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Breast CancerPhase 1PIKASSO-01NCT05307705

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

A Phase 1 study testing LOXO-783, Fulvestrant and Imlunestrant in people with Breast Cancer, run by Eli Lilly and Company at 50 sites in 12 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
Search all trials

Trial summary

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). Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Breast Cancer
What is being tested?
LOXO-783, Fulvestrant and Imlunestrant
Could I receive a placebo?
No, everyone receives an active treatment
How many people
260 participants
Where
50 sitesin 12 countries
Study dates
11 May 2022to Dec 2026
Phase
Phase 1
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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
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  • 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

Who cannot join

  • 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).
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  • 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

Trial locations and contacts

50 sites in 12 countries.

50 sites in 12 countries

United States17 sites

  • Winship Cancer Center Emory University

    Atlanta, Georgia, 30322

  • Massachusetts General Hospital

    Boston, Massachusetts, 02114

  • Dana-Farber Cancer Institute

    Boston, Massachusetts, 02215

  • Texas Oncology-Baylor Charles A. Sammons Cancer Center

    Dallas, Texas, 75246

  • UT Southwestern Medical Center

    Dallas, Texas, 75390-8884

  • University of Texas MD Anderson Cancer Center

    Houston, Texas, 77030

  • Mayo Clinic

    Jacksonville, Florida, 32224

  • UCLA Medical Center

    Los Angeles, California, 90095

  • Tennessee Oncology PLLC

    Nashville, Tennessee, 37203

  • Memorial Sloan Kettering Cancer Center

    New York, New York, 10065

  • Mayo Clinic

    Rochester, Minnesota, 55905-0002

  • Wilmot Cancer Institute

    Rochester, New York, 14642

  • South Texas Accelerated Research Therapeutics (START)

    San Antonio, Texas, 78229

  • UCSF Medical Center at Mission Bay

    San Francisco, California, 94158

  • Mayo Clinic of Scottsdale

    Scottsdale, Arizona, 85259

  • Washington University Medical School

    St Louis, Missouri, 63110

  • Stanford University Hospital

    Stanford, California, 94305

Other trials in United States

Spain8 sites

  • Hospital Universitario Quiron Dexeus

    Barcelona, 08028

  • Hospital Universitari Vall d'Hebron

    Barcelona, 08035

  • Hospital Clinic de Barcelona

    Barcelona, 08036

  • Hospital General Universitario Gregorio Maranon

    Madrid, 28007

  • Hospital Universitario 12 de Octubre

    Madrid, 28041

  • Hospital Quironsalud Madrid

    Pozuelo de Alarcón, 28223

  • Hospital Clinico Universitario de Valencia

    Valencia, 46010

  • Hospital Arnau de Vilanova Valencia

    Valencia, 46015

Other trials in Spain

France5 sites

  • Centre Leon Berard

    Lyon, 69373

  • Institut Curie

    Paris, 75248

  • Institut de Cancérologie de l'Ouest

    Saint-Herblain, 44805

  • ICANS_Institut de Cancerologie Strasbourg Europe

    Strasbourg, 67033

  • Gustave Roussy

    Villejuif, 94805

Other trials in France

Japan4 sites

  • National Cancer Center Hospital

    Chūōku, 104-0045

  • The Cancer Institute Hospital of JFCR

    Kōtō City, 135-8550

  • Kyoto University Hospital

    Kyoto, 606-8507

  • Aichi Cancer Center Hospital

    Nagoya, 464-8681

Other trials in Japan

Australia3 sites

  • Cancer Research SA

    Adelaide, 5000

  • Peter Maccallum Cancer Institute Erb

    East Melbourne, 3002

  • St Vincent's Hospital

    Sydney, 2010

Other trials in Australia

China3 sites

  • Beijing Cancer hospital

    Beijing, 100036

  • The Third Hospital of Nanchang

    Nanchang, 330009

  • Fudan University Shanghai Cancer Center

    Shanghai, 200032

Other trials in China

Belgium2 sites

  • Institut Jules Bordet

    Anderlecht, 1070

  • Universitaire Ziekenhuizen Leuven - Campus Gasthuisberg

    Leuven, 3000

Other trials in Belgium

Canada2 sites

  • Princess Margaret Hospital (Hong Kong)

    Toronto, M5G 2M9

  • BC Cancer Vancouver

    Vancouver, V5Z4E6

Other trials in Canada

South Korea2 sites

  • Samsung Medical Center

    Seoul, 06351

  • Asan Medical Center

    Seoul, 5505

Other trials in South Korea

United Kingdom2 sites

  • Royal Marsden NHS Trust

    London, SW3 6JJ

  • Royal Marsden Hospital (Sutton)

    Sutton, SM2 5PT

Other trials in United Kingdom

Germany1 site

  • Universitätsklinikum Erlangen

    Erlangen, 91054

Other trials in Germany

Singapore1 site

  • National Cancer Centre Singapore

    Singapore, 169610

Other trials in Singapore

About this study

Official title: 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.

