Receptors, EstrogenPhase 1NCT04288089
A Study of H3B-6545 in Combination With Palbociclib in Women With Advanced or Metastatic Estrogen Receptor-Positive Human Epidermal Growth Factor Receptor-2 (HER2)-Negative Breast Cancer
A Phase 1 study testing Palbociclib (75, 100, 125 milligram [mg]) and H3B-6545 (150, 300, 450 mg) in people with Receptors, Estrogen and Genes, Erbb-2, run by Eisai Inc. at 8 sites in 2 countries.
Trial summary
The primary objective of this study is to evaluate the safety and tolerability of H3B-6545 and palbociclib when administered in combination in order to determine the maximum tolerated dose (MTD) and/or the recommended Phase 2 dose (RP2D) of this combination in women with advanced or metastatic estrogen… Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Receptors, Estrogen, Genes, Erbb-2, Breast Neoplasms
- What is being tested?
- Palbociclib (75, 100, 125 milligram [mg]) and H3B-6545 (150, 300, 450 mg)
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 31 participants
- Where
- 8 sitesin 2 countries
- Study dates
- 1 Apr 2020to 31 Mar 2027
- Phase
- Phase 1
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ER+ HER2- locally advanced, recurrent, or metastatic breast cancer, as per local laboratory
- Prior therapy in the advanced/metastatic setting
- Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
- Has adequate bone marrow and organ function
Who cannot join
- Uncontrolled significant active infections
- Major surgery or other locoregional treatment within 4 weeks before the 1st dose of study drug
- Inability to take oral medication or presence of malabsorption
- Active cardiac disease or a history of cardiac dysfunction
- Evidence of ongoing Alcohol or Drug Abuse
Trial locations and contacts
8 sites in 2 countries.
8 sites in 2 countries
United States5 sites
Massachusetts General Hospital
Boston, Massachusetts, 02114
Saint Luke's Cancer Institute
Kansas City, Missouri, 64111
Comprehensive Cancer Centers of Nevada
Las Vegas, Nevada, 89169
Tennessee Oncology, PLLC - SCRI - PPDS
Nashville, Tennessee, 37203
Florida Cancer Specialists South - SCRI - PPDS
Sarasota, Florida, 34232
United Kingdom3 sites
Royal Marsden NHS Foundation Trust
London
Sarah Cannon Research Institute UK - SCRI
London
Royal Marsden NHS Foundation Trust
Sutton
About this study
Official title: An Open-Label Multicenter Phase 1b Study of H3B-6545 in Combination With Palbociclib in Women With Advanced or Metastatic Estrogen Receptor-Positive HER2-Negative Breast Cancer
The primary objective of this study is to evaluate the safety and tolerability of H3B-6545 and palbociclib when administered in combination in order to determine the maximum tolerated dose (MTD) and/or the recommended Phase 2 dose (RP2D) of this combination in women with advanced or metastatic estrogen receptor-positive (ER+) HER2- breast cancer.
- Conditions
- Receptors, Estrogen, Genes, Erbb-2, Breast Neoplasms
- Being tested
- Palbociclib (75, 100, 125 milligram [mg]), H3B-6545 (150, 300, 450 mg)
- Keywords
- H3B-6545, Palbociclib, Metastatic Estrogen Receptor-Positive, HER2-Negative Breast Cancer
- Medical subject headings
- Breast Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Palbociclib (75, 100, 125 milligram [mg])Drug
Palbociclib orally, once daily (QD).
H3B-6545 (150, 300, 450 mg)Drug
H3B-6545 orally, QD.
