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Study to Evaluate Exemestane With and Without SNDX-275 in Treatment of Postmenopausal Women With Advanced Breast Cancer (ENCORE301)

This study has been completed.
Information provided by (Responsible Party):
Syndax Pharmaceuticals Identifier:
First received: May 9, 2008
Last updated: March 19, 2014
Last verified: March 2014
The purpose of this study is to evaluate the safety and efficacy of entinostat in combination with exemestane in the treatment of advanced breast cancer.

Condition Intervention Phase
Breast Cancer
Estrogen Receptor-Positive Breast Cancer
Breast Cancer, Estrogen Receptor-Positive
ER+ Breast Cancer
Drug: entinostat
Drug: exemestane
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Care Provider, Investigator)
Primary Purpose: Treatment
Official Title: A Ph 2, Randomized, Double-Blind, Multicenter Study of Exemestane +/- Entinostat in Postmenopausal Women With Locally Recurrent or Metastatic ER+ Breast Cancer, Progressing on Treatment With a Non-Steroidal AI

Resource links provided by NLM:

Further study details as provided by Syndax Pharmaceuticals:

Primary Outcome Measures:
  • To compare the efficacy of exemestane alone with exemestane plus entinostat, as determined by the duration of progression free survival (PFS) measured from the date of randomization. [ Time Frame: from date of randomization to discontinuation due to disease progression or intolerable AE ]

Secondary Outcome Measures:
  • To compare objective response rate (ORR) and clinical benefit rate (CBR) [ Time Frame: From date of randomization to discontinutation due to disease progression or intolerable AE ]
  • To evaluate the safety and tolerability of entinostat in combination with exemestane as measured by adverse events and laboratory safety parameters. [ Time Frame: from date of randomization to discontinuation due to disease progression or intolerable AE ]

Enrollment: 130
Study Start Date: May 2008
Study Completion Date: October 2012
Primary Completion Date: December 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 1
exemestane (Aromasin) 25mg daily plus entinostat 5mg PO once/week
Drug: entinostat
SNDX-275 5mg tablet PO once/week
Drug: exemestane
exemestane 25mg PO QD
Other Name: Aromasin
Placebo Comparator: 2
exemestane (Aromasin) 25mg daily plus placebo PO once/week
Drug: exemestane
exemestane 25mg PO QD
Other Name: Aromasin


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Postmenopausal female patients
  • Histologically or cytologically confirmed ER+ breast cancer
  • Relapsed or progressed on prior treatment with AI
  • Metastatic disease must be measurable
  • Patients receiving palliative radiation at the non-target lesions must have a 2 week wash out period following completion of the treatment prior to enrollment
  • Patient may have had one prior chemotherapy as part of first line therapy as long as it was received before initiation of prior AI
  • ECOG performance status: 0 to 1
  • Laboratory parameters: a)Hemoglobin ≥ 9.0 g/dL; platelets ≥ 100.0 x 109/L; ANC ≥ 1.5 x 109/L without the use of hematopoietic growth factors b)Creatinine less than 2.5 times the upper limit of normal for the institution c)AST and ALT less than 2.5 times the upper limit of normal for the institution
  • Able to understand and give written informed consent and comply with study procedures

Exclusion Criteria:

  • Relapse on treatment with non-steroidal AI after less than 12 months for patients in the adjuvant setting
  • Progressive disease after less than 3 months treatment with most recent AI for patients with metastatic disease
  • Rapidly progressive, life-threatening metastases
  • Any palliative radiotherapy to the measurable lesion
  • Previous treatment with SNDX-275 or any other HDAC inhibitor including valproic acid
  • Allergy to benzamides or inactive components of the study drug
  • A history of allergies to any active or inactive ingredients of exemestane
  • Any concomitant medical condition that precludes adequate study treatment compliance
  • Patient is currently enrolled in (or completed within 30 days before study drug administration) another investigational drug study
  • Patient is currently receiving treatment with valproic acid, Zolinza(vorinostat) or any other HDAC inhibitor or DNA methyltransferase inhibitor or any systemic anticancer treatment (with the exception of Lupron)
  Contacts and Locations
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Please refer to this study by its identifier: NCT00676663

  Show 44 Study Locations
Sponsors and Collaborators
Syndax Pharmaceuticals
Principal Investigator: Denise Yardley, MD Sarah Cannon Cancer Center
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Syndax Pharmaceuticals Identifier: NCT00676663     History of Changes
Other Study ID Numbers: SNDX-275-0301
Study First Received: May 9, 2008
Last Updated: March 19, 2014

Keywords provided by Syndax Pharmaceuticals:
Breast Neoplasms
Breast Tumor
Mammary Neoplasms

Additional relevant MeSH terms:
Breast Neoplasms
Neoplasms by Site
Breast Diseases
Skin Diseases
Antineoplastic Agents
Histone Deacetylase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Aromatase Inhibitors
Steroid Synthesis Inhibitors
Estrogen Antagonists
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists
Physiological Effects of Drugs processed this record on May 25, 2017