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LOXO-783 for Breast Cancer and Other Solid Tumors

This study is investigating LOXO-783, a new oral medication, for people with advanced breast cancer or other solid tumors. It's also being studied alongside other approved treatments like Fulvestrant, Imlunestrant, Abemaciclib, Anastrozole, Exemestane, or Letrozole. You might be able to join if your cancer has a specific change in the PIK3CA gene. The main goals are to understand the safety, side effects, and how well LOXO-783 works. Researchers will also look for the highest safe dose of LOXO-783. The study is currently unclear on its recruitment status and plans to enroll about 260 participants. Your participation could last up to three years, or longer if your disease doesn't worsen.

Study design
This is an interventional study, meaning participants will receive specific treatments. It aims to enroll about 260 participants.
What's involved
Participation could last up to 36 months (3 years) and possibly longer if the disease does not get worse.
Compensation
Not stated in the trial record.
Follow-up
The primary endpoints for safety are measured during the first 28-day cycle of LOXO-783 treatment.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05307705

A Study of LOXO-783 in Patients With Breast Cancer/Other Solid Tumors

Recruiting
PHASE1Ages 18+InterventionalTreatment
Eli Lilly and Company
~260 participants
Updated 2026-07-20 on ClinicalTrials.gov
What's tested:LOXO-783FulvestrantImlunestrantAbemaciclibAnastrozole, Exemestane, or LetrozolePaclitaxel

At a glance

Recruiting sites
27 of 50 listed sites are recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Phase 1 a: To determine the maximum tolerated dose/recommended phase 2 dose (MTD/RP2D) of LOXO-783: Number of patients with dose-limiting toxicities (DLTs)
Measured over During the first 28-day cycle of LOXO-783 treatment
+1 more outcome measured

Conditions

Breast Cancer

Explore related trials

Breast CarcinomaSolid NeoplasmPIK3CA Gene

Where it's being run

50 sites across 21 states
Spain8
France5
Texas4
Japan4
California3
Australia3
China3
Massachusetts2

Study leadership

  • 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) · STUDY_DIRECTOR · Eli Lilly and Company

Who to contact

There may be multiple sites in this clinical trial 1-877-CTLILLY (1-877-285-4559) or
[email protected]
13176154559
Email the study team

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Do you actually qualify for this trial?

Add a private profile and we'll compare every criterion below against your situation — and tell you which ones are met, uncertain, or excluding.

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Eligibility criteria

Inclusion

Have advanced breast cancer or another solid tumor with the presence of a phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) H1047R mutation (or other Sponsor and safety review committee (SRC)-approved, activating PIK3CA mutations other than H1047R mutation)
Have adequate archival tumor tissue sample available or be approved by the Sponsor for enrollment if no tumor sample is available.
Have stopped all cancer treatment and have recovered from the major side effects
Have adequate organ function, as measured by blood tests
Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) scale
Patients must have
Measurable disease
Non-measurable bone disease (at least 1 bone lesion in breast cancer patients only)
For patients with an estrogen receptor (ER)+ breast cancer diagnosis:
If female, must be postmenopausal
If male, must agree to use hormone suppression
Phase 1a:
Advanced solid tumor
Patients may have had up to 5 prior regimens for advanced disease
Phase 1b:
Part A:
ER+/human epidermal growth factor receptor 2 (HER2)- advanced breast cancer
Patients may have had up to 5 prior regimens for advanced disease ---- Prior cyclin dependent kinase (CDK)4/6 inhibitor therapy required
Part B:
ER+/HER2- advanced breast cancer
Patients may have had up to 2 prior regimens for advanced disease.
Part C:
ER+/HER2- advanced breast cancer
Patients may have had up to 5 prior regimens for advanced disease.
Have a diagnosis of diabetes mellitus Type 2
Part D:
Advanced breast cancer
Patients may have had up to 5 prior regimens for advanced disease.
Part E:
Advanced solid tumor
Patients may have had up to 3 prior regimens for advanced disease advanced disease
Part F:
ER+/HER2- advanced breast cancer
Patients may have had up to 5 prior regimens for advanced disease
Prior cyclin dependent kinase (CDK)4/6 inhibitor therapy required

Exclusion

Medical Conditions
Colorectal cancer
Endometrial cancers with specific concurrent oncogenic alterations
A history of known active or suspected
Diabetes mellitus Type 1 or
Diabetes mellitus Type 2 requiring antidiabetic medication (Phase 1a and all parts of Phase 1b except Part C).
Serious concomitant systemic disorder
Known or suspected history of untreated or uncontrolled central nervous system (CNS) involvement.
Active uncontrolled systemic bacterial, viral, fungal, or parasitic infection, or other clinically significant active disease process
Prior exposure to phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) inhibitor(s), except in certain circumstances

What this trial measures

  • Phase 1 a: To determine the maximum tolerated dose/recommended phase 2 dose (MTD/RP2D) of LOXO-783: Number of patients with dose-limiting toxicities (DLTs)During the first 28-day cycle of LOXO-783 treatment

    Number of patients with DLTs

  • Phase 1 a: To determine the MTD/RP2D of LOXO-783: Number of patients with DLT-equivalent toxicitiesDuring the first 28-day cycle of LOXO-783 treatment

    Number of patients with DLT-equivalent toxicities