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Breast CancerPhase 2NCT06188559

A Study of BB-1701 in Previously Treated Participants With Human Epidermal Growth Factor Receptor 2 (HER2)-Positive or HER2-low Unresectable or Metastatic Breast Cancer

A Phase 2 study testing BB-1701 in people with Breast Cancer, run by Eisai Inc. at 49 sites in 4 countries.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
Search all trials

Trial summary

The primary purpose of the Dose Optimization (Part 1) of this study is to assess the safety and tolerability of BB-1701 and to determine the recommended dose (RD) of BB-1701 for Dose Expansion (Part 2). 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?
BB-1701
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
56 participants
Where
49 sitesin 4 countries
Study dates
10 Apr 2024to 18 Mar 2026
Phase
Phase 2
Are there results?
None posted in the registry

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

  • Male or female, aged >=18 years at the time of informed consent.
  • Metastatic or unresectable BC that is histologically confirmed to be either HER2-positive (defined as an immunohistochemistry [IHC] status of 3+, or a positive in situ hybridization [ISH] test [fluorescence, chromogenic, or silver-enhanced ISH] if IHC status is 2+) or HER2-low (defined as an IHC status of 1+, or 2+ and negative ISH) per the American Society of Clinical Oncology/College of American Pathology guidelines as documented prior to trastuzumab deruxtecan (T-DXd) treatment.
  • Must have previously received T-DXd.
  • Sufficient tumor tissue is required for HER2 status testing at a central laboratory.
  • Measurable disease per RECIST 1.1 as assessed by the investigator. Participants with bone only disease may be eligible if there is a measurable soft tissue component associated with the bone lesion.
  • Must have previously received at least 1 but no more than 3 prior chemotherapy-based regimes in the unresectable or metastatic setting. If recurrence occurred during or within 6 months of (neo) adjuvant chemotherapy, this would count as 1 line of chemotherapy.
Show all 10Show fewer
  • If HR-positive HER2-low BC, must have previously received endocrine therapy and is not expected to further benefit from it.
  • ECOG PS 0 or 1.
  • Life expectancy of at least 3 months.
  • Adequate organ function and laboratory parameters.

Who cannot join

  • Presence of brain or subdural metastases, unless participant has completed local therapy and has discontinued the use of corticosteroids for this indication for at least 2 weeks prior to starting treatment in this study.
  • Diagnosed with meningeal carcinomatosis.
  • Received anticancer therapy (chemotherapy or other systemic anticancer therapies, immunotherapy, radiation therapy, etc) or an investigational drug or device within the past 28 days or 5 half-lives, whichever is shorter.
  • Prior treatment with eribulin.
  • Any prior allergic reactions of Grade >=3 to monoclonal antibodies or contraindication to the receipt of corticosteroids or any of the excipients (investigators should refer to the prescribing information for the selected corticosteroid).
  • Residual toxic effects of prior therapies or surgical procedures that is Grade >=2 (except alopecia or anemia).
Show all 16Show fewer
  • Grade >=2 peripheral neuropathy or history of Grade >=3 peripheral neuropathy or discontinued any prior treatment due to peripheral neuropathy.
  • Active pneumonitis/interstitial lung disease (ILD) or any clinically significant lung disease (example, chronic obstructive pulmonary disease), history of Grade >=2 pneumonitis/ILD, or received radiotherapy to lung fields within 12 months of Cycle 1 Day 1 of study treatment.
  • Congestive heart failure greater than (>) New York Heart Association Class II or left ventricular ejection fraction (LVEF) less than (<) 50 percent (%) measured by multigated acquisition scan (MUGA) or echocardiogram.
  • Has a corrected QT interval prolongation per Fridericia formula (QTcF) >470 millisecond (ms) (for both males and females) based on screening triplicate 12-lead ECG.
  • Concomitant active infection requiring systemic treatment, except:
  • If known to be human immunodeficiency virus (HIV)-positive, must be on anti-HIV therapy for at least 4 weeks and have a clusters of differentiation 4+ T-cell (CD4+) count >=350 cells per microliter (cells/mcL) and an HIV viral load <400 copies per milliliter (copies/mL).
  • If meets the criteria for anti-hepatitis B virus (HBV) therapy, must agree to take anti-HBV therapy, if known to be HBV-positive as defined by positive hepatitis B surface antigen or hepatitis B core antibody. HBV viral load must be undetectable.
  • If known to be hepatitis C virus (HCV)-positive must have completed curative therapy for HCV. HCV viral load must be undetectable.
  • Known history of active bacillus tuberculosis (TB).
  • Any medical or other condition which, in the opinion of the investigator would preclude the participant's participation in the clinical study.

