A Study of Tirzepatide (LY3298176) Compared With Placebo in Adults With Type 1 Diabetes and Obesity or Overweight (SURPASS-T1D-1)

May 11, 2026 updated by: Eli Lilly and Company

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

The main purpose of this study is to find out how well and how safely tirzepatide works in adults who have type 1 diabetes and obesity or overweight. Participation in the study will last about 49 weeks.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

905

Phase

  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Argentina
      • Buenos Aires, Argentina, C1119ACN
        • CIPREC
      • Buenos Aires, Argentina, C1440AAD
        • CENUDIAB
      • Buenos Aires, Argentina, C1056ABI
        • Centro de Investigaciones Metabólicas (CINME)
      • Buenos Aires, Argentina, C1405BUB
        • Consultorio de Investigacion Clinica EMO SRL
      • Buenos Aires, Argentina, C1056ABH
        • Investigaciones Medicas IMOBA SRL
      • Córdoba, Argentina, 5000
        • Instituto de Investigaciones Clinicas Cordoba
      • Córdoba, Argentina, 5006
        • Centro Medico Privado San Vicente Diabetes
      • Mar del Plata, Argentina, 7600
        • Centro de Investigaciones Médicas Mar del Plata
      • Rosario, Argentina, 2000
        • Fundacion Estudios Clinicos
      • Río Cuarto, Argentina, X5800AEV
        • Instituto Médico Río Cuarto
      • Santa Fe, Argentina, 3000
        • Centro de Diagnóstico y Rehabilitación (CEDIR)
      • Santa Rosa, Argentina, L6300
        • Centro de Salud e Investigaciones Médicas
  • Brazil
      • Curitiba, Brazil, 80810-040
        • Centro de Diabetes Curitiba
      • Fortaleza, Brazil, 60175-047
        • Centro de Diabetes Metabolismo e Endocrinologia
      • Fortaleza, Brazil, 60430-350
        • Private Practice - Dr.Miguel N. Hissa
      • Goiânia, Brazil, 74605-020
        • Universidade Federal de Goias
      • São Paulo, Brazil, 01228-000
        • CPQuali Pesquisa Clínica
      • São Paulo, Brazil, 04266-010
        • CEPIC - Centro Paulista de Investigacao Clinica
      • São Paulo, Brazil, 01228-200
        • CPCLIN
      • São Paulo, Brazil, 05403-000
        • Hospital das Clinicas FMUSP
      • São Paulo, Brazil, 04038-032
        • IBTED - Tecnologia e Educação em Diabetes
      • Vitória, Brazil, 29055450
        • CEDOES
  • Denmark
      • Esbjerg, Denmark, 6700
        • Esbjerg sygehus, Syddansk Universitetshospital
      • Herlev, Denmark, 2730
        • Steno Diabetes Center - Copenhagen
      • Herning, Denmark, 7400
        • Regionshospitalet Gødstrup
      • Hillerød, Denmark, 3400
        • Nordsjællands Hospital - Hillerød
      • Køge, Denmark, 4600
        • Sjællands Universitetshospital Køge
  • France
      • Caen, France, 14033
        • Centre Hospitalier Universitaire de Caen - Hôpital Côte de Nacre
      • Corbeil-Essonnes, France, 91106
        • Centre hospitalier Sud Francilien
      • Le Creusot, France, 71200
        • Hôtel-Dieu du Creusot - site Harfleur
      • Lyon, France, 69008
        • Centre du diabète DIAB-eCARE
      • Marseille, France, 13005
        • Hôpital de la Conception
      • Marseille, France, 13003
        • Hôpital Européen Marseille
      • Montpellier, France, 34295
        • CHU Montpellier Lapeyronie Hospital
      • Nantes, France, 44093
        • Hôpital Nord Guillaume-et-René-Laennec / CHU de Nantes
      • Pontoise, France, 95300
        • Hôpital NOVO
      • Strasbourg, France, 67098
        • CHU Strasbourg-Hautepierre
      • Toulon, France, 83100
        • Centre Hospitalier intercommunal de Toulon La Seyne sur Mer
      • Toulouse, France, 31059
        • CHU Rangueil
      • Vénissieux, France, 69200
        • Groupe Hospitalier Mutualiste Les Portes du Sud
  • Germany
      • Bad Mergentheim, Germany, 97980
        • Diabetespraxis Mergentheim
      • Bochum, Germany, 44869
        • Diabetes- und Stoffwechselpraxis Bochum
      • Essen, Germany, 45136
        • InnoDiab Forschung GmbH
      • Hamburg, Germany, 21109
        • Diabetes Zentrum Wilhelmsburg
      • Karlsburg, Germany, 17495
        • Klinikum Karlsburg
      • Leipzig, Germany, 04103
        • Universitatsklinikum Leipzig
      • Münster, Germany, 48145