| Study group | Role | What they receive |
|---|---|---|
| Palbociclib + H3B-6545 (Dose Escalation and Dose Expansion) | Experimental | Participants will receive Palbociclib 75, 100, 125 milligram (mg) capsules or tablets, orally, once daily from Days 1 to 21 followed by 7 days off treatment in 28-day cycles along with H3B-6545 150, 300, 450 mg capsules or tablets, orally, once daily from Days 1 to 28 in 28-day cycles in dose escalation part. Based on MTD or RP2D determined for H3B-6545 in combination with palbociclib in dose escalation part, participants will continue to receive study treatment in dose expansion part until PD, development of unacceptable toxicity, or withdrawal of consent (up to 24 months). Receives: Drug: Palbociclib (75, 100, 125 milligram [mg]); Drug: H3B-6545 (150, 300, 450 mg) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maximum Tolerated Dose (MTD) of H3B-6545 and Palbociclib
The MTD was defined as the highest dose at which no more than 1 of 6 participants experienced a Dose-Limiting Toxicity (DLT) in the dose cohort. DLT was graded as per National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. DLTs were defined as the following events that occurred in Cycle 1, for which a causal relationship with the study drug could not be ruled out: febrile neutropenia; Grade 4 neutropenia that was not resolved within 7 days; Grade 4 thrombocytopenia; Grade 3 thrombocytopenia lasting greater than (>) 7 days or associated with clinically significant bleeding; Grade 4 vomiting and diarrhea; Grade 3 vomiting and diarrhea lasting > 72 hours despite treatment; Grade 4 electrolyte abnormality or Grade 3 abnormality lasting > 24 hours; Grade 3 or 4 serum creatinine or bilirubin increase; Grade 4 biochemistry or Grade 3 lasting > 7 days; Grade 4 or Grade 3 or intolerable grade 2 toxicities of any non-hematologic adverse event.
Measured: Cycle 1 (Cycle length = 28 Days)
Secondary outcomes (16)
Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs)
TEAE was defined as an adverse event (AE) with an onset that had occurred after receiving study drug. An AE was defined as any untoward medical occurrence in a participants or clinical investigation participant administered an investigational product. An AE does not necessarily have a causal relationship with medicinal product. A serious adverse event (SAE) was defined as any AE if it resulted in death or life-threatening AE or required inpatient hospitalization or prolongation of existing hospitalization or resulted in persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions or was a congenital anomaly/birth defect. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: From first dose up to 28 days after the last dose of study drug (up to Month 48)
AUC(0-t): Area Under the Plasma Concentration-time Curve From Time 0 to the Last Measurable Point for Palbociclib and H3B-6545
Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Cmax: Maximum Observed Plasma Concentration for Palbociclib and H3B-6545
Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Tmax: Time to Reach the Cmax for Palbociclib and H3B-6545
Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
C24: Plasma Concentration at 24 Hour Post-dose for Palbociclib and H3B-6545
Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of Pharmacokinetic (PK) Cmax Parameter Estimates Between Day 21 (Palbociclib) and Day 8 (Palbociclib)
Ratio of palbociclib Cmax Day 21/Day 8, is the ratio of palbociclib exposure on Day 21 and palbociclib exposure on Day 8. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8 and 21: 0-24 hours postdose
Ratio of PK AUC24 Parameter Estimates Between Day 21 (Palbociclib) and Day 8 (Palbociclib)
Ratio of palbociclib AUC24 Day 21/Day 8, is the ratio of palbociclib exposure on Day 21 and palbociclib exposure on Day 8. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8 and 21: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK C24 Parameter Estimates Between Day 21 (Palbociclib) and Day 8 (Palbociclib)
Ratio of palbociclib C24 Day 21/Day 8, is the ratio of palbociclib exposure on Day 21 and palbociclib exposure on Day 8. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 8 and 21: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK Cmax Parameter Estimates Between Day 21 (H3B-6545) and Day 28 (H3B-6545)
Ratio of palbociclib Cmax Day 21/Day 28, is the ratio of H3B-6545 exposure on Day 21 and H3B-6545 exposure on Day 28. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK AUC24 Parameter Estimates Between Day 21 (H3B-6545) and Day 28 (H3B-6545)