Trial locations and contacts

49 sites in 4 countries.

49 sites in 4 countries

United States27 sites

  • New Mexico Oncology Hematology Consultants

    Albuquerque, New Mexico, 87109

  • University of Michigan Hospital

    Ann Arbor, Michigan, 48109-5000

  • Cleveland Clinic - Fairview Hospital - Cancer Center (Moll Cancer Center)

    Cleveland, Ohio, 44111

  • Cleveland Clinic - Hillcrest Hospital - Hillcrest Cancer Center

    Cleveland, Ohio, 44124

  • Cleveland Clinic

    Cleveland, Ohio, 44195-0001

  • Mission Blood and Cancer

    Des Moines, Iowa, 50309

  • Astera Cancer Care

    East Brunswick, New Jersey, 08816

  • Summit Medical Group

    Florham Park, New Jersey, 07932-1049

  • Fort Wayne Medical Oncology & Hematology

    Fort Wayne, Indiana, 48604

  • The West Clinic, PLLC dba West Cancer Cente

    Germantown, Tennessee, 38138-1762

  • St. Francis Cancer Center

    Greenville, South Carolina, 29607-5253

  • Community Cancer Center South

    Indianapolis, Indiana, 46227

  • NHO Revive Research Institute LLC

    Lincoln, Nebraska, 68506

  • Cancer and Blood Specialty Clinic

    Los Alamitos, California, 90720

  • UCLA Center for East-West Medicine

    Los Angeles, California, 90095

  • Rutgers Cancer Institute of New Jersey

    New Brunswick, New Jersey, 08903

  • Yale New Haven Hospital

    New Haven, Connecticut, 06510

  • Memorial Sloan-Kettering Cancer Center

    New York, New York, 10065

  • Nebraska Cancer Specialist

    Omaha, Nebraska, 68130-2042

  • AdventHealth Cancer Institute - Orlando

    Orlando, Florida, 32804

  • UPMC CancerCenter at Magee - Womens Hospital

    Pittsburgh, Pennsylvania, 15213-3108

  • Northwest Medical Specialties

    Puyallup, Washington, 98373-1428

  • Oregon Oncology Specialists

    Salem, Oregon, 97301

  • UCSF

    San Francisco, California, 94143-2208

  • Avera Cancer Institute

    Sioux Falls, South Dakota, 57105

  • Washington University in St. Louis School of Medicine

    St Louis, Missouri, 63110-1032

  • Moffitt Cancer Center

    Tampa, Florida, 33612-9416

Other trials in United States

Japan15 sites

  • National Cancer Center Hospital (NCCH)

    Chuo-Ku, Tokyo

  • St. Luke's International Hospital

    Chuou-ku, Tokyo

  • Saitama Medical University International Medical Center

    Hidaka-shi, Saitama

  • Hiroshima City Hiroshima Citizens Hospital

    Hiroshima, Hiroshima

  • Sagara Hospital, Social Medical Corporation Hakuaikai

    Kagoshima, Kagoshima-ken

  • Saitama Cancer Center

    Kitaadachi-gun, Saitama

  • The Cancer Institute Hospital of Japanese Foundation for Cancer Research

    Koto Ku, Tokyo

  • Nagoya University Hospital

    Nagoya, Aichi-ken

  • Hyogo Medical University Hospital

    Nishinomiya-shi, Hyōgo

  • Okayama University Hospital

    Okayama, Okayama-ken

  • Kyoto University Hospital

    Sakyo-ku, Kyoto

  • Hokkaido University Hospital

    Sapporo, Hokkaido

  • Tohoku University Hospital

    Sendai, Miyagi

  • Showa Medical University

    Shinagawa Ku, Tokyo

  • Kanagawa Cancer Center

    Yokohama, Kanagawa

Other trials in Japan

France4 sites

  • CHU Besançon - Hôpital Jean Minjoz

    Besançon

  • Institut Régional du Cancer de Montpellier

    Montpellier

  • Centre Armoricain de Radiotherapie Imagerie & Oncologie (CARIO)