        • Institut für Diabetesforschung GmbH Münster
      • Oldenburg, Germany, 23758
        • Red-Institut GmbH
      • Pirna, Germany, 01796
        • Arztpraxis Christine Kosch Pirna
  • Israel
      • Beer Yaacov, Israel, 70300
        • Yitzhak Shamir Medical Center
      • Beersheba, Israel, 8410101
        • Soroka Medical Center
      • Haifa, Israel, 3109601
        • Rambam Health Care Campus
      • Herzliya, Israel, 4600201
        • Institute of Diabetes, Technology and Research - Clalit Health
      • Jerusalem, Israel, 9112001
        • Hadassah Medical Center
      • Petah Tikva, Israel, 4941492
        • Rabin Medical Center
      • Petah Tikva, Israel, 4920235
        • Schneider Children's Medical Center
      • Ramat Gan, Israel, 5262100
        • Sheba Medical Center
      • Tel Aviv, Israel, 6423906
        • Sourasky Medical Center
      • Tel Aviv, Israel, 51549
        • Diabetes Medical Center
  • Italy
      • Bologna, Italy, 40138
        • IRCCS - AOU di Bologna
      • Catanzaro, Italy, 88100
        • AOU Renato Dulbecco
      • Florence, Italy, 50134
        • Azienda Ospedaliera Universitaria Careggi
      • Milan, Italy, 20132
        • Ospedale San Raffaele
      • Naples, Italy, 80100
        • University of Naples Federico II
      • Padova, Italy, 35128
        • Azienda Ospedale - Università Padova
      • Roma, Italy, 00168
        • Fondazione Policlinico Universitario Agostino Gemelli IRCCS - Universita Cattolica del Sacro Cuore
      • Torino, Italy, 10126
        • Azienda Ospedaliero-Universitaria Città della Salute e della Scienza di Torino
  • Japan
      • Chūōku, Japan, 103-0002
        • The Institute of Medical Science, Asahi Life Foundation
      • Ebina, Japan, 243-0432
        • Matoba Internal Medicine Clinic
      • Fukuoka, Japan, 815-8555
        • Japanese Red Cross Fukuoka Hospital
      • Fukuoka, Japan, 815-0071
        • Clinic Masae Minami
      • Hachioji-shi, Japan, 192-0083
        • Hachioji Diabetes Clinic
      • Kamakura-shi, Japan, 247-0056
        • Takai Internal Medicine Clinic
      • Kashiwara, Japan, 582-0005
        • Shiraiwa Medical Clinic
      • Kasugai, Japan, 486-8510
        • Kasugai Municipal Hospital
      • Kisarazu, Japan, 292-8535
        • Kimitsu Chuo Hospital
      • Kofu, Japan, 400-8506
        • Yamanashi Prefectural Central Hospital
      • Kumamoto, Japan, 862-0976
        • Jinnouchi Hospital
      • Kumamoto, Japan, 862-0965
        • Kumamoto Central Hospital - Kumamoto
      • Kure, Japan, 737-0023
        • Kure Medical Center
      • Matsuyama, Japan, 790-0034
        • Mikannohana Clinic, Diabetes, Endocrinology and Metabolism
      • Mito, Japan, 310-0845
        • Kozawa Eye Hospital And Diabetes Center
      • Miyazaki, Japan, 880-0034
        • Heiwadai Hospital
      • Nagoya, Japan, 464-0858
        • Soleil Chikusa Clinic
      • Nagoya, Japan, 468-0009
        • Tosaki Clinic for Diabetes and Endocrinology
      • Naka, Japan, 311-0113
        • Nakakinen clinic
      • Osaka, Japan, 534-0021
        • Osaka City General Hospital
      • Sapporo, Japan, 060-0062
        • Manda Memorial Hospital
      • Sapporo, Japan, 060-0001
        • Odori Diabetes
      • Shimonoseki, Japan, 750-0061
        • Shimonoseki Medical Center
      • Shinjuku, Japan, 160-0022
        • Tomonaga Clinic
      • Shizuoka, Japan, 424-0855
        • Suruga Clinic
      • Tama, Japan, 206-0033
        • Tama Center Clinic Mirai
      • Ushiku, Japan, 300-1207
        • Noritake Clinic
      • Wakayama, Japan, 640-8558
        • Japanese Red Cross Society - Wakayama Medical Center
      • Ōita, Japan, 870-0039
        • Abe Clinic
  • Mexico
      • Chihuahua City, Mexico, 31110
        • Enclifar Ensayos Clínicos Farmacológicos Sc
      • Guadalajara, Mexico, 44670
        • Unidad de Investigación Clínica y Atención Médica HEPA S.C.
      • Guadalajara, Mexico, 44260
        • Centro de Investigacion Medica de Occidente, S.C.
      • Guadalajara, Mexico, 44150
        • Unidad de Investigaci�n Cl�nica Cardiometabolica de Occidente
      • Hacienda de Las Palmas, Mexico, 52763
        • Invecordis S.C.
      • Monterrey, Mexico, 64020
        • CEINV Salud
      • Monterrey, Mexico, 64610
