A Study of LY3439539 in Participants With Alzheimer's Disease

May 14, 2026 updated by: Eli Lilly and Company

A Phase 1, Open Label, Multiple-Dose Study to Assess the Changes in Cerebrospinal Fluid Biomarkers for Alzheimer's Disease Following Treatment With LY3439539 in Participants With Symptomatic Alzheimer's Disease

The purpose of this study is to see how LY3439539 affects certain proteins found in the spinal fluid of participants with Alzheimer's disease.

Participation in the study will last approximately 9 months with visits about once a month.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

30

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

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

Study Contact Backup

Study Locations

  • Australia
      • Adelaide, Australia, 5042
        • Flinders Medical Centre
        • Contact:
          • Phone Number: +61 482 130 622
        • Principal Investigator:
          • Lauren Priest
      • Birtinya, Australia, 4575
        • University of the Sunshine Coast Clinical Trial Centre
        • Principal Investigator:
          • Peter De Wet
        • Contact:
          • Phone Number: +617 54563872
      • Ivanhoe, Australia, 3079
        • Austin Health - Heidelberg Repatriation Hospital
        • Principal Investigator:
          • Paul Yates
        • Contact:
          • Phone Number: +613 9496 2388
      • Kogarah, Australia, 2217
        • Southern Neurology
        • Principal Investigator:
          • Raymond Schwartz
        • Contact:
          • Phone Number: +612 8566 1500
      • Macquarie University, Australia, 2109
        • Macquarie University Hospital
        • Contact:
          • Phone Number: 0298122956
        • Principal Investigator:
          • James Burrell
      • Melbourne, Australia, 3004
        • The Alfred
        • Principal Investigator:
          • David Darby
        • Contact:
          • Phone Number: 0437 498 365
  • Singapore
      • Singapore, Singapore, 138623
        • Lilly Centre for Clinical Pharmacology
        • Contact:
          • Phone Number: +65 6413 9811
        • Principal Investigator:
          • Jeffer Hann Wei Pang

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 gradual and progressive change in memory function reported by the participant or informant for 6 months or longer consistent with a diagnosis of dementia due to Alzheimer's disease
  • Have a Mini Mental Score Examination score of 16 to 24, inclusive
  • Meet plasma pTau criteria, as defined by the sponsor
  • Have body mass index within the range of 17 and 32 kilograms per square meter (kg/m²) (inclusive) at screening
  • Are women not of childbearing potential and men willing to practice effective contraception throughout the study.
  • Have adequate premorbid literacy, vision, and hearing throughout the study duration and able to complete study procedures.
  • Have at least 1, and up to 2, study partners who are in frequent contact with the participant (defined as at least 10 hours per week).

Exclusion Criteria:

  • Have any contraindications for magnetic resonance imaging (MRI), including claustrophobia or the presence of contraindicated metal (ferromagnetic) implants/cardiac pacemaker.
  • Have a screening MRI that shows evidence of significant abnormality.
  • Have history of suicidal behavior, or a lifetime history of suicide attempt or acute suicidality.

  • Have a history of

    • Severe or ongoing allergy or hypersensitivity reactions
    • Hypersensitivity to immunizations or immunoglobulins
    • Two or more clinically significant or severe drug allergies,
    • Intolerance to topical corticosteroids or severe posttreatment hypersensitivity reactions
  • Have current serious or unstable illnesses, including hepatic, renal, gastroenterological, respiratory, cardiovascular, neurologic (other than AD), psychiatric, endocrinologic, immunologic, hematologic disease, or other conditions
  • Require treatment with another monoclonal antibody or have received treatment with biologic agents (such as monoclonal antibodies, including marketed drugs) within 3 months or 5 half-lives (whichever is longer) prior to dosing.
  • Have criteria that would preclude a lumbar puncture (LP).
  • Are currently enrolled in a clinical study involving an investigational product (IP) or any other type of medical research judged not to be scientifically or medically compatible with this study.
  • Have a current exposure to amyloid-targeting therapies (ATTs). Prior exposure to ATTs greater than 1 year from the last dose may be permitted at the discretion of the investigator and in consultation with the sponsor.

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: LY3439539
LY3439539 administered intravenously (IV)
Drug: LY3439539
Administered IV

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in Cerebrospinal Fluid (CSF) Neurofilament Light Chain (NfL)
Time Frame: Baseline through end of the Follow-up Period (Week 24)
Baseline through end of the Follow-up Period (Week 24)

Secondary Outcome Measures

Outcome Measure
Time Frame
Change from Baseline in Phospho-Tau (pTau)
Time Frame: Baseline through end of the Follow-up Period (Week 24)
Baseline through end of the Follow-up Period (Week 24)
Change from Baseline in Plasma NfL
Time Frame: Baseline through end of the Follow-up Period (Week 24)
Baseline through end of the Follow-up Period (Week 24)
Pharmacokinetics (PK) Maximum LY3439539 Serum Concentration (Cmax)
Time Frame: Baseline through end of the Follow-up Period (Week 24)
Baseline through end of the Follow-up Period (Week 24)
PK: Minimum LY3439539 Serum Concentration (Cmin)
Time Frame: Time Frame: Baseline through end of Follow up Period (Week 24)
Time Frame: Baseline through end of Follow up Period (Week 24)

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

May 1, 2027

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

May 14, 2026

First Submitted That Met QC Criteria

May 14, 2026

First Posted (Actual)

May 20, 2026

Study Record Updates

Last Update Posted (Actual)

May 20, 2026

Last Update Submitted That Met QC Criteria

May 14, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 18818
  • I9M-MC-ONAA (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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