Combination epigenetic therapy in metastatic colorectal cancer (mCRC) with subcutaneous 5-azacitidine and entinostat: a phase 2 consortium/stand up 2 cancer study

Oncotarget. 2017 May 23;8(21):35326-35338. doi: 10.18632/oncotarget.15108.


Purpose: Therapy with demethylating agent 5-azacitidine and histone deacetylase inhibitor entinostat shows synergistic re-expression of tumor-suppressor genes and growth inhibition in colorectal (CRC) cell lines and in vivo studies.

Experimental design: We conducted a phase II, multi-institutional study of the combination in metastatic CRC patients. Subcutaneous azacitidine was administered at 40 mg/m2 days 1-5 and 8-10 and entinostat was given 7 mg orally on days 3 and 10. An interim analysis indicated toxicity crossed the pre-specified safety boundary but was secondary to disease. A 2nd cohort with added eligibility restrictions was accrued: prior therapies were limited to no more than 2 or 3 (KRAS-mutated and KRAS-wildtype cancers, respectively) and <30% of liver involvement. The primary endpoint was RECIST response. Serial biopsies were performed at baseline and after 2 cycles of therapy.

Results: Forty-seven patients were enrolled (24:Cohort 1, 23:Cohort 2). Patients were heavily pre-treated (median prior therapies 4: Cohort 1 and 2.5: cohort 2). No responses were observed. Median progression-free survival was 1.9 months; overall survival was 5.6 and 8.3 months in Cohorts 1 and 2, respectively. Toxicity was tolerable and as expected. Unsupervised cluster analysis of serial tumor biopsies suggested greater DNA demethylation in patients with PFS above the median.

Conclusion: In this first trial of CRC patients with combination epigenetic therapy, we show tolerable therapy without significant clinical activity as determined by RECIST responses. Reversal of hypermethylation was seen in a subset of patients and correlated with improved PFS.

Keywords: DNA methyltransferases inhibitors; colorectal cancer; epigenetics; histone deacetylase inhibitors.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage*
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Azacitidine / administration & dosage*
  • Azacitidine / pharmacology
  • Benzamides / administration & dosage*
  • Benzamides / pharmacology
  • Cell Line, Tumor
  • Cohort Studies
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / genetics
  • DNA Methylation / drug effects*
  • Drug Administration Schedule
  • Epigenesis, Genetic / drug effects
  • Female
  • HCT116 Cells
  • Humans
  • Male
  • Middle Aged
  • Pyridines / administration & dosage*
  • Pyridines / pharmacology
  • Survival Analysis
  • Treatment Outcome


  • Benzamides
  • Pyridines
  • entinostat
  • Azacitidine