Abstract
Purpose: In breast cancer models, combination epigenetic therapy with a DNA methyltransferase inhibitor and a histone deacetylase inhibitor led to reexpression of genes encoding important therapeutic targets, including the estrogen receptor (ER). We conducted a multicenter phase II study of 5-azacitidine and entinostat in women with advanced hormone-resistant or triple-negative breast cancer (TNBC). Experimental Design: Patients received 5-azacitidine 40 mg/m2 (days 1-5, 8-10) and entinostat 7 mg (days 3, 10) on a 28-day cycle. Continuation of epigenetic therapy was offered with the addition of endocrine therapy at the time of progression [optional continuation (OC) phase]. Primary endpoint was objective response rate (ORR) in each cohort. We hypothesized that ORR would be >20% against null of 5% using Simon twostage design. At least one response was required in 1 of 13 patients per cohort to continue accrual to 27 per cohort (type I error, 4%; power, 90%). Results: There was one partial response among 27 women with hormone-resistant disease (ORR = 4%; 95% CI, 0-19), and none in 13 women with TNBC. One additional partial response was observed in the OC phase in the hormone-resistant cohort (n = 12). Mandatory tumor samples were obtained pre- and posttreatment (58% paired) with either up- or downregulation of ER observed in approximately 50% of posttreatment biopsies in the hormone-resistant, but not TNBC cohort. Conclusions: Combination epigenetic therapy was well tolerated, but our primary endpoint was not met. OC phase results suggest that some women benefit from epigenetic therapy and/or reintroduction of endocrine therapy beyond progression, but further study is needed.
Original language | English (US) |
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Pages (from-to) | 2691-2701 |
Number of pages | 11 |
Journal | Clinical Cancer Research |
Volume | 23 |
Issue number | 11 |
DOIs | |
State | Published - Jun 1 2017 |
ASJC Scopus subject areas
- General Medicine