Ratio of H3B-6545 AUC24 Day 21/Day 28, is the ratio of H3B-6545 exposure on Day 21 and H3B-6545 exposure on Day 28. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK C24 Parameter Estimates Between Day 21 (H3B-6545) and Day 28 (H3B-6545)
Ratio of H3B-6545 C24 Day 21/Day 28, is the ratio of H3B-6545 exposure on Day 21 and H3B-6545 exposure on Day 28. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: Dose Escalation Part: Cycle 1 Days 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Objective Response Rate (ORR)
ORR is defined as the percentage of participants achieving a best overall response (BOR) of confirmed partial response (PR) or complete response (CR). The ORR will be assessed according to Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: From first dose of study drug up to Month 48
Duration of Response (DoR)
DoR is defined as the time from the date of the first documented CR/PR until the first documentation of disease progression (PD) or death, whichever comes first. The DoR will be assessed according to RECIST version 1.1. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: From the date of first documented CR/PR until the PD or death, whichever occurs first (up to Month 48)
Clinical Benefit Rate (CBR)
CBR is defined as the percentage of participants with BOR of PR, CR, or durable stable disease (SD) (duration of SD greater than or equal to 23 weeks). Duration of SD is defined as the time from the date of first dose to the date of the first documentation of disease progression or death, whichever occurs first. It will be calculated for participants whose BOR is SD. The CBR will be assessed according to RECIST version 1.1. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: From the first dose of study drug until disease progression or death, whichever occurs first (up to Month 48)
Progression-free Survival (PFS)
PFS is defined as the time from the first dose date to the date of the first documentation of PD or death (whichever occurs first). Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: From first dose of study drug until first documentation of PD or death, whichever occurs first (up to Month 48)
Overall Survival (OS)
OS is defined as the time from first dose date to the date of death from any cause. Analysis is not final for this outcome measure, and complete data will be posted at study completion date.
Measured: From the date of first dose to the date of death from any cause (up to Month 48)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Feb 2020
- Study start1 Apr 2020
- Primary completion16 Sep 2022
- Study completion31 Mar 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Receptors, EstrogenStudies of the same condition, open and under way.
- More trials run by Eisai Inc.The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 31 participants (actual)
Sponsor and investigators
- Lead sponsor
- Eisai Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04288089
- Sponsor's protocol ID
- H3B-6545-G000-102
- Other IDs
- 2019-004622-17, 2019
- Status last verified
- Aug 2026
- First submitted
- 26 Feb 2020
- Last updated
- 27 Aug 2026
- Results posted
- Yes, on ClinicalTrials.gov
- 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/.
Publications
Furman C, Puyang X, Zhang Z, Wu ZJ, Banka D, Aithal KB, Albacker LA, Hao MH, Irwin S, Kim A, Montesion M, Moriarty AD, Murugesan K, Nguyen TV, Rimkunas V, Sahmoud T, Wick MJ, Yao S, Zhang X, Zeng H, Vaillancourt FH, Bolduc DM, Larsen N, Zheng GZ, Prajapati S, Zhu P, Korpal M. Covalent ERalpha Antagonist H3B-6545 Demonstrates Encouraging Preclinical Activity in Therapy-Resistant Breast Cancer. Mol Cancer Ther. 2022 Jun 1;21(6):890-902. doi: 10.1158/1535-7163.MCT-21-0378.
PubMed 35642432
Study at a glance
From the registry record, last updated by the sponsor on 27 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- An Open-Label Multicenter Phase 1b Study of H3B-6545 in Combination With Palbociclib in Women With Advanced or Metastatic Estrogen Receptor-Positive HER2-Negative Breast Cancer
- ClinicalTrials.gov ID
- NCT04288089
- Acronym / sponsor ID
- H3B-6545-G000-102
- Conditions
- Receptors, Estrogen, Genes, Erbb-2, Breast Neoplasms
- Keywords
- H3B-6545, Palbociclib, Metastatic Estrogen Receptor-Positive, HER2-Negative Breast Cancer
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 31 participants (actual)
- Lead sponsor
- Eisai Inc.Industry (pharma, biotech, devices)
