A Study of LOXO-783 in Patients With Breast Cancer/Other Solid Tumors (PIKASSO-01)

August 6, 2026 updated by: Eli Lilly and Company

A Study of LOXO-783 Administered as Monotherapy and in Combination With Anticancer Therapies for Patients With Advanced Breast Cancer and Other Solid Tumors With a PIK3CA H1047R Mutation

The main purpose of this study is to learn more about the safety, side effects, and effectiveness of LOXO-783. LOXO-783 may be used to treat breast cancer and other solid tumors that have a change in a particular gene (known as the PIK3CA gene). Participation could last up to 36 months (3 years) and possibly longer if the disease does not get worse.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

260

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: There may be multiple sites in this clinical trial 1-877-CTLILLY (1-877-285-4559) or
  • Phone Number: 13176154559
  • Email: ClinicalTrials.gov@lilly.com

Study Locations

  • Australia
      • Adelaide, Australia, 5000
        • Not yet recruiting
        • Cancer Research SA
      • East Melbourne, Australia, 3002
        • Not yet recruiting
        • Peter Maccallum Cancer Institute Erb
      • Sydney, Australia, 2010
        • Not yet recruiting
        • St Vincent's Hospital
  • Belgium
      • Anderlecht, Belgium, 1070
        • Not yet recruiting
        • Institut Jules Bordet
      • Leuven, Belgium, 3000
        • Not yet recruiting
        • Universitaire Ziekenhuizen Leuven - Campus Gasthuisberg
  • Canada
      • Toronto, Canada, M5G 2M9
        • Recruiting
        • Princess Margaret Hospital (Hong Kong)
      • Vancouver, Canada, V5Z4E6
        • Recruiting
        • BC Cancer Vancouver
  • China
      • Beijing, China, 100036
        • Not yet recruiting
        • Beijing Cancer Hospital
      • Nanchang, China, 330009
        • Recruiting
        • The Third Hospital of Nanchang
      • Shanghai, China, 200032
        • Recruiting
        • Fudan University Shanghai Cancer Center
  • France
      • Lyon, France, 69373
        • Recruiting
        • Centre Léon Bérard
      • Paris, France, 75248
        • Not yet recruiting
        • Institut Curie
      • Saint-Herblain, France, 44805
        • Recruiting
        • Institut de Cancérologie de l'Ouest
      • Strasbourg, France, 67033
        • Recruiting
        • ICANS_Institut de Cancerologie Strasbourg Europe
      • Villejuif, France, 94805
        • Not yet recruiting
        • Gustave Roussy
  • Germany
      • Erlangen, Germany, 91054
        • Not yet recruiting
        • Universitätsklinikum Erlangen
  • Japan
      • Chūōku, Japan, 104-0045
        • Recruiting
        • National Cancer Center Hospital
      • Kyoto, Japan, 606-8507
        • Not yet recruiting
        • Kyoto University Hospital
      • Kōtō City, Japan, 135-8550
        • Recruiting
        • The Cancer Institute Hospital of JFCR
      • Nagoya, Japan, 464-8681
        • Recruiting
        • Aichi Cancer Center Hospital
  • Singapore
      • Singapore, Singapore, 169610
        • Not yet recruiting
        • National Cancer Centre Singapore
  • South Korea
      • Seoul, South Korea, 06351
        • Not yet recruiting
        • Samsung Medical Center
      • Seoul, South Korea, 5505
        • Not yet recruiting
        • Asan Medical Center
  • Spain
      • Barcelona, Spain, 08036
        • Recruiting
        • Hospital Clinic de Barcelona
      • Barcelona, Spain, 08035
        • Not yet recruiting
        • Hospital Universitari Vall D'Hebron
      • Barcelona, Spain, 08028
        • Recruiting
        • Hospital Universitario Quiron Dexeus
      • Madrid, Spain, 28007
        • Recruiting
        • Hospital General Universitario Gregorio Marañón
        • Contact:
          • Phone Number: 855-569-6305
      • Madrid, Spain, 28041
        • Not yet recruiting
        • Hospital Universitario 12 de Octubre
      • Pozuelo de Alarcón, Spain, 28223
        • Recruiting
        • Hospital Quirónsalud Madrid
      • Valencia, Spain, 46010
        • Recruiting
        • Hospital Clínico Universitario de Valencia
        • Contact:
          • Phone Number: 8555696305
      • Valencia, Spain, 46015
        • Recruiting
        • Hospital Arnau de Vilanova Valencia
        • Contact:
          • Phone Number: 855-569-6305
  • United Kingdom
      • London, United Kingdom, SW3 6JJ
        • Recruiting
        • Royal Marsden NHS Trust
      • Sutton, United Kingdom, SM2 5PT
        • Not yet recruiting
        • Royal Marsden Hospital (Sutton)
  • United States
    • Arizona
      • Scottsdale, Arizona, United States, 85259
        • Not yet recruiting
        • Mayo Clinic of Scottsdale
    • California
      • Los Angeles, California, United States, 90095
        • Completed
        • UCLA Medical Center
      • San Francisco, California, United States, 94158
        • Recruiting
        • UCSF Medical Center at Mission Bay
      • Stanford, California, United States, 94305
        • Recruiting
        • Stanford University Hospital
    • Florida
      • Jacksonville, Florida, United States, 32224
        • Not yet recruiting
        • Mayo Clinic
    • Georgia
      • Atlanta, Georgia, United States, 30322
        • Completed
        • Winship Cancer Center Emory University
    • Massachusetts
      • Boston, Massachusetts, United States, 02215
        • Not yet recruiting
        • Dana-Farber Cancer Institute
      • Boston, Massachusetts, United States, 02114
        • Completed
        • Massachusetts General Hospital
    • Minnesota
      • Rochester, Minnesota, United States, 55905-0002
        • Recruiting
        • Mayo Clinic
        • Contact:
          • Phone Number: 855-569-6305
    • Missouri
      • St Louis, Missouri, United States, 63110
        • Not yet recruiting
        • Washington University Medical School
    • New York
      • New York, New York, United States, 10065
        • Completed
        • Memorial Sloan Kettering Cancer Center
      • Rochester, New York, United States, 14642
        • Not yet recruiting
        • Wilmot Cancer Institute
    • Tennessee
      • Nashville, Tennessee, United States, 37203
        • Completed
        • Tennessee Oncology PLLC
    • Texas
      • Dallas, Texas, United States, 75246
        • Not yet recruiting
        • Texas Oncology-Baylor Charles A. Sammons Cancer Center
      • Dallas, Texas, United States, 75390-8884
        • Recruiting
        • UT Southwestern Medical Center
      • Houston, Texas, United States, 77030
        • Not yet recruiting
        • University of Texas MD Anderson Cancer Center
      • San Antonio, Texas, United States, 78229
        • Not yet recruiting
        • South Texas Accelerated Research Therapeutics (START)

