A phase I study of vorinostat (suberoylanilide hydroxamic acid, SAHA) in Japanese patients with gastrointestinal (GI) cancer

15656 Background: Vorinostat is an inhibitor of histone deacetylases with clinical activity in patients (pts) with various types of cancer including cutaneous T-cell lymphoma. However, the safety, clinical activity and PK profile in Japanese pts with GI cancer had not been evaluated until now. Methods: Japanese pts with GI cancers who failed standard therapy were enrolled into 2 dose levels that were recommended doses used outside Japan. For a course of 21 days, vorinostat was to be administered 300 mg BID for 3 consecutive days followed by a 4 day-rest (Level 1) and to be escalated to 400 mg QD continuous (Level 2) to evaluate its safety. PK and response were also assessed. Results: All 16 enrolled pts had GI cancer: 10 gastric cancer, 3 rectal cancer, and 3 colon cancer. Median age was 58 yrs [32–73] and no. of prior regimens was 4 [2–6]. All were assessed for safety and 1 pt was excluded from PK assessment due to incomplete dose received on the first day. At level 1, none of the 10 pts experienced DLT....