    Plérin

  • Institut de Cancerologie de Ouest (ICO) - Saint-Herblain

    Saint-Herblain

Other trials in France

Spain3 sites

  • Hospital Universitario Vall d'Hebron

    Barcelona

  • HM Universitario Sanchinarro

    Madrid

  • Hospital Beata María Ana

    Madrid

Other trials in Spain

About this study

Official title: An Open-label, Multicenter, Phase 2 Dose Optimization and Expansion Study to Evaluate the Safety and Efficacy of BB-1701, an Anti-human Epidermal Growth Factor Receptor 2 (Anti-HER2) Antibody-drug Conjugate (ADC), in Previously Treated Subjects With HER2-positive or HER2-low Unresectable or Metastatic Breast Cancer

The primary purpose of the Dose Optimization (Part 1) of this study is to assess the safety and tolerability of BB-1701 and to determine the recommended dose (RD) of BB-1701 for Dose Expansion (Part 2). The primary purpose of Dose Expansion (Part 2) is to assess the antitumor activity of BB-1701 at RD in the selected population(s) of breast cancer (BC).

Conditions
Breast Cancer
Being tested
BB-1701
Keywords
Breast cancer, Breast carcinoma, Unresectable or metastatic breast cancer, HER2-positive or HER2-low unresectable or metastatic breast cancer, BB-1701
Medical subject headings
Breast Neoplasms

What participants receive

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

  • BB-1701Drug

    BB-1701 will be administered as an intravenous infusion, every 3 weeks (21-day cycle).

Study groups in NCT06188559
Study groupRoleWhat they receive
Part 1, Dose Optimization, Cohort 1ExperimentalHER2-positive or HER2-low, unresectable or metastatic BC.
Receives: Drug: BB-1701
Part 1, Dose Optimization, Cohort 2ExperimentalHER2-positive or HER2-low, unresectable or metastatic BC.
Receives: Drug: BB-1701
Part 1, Dose Optimization, Cohort 3ExperimentalHER2-positive or HER2-low, unresectable or metastatic BC.
Receives: Drug: BB-1701
Part 2, Dose ExpansionExperimentalHER2-positive or HER2-low, unresectable or metastatic BC.
Receives: Drug: BB-1701

What is being measured

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

  1. Part 1, Dose Optimization: Number of Participants With Adverse Events (AEs)

    An AE is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of an investigational product, whether or not considered related to the investigational product; Any new disease or exacerbation of an existing disease; any deterioration in non-protocol-required measurements of a laboratory value or other clinical test (example, electrocardiogram [ECG] or x-ray) that results in symptoms, a change in treatment, or discontinuation of study drug; Recurrence of an intermittent medical condition (example, headache) not present pretreatment (baseline); An abnormal laboratory test result should be considered an AE if the identified laboratory abnormality leads to any type of intervention, withdrawal of study drug, or withholding of study drug, whether prescribed in the protocol or not. An AE does not necessarily have a causal relationship with the medicinal product.

    Measured: Baseline up to 35 months

  2. Part 1, Dose Optimization: Number of Participants With Clinically Significant Laboratory Values

    Clinical laboratory parameters includes hematology, chemistry, and urinalysis.

    Measured: Baseline up to 35 months

  3. Part 1, Dose Optimization: Number of Participants With Clinically Significant Vital Sign Values

    Vital sign parameters includes systolic and diastolic blood pressure (BP), pulse, respiratory rate, body temperature.

    Measured: Baseline up to 35 months

  4. Part 1, Dose Optimization: Number of Participants With Clinically Significant 12-lead ECGs Values

    Number of participants with clinically significant 12-lead ECGs values will be reported.

    Measured: Baseline up to 35 months

  5. Part 1, Dose Optimization: Number of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status (PS)

    Number of participants with ECOG PS will be reported.

    Measured: Baseline up to 35 months

  6. Part 1, Dose Optimization: Objective Response Rate (ORR)

    ORR is defined as the percentage of participants achieving a confirmed complete response (CR) or confirmed partial response (PR) by investigator assessment per Response Evaluation Criteria for Solid Tumours (RECIST) version (v) 1.1.

