A Study of LY4213663 in Healthy Participants and Participants With Rheumatoid Arthritis

A Phase 1, Multicenter, Randomized, Placebo-Controlled, Investigator- and Participant-Blinded, Single- and Multiple-Ascending Dose Study to Evaluate Safety, Tolerability, and Pharmacokinetics of LY4213663 in Healthy Participants, and Two Open-Label, Multiple-Dose Evaluations of LY4213663 in Patients With Rheumatoid Arthritis.

Status

Recruiting

Phases

Phase 1

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07258849

Enrollment

141

Registered

2025-12-02

Start date

2025-12-02

Completion date

2028-03-01

Last updated

2026-06-23

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Rheumatoid Arthritis (RA)

Brief summary

The purpose of this study is to evaluate how well LY4213663 is tolerated and what side effects may occur in healthy participants and participants with rheumatoid arthritis (RA). The study drug will be administered either subcutaneously (SC) (under the skin) or intravenously (IV) (into a vein in the arm). Blood tests will be performed to investigate how the body processes the study drug and how the study drug affects the body. The study will last approximately 33 weeks excluding screening.

Interventions

DRUGLY4213663

Administered SC

DRUGPlacebo

Administered SC

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 75 Years

Healthy volunteers

Yes

Inclusion criteria

* Have a body mass index (BMI) of 18.0 to 32.0 kilogram per square meter (kg/m²), inclusive Part C and D Only: * Have a body weight at least 50 kilograms and BMI within the range 18.0 to 40.0 kg/m² (inclusive) at screening * Have a diagnosis of adult-onset RA for at least 3 months prior to screening

Exclusion criteria

Healthy Participants for SAD Part A and MAD Part B Only: * Have a history or presence of cardiovascular, respiratory, hepatic, ophthalmological, renal, gastrointestinal, endocrine, hematological, neurological, or psychiatric disorders capable of significantly altering the absorption, metabolism, or elimination of drugs Participants with RA for Parts C and D Only: * Have Class 4 RA according to American College of Rheumatology (ACR) revised criteria * Have a 12-lead electrocardiogram (ECG) abnormality at screening * Have a current or recent acute active infection

Design outcomes

Primary

Measure	Time frame	Description
Number of Participants with One or More Serious Adverse Event(s) (SAEs) Considered by the Investigator to be Related to Study Drug Administration	Baseline up to Week 33	A summary of SAEs regardless of causality, will be reported in the Reported Adverse Events module

Secondary

Measure	Time frame	Description
Pharmacokinetics (PK): Maximum Concentration (Cmax) of LY4213663	Baseline up to Week 33	PK: Cmax of LY4213663
PK: Area Under the Concentration Versus Time Curve (AUC) of LY4213663	Baseline up to Week 33	PK: AUC of LY4213663

Countries

Germany, United States

Contacts

CONTACTTrial questions or participation questions: 1-877-CTLILLY (1-877-285-4559) or

LillyTrials@Lilly.com1-317-615-4559

CONTACTPhysicians interested in becoming principal investigators please contact

clinical_inquiry_hub@lilly.com

STUDY_DIRECTORCall 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

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Jun 24, 2026