- Study start
- 1 Apr 2020 (actual)
- Primary completion
- 16 Sep 2022 (actual)
- Study completion
- 31 Mar 2027 (estimated)
- First posted
- 27 Feb 2020 (actual)
- Results
- Posted 22 Mar 2024
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary objective of this study is to evaluate the safety and tolerability of H3B-6545 and palbociclib when administered in combination in order to determine the maximum tolerated dose (MTD) and/or the recommended Phase 2 dose (RP2D) of this combination in women with advanced or metastatic estrogen receptor-positive (ER+) HER2- breast cancer.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Palbociclib + H3B-6545 (Dose Escalation and Dose Expansion) | Experimental | Drug: Palbociclib (75, 100, 125 milligram [mg]), Drug: H3B-6545 (150, 300, 450 mg)Participants will receive Palbociclib 75, 100, 125 milligram (mg) capsules or tablets, orally, once daily from Days 1 to 21 followed by 7 days off treatment in 28-day cycles along with H3B-6545 150, 300, 450 mg capsules or tablets, orally, once daily from Days 1 to 28 in 28-day cycles in dose escalation part. Based on MTD or RP2D determined for H3B-6545 in combination with palbociclib in dose escalation part, participants will continue to receive study treatment in dose expansion part until PD, development of unacceptable toxicity, or withdrawal of consent (up to 24 months). |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- ER+ HER2- locally advanced, recurrent, or metastatic breast cancer, as per local laboratory
- Prior therapy in the advanced/metastatic setting
- Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
- Has adequate bone marrow and organ function
Key exclusion criteria (5 listed)
- Uncontrolled significant active infections
- Major surgery or other locoregional treatment within 4 weeks before the 1st dose of study drug
- Inability to take oral medication or presence of malabsorption
- Active cardiac disease or a history of cardiac dysfunction
- Evidence of ongoing Alcohol or Drug Abuse
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Palbociclib (75, 100, 125 milligram [mg])Palbociclib orally, once daily (QD). | Drug | Palbociclib + H3B-6545 (Dose Escalation and Dose Expansion) |
| H3B-6545 (150, 300, 450 mg)H3B-6545 orally, QD. | Drug | Palbociclib + H3B-6545 (Dose Escalation and Dose Expansion) |
Primary outcome
Maximum Tolerated Dose (MTD) of H3B-6545 and Palbociclib
Time frame: Cycle 1 (Cycle length = 28 Days)
The MTD was defined as the highest dose at which no more than 1 of 6 participants experienced a Dose-Limiting Toxicity (DLT) in the dose cohort. DLT was graded as per National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. DLTs were defined as the following events that occurred in Cycle 1, for which a causal relationship with the study drug could not be ruled out: febrile neutropenia; Grade 4 neutropenia that was not resolved within 7 days; Grade 4 thrombocytopenia; Grade 3 thrombocytopenia lasting greater than (>) 7 days or associated with clinically significant bleeding; Grade 4 vomiting and diarrhea; Grade 3 vomiting and diarrhea lasting > 72 hours despite treatment; Grade 4 electrolyte abnormality or Grade 3 abnormality lasting > 24 hours; Grade 3 or 4 serum creatinine or bilirubin increase; Grade 4 biochemistry or Grade 3 lasting > 7 days; Grade 4 or Grade 3 or intolerable grade 2 toxicities of any non-hematologic adverse event.
16 secondary outcomes
Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs)
Time frame: From first dose up to 28 days after the last dose of study drug (up to Month 48)
AUC(0-t): Area Under the Plasma Concentration-time Curve From Time 0 to the Last Measurable Point for Palbociclib and H3B-6545
Time frame: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Cmax: Maximum Observed Plasma Concentration for Palbociclib and H3B-6545
Time frame: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Tmax: Time to Reach the Cmax for Palbociclib and H3B-6545
Time frame: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
C24: Plasma Concentration at 24 Hour Post-dose for Palbociclib and H3B-6545
Time frame: Dose Escalation Part: Cycle 1 Days 8, 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of Pharmacokinetic (PK) Cmax Parameter Estimates Between Day 21 (Palbociclib) and Day 8 (Palbociclib)
Time frame: Dose Escalation Part: Cycle 1 Days 8 and 21: 0-24 hours postdose
Ratio of PK AUC24 Parameter Estimates Between Day 21 (Palbociclib) and Day 8 (Palbociclib)