    Measured: From date of first dose of study drug until first documentation of CR or PR (up to 35 months)

  7. Part 2, Dose Expansion: Objective Response Rate (ORR) Based on Blinded Independent Central Review (BICR) Assessment per RECIST v1.1

    ORR is defined as the percentage of participants achieving a confirmed CR or confirmed PR based on BICR assessment per RECIST v1.1.

    Measured: From date of first dose of study drug until first documentation of CR or PR (up to 35 months)

Secondary outcomes (26)

  1. Part 1, Dose Optimization: Duration of Response (DOR)

    DOR defined as the time from the onset date of documented CR or PR for confirmed responses by investigator per RECIST v1.1 to the date of disease progression (PD) or death, whichever occurs first.

    Measured: From the date of documented CR or PR to the date of PD or death, whichever occurs first (up to 35 months)

  2. Part 1, Dose Optimization: Progression-free Survival (PFS)

    PFS is defined as the time from the date of first dose to the date of the first documentation of PD by investigator per RECIST v1.1 or death, whichever occurs first.

    Measured: From the date of first dose to the date of the first documentation of PD or death, whichever occurs first (up to 35 months)

  3. Part 1, Dose Optimization: Overall Survival (OS)

    Overall survival (OS) is defined as the time from the date of first dose to the date of death. OS will be based on Kaplan-Meier estimates.

    Measured: From the date of first dose to the date of death (up to 35 months)

  4. Part 1, Dose Optimization: Disease Control Rate (DCR)

    DCR is defined as the percentage of participants with CR, PR, or stable disease (SD) (greater than or equal to [>=] 5 weeks from the first dose) by investigator per RECIST v1.1.

    Measured: From the date of first dose until PD or death, whichever occurs first (up to 35 months)

  5. Part 1, Dose Optimization: Clinical Benefit Rate (CBR)

    CBR is defined as the percentage of participants with CR, PR, or durable SD (duration of SD >=23 weeks) by investigator per RECIST v1.1.

    Measured: From the date of first dose until PD or death, whichever occurs first (up to 35 months)

  6. Part 1, Dose Optimization: Time to Response (TTR)

    TTR is defined as the time from the date of first dose to the day of the first documented CR or PR for confirmed responses by investigator per RECIST v1.1

    Measured: From the date of first dose to the day of the first documented CR or PR (up to 35 months)

  7. Part 1, Dose Optimization, Cmax: Maximum Observed Concentration of BB-1701, Total Antibody and Eribulin (Payload)

    Measured: Baseline up to 35 months

  8. Part 1, Dose Optimization, Tmax: Time to Reach Maximum Observed Concentration (Cmax) of BB-1701, Total Antibody and Eribulin (Payload)

    Measured: Baseline up to 35 months

  9. Part 1, Dose Optimization, AUC(0-t): Area Under the Concentration-time Curve From Zero Time to Time of Last Quantifiable Concentration of BB-1701, Total Antibody and Eribulin (Payload)

    Measured: Baseline up to 35 months

  10. Part 1, Dose Optimization, AUC(0-inf): Area Under the Concentration-time Curve From Zero Time to Infinity of BB-1701, Total Antibody and Eribulin (Payload)

    Measured: Baseline up to 35 months

  11. Part 1, Dose Optimization, t1/2: Terminal Phase Elimination Half-life of BB-1701

    Measured: Baseline up to 35 months

  12. Part 1, Dose Optimization, CL: Total Body Clearance of BB-1701

    Measured: Baseline up to 35 months

  13. Part 1, Dose Optimization, Vss: Volume of Distribution at Steady State for BB-1701

    Measured: Baseline up to 35 months

  14. Part 1, Dose Optimization, Ctrough: Trough Concentration of BB-1701

    Measured: Baseline up to 35 months

  15. Part 1, Dose Optimization: Statistical Correlation Between Serum Concentrations of BB-1701 with ORR and AEs

    Measured: Baseline up to 35 months

  16. Part 2, Dose Expansion: Duration of Response (DOR) Based on BICR Assessment by RECIST v1.1

    DOR is defined as the time from the onset date of documented CR or PR for confirmed responses based on BICR by RECIST v1.1 to the date of PD or death, whichever occurs first.

    Measured: From the date of documented CR or PR to the date of PD or death, whichever occurs first (up to 35 months)

  17. Part 2, Dose Expansion: Disease Control Rate (DCR) Based on BICR Assessment per RECIST v1.1

    DCR is defined as the percentage of participants with CR, PR, or stable disease (SD) (>=5 weeks from the first dose) based on BICR per RECIST v1.1.