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 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

      --- Patients with non-breast tumor types must have at least 1 measurable lesion

    • 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:

    -- Dose escalation and backfill patients:

    • 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.

        ---- Prior CDK4/6 inhibitor therapy required.

      • 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 Criteria:

  • 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

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: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Sequential Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Phase 1A: LOXO-783 Monotherapy Dose Escalation
LOXO-783 administered orally
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Experimental: Phase 1B: Part B
LOXO-783 orally in combination with abemaciclib and either physician's choice aromatase inhibitor orally, fulvestrant intramuscularly, or imlunestrant orally
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Drug: Fulvestrant
Intramuscular
Drug: Imlunestrant
Oral
Other Names:
  • LY3484356
Drug: Abemaciclib
Oral
Other Names:
  • LY2835219
Drug: Anastrozole, Exemestane, or Letrozole
Oral
Experimental: Phase 1B: Part C
LOXO-783 orally in combination with fulvestrant intramuscularly
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Drug: Fulvestrant
Intramuscular
Experimental: Phase 1B: Part D
LOXO-783 orally in combination with paclitaxel intravenously
Drug: Paclitaxel
Intravenous
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Experimental: Phase 1B: Part E
LOXO-783 orally
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Experimental: Phase 1B: Part A
LOXO-783 administered orally in combination with fulvestrant intramuscularly, imlunestrant orally, or an aromatase inhibitor orally
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Drug: Fulvestrant
Intramuscular
Drug: Imlunestrant
Oral
Other Names:
  • LY3484356
Drug: Anastrozole, Exemestane, or Letrozole
Oral
Experimental: Phase 1B: Part F
Multiple randomized dose levels of LOXO-783 orally with fulvestrant intramuscularly
Drug: LOXO-783
Oral
Other Names:
  • LY3849524
Drug: Fulvestrant
Intramuscular

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Phase 1 a: To determine the MTD/RP2D of LOXO-783: Number of patients with DLT-equivalent toxicities
Time Frame: During the first 28-day cycle of LOXO-783 treatment
Number of patients with DLT-equivalent toxicities
During the first 28-day cycle of LOXO-783 treatment
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)
Time Frame: During the first 28-day cycle of LOXO-783 treatment
Number of patients with DLTs
During the first 28-day cycle of LOXO-783 treatment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
To assess the pharmacokinetics (PK) of LOXO-783: Area under the concentration versus time curve (AUC)
Time Frame: Up to 2 months
PK of LOXO-783: AUC
Up to 2 months
To assess the PK of LOXO-783: Maximum drug concentration (Cmax)
Time Frame: Up to 2 months
PK of LOXO-783: Cmax
Up to 2 months
To evaluate the preliminary antitumor activity of LOXO-783: Best overall response (BOR)
Time Frame: Up to approximately 36 months or 3 years
BOR per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Duration of response (DOR)
Time Frame: Up to approximately 36 months or 3 years
DOR per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Disease control rate (DCR)
Time Frame: Up to approximately 36 months or 3 years
DCR per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Clinical benefit rate (CBR)
Time Frame: Up to approximately 36 months or 3 years
CBR per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Time to response (TTR)
Time Frame: Up to approximately 36 months or 3 years
TTR per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Progression free survival (PFS)
Time Frame: Up to approximately 36 months or 3 years
PFS per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Overall survival (OS)
Time Frame: Up to approximately 36 months or 3 years
OS per investigator assessed RECIST 1.1
Up to approximately 36 months or 3 years
To evaluate the preliminary antitumor activity of LOXO-783: Overall response rate (ORR)
Time Frame: Up to approximately 36 months or 3 years
ORR per investigator assessed Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1)
Up to approximately 36 months or 3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Eli Lilly and Company

Collaborators

Loxo Oncology, Inc.

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

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

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)

May 11, 2022

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

March 25, 2022

First Submitted That Met QC Criteria

March 25, 2022

First Posted (Actual)

April 1, 2022

Study Record Updates

Last Update Posted (Actual)

August 7, 2026

Last Update Submitted That Met QC Criteria

August 6, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 18394
  • LOXO-PIK-21001 (Other Identifier: Eli Lilly and Company)
  • J4C-OX-JZUA (Other Identifier: Eli Lilly and Company)
  • 2022-000175-40 (EudraCT Number)

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

Yes

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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