A Phase 2, Multicenter Study of the Effect of the Addition of SNDX-275 to Continued Aromatase Inhibitor (AI) Therapy in Postmenopausal Women With ER+ Breast Cancer Whose Disease is Progressing

This study has been completed.
Information provided by:
Syndax Pharmaceuticals
ClinicalTrials.gov Identifier:
First received: January 23, 2009
Last updated: February 2, 2010
Last verified: February 2010

The addition of SNDX-275 to an AI will result in a maximal abrogation of estrogen receptor-α mediated activity and inhibit mechanisms of resistance to the aromatase inhibitor.

It is hypothesized that SNDX-275 with continued AI will increase the estimated AI clinical benefit rate (CBR) from 5% to 25% with an acceptable safety profile.

Condition Intervention Phase
ER+ Breast Cancer
Drug: entinostat (SNDX-275)
Phase 2

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: A Phase 2, Multicenter Study of the Effect of the Addition of SNDX-275 to Continued Aromatase Inhibitor (AI) Therapy in Postmenopausal Women With ER+ Breast Cancer Whose Disease is Progressing

Resource links provided by NLM:

Further study details as provided by Syndax Pharmaceuticals:

Primary Outcome Measures:
  • Clinical benefit rate (CBR) [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Progression free survival (PFS) [ Designated as safety issue: No ]
  • Objective response rate (ORR) during the first 6 cycles of study treatment [ Time Frame: 6 months ] [ Designated as safety issue: No ]

Estimated Enrollment: 25
Study Start Date: April 2008
Primary Completion Date: February 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: treatment
Continued treatment with same AI at labeled dose and schedule, plus Entinostat (5mg PO every week)
Drug: entinostat (SNDX-275)
5 mg PO every week


Genders Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Postmenopausal female patients.
  2. Histologically or cytologically confirmed ER+ breast cancer.
  3. Progressive disease (PD) after at least 3 months on treatment with a 3rd generation AI in the advanced disease setting as measured by RECIST criteria.
  4. At least 1 measurable lesion ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan with the last imaging performed within 4 weeks prior to study entry. If there is only one measurable lesion and it is located in previously irradiated field, it must have demonstrated progression according to RECIST criteria.
  5. ECOG 0-1.
  6. Laboratory parameters:

    1. Hemoglobin ≥ 9.0 g/dL; platelets ≥ 100 x109/L; ANC ≥ 1.5 x 109/L without the use of hematopoietic growth factors.
    2. Creatinine less than 2.5 times the upper limit of normal for the institution.
    3. AST and ALT less than 2.5 times the upper limit of normal for the institution.
  7. Able to understand and give written informed consent and comply with study procedures.

Exclusion Criteria:

  1. Discontinuation of AI therapy prior to study entry.
  2. Less than 3 months treatment with most recent AI.
  3. Rapidly progressive, life-threatening metastases, including any of the following:

    1. Symptomatic lymphangitic metastases.
    2. Patients with known active brain or leptomeningeal involvement.
  4. More than one prior chemotherapy for metastatic disease.
  5. Any chemotherapy within 3 months prior to study.
  6. Radiotherapy to measurable lesion within 2 months prior to study.
  7. Bisphosphonates initiated within 4 weeks prior to study start.
  8. Allergy to benzamides or inactive components of study drug.
  9. Previous treatment with entinostat or any other HDAC inhibitor including valproic acid.
  10. Patient is currently receiving treatment with any agent listed on the prohibited medication list such as valproic acid or other systemic cancer agents
  11. Any concomitant medical condition that precludes adequate study treatment compliance or assessment, or increases patient risk in the opinion of the investigator:

    1. Myocardial infarction or arterial thromboembolic events within 6 months, or experiencing severe or unstable angina, New York Heart Association (NYHA) Class III or IV disease and a QTc interval >0.47 second.
    2. Uncontrolled heart failure or hypertension, uncontrolled diabetes mellitus, uncontrolled systemic infection,
    3. Other active malignancy within 5 years excluding basal cell carcinoma or cervical intraepithelial neoplasia [CIN / cervical carcinoma in situ] or melanoma in situ).
  12. Patient currently is enrolled in (or completed within 30 days before study drug administration) another investigational drug study.
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00828854

St. Vincent's University Hospital
Dublin, Ireland
United Kingdom
The University of Birmingham
Birmingham, United Kingdom
Velindre Hospital - Whitchurch
Cardiff, United Kingdom
Whiston Hospital; Clatterbridge Centre for Oncology
Liverpool, United Kingdom
University College London Hospitals
London, United Kingdom
Christie Hospital, Manchester Breast Centre
Manchester, United Kingdom
Sponsors and Collaborators
Syndax Pharmaceuticals
  More Information

Responsible Party: Judy Billingsley, RN, BSN, OCN, Syndax Pharmaceuticals, Inc.
ClinicalTrials.gov Identifier: NCT00828854     History of Changes
Other Study ID Numbers: SNDX-275-0303 
Study First Received: January 23, 2009
Last Updated: February 2, 2010
Health Authority: United Kingdom: Medicines and Healthcare Products Regulatory Agency
Ireland: Irish Medicines Board

Keywords provided by Syndax Pharmaceuticals:
breast cancer
estrogen receptor postive

Additional relevant MeSH terms:
Breast Neoplasms
Breast Diseases
Neoplasms by Site
Skin Diseases
Aromatase Inhibitors
Antineoplastic Agents
Enzyme Inhibitors
Estrogen Antagonists
Histone Deacetylase Inhibitors
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Steroid Synthesis Inhibitors

ClinicalTrials.gov processed this record on May 23, 2016