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Entinostat

Phase 1

Breast Neoplasms | Small molecule | Oncology |Roche Holding AG|Last Updated: Nov 10, 2025

Success Probability

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Market & Valuation

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Trial Design

RandomizedACTIVE_CONTROLLED
Total Trials1
Total Enrollment144

FDA Designations

No designations recorded

Clinical trial landscape

Entinostat · 1 trial · 1 indication

Phase 1 1
NCT03280563A Study of Multiple Immunotherapy-Based Treatment Combinations in Hormone Receptor (HR)-Positive Human Epidermal Growth Factor Receptor 2 (HER2)-Negative Breast CancerBreast Neoplasms
COMPLETED144 Analytics
PHASE1COMPLETED
A Study of Multiple Immunotherapy-Based Treatment Combinations in Hormone Receptor (HR)-Positive Human Epidermal Growth Factor Receptor 2 (HER2)-Negative Breast Cancer
Breast NeoplasmsUnlock trial analytics

Study Endpoints

Primary Endpoints

Stage 1: Percentage of Participants With Objective Response
Up to 50.4 months

Objective response rate (ORR) was defined as the percentage of participants with an objective response of complete response (CR) or partial response (PR) as determined by the investigator according to Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1). CR was defined as the disappearance of all target lesions and any pathological lymph nodes (whether target or non-target) that have a reduction in short axis to \< 10 millimeters (mm). PR was defined as at least a 30% decrease in the sum of diameters (SOD) of all target lesions, taking as reference the baseline SOD, in the absence of CR. Participants with missing or no response assessments were classified as non-responders. Percentages have been rounded off to the nearest whole number.

Secondary Endpoints

Stage 1: Progression-free Survival (PFS)
From randomization to the first occurrence of PD or death (up to 51.9 months)
Stage 1: Clinical Benefit Rate (CBR)
Up to 51.9 months
Stage 1: Overall Survival (OS)
From randomization to death (up to 62.2 months)
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Study Design & Arms

AllocationRANDOMIZED
MaskingNONE
ModelSEQUENTIAL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Stage 1: FulvestrantACTIVE_COMPARATORParticipants will receive fulvestrant until unacceptable toxicity or disease progression according to RECIST v1.1.
Stage 1: Atezolizumab + EntinostatEXPERIMENTALParticipants will receive doublet combination treatment with atezolizumab plus entinostat until unacceptable toxicity or loss of clinical benefit as determined by the investigator.
Stage 1: Atezolizumab + FulvestrantEXPERIMENTALParticipants will receive doublet combination treatment with atezolizumab plus fulvestrant until unacceptable toxicity or loss of clinical benefit as determined by the investigator.
Stage 1: Atezolizumab + IpatasertibEXPERIMENTALParticipants will receive doublet combination treatment with atezolizumab plus ipatasertib until unacceptable toxicity or loss of clinical benefit as determined by the investigator. Prior to enrollment into this arm, the first 6 participants in the study will complete a safety run-in with atezolizumab plus ipatasertib.
Stage 1: Atezolizumab + Ipatasertib + FulvestrantEXPERIMENTALParticipants will receive triplet combination treatment with atezolizumab plus ipatasertib plus fulvestrant until unacceptable toxicity or loss of clinical benefit as determined by the investigator. Prior to enrollment into this arm, the first 6 participants in the study will complete a safety run-in with atezolizumab plus ipatasertib.
Stage 2: Atezolizumab + Bevacizumab + Endocrine TherapyEXPERIMENTALThose who progress or experience unacceptable toxicity during treatment in Stage 1 may be eligible to enter Stage 2. Participants will receive triplet combination therapy with atezolizumab plus bevacizumab plus one of three endocrine therapies (fulvestrant, exemestane, or tamoxifen) selected by the physician. Treatment in Stage 2 will continue until unacceptable toxicity or loss of clinical benefit as determined by the investigator.
Stage 1: Mandatory On-Treatment BiopsyEXPERIMENTALFor experimental combination arms that demonstrate clinical activity during the preliminary phase, the Sponsor may open enrollment into a separate mandatory on-treatment biopsy cohort for that combination.
Stage 1: Atezolizumab + Abemaciclib + FulvestrantEXPERIMENTALParticipants will receive triplet combination treatment with atezolizumab plus abemaciclib plus fulvestrant until unacceptable toxicity or loss of clinical benefit as determined by the investigator.

