A Study of Retatrutide (LY3437943) in Participants With Obesity or Overweight (TRIUMPH-8)

April 16, 2026 updated by: Eli Lilly and Company

A Phase 3b Study to Investigate the Efficacy and Safety of Retatrutide Once Weekly in Participants Without Type 2 Diabetes Who Have Obesity or Overweight: A Randomized, Double-Blind, Placebo-Controlled Trial

The purpose of this study is to evaluate the efficacy and safety of retatrutide compared with placebo for body weight reduction.

Participation in the study will last about 65 weeks and may include about 18 visits.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

250

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

  • United Kingdom
      • Birmingham, United Kingdom, B21 9RY
        • FutureMeds - Birmingham
      • Blackpool, United Kingdom, FY3 7EN
        • Layton Medical Centre
      • Bradford-on-Avon, United Kingdom, BA15 1DQ
        • Bradford on Avon Health Centre
      • Bromborough, United Kingdom, CH62 6EE
        • FutureMeds - Liverpool
      • Cheadle, United Kingdom, ST10 1NS
        • Cheadle Community Hospital
      • Hounslow, United Kingdom, TW4 7NR
        • HMC Health Group - Meadows Centre for Health
      • Oxford, United Kingdom, OX4 1XB
        • St Bartholomew's Medical Centre
      • Penzance, United Kingdom, TR18 3DX
        • Atlantic Medical
      • Poole, United Kingdom, BH16 5PW
        • The Adam Practice
      • Rotherham, United Kingdom, S61 1AH
        • Woodstock Bower Surgery
      • Torpoint, United Kingdom, PL11 2TB
        • Rame Group Practice
      • Wellingborough, United Kingdom, NN8 4RW
        • Albany House Medical Centre
  • United States
    • California
      • Riverside, California, United States, 92503
        • Artemis Institute for Clinical Research
    • Florida
      • Atlantis, Florida, United States, 33462
        • JEM Research Institute
      • Orlando, Florida, United States, 32806
        • Headlands Research Orlando
      • Tamarac, Florida, United States, 33321
        • Care Access - Tamarac
    • Illinois
      • Arlington Heights, Illinois, United States, 60005
        • Care Access - Arlington Heights
    • Kentucky
      • Louisville, Kentucky, United States, 40213
        • L-MARC Research Center
    • Louisiana
      • Monroe, Louisiana, United States, 71201
        • IMA Clinical Research Monroe - Armand
    • Maryland
      • Baltimore, Maryland, United States, 21208
        • Pharmasite Research, Inc.
    • Missouri
      • Chesterfield, Missouri, United States, 63005
        • Clinical Research Professionals
      • Springfield, Missouri, United States, 65807
        • Clinvest Headlands Llc
    • New Jersey
      • Warren Township, New Jersey, United States, 07059
        • IMA Clinical Research Warren
    • New York
      • New York, New York, United States, 10036
        • Ima Clinical Research Manhattan
    • North Carolina
      • Wilmington, North Carolina, United States, 28403
        • Trial Management Associates - Wilmington - Floral Parkway
    • Texas
      • Dallas, Texas, United States, 75251
        • Cedar Health Research
      • El Paso, Texas, United States, 79902
        • Headlands Research-El Paso
      • Euless, Texas, United States, 76040
        • Cedar Health Research - Euless
      • Fort Worth, Texas, United States, 76132
        • Cedar Health Research - Fort Worth
      • Houston, Texas, United States, 77054
        • Care Access - Houston
      • San Antonio, Texas, United States, 78229
        • IMA Clinical Research San Antonio

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 a body mass index (BMI) of:

    • ≥30 kilogram per square meter (kg/m2) OR
    • ≥27 kg/m2 with at least one of the following weight-related conditions: high blood pressure, abnormal levels of lipid, obstructive sleep apnea, heart disease
  • Have at least one unsuccessful attempt to lose weight by dieting

Exclusion Criteria:

  • Have a self-reported change in body weight >5 kg (11 pounds) within 90 days before screening
  • Have a prior or planned surgical treatment for obesity
  • Have type 1 diabetes or type 2 diabetes
  • Have a family or personal history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN-2)

  • Have had within the past 90 days before screening

    • acute myocardial infarction
    • cerebrovascular accident (stroke)
    • hospitalization for unstable angina, or
    • hospitalization due to congestive heart failure
  • Have New York Heart Association Functional Classification Class IV congestive heart failure
  • Have a history of chronic or acute pancreatitis
  • Have taken weight loss drugs, including over-the counter medications 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: Retatrutide Dose 1
Participants will receive retatrutide subcutaneously (SC)
Drug: Retatrutide
Administered SC
Other Names:
  • LY3437943
Experimental: Retatrutide Dose 2
Participants will receive retatrutide SC
Drug: Retatrutide
Administered SC
Other Names:
  • LY3437943

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Percent Change from Baseline in Body Weight
Time Frame: Baseline, Week 56
Baseline, Week 56

Secondary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in Systolic Blood Pressure
Time Frame: Baseline, Week 56
Baseline, Week 56
Change from Baseline in Waist Circumference
Time Frame: Baseline, Week 56
Baseline, Week 56
Percent Change from Baseline in Non-High-Density Lipoprotein (HDL) Cholesterol
Time Frame: Baseline, Week 56
Baseline, Week 56
Pharmacokinetics (PK): Steady State Area Under the Concentration Time Curve (AUC)
Time Frame: Baseline through Week 56
Baseline through Week 56

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)

November 17, 2025

Primary Completion (Estimated)

July 1, 2027

Study Completion (Estimated)

July 1, 2027

Study Registration Dates

First Submitted

November 14, 2025

First Submitted That Met QC Criteria

November 14, 2025

First Posted (Actual)

November 18, 2025

Study Record Updates

Last Update Posted (Actual)

April 17, 2026

Last Update Submitted That Met QC Criteria

April 16, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 27769
  • J1I-MC-GZQJ (Other Identifier: Eli Lilly and Company)

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 or 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 should be approved by an independent review panel and researchers should 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

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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