    Measured: From the date of first dose until first documentation of CR or PR or SD (up to 35 months)

  18. Part 2, Dose Expansion: Time to Response (TTR) Based on BICR Assessment per RECIST v1.1

    TTR is defined as the time from the date of first dose to the day of the first documented CR or PR for confirmed responses based on BICR per RECIST v1.1

    Measured: From the date of first dose to the day of the first documented CR or PR (up to 35 months)

  19. Part 2, Dose Expansion: Clinical Benefit Rate (CBR) Based on BICR Assessment per RECIST v1.1

    CBR is defined as the percentage of participants with CR, PR, or durable SD (duration of SD >=23 weeks) based on BICR per RECIST v1.1.

    Measured: From the date of first dose until PD or death, whichever occurs first (up to 35 months)

  20. Part 2, Dose Expansion: Progression-free Survival (PFS) Based on BICR Assessment per RECIST v1.1

    PFS is defined as the time from the date of first dose to the date of the first documentation of PD based on BICR per RECIST v1.1 or death, whichever occurs first.

    Measured: From the date of first dose to the date of the first documentation of PD or death, whichever occurs first (up to 35 months)

  21. Part 2, Dose Expansion: Overall Survival (OS)

    Overall survival (OS) is defined as the time from the date of first dose to the date of death. OS will be based on Kaplan-Meier estimates.

    Measured: From the date of first dose to the date of death (up to 35 months)

  22. Part 2, Dose Expansion: Number of Participants With AEs

    An AE is defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of an investigational product, whether or not considered related to the investigational product; Any new disease or exacerbation of an existing disease; any deterioration in non-protocol-required measurements of a laboratory value or other clinical test (example, ECG or x-ray) that results in symptoms, a change in treatment, or discontinuation of study drug; Recurrence of an intermittent medical condition (example, headache) not present pretreatment (baseline); An abnormal laboratory test result should be considered an AE if the identified laboratory abnormality leads to any type of intervention, withdrawal of study drug, or withholding of study drug, whether prescribed in the protocol or not. An AE does not necessarily have a causal relationship with the medicinal product.

    Measured: Baseline up to 35 months

  23. Part 2, Dose Expansion: Number of Participants With Clinically Significant Laboratory Values

    Clinical laboratory parameters includes hematology, chemistry, and urinalysis.

    Measured: Baseline up to 35 months

  24. Part 2, Dose Expansion: Number of Participants With Clinically Significant Vital Sign Values

    Vital sign parameters includes systolic and diastolic BP, pulse, respiratory rate, body temperature.

    Measured: Baseline up to 35 months

  25. Part 2, Dose Expansion: Number of Participants With Clinically Significant 12-lead ECGs Values

    Number of participants with clinically significant 12-lead ECGs values will be reported.

    Measured: Baseline up to 35 months

  26. Part 2, Dose Expansion: Number of Participants With Eastern Cooperative Oncology Group (ECOG) Performance Status (PS)

    Number of participants with ECOG PS will be reported.

    Measured: Baseline up to 35 months

Timeline

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

  1. First posted3 Jan 2024
  2. Study start10 Apr 2024
  3. Primary completion18 Mar 2026
  4. Study completion18 Mar 2026

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 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
For Dose Optimization (Part 1), this study is randomized and for Dose Expansion (Part 2), there will be no randomization.
Masking
None (open label)
Enrolment
56 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06188559
Sponsor's protocol ID
BB-1701-G000-205
Other IDs
2023-506866-30, 2023
Status last verified
Apr 2025
First submitted
28 Nov 2023
Last updated
22 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: Eisai's data sharing commitment and further information on how to request data can be found on our website http://eisaiclinicaltrials.com/.

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing BB-1701 in people with Breast Cancer, run by Eisai Inc. at 49 sites in 4 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 10 inclusion and 16 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: finished, as of the sponsor's last update on 22 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 49 sites in United States, Japan, France, Spain. 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 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

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

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

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?

Part 1, Dose Optimization: Number of Participants With Adverse Events (AEs) (time frame: Baseline up to 35 months). The study lists 7 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 NCT06188559.

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 22 May 2026; AzTrials last refreshed its copy on 7 Nov 2026.

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