Interventions

NameTypeDescription
Atezolizumab (MPDL3280A), an engineered anti-programmed death-ligand 1 (PD-L1) antibodyDRUGAtezolizumab will be given as 840 milligrams (mg) via intravenous (IV) infusion on Days 1 and 15 of each 28-day cycle. This regimen will apply to all arms except when given with entinostat in Stage 1, or exemestane or tamoxifen in Stage 2, in which atezolizumab will be given as 1200 mg via IV infusion on Day 1 of each 21-day cycle.
BevacizumabDRUGBevacizumab will be given as 10 milligrams per kilogram (mg/kg) via IV infusion on Days 1 and 15 of each 28-day cycle in the regimen containing fulvestrant. When given with exemestane or tamoxifen, bevacizumab will be given as 15 mg/kg via IV infusion on Day 1 of each 21-day cycle.
EntinostatDRUGEntinostat will be given as 5 mg orally once a week on Days 1, 8 and 15 of each 21-day cycle.
ExemestaneDRUGExemestane will be given as 25 mg orally QD in each 21-day cycle.
FulvestrantDRUGFulvestrant will be given as 500 mg intramuscularly on Days 1 and 15 of Cycle 1 and thereafter on Day 1 of each 28-day cycle.
IpatasertibDRUGIpatasertib will be given as 400 mg orally QD on Days 1-21 of each 28-day cycle.
TamoxifenDRUGTamoxifen will be given as 20 mg orally QD in each 21-day cycle.
AbemaciclibDRUGAbemaciclib will be given as 150mg twice daily during each 28-day cycle.
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Eligibility Criteria

Age Range18 Years to N/A
SexFEMALE
Healthy VolunteersNo
Study Sites22

Inclusion Criteria for Both Stages: * Measurable disease per RECIST v1.1 * Adequate hematologic and end organ function * Disease progression during or after first- or second-line hormonal therapy with CDK4/6 inhibitor Inclusion Criteria for Stage 1: * Eastern Cooperative Oncology Group (ECOG) per...

Countries:United StatesIsraelSouth Korea
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Frequently asked questions about Entinostat

What is Entinostat used for in breast cancer?

Entinostat is an investigational small molecule being studied for the treatment of breast neoplasms, specifically in hormone receptor (HR)-positive, HER2-negative breast cancer. It is being evaluated as part of an immunotherapy-based combination treatment regimen. The drug is currently in Phase 1 clinical development and is not yet approved for any use.

What does Entinostat target?

Entinostat is a small molecule that targets histone deacetylases (HDACs), which are enzymes involved in gene expression regulation. By inhibiting HDACs, it may alter the epigenetic landscape of cancer cells, potentially enhancing the anti-tumor immune response. This mechanism is being explored in combination with other immunotherapies for breast cancer.

Who is developing Entinostat?

Entinostat is being developed by Roche Holding AG, a multinational healthcare company. The company's stock is traded under the ticker RHHBY. Roche is conducting clinical trials to evaluate the drug's safety and efficacy in patients with breast cancer.

What phase is Entinostat in?

Entinostat is in Phase 1 clinical development. It is an investigational drug, meaning it has not been approved by regulatory authorities. The ongoing Phase 1 trial is designed to assess the safety, tolerability, and preliminary efficacy of the drug in combination with other treatments for breast cancer.

What clinical trials is Entinostat in?

Entinostat is being studied in a Phase 1 clinical trial with the identifier NCT03280563. This trial, titled 'A Study of Multiple Immunotherapy-Based Treatment Combinations in Hormone Receptor (HR)-Positive Human Epidermal Growth Factor Receptor 2 (HER2)-Negative Breast Cancer,' has been completed. It enrolled 144 female participants aged 18 years and older across the United States, Israel, and South Korea.

Is Entinostat the same as other HDAC inhibitors?

Entinostat is a specific histone deacetylase (HDAC) inhibitor, but it is not the same as other HDAC inhibitors. Each HDAC inhibitor has a unique chemical structure and selectivity profile. Entinostat is being developed by Roche for breast cancer, whereas other HDAC inhibitors may be developed by different companies for various indications.