ONO-4578-06:Phase I Study of ONO-4578 and Letrozole Plus CDK4 /6 Inhibitors in Breast Cancer

June 3, 2026 updated by: Ono Pharmaceutical Co., Ltd.

ONO-4578-06: Phase I , Open-label, Non-blind, First-line Endocrine Therapy With ONO-4578 and Standard Treatment Letrozole and CDK4/6 Inhibitors (Palbociclib or Abemaciclib) in Patients With Metastatic or Recurrent Postmenopausal Hormone Receptor-positive HER2-negative Breast Cancer

This is a multicenter, open-label, non-controlled, phase I study to investigate the tolerability and safety of ONO-4578 used in combination with standard-of-care letrozole and a CDK4/6 inhibitor (palbociclib or Abemaciclib) as first-line endocrine therapy in postmenopausal patients with metastatic or recurrent hormone receptor-positive, HER2-negative breast cancer.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
46

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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 Locations

  • Japan
    • Aichi-ken
      • Nagoya, Aichi-ken, Japan
        • Aichi Cancer Center Hospital
      • Nagoya, Aichi-ken, Japan
        • Nagoya University Hospital
    • Chiba
      • Chiba, Chiba, Japan
        • Chiba Cancer Center
      • Kashiwa-shi, Chiba, Japan
        • National Cancer Center Hospital East
    • Kanagawa
      • Kawasaki-shi, Kanagawa, Japan
        • St. Marianna University Hospital
      • Yokohama, Kanagawa, Japan
        • Kanagawa Cancer Center
    • Kyoto
      • Kyoto, Kyoto, Japan
        • University Hospital Kyoto Prefectural University of Medicine
    • Miyagi
      • Sendai, Miyagi, Japan
        • Tohoku University Hospital
    • Osaka
      • Osaka, Osaka, Japan
        • Osaka International Cancer Institute
    • Saitama
      • Shinden, Saitama, Japan
        • Saitama Cancer Center
    • Tokyo
      • Chuo-ku, Tokyo, Japan
        • National Cancer Center Hospital
      • Koto-ku, Tokyo, Japan
        • The Cancer Institute Hospital of JFCR
      • Shinjuku-ku, Tokyo, Japan
        • Tokyo Medical University Hospital

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  1. Patients with postmenopausal metastatic or recurrent breast cancer
  2. Patients with ECOG Performance Status 0 to 1
  3. ER-positive, PgR-positive and HER2-negative patients

Exclusion Criteria:

  1. Patients are unable to swallow oral medications
  2. Patients with severe complication

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: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: ONO-4578 + letrozole + palbociclib
Drug: ONO-4578
Specified dose on specified days
Drug: letrozole
Specified dose on specified days
Drug: Palbociclib
Specified dose on specified days
Experimental: ONO-4578 + letrozole + abemaciclib
Drug: ONO-4578
Specified dose on specified days
Drug: letrozole
Specified dose on specified days
Drug: abemaciclib
Specified dose on specified days

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Adverse events
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Serious adverse events
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Dose-limiting toxicity (Tolerability Confirmation part only)
Time Frame: 28 days
28 days
Laboratory abnormality profile of Drugs as measured by incidence and severity of clinical laboratory abnormalities
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Body temperature
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Pulse rate
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Systolic/diastolic blood pressure
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Saturation of Percutaneous Oxygen (SpO2)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Weight
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Eastern Cooperative Oncology Group Performance Status
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Chest X-ray
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
CT scan
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
12-lead electrocardiography (Heart rate)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
12-lead electrocardiography (PR interval)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
12-lead electrocardiography (RR interval)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
12-lead electrocardiography (QRS width)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
12-lead electrocardiography (QT interval)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Overall response rate (ORR)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Disease control rate (DCR)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Clinical benefit rate (CBR)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Overall survival (OS)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Progression-free survival (PFS)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Duration of response (DOR)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Time to response (TTR)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Best overall response (BOR)
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Percent change in the sum of diameters of target lesions
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Maximum percent change in the sum of diameters of target lesions
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Changes in tumor markers
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year
Plasma ONO-4578 concentration
Time Frame: Through study completion, an average of 4 year
Through study completion, an average of 4 year

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Ono Pharmaceutical Co., Ltd.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Director: Project Leader, Ono Pharmaceutical Co., Ltd.

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 9, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 30, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 30, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 31, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 21, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 26, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 5, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 3, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • ONO-4578-06

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

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.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings