SURPASS-T1D-2

Active not recruitingPhase 3

A Long-Term Study of Tirzepatide (LY3298176) in Adults With Type 1 Diabetes and Obesity or Overweight

A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study Evaluating the Efficacy and Long-Term Safety of Tirzepatide Once Weekly Compared to Placebo in Adults With Type 1 Diabetes and Obesity or Overweight

Lead sponsor

Eli Lilly and Company

Asset

Tirzepatide

Subcutaneous · GLP-1 / GIP dual

Listed sites

Recruiting sites

—

Enrollment

465

estimated

Study population

Obesity / overweight, Type 1 diabetes

Key I/E criteria

•BMI ≥25•HbA1c 7-10.5%

Primary endpoint

•HbA1c, change

Footprint

Where this trial recruits

Site locations as reported to ClinicalTrials.gov. Site count is not enrollment count; per-site enrollment is not available from source.

Identifiers

Registered as

NCT IDNCT06962280

Org study ID27340

Secondary ID2024-519685-51-00

Secondary IDI8F-MC-GPJDEli Lilly and Company

Timeline

Milestones

Study first posted2025-05-08actual

Study start2025-05-12actual

Last update posted2026-02-17actual

Primary completion2026-11estimated (month precision)

Study completion2027-07estimated (month precision)

Assets

Investigational agents

Tirzepatide

Study populations

Who this study enrolls

Obesity / overweightType 1 diabetes

Eligibility

Who can enroll

Minimum age18 Years

SexAll

Healthy volunteersNot accepted

Inclusion criteria

•Have type 1 diabetes and on insulin treatment for at least one year prior to screening

•Have an HbA1c value of 7.0% to 10.5% inclusive, at screening

•Have a body mass index (BMI) of ≥25 kilograms per square meter (kg/m2) at screening

•Are of stable weight for at least 90 days prior to screening and agree to not start an intensive diet or exercise program during the study

Exclusion criteria

•Have experienced two or more events requiring hospitalization due to poor glucose control (hyperglycemia or (diabetic ketoacidosis (DKA)) during the period of 180 days prior to screening and until randomization.

•Have experienced one or more events of severe hypoglycemia during the period of 90 days prior to screening and until randomization.

•Are currently receiving or planning to receive treatment for diabetic retinopathy and/or macular edema

•Have had chronic or acute pancreatitis

•Have used any weight loss drugs or alternative remedies, including herbal or nutritional supplements, within 90 days prior to screening

Endpoints (15)

What's being measured

Protocol endpoints and posted registry outcome measures, grouped into outcome categories. Composite endpoints show their component event types. Standard codes (LOINC, SNOMED CT) are shown where available.

Coverage by outcome category

Weight & body composition

Glycemic / diabetes

Cardiometabolic biomarkers

Patient-reported / QoL

Weight & body composition

6 endpoints

Secondary/protocol endpoint

Change from Baseline in Body Weight

Time frame:Baseline, Week 40, Week 72

Body weight, absolute change (kg)

change from baseline, improvement

Secondary/protocol endpoint

Percent Change from Baseline in Body Weight

Time frame:Baseline, Week 40, Week 72

Body weight, % change

percent change from baseline, improvement

Secondary/protocol endpoint

Percentage of Participants with ≥5% Body Weight Reduction

Time frame:Baseline, Week 40, Week 72

≥5% weight-loss responders

threshold achievement, improvement

Secondary/protocol endpoint

Percentage of Participants with ≥10% Body Weight Reduction

Time frame:Baseline, Week 40, Week 72

≥10% weight-loss responders

threshold achievement, improvement

Secondary/protocol endpoint

Percentage of Participants with ≥15% Body Weight Reduction

Time frame:Baseline, Week 40, Week 72

≥15% weight-loss responders

threshold achievement, improvement

Secondary/protocol endpoint

Change from Baseline in Waist Circumference

Time frame:Baseline, Week 40, Week 72

Waist circumference, change

change from baseline, improvement

Glycemic / diabetes

4 endpoints

Primary/protocol endpoint

Change from Baseline in Hemoglobin A1c (HbA1c)

Time frame:Baseline, Week 40

HbA1c, change

change from baseline, improvement

LOINC 4548-4

Secondary/protocol endpoint

Change from Baseline in HbA1c

Time frame:Baseline, Week 72

HbA1c, change

change from baseline, improvement

LOINC 4548-4

Secondary/protocol endpoint

Percentage of Time Continuous Glucose Monitor (CGM) Glucose Values are Between 70 and 180 milligrams per deciliter (mg/dL) (3.9 and 10.0 millimoles per liter (mmol/L)) Inclusive, Per Day

Time frame:Within 30 days prior to Week 40, Within 30 days prior to Week 72

CGM time-in-range

descriptive, improvement

Secondary/protocol endpoint/low confidence

Percent Change from Baseline in Total Daily Insulin Dose

Time frame:Baseline, Week 40, Week 72

percent change from baseline, improvement

Cardiometabolic biomarkers

4 endpoints

Secondary/protocol endpoint

Change from Baseline in Systolic Blood Pressure (SBP)

Time frame:Baseline, Week 40, Week 72

Systolic BP, change

change from baseline, improvement

LOINC 8480-6

Secondary/protocol endpoint

Percent Change from Baseline in Fasting Triglycerides

Time frame:Baseline, Week 40, Week 72

Triglycerides, change

percent change from baseline, improvement

LOINC 2571-8

Secondary/protocol endpoint

Percent Change from Baseline in Fasting Non-High-Density Lipoprotein (non-HDL) Cholesterol

Time frame:Baseline, Week 40, Week 72

Non-HDL cholesterol, change

percent change from baseline, improvement

Secondary/protocol endpoint

Percent Change from Baseline in High-Sensitivity C-Reactive Protein (hsCRP)

Time frame:Baseline, Week 40, Week 72

hs-CRP, change

percent change from baseline, improvement

LOINC 30522-7

Patient-reported / QoL

1 endpoint

Secondary/protocol endpoint

Change from Baseline in EQ-5D-5L

Time frame:Baseline, Week 40, Week 72

EQ-5D index

change from baseline, improvement

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2

Snapshot dateJuly 1, 2026

Endpoint classificationDelfa endpoint taxonomy v2 (May 13, 2026)

Results tableno registry results posted yet

Trial facts come from public ClinicalTrials.gov records. Endpoint categories are Delfa's classification of those records, not a ClinicalTrials.gov field. All figures reflect the July 1, 2026 snapshot.