A phase I trial of the histone deacetylase inhibitor panobinostat (LBH589) and epirubicin in patients with solid tumor malignancies.

3058 Background: Preclinical and clinical data suggest pre-exposure of cancer cells to a histone deacetylase inhibitor (HDACi) potentiates topoisomerase inhibitors. HDACi-induced histone acetylation and chromatin modulation facilitates DNA access and target recruitment for topo II inhibitors. In vitro data further suggest effective inhibition of HDAC2 is necessary for enhanced epirubicin-induced apoptosis. Methods: This phase I trial explores the safety, tolerability, and maximum tolerated dose (MTD) of escalating doses of panobinostat given orally on days 1, 3, and 5 followed by epirubicin administered intravenously at 75 mg/m2 on day 5 in 21-day cycles. Histone acetylation and HDAC2 expression are evaluated in pre- and post-treatment peripheral blood mononuclear cells (PBMCs) in all patients and in tumor cells of 16 patients treated at the MTD. Results: 36 patients have enrolled [10M/26F, median age 47 years (22-80)] in 5 panobinostat cohorts: 20, 30, 40, 50, 60 mg. Tumor types include melanoma (n=6), b...