Abstract 1172: Phase I study of histone deacetylase inhibitor belinostat in combination with warfarin in patients with solid tumors or hematological malignancies.

Abstract

Abstract Background: The family of Histone Deacetylase (HDAC) enzymes serves as important epigenetic regulators of gene expression through modulation of acetylation on important histone and non-histone proteins. Aberrant acetylation of histones can alter gene expression believed to be important in the tumorigenic process. Belinostat, a potent inhibitor of HDAC proteins has demonstrated anti tumor activity in animal models and in humans. The purpose of this study was to examine the pharmacokinetic and pharmacodynamic properties of warfarin in combination with belinostat and to evaluate the safety profile of belinostat with concomitant warfarin. Methods: Eligible patients enrolled on the study received 5 mg PO warfarin 14 days prior to administration of belinostat. Belinostat was administered as an iv infusion, 1000mg/m2 over 30 minutes for 5 consecutive days every 21 days. On day 3, cycle 1 of belinostat treatment, a second dose of 5mg PO warfarin was administered 2 hours prior to belinostat. Pharmacokinetic blood samples were obtained during cycle 1 of the study to measure warfarin and belinostat metabolism. Toxicities were monitored regularly throughout treatment and response was monitored according to standard of care guidelines. Results: 18 patients, with solid tumors or hematologic malignancies, treated with belinostat and warfarin were included in this analysis. Median age was 55 years (31-77). 11 (61%) patients were male and 7(39%) patients were female. The most common Grade 1 or 2, toxicities observed during the study were anemia (78%), fatigue (72%) and nausea (61%). The most frequent Grade 3 or 4 toxicities were nausea (11%) and hyperuricemia (11%). No Grade 3 or 4 thrombocytopenia or neutropenia were reported. No treatment related Grade 5 toxicities were reported. During cycle 1 no patient experienced treatment delays or discontinued study as result of treatment related toxicity. Conclusion: Belinostat was generally well tolerated in patients with solid tumors or hematologic malignancies with the major toxicity being anemia, fatigue or nausea. Pharmacokinetic results will be presented at the conference. Citation Format: Neeraj Agarwal, Mark L. Wade, Julia Batten, Cynthia Davidson, Show-Li Sun, Sunil Sharma. Phase I study of histone deacetylase inhibitor belinostat in combination with warfarin in patients with solid tumors or hematological malignancies. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1172. doi:10.1158/1538-7445.AM2013-1172