A Study of LY4298445 in Healthy Participants and Participants With Systemic Lupus Erythematosus (SLE) or Rheumatoid Arthritis (RA)

April 16, 2026 updated by: Eli Lilly and Company

A Phase 1, Multicenter, Randomized, Placebo-Controlled, Participant-Blind, Single-Ascending Dose Study of LY4298445 in Healthy Participants and an Open-Label Single-Ascending Dose and Multiple-Ascending Dose Study of LY4298445 in Participants With Systemic Lupus Erythematosus or Rheumatoid Arthritis

The purpose of this study is to investigate the safety and tolerability of LY4298445 in healthy participants and in participants with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA). Participation in the study will last up to approximately 52 weeks.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

63

Phase

  • Phase 1

Contacts and Locations

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

Study Contact

Study Contact Backup

  • Name: Trial questions or participation questions: 1-877-CTLILLY (1-877-285-4559)
  • Phone Number: 1-317-615-4559
  • Email: LillyTrials@Lilly.com

Study Locations

  • Australia
      • Brisbane, Australia, 4006
        • Recruiting
        • Nucleus Network
        • Contact:
          • Phone Number: +617 3707 2720
        • Principal Investigator:
          • Gloria Wong
      • Melbourne, Australia, VIC 3004
        • Recruiting
        • Nucleus Network
        • Contact:
          • Phone Number: +61 1800 243 733
        • Principal Investigator:
          • Christina Catherine Chang
  • China
      • Beijing, China, 100191
        • Not yet recruiting
        • Peking University Third Hospital
        • Principal Investigator:
          • Rong MU
        • Contact:
          • Phone Number: 010-82266699
      • Beijing, China, 100034
        • Not yet recruiting
        • Peking University First Hospital
        • Principal Investigator:
          • Zhuoli Zhang
        • Contact:
          • Phone Number: 010-83572211
      • Changsha, China, 410008
        • Not yet recruiting
        • Xiangya Hospital of Central South University
        • Principal Investigator:
          • Hui LUO
        • Contact:
          • Phone Number: 0731-89753999
      • Shanghai, China, 200127
        • Not yet recruiting
        • Renji Hospital, Shanghai Jiaotong University School of Medicine
        • Principal Investigator:
          • Shuang YE
        • Contact:
          • Phone Number: 021-58752345
      • Wuhan, China, 430022
        • Not yet recruiting
        • Union Hospital Tongji Medical College Huazhong University of Science and Technology
        • Contact:
          • Phone Number: 027-85726114
        • Principal Investigator:
          • Qiubai LI

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

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria: Healthy Participants

Healthy participants between the ages of 18 and 55 years.

  • Have body weight of at least 50 kilograms (kg) and body mass index (BMI) between 18 and 32 kilogram per square meter (kg/m²), inclusive.

Participants with Systemic Lupus Erythematosus (SLE)

  • Are 18 to 75 years of age, inclusive.
  • Have body weight between 45 and 145 kg, inclusive, and BMI between 18 and 35 kg/m², inclusive.
  • Have a clinical diagnosis of SLE according to the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria at least 6 months prior to screening.

Participants with Rheumatoid Arthritis (RA)

  • Are 18 to 75 years of age, inclusive.
  • Have body weight between 45 and 145 kg, inclusive, and BMI between 18 and 35 kg/m², inclusive.
  • Have a diagnosis of adult-onset RA for at least 6 months prior to screening, as defined by the 2010 ACR/EULAR classification criteria
  • Have Disease Activity Score in 28 joints (DAS28)-high-sensitivity C-reactive protein (hsCRP) greater than or equal to 4.4.
  • Have positive test results for rheumatoid factor or anti-citrullinated peptide antibodies
  • Have had a history of failure (an inadequate response, intolerance, or loss of response) to at least 2 advanced therapies (biological disease-modifying antirheumatic drug [bDMARD] or targeted synthetic DMARD [tsDMARD]) after failing a conventional synthetic DMARD (csDMARD).

Exclusion Criteria:

  • Have known allergies to LY4298445, related compounds, or any components of the formulation
  • Are individuals assigned female at birth (AFAB) who are lactating or have a positive pregnancy test at screening or Day -1.

  • Have severe active lupus-associated renal disease (lupus nephritis) defined clinically and/or by

    • urine protein/creatinine ratio greater than 200 milligrams per millimole (mg/mmol) (as an estimate of approximate proteinuria greater than 2 reams (g) per day) or
    • an estimated glomerular filtration rate (eGFR) less than 40 milliliters per minute (mL/min)/1.73 m² at screening, as calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD EPI) 2021.
    • requiring hemodialysis within 6 months prior to screening
  • Have active central nervous system lupus as defined by ACR nomenclature for neuropsychiatric lupus syndromes and as captured by Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K); seizure, psychosis, organic brain syndrome, visual disturbance, cranial nerve disorder, lupus headache, and cerebrovascular accident, within 2 months prior to screening
  • Have a Class 4 RA according to the ACR revised criteria

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: LY4298445 (Part A1)
Single-ascending dose (SAD) of LY4298445 administered subcutaneously (SC) or intravenously (IV) in healthy participants
Drug: LY4298445
Administered SC
Drug: LY4298445
Administered IV
Placebo Comparator: LY4298445 Placebo (Part A1)
SAD of LY4298445 administered SC or IV in healthy participants
Drug: LY4298445
Administered SC
Drug: LY4298445
Administered IV
Experimental: LY4298445 (Part A2)
SAD of LY4298445 administered SC in participants with systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA)
Drug: LY4298445
Administered SC
Drug: LY4298445
Administered IV
Experimental: LY4298445 (Part B)
Multiple-ascending doses (MAD) of LY4298445 administered SC in participants with SLE or RA
Drug: LY4298445
Administered SC
Drug: LY4298445
Administered IV
Experimental: LY4298445 (Part C)
Single dose of LY4298445 administered SC in healthy Japanese and Chinese participants
Drug: LY4298445
Administered SC
Drug: LY4298445
Administered IV
Placebo Comparator: LY4298445 Placebo (Part C)
Single dose of LY4298445 administered SC in healthy Japanese and Chinese participants
Drug: LY4298445
Administered SC
Drug: LY4298445
Administered IV

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants with One or More Serious Adverse Event(s) (SAEs) Considered by the Investigator to be Related to Study Drug Administration
Time Frame: Baseline up to Week 52
A summary of SAEs regardless of causality, will be reported in the Reported Adverse Events module
Baseline up to Week 52

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pharmacokinetics (PK): Area Under the Concentration Versus Time Curve (AUC) of LY4298445
Time Frame: Baseline up to Approximately Week 57
PK: AUC of LY4298445
Baseline up to Approximately Week 57
PK: Maximum Concentration (Cmax) of LY4298445
Time Frame: Baseline up to Week 52
PK: Cmax of LY4298445
Baseline up to Week 52
Pharmacodynamic (PD): Degree of Peripheral B Cell Depletion Following Biopsy in Participants
Time Frame: Baseline up to Week 52
PD: Peripheral B cell depletion
Baseline up to Week 52

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

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)

February 4, 2026

Primary Completion (Estimated)

March 1, 2028

Study Completion (Estimated)

March 1, 2028

Study Registration Dates

First Submitted

December 1, 2025

First Submitted That Met QC Criteria

December 1, 2025

First Posted (Actual)

December 11, 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

  • 27747
  • J6S-MC-KCAA (Other Identifier: Eli Lilly and Company)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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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