        • Clínica García Flores SC
      • Puebla City, Mexico, 72190
        • Consultorio Médico de Endocrinología y Pediatría
      • Tampico, Mexico, 89210
        • Medsal Centro Médico
  • Puerto Rico
      • Bayamón, Puerto Rico, 00959
        • Advanced Clinical Research, LLC
      • Manati, Puerto Rico, 00674
        • Manati Center for Clinical Research
  • Spain
      • A Coruña, Spain, 15006
        • CHUAC-Complejo Hospitalario Universitario A Coruña
      • Barcelona, Spain, 08036
        • Hospital Clinic de Barcelona
      • Barcelona, Spain, 08035
        • Hospital Universitari Vall d'Hebron
      • Barcelona, Spain, 08041
        • Hospital de la Santa Creu i Sant Pau
      • Ferrol, Spain, 15405
        • Complejo Hospitalario Universitario de Ferrol (CHUF)- Hospital Naval
      • Móstoles, Spain, 28935
        • Hospital Universitario de Móstoles
      • Santander, Spain, 39008
        • Hospital Universitario Marques de Valdecilla
      • Seville, Spain, 41013
        • Hospital Universitario Virgen del Rocio
  • United States
    • California
      • Santa Barbara, California, United States, 93105
        • Sansum Diabetes Research Institute
      • Santa Clarita, California, United States, 91321
        • Care Access - Santa Clarita
    • Colorado
      • Aurora, Colorado, United States, 80045
        • University of Colorado Anschutz Medical Campus
    • Georgia
      • Atlanta, Georgia, United States, 30318
        • Atlanta Diabetes Associates
      • Decatur, Georgia, United States, 30034
        • Orita Clinical Research
      • Woodstock, Georgia, United States, 30189
        • North Georgia Clinical Research
    • Hawaii
      • Honolulu, Hawaii, United States, 96814
        • East-West Medical Research Institute
    • Idaho
      • Idaho Falls, Idaho, United States, 83404
        • Rocky Mountain Clinical Research
    • Illinois
      • Springfield, Illinois, United States, 62702
        • Southern Illinois University School of Medicine
    • Indiana
      • Indianapolis, Indiana, United States, 46202
        • Indiana University Health University Hospital
    • Iowa
      • West Des Moines, Iowa, United States, 50266
        • Iowa Diabetes and Endocrinology Research Center
    • Maryland
      • Rockville, Maryland, United States, 20852
        • Endocrine and Metabolic Consultants
    • Minnesota
      • Minneapolis, Minnesota, United States, 55416
        • HealthPartners Institute dba International Diabetes Center
    • Mississippi
      • Ridgeland, Mississippi, United States, 39157
        • SKY Integrative Medical Center/SKYCRNG
    • Montana
      • Missoula, Montana, United States, 59804
        • Boeson Research MSO
    • Nevada
      • Las Vegas, Nevada, United States, 89148
        • Palm Research Center Sunset
      • Las Vegas, Nevada, United States, 89128
        • Palm Research Center Tenaya
    • New York
      • Albany, New York, United States, 12203
        • Albany Medical College, Division of Community Endocrinology
      • Buffalo, New York, United States, 14221
        • Research Foundation of SUNY - University of Buffalo
      • New York, New York, United States, 10016
        • NYC Research
      • Syracuse, New York, United States, 13210
        • Suny Upstate Medical University
    • North Carolina
      • Morehead City, North Carolina, United States, 28557
        • Lucas Research, Inc.
    • Ohio
      • Lima, Ohio, United States, 45805
        • Care Access - Lima
    • Oklahoma
      • Norman, Oklahoma, United States, 73069
        • Alliance for Multispecialty Research, LLC
    • Pennsylvania
      • West Chester, Pennsylvania, United States, 19380
        • Suburban Research Associates
    • Texas
      • Austin, Texas, United States, 78731
        • Texas Diabetes & Endocrinology, P.A.
      • Dallas, Texas, United States, 75230
        • Velocity Clinical Research, Dallas
      • McKinney, Texas, United States, 75069
        • Tekton Research, LLC.
      • Wylie, Texas, United States, 75098
        • Medrasa Clinical Research
    • Washington
      • Redmond, Washington, United States, 98052
        • Eastside Research Associates
      • Renton, Washington, United States, 98057
        • Rainier Clinical Research Center