Time frame: Dose Escalation Part: Cycle 1 Days 8 and 21: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK C24 Parameter Estimates Between Day 21 (Palbociclib) and Day 8 (Palbociclib)
Time frame: Dose Escalation Part: Cycle 1 Days 8 and 21: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK Cmax Parameter Estimates Between Day 21 (H3B-6545) and Day 28 (H3B-6545)
Time frame: Dose Escalation Part: Cycle 1 Days 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK AUC24 Parameter Estimates Between Day 21 (H3B-6545) and Day 28 (H3B-6545)
Time frame: Dose Escalation Part: Cycle 1 Days 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Ratio of PK C24 Parameter Estimates Between Day 21 (H3B-6545) and Day 28 (H3B-6545)
Time frame: Dose Escalation Part: Cycle 1 Days 21 and 28: 0-24 hours postdose; Dose Expansion Part: Cycle 1 Day 21: 0-24 hours postdose (Each Cycle length=28 days)
Objective Response Rate (ORR)
Time frame: From first dose of study drug up to Month 48
Duration of Response (DoR)
Time frame: From the date of first documented CR/PR until the PD or death, whichever occurs first (up to Month 48)
Clinical Benefit Rate (CBR)
Time frame: From the first dose of study drug until disease progression or death, whichever occurs first (up to Month 48)
Progression-free Survival (PFS)
Time frame: From first dose of study drug until first documentation of PD or death, whichever occurs first (up to Month 48)
Overall Survival (OS)
Time frame: From the date of first dose to the date of death from any cause (up to Month 48)
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Aug 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 35642432Furman C, Puyang X, Zhang Z, Wu ZJ, Banka D, Aithal KB, Albacker LA, Hao MH, Irwin S, Kim A, Montesion M, Moriarty AD, Murugesan K, Nguyen TV, Rimkunas V, Sahmoud T, Wick MJ, Yao S, Zhang X, Zeng H, Vaillancourt FH, Bolduc DM, Larsen N, Zheng GZ, Prajapati S, Zhu P, Korpal M. Covalent ERalpha Antagonist H3B-6545 Demonstrates Encouraging Preclinical Activity in Therapy-Resistant Breast Cancer. Mol Cancer Ther. 2022 Jun 1;21(6):890-902. doi: 10.1158/1535-7163.MCT-21-0378.
- Individual participant dataSharing planned: Yes. Eisai's data sharing commitment and further information on how to request data can be found on our website http://eisaiclinicaltrials.com/.
Related trials for Receptors, Estrogen
Recruiting
Signatera-Guided CDK4/6 Inhibitor Therapy in Breast Cancer
Breast Neoplasms, Carcinoma, Ductal, Breast
RecruitingPhase 2
Reishi Mushroom Extract for Fatigue and/or Arthralgias/Myalgias in Patients With Breast Cancer on Aromatase Inhibitors
Estrogen Receptor-Positive Breast Carcinoma
RecruitingPhase 3
Testing Whether Hormone Therapy With Ribociclib is as Effective as Chemotherapy Followed by Hormone Therapy With Ribociclib for the Treatment of High Anatomic Stage Breast Cancer With Low Recurrence Risk, The RxFINE-Low Trial
Anatomic Stage II Breast Cancer AJCC v8, Anatomic Stage IIIA Breast Cancer AJCC v8
Active, not recruitingPhase 2
A Study to See Whether Estrogen Can Slow the Growth of Some ER Positive Breast Cancers
Estrogen Receptor Positive Breast Cancer
Active, not recruitingPhase 3
A Study Evaluating the Efficacy and Safety of Giredestrant Plus Everolimus Compared With the Physician's Choice of Endocrine Therapy Plus Everolimus in Participants With Estrogen Receptor-Positive, HER2-Negative, Locally Advanced or Metastatic Breast Cancer (evERA Breast Cancer)
Estrogen Receptor (ER)-Positive, HER2-negative, Locally Advanced or Metastatic Breast Cancer
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
8 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing Palbociclib (75, 100, 125 milligram [mg]) and H3B-6545 (150, 300, 450 mg) in people with Receptors, Estrogen and Genes, Erbb-2, run by Eisai Inc. at 8 sites in 2 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 4 inclusion and 5 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 27 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 8 sites in United States, United Kingdom. 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?
Yes. Results are posted in the registry (first posted 22 Mar 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Maximum Tolerated Dose (MTD) of H3B-6545 and Palbociclib (time frame: Cycle 1 (Cycle length = 28 Days)). 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 NCT04288089, which also lists 1 linked publication.
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 27 Aug 2026; AzTrials last refreshed its copy on 6 Nov 2026.