NCT06820281

Acute Metabolic Effects of Tirzepatide in Type 1 Diabetes

Acute Metabolic Effects of Tirzepatide in Type 1 Diabetes: a Phase 2 Double Blinded Placebo Controlled Clinical Trial (TIRTLE2)

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 44 (estimated)
• Sponsor: Garvan Institute of Medical Research · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Not accepted

Summary

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.

Detailed description

TIRTLE2 is a phase 2 double-blinded placebo-controlled mechanistic clinical trial that extends upon the findings of TIRTLE1, a phase 2 double-blinded placebo-controlled trial (TZP 5.0mg vs placebo over 12 weeks) in T1D (trial registration: ACTRN12624000111572). TIRTLE2 is a designed to determine whether TZP can 1) improve whole body insulin sensitivity, 2) reduce prandial glucagon secretion, 3) impacts lipolysis and growth hormone secretion overnight, and 4) determine if TZP can maintain the glucagon response to hypoglycemia. The acute effects of TZP on metabolism will be assessed after 6 weeks, to limit the degree of weight loss (indicating a role for TZP on improving metabolic physiology in T1D, beyond weight management in T1D). To address these research aims, a single comprehensive clinical trial will be performed in 44 participants with T1D, who will receive a weekly injection of TZP 2.5mg or placebo for 6 weeks. A short treatment duration was chosen to assess if TZP offers T1D-specific benefits prior to significant weight loss. TIRTLE2 will employ the 'gold standard' hyperinsulinemic-euglycemic and hypoglycemic clamps, in conjunction with complementary analyses of the effects of TZP on metabolism across multiple physiological states. This mechanistic study will define mechanisms by which GLP1-GIP co-agonism may uniquely provide clinical benefits in T1D during the fasting and fed states, and during hypoglycemia.

Conditions

• Type 1 Diabetes Mellitus

Interventions

Type	Name	Description
DRUG	Tirzepatide 2.5mg weekly	Tirzepatide 2.5 mg/0.5 mL solution for injection vial or pre-filled pen. Each vial/ pre-filled pen contains tirzepatide 2.5 mg in 0.5 mL solution (2.5mg in 0.6mL if Kwikpen) Tirzepatide will be administered by drawing up into a syringe, then administering by subcutaneous injection weekly by study nurses.
DRUG	Placebo injection (normal saline)	Placebo will be given as 0.5mL normal saline (if comparator against vial or pre-filled pen), or 0.6mL (if comparator against Mounjaro Kwikpen), drawn up into a syringe and administered by subcutaneous injection weekly by study nurses.

Timeline

• Start date: 2025-12-01
• Primary completion: 2027-12-31
• Completion: 2027-12-31
• First posted: 2025-02-11
• Last updated: 2025-10-08

Locations

1 site across 1 country: Australia

Regulatory

• FDA-regulated drug study