A Study of LY3484356 in Chinese Participants With Advanced Breast Cancer

A Phase 1 Study of LY3484356 in Chinese Patients With Estrogen Receptor Positive, HER2 Negative Locally Advanced or Metastatic Breast Cancer

This is a study of LY3484356 in Chinese participants with advanced breast cancer. Participants must have breast cancer that is estrogen receptor positive (ER+), HER2 negative (HER2-). The purpose of this study is to measure how much LY3484356 gets into the bloodstream and how long it takes the body to remove it. The safety and effectiveness of LY3484356 will also be studied. Participation could last up to 28 months.

Study Overview

• Status: Active, not recruiting
• Conditions: Breast Neoplasms
• Intervention / Treatment: Drug: LY3484356

• Study Type: Interventional
• Enrollment (Actual): 17
• Phase: Phase 1

Contacts and Locations

Study Locations

• China
  • Anhui
    • Wuhu, Anhui, China, 241001
      • Wannan Medical College Yijishan Hospital
  • Hunan
    • Changsha, Hunan, China, 410013
      • Hunan Cancer Hospital
  • Jiangxi
    • Nanchang, Jiangxi, China, 330025
      • The Third Hospital of Nanchang
  • Shanghai Municipality
    • Shanghai, Shanghai Municipality, China, 201315
      • Fudan University Shanghai Cancer Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Native Chinese participants must be of an acceptable age to provide informed consent
• Have locally advanced (not amenable to curative treatment by surgery) or metastatic disease and be an appropriate candidate for experimental therapy in the judgment of the investigator, after available standard therapies have ceased to provide clinical benefit
• Have a diagnosis of ER+, HER2- breast cancer
• Female participants have postmenopausal status due either surgical/natural menopause or ovarian suppression
• If postmenopausal status is due to ovarian suppression, participants must have a negative serum pregnancy test and agree to use highly effective, medically approved precautions to prevent pregnancy
• Have a performance status less than or equal to (≤)1 on the Eastern Cooperative Oncology Group (ECOG) scale
• Have adequate organ function
• Must be able to swallow capsules/tablets

Exclusion Criteria:

• Have symptomatic central nervous system (CNS) metastasis and/or carcinomatous meningitis

• Have a serious concomitant systemic disorder

  • Human immunodeficiency virus (HIV) positive patients are excluded unless they are well controlled on highly active antiretroviral therapy with no evidence of autoimmune deficiency syndrome-defining opportunistic infections within the last 2 years, and cluster of differentiation 4 (CD4) count greater than (>)350 cells/microliter (μL)
  • Active hepatitis B or C virus infection
  • Severe renal impairment, interstitial lung disease, severe dyspnea at rest or requiring oxygen therapy, history of major surgical resection involving the stomach or small bowel, preexisting Crohn's disease or ulcerative colitis or a preexisting chronic condition resulting in clinically significant diarrhea
• Have visceral crisis
• Have a serious cardiac condition
• Have an acute leukemia or other relevant cancers
• Females who are pregnant or lactating
• Known allergic reaction against any of the components of the study drug

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: LY3484356 Dose Level 1; Administered orally.	Drug: LY3484356; Administered orally.
Experimental: LY3484356 Dose Level 2; Administered orally.	Drug: LY3484356; Administered orally.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pharmacokinetics (PK): Plasma Concentration of LY3484356	PK: Plasma Concentration of LY3484356	Time Frame: Cycle 1, Day 1 through Day 3 and Day 17 through Day 18; Cycle 2 Day 1 (Cycle 1 = 30 days, Cycle 2 = 28 days)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
2. Percentage of Participants Who Achieve a Best Overall Response (BOR) of Complete Response (CR) or Partial Response (PR): Overall Response Rate (ORR)	ORR	Randomization to Disease Progression or Death from Any Cause (Estimated up to 28 months)
Disease Control Rate (DCR): Percentage of Participants With a BOR of Complete Response (CR), Partial Response (PR) or Stable Disease (SD)	DCR	Randomization to Disease Progression or Death from Any Cause (Estimated up to 28 months)
Progression-Free Survival (PFS)	PFS	Randomization to Disease Progression or Death from Any Cause (Estimated up to 28 months)

Collaborators and Investigators

• Sponsor: Eli Lilly and Company
• Investigators: Study Director: Call 1-877-CTLILLY (1-877-285-4559) or 1-317-615-4559 Mon - Fri 9 AM - 5 PM Eastern time (UTC/GMT - 5 hours, EST), Eli Lilly and Company

Study record dates

Study Major Dates

• Study Start (Actual): October 9, 2022
• Primary Completion (Actual): February 18, 2024
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: August 19, 2022
• First Submitted That Met QC Criteria: August 19, 2022
• First Posted (Actual): August 22, 2022

Study Record Updates

• Last Update Posted (Actual): April 13, 2026
• Last Update Submitted That Met QC Criteria: April 7, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Skin and Connective Tissue Diseases; Breast Neoplasms; Imlunestrant
• Other Study ID Numbers: 18291; J2J-MC-JZLF (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
• product manufactured in and exported from the U.S.: No