE)

    Time frame · 6 weeks

    Registry description

    Change from baseline REE as measured by indirect calorimetry

  6. Overnight growth hormone curve

    Time frame · 6 weeks

    Registry description

    Change from baseline growth hormone area under the curve (AUC) as measured overnight blood samples

  7. Overnight free-fatty acids (FFA) curve

    Time frame · 6 weeks

    Registry description

    Change from baseline FFA under the curve (AUC) as measured overnight blood samples

  8. Total daily insulin dose

    Time frame · 6 weeks

    Registry description

    Change from baseline total daily insulin dose as measured by pump record

  9. Total daily basal insulin dose

    Time frame · 6 weeks

    Registry description

    Change from baseline total daily basal insulin dose as measured by pump record

  10. Total daily bolus insulin dose

    Time frame · 6 weeks

    Registry description

    Change from baseline total daily bolus insulin dose as measured by pump record

  11. % Time in Range (TIR)

    Time frame · 6 weeks

    Registry description

    Change from baseline %TIR (defined by % readings between 70mg/dL - 180 mg/dL \[3.9 - 10.0 mmol/L\]) as measured by continuous glucose monitoring

  12. % Time Below Range (TBR)

    Time frame · 6 weeks

    Registry description

    Change from baseline %TBR (defined by % readings below 70mg/dL \[3.9mmol/L\]) as measured by continuous glucose monitoring

  13. % Time level 1 hyperglycemia

    Time frame · 6 weeks

    Registry description

    Change from baseline % time level 1 hyperglycemia (defined by glucose \> 180 mg/dL \[10 mmol/L\] and glucose ≤ 250 mg/dL \[13.9 mmol/L\]) as measured by continuous glucose monitoring

  14. % Time level 2 hyperglycemia

    Time frame · 6 weeks

    Registry description

    Change from baseline % time level 1 hyperglycemia (defined by glucose \> 250 mg/dL \[13.9 mmol/L\])) as measured by continuous glucose monitoring

  15. Glycemic variability

    Time frame · 6 weeks

    Registry description

    Change from glycemic variability as measured by continuous glucose monitoring

  16. Gastric emptying

    Time frame · 6 weeks

    Registry description

    Change from baseline gastric emptying during the mixed meal tolerance test (MMTT) assessed using radiolabelled isotope and breath sampling

Posted results

Values are shown as posted at ClinicalTrials.gov, with their units. PepBank has not converted, pooled or compared them.

No results are posted for this trial.

A trial that is still running, or that stopped early, may post results later.

Registry data comes from ClinicalTrials.gov. Study results come from studies, not from the registry. How PepBank works

Studies1

Studies that cite this trial.

Studies with results

1 study on this page

Indexing hint: Randomized controlled trial · 2026

6 results

Tirzepatide in Adults With Type 1 Diabetes: A Phase 2 Randomized Placebo-Controlled Clinical Trial.

Snaith et al. 2026Diabetes carecited by 26

PMID 41264593PMC12719702DOI 10.2337/dc25-2379PUB-41264593

Rights unknown6 results
Source linkSee results (6)

Eligibility

Who could join, as posted.

Sex
All
Age
from 18 Years up to 70 Years
Healthy volunteers
Not accepted
Inclusion and exclusion criteria, as posted
Inclusion Criteria: * age 18-70 years * BMI ≥ 25 kg/m2 * HbA1c ≤ 9.0% * insulin delivery using an automated insulin delivery system * at least 2 years since diagnosis of type 1 diabetes Exclusion Criteria: * TZP or GLP-1 receptor agonist in last 3 months; metformin or sodium glucose co-transporter 2 (SGLT2) inhibitor in the last 6 weeks; systemic steroids, antipsychotics, in the last 6 weeks. * Hypoglycemic unawareness or severe hypoglycemia last 6 months. * History of seizure disorder. * History of weight loss surgery. * eGFR \<60 mL/min/1.73 m2. * Liver disease (known cirrhosis, LFTs \> 3x upper limit of normal). * Active malignancy. * Pregnant, breastfeeding, planning pregnancy within 6 months, or not using adequate contraception. * Coronary event or stroke in last 6 months * Active or untreated proliferative diabetic retinopathy * Hemoglobin level \< 13.5 g/dL in men, \< 12.0 g/dL in women

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