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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

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
Intervention / Treatment
Placebo Comparator: Placebo
Participants will receive placebo SC
Drug: Placebo
Administered SC
Experimental: Tirzepatide Dose 1
Participants will receive tirzepatide subcutaneously (SC)
Drug: Tirzepatide
Administered SC
Other Names:
  • LY3298176
Experimental: Tirzepatide Dose 2
Participants will receive tirzepatide SC
Drug: Tirzepatide
Administered SC
Other Names:
  • LY3298176
Experimental: Tirzepatide Dose 3
Participants will receive tirzepatide SC
Drug: Tirzepatide
Administered SC
Other Names:
  • LY3298176
Experimental: Tirzepatide Dose 4
Participants will receive tirzepatide SC
Drug: Tirzepatide
Administered SC
Other Names:
  • LY3298176

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in Hemoglobin A1c (HbA1c)
Time Frame: Baseline, Week 40
Baseline, Week 40

Secondary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in Waist Circumference
Time Frame: Baseline, Week 40
Baseline, Week 40
Change from Baseline in Body Weight
Time Frame: Baseline, Week 40
Baseline, Week 40
Change from Baseline in Systolic Blood Pressure (SBP)
Time Frame: Baseline, Week 40
Baseline, Week 40
Percent Change from Baseline in Body Weight
Time Frame: Baseline, Week 40
Baseline, Week 40
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 40
Percentage of Participants with ≥5% Body Weight Reduction
Time Frame: Baseline, Week 40
Baseline, Week 40
Percentage of Participants with ≥10% Body Weight Reduction
Time Frame: Baseline, Week 40
Baseline, Week 40
Percentage of Participants with ≥15% Body Weight Reduction
Time Frame: Baseline, Week 40
Baseline, Week 40
Percent Change from Baseline in Fasting Triglycerides
Time Frame: Baseline, Week 40
Baseline, Week 40
Percent Change from Baseline in Fasting Non-High-Density Lipoprotein (non-HDL) Cholesterol
Time Frame: Baseline, Week 40
Baseline, Week 40
Percent Change from Baseline in Total Daily Insulin Dose
Time Frame: Baseline, Week 40
Baseline, Week 40
Percent Change from Baseline in High-Sensitivity C-Reactive Protein (hsCRP)
Time Frame: Baseline, Week 40
Baseline, Week 40
Change from Baseline in EQ-5D-5L
Time Frame: Baseline, Week 40
Baseline, Week 40

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Eli Lilly and Company

Investigators

  • Study Director: Call 1-877-CTLILLY (1-877-285-4559) or 1-317-615-4559 Mon - Fri 8 AM - 8 PM Eastern time (UTC/GMT - 5 hours, EST), Eli Lilly and Company

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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)

April 25, 2025

Primary Completion (Estimated)

November 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

April 4, 2025

First Submitted That Met QC Criteria

April 4, 2025

First Posted (Actual)

April 6, 2025

Study Record Updates

Last Update Posted (Actual)

May 12, 2026

Last Update Submitted That Met QC Criteria

May 11, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 27285
  • I8F-MC-GPJA (Other Identifier: Eli Lilly and Company)
  • 2024-519684-17-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.

IPD Sharing Time Frame

Data are available 6 months after the primary publication and approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.

IPD Sharing Access Criteria

A research proposal must be approved by an independent review panel and researchers must sign a data sharing agreement.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • CSR

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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