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CompletedPhase 1Results posted

A Study of Tirzepatide (LY3298176) in Healthy Lactating Females

A Study to Evaluate Tirzepatide Concentrations in Breastmilk Following Administration of Single Dose of Tirzepatide by Subcutaneous Injection in Healthy Lactating Females

Asset

Tirzepatide

Subcutaneous · GLP-1 / GIP dual

Listed sites

1

Recruiting sites

Enrollment

11

actual

Study population

Healthy volunteers

Key I/E criteria

BMI 18.5-40FemaleHealthy volunteers

Primary endpoint

AUC of Tirzepatide in Breastmilk From Zero to Infinity (AUC [0-∞])

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 IDNCT05978713
Org study ID18614
Secondary IDI8F-MC-GPINEli Lilly and Company

Timeline

Milestones

Study start2023-07-31actual
Study first posted2023-08-07actual
Primary completion2024-03-12actual
Study completion2024-03-12actual
Last update posted2025-04-27actual
Results first posted2025-04-27actual

Assets

Investigational agents

Study populations

Who this study enrolls

Healthy volunteers

Eligibility

Who can enroll

Minimum age18 Years
SexFemale
Healthy volunteersAccepted

Inclusion criteria

Participants who are overtly healthy females as determined by medical evaluation
Female participants who delivered normal-term infant (at least 37 weeks gestation) and are at least 6 weeks postpartum at the time of screening
Body mass index (BMI) between 18.5 and 40.0 kilograms per meter squared (kg/m²), inclusive
Female participants who has well-established lactation and is breastfeeding her infant. Note: Breastfeeding must be discontinued prior to the administration of tirzepatide on Day 1 and not resumed for the remaining duration of the study until a follow-up visit (or for total of 29 days after tirzepatide dosing for participants who discontinue early).

Exclusion criteria

Have a history of inadequate lactation (for multiparous females who have previously breastfed)
Have confirmed type 1 or type 2 diabetes mellitus
Regularly use known drugs of abuse or show positive findings on drug screen

Endpoints (2)

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.

Safety / tolerability / PK

2 endpoints
Primary/registry result

Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve of Tirzepatide in Breastmilk From Zero to Infinity (AUC [0-∞])

Time frame:Predose, 3, 6, 9, 12, 16, 24, 36, 48, 72, 96, 120, 168, 336, 504, 672 hours post-dose

AUC₀–∞

concentration, descriptive

Posted result

GroupValue (geometric_mean), nanogram*hours per milliliter (ng*h/mL)95% CI
5 mg TirzepatideNA
Primary/protocol endpoint

Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve of Tirzepatide in Breastmilk From Zero to Infinity (AUC [0-∞])

Time frame:Predose, 3, 6, 9, 12, 16, 24, 36, 48, 72, 96, 120, 168, 336, 504, 672 hours post-dose

AUC₀–∞

concentration, descriptive

Provenance

Sources

Trial identity, design, statusClinicalTrials.gov API v2
Snapshot dateJuly 1, 2026
Endpoint classificationDelfa endpoint taxonomy v2 (May 13, 2026)
Results tableClinicalTrials.gov results section

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.