A phase 1 study to assess the food effect on the pharmacokinetics (PK) of entinostat.

591 Background: Entinostat (ENT) is an oral, class 1 isoform selective histone deacetylase inhibitor shown to extend progression free and overall survival when combined with exemestane (EXE) in post-menopausal women with estrogen receptor positive (ER+) metastatic breast cancer (MBC) who have progressed on prior non-steroidal aromatase inhibitors (Yardley et al; JCO 31:2128;2013). Based on these results ENT was granted Breakthrough Therapy designation by the FDA for this indication. This Phase 1 study evaluated the effect of food on ENT PK in patients (pts) with MBC and advanced non-small cell lung cancer (NSCLC). Methods: A total of 17 pts (14 postmenopausal ER+ MBC and 3 NSCLC) were randomized 1:1 to receive ENT 10 mg administered Day 1 and 15 of a 28 day lead-in cycle, fasting and with food. Pts randomized to ENT with food on Cycle 1 Day 1 (C1D1) received ENT fasted on Cycle 1 Day 15 (C1D15); pts randomized to ENT fasted on C1D1 received ENT with food on C1D15. Blood samples were obtained pre-dose C1D1...