Conditions
Breast Cancer
Being tested
LOXO-783, Fulvestrant, Imlunestrant, Abemaciclib, Anastrozole, Exemestane, or Letrozole
Medical subject headings
Breast Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • LOXO-783Drug

    Also called LY3849524

    Oral

  • FulvestrantDrug

    Intramuscular

  • ImlunestrantDrug

    Also called LY3484356

    Oral

  • AbemaciclibDrug

    Also called LY2835219

    Oral

  • Anastrozole, Exemestane, or LetrozoleDrug

    Oral

  • PaclitaxelDrug

    Intravenous

Study groups in NCT05307705
Study groupRoleWhat they receive
Phase 1A: LOXO-783 Monotherapy Dose EscalationExperimentalLOXO-783 administered orally
Receives: Drug: LOXO-783
Phase 1B: Part AExperimentalLOXO-783 administered orally in combination with fulvestrant intramuscularly, imlunestrant orally, or an aromatase inhibitor orally
Receives: Drug: LOXO-783; Drug: Fulvestrant; Drug: Imlunestrant; Drug: Anastrozole, Exemestane, or Letrozole
Phase 1B: Part BExperimentalLOXO-783 orally in combination with abemaciclib and either physician's choice aromatase inhibitor orally, fulvestrant intramuscularly, or imlunestrant orally
Receives: Drug: LOXO-783; Drug: Fulvestrant; Drug: Imlunestrant; Drug: Abemaciclib; Drug: Anastrozole, Exemestane, or Letrozole
Phase 1B: Part CExperimentalLOXO-783 orally in combination with fulvestrant intramuscularly
Receives: Drug: LOXO-783; Drug: Fulvestrant
Phase 1B: Part DExperimentalLOXO-783 orally in combination with paclitaxel intravenously
Receives: Drug: LOXO-783; Drug: Paclitaxel
Phase 1B: Part EExperimentalLOXO-783 orally
Receives: Drug: LOXO-783
Phase 1B: Part FExperimentalMultiple randomized dose levels of LOXO-783 orally with fulvestrant intramuscularly
Receives: Drug: LOXO-783; Drug: Fulvestrant

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. 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)

    Number of patients with DLTs

    Measured: During the first 28-day cycle of LOXO-783 treatment

  2. Phase 1 a: To determine the MTD/RP2D of LOXO-783: Number of patients with DLT-equivalent toxicities

    Number of patients with DLT-equivalent toxicities

    Measured: During the first 28-day cycle of LOXO-783 treatment

Secondary outcomes (10)

  1. To assess the pharmacokinetics (PK) of LOXO-783: Area under the concentration versus time curve (AUC)

    PK of LOXO-783: AUC

    Measured: Up to 2 months

  2. To assess the PK of LOXO-783: Maximum drug concentration (Cmax)

    PK of LOXO-783: Cmax

    Measured: Up to 2 months

  3. To evaluate the preliminary antitumor activity of LOXO-783: Overall response rate (ORR)

    ORR per investigator assessed Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1)

    Measured: Up to approximately 36 months or 3 years

  4. To evaluate the preliminary antitumor activity of LOXO-783: Best overall response (BOR)

    BOR per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

  5. To evaluate the preliminary antitumor activity of LOXO-783: Duration of response (DOR)

    DOR per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

  6. To evaluate the preliminary antitumor activity of LOXO-783: Disease control rate (DCR)

    DCR per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

  7. To evaluate the preliminary antitumor activity of LOXO-783: Clinical benefit rate (CBR)

    CBR per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

  8. To evaluate the preliminary antitumor activity of LOXO-783: Time to response (TTR)

    TTR per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

  9. To evaluate the preliminary antitumor activity of LOXO-783: Progression free survival (PFS)

    PFS per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

  10. To evaluate the preliminary antitumor activity of LOXO-783: Overall survival (OS)

    OS per investigator assessed RECIST 1.1

    Measured: Up to approximately 36 months or 3 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted1 Apr 2022
  2. Study start11 May 2022
  3. Primary completion2 Apr 2025
  4. Study completionDec 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 1
Primary purpose
Treatment
Allocation
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
260 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05307705
Sponsor's protocol ID
18394
Other IDs
2022-000175-40, J4C-OX-JZUA, LOXO-PIK-21001
Acronym
PIKASSO-01
Status last verified
Oct 2026
First submitted
25 Mar 2022
Last updated
14 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A Phase 1 study testing LOXO-783, Fulvestrant and Imlunestrant in people with Breast Cancer, run by Eli Lilly and Company at 50 sites in 12 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 38 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 14 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 50 sites in United States, Spain, France, Japan, Australia and 7 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

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). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05307705.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Oct 2026.

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