572 Oral panobinostat in patients with advanced tumors and impaired renal function: Relationship between pharmacokinetics and key safety parameters

KDM1A, a FAD dependent histone demethylase with high homology to amino-oxidases, is responsible of the demethylation of mono and dimethyl lysine 4 on histone H3. KDM1A is part of various transcriptional corepressor complexes and interacts with the co-repressor complex CoREST and histone deacetylases (HDAC) 1 and 2. KDM1A is an essential gene with important roles in different biological relevant processes, including hematopoietic maturation. Its activity has also been demonstrated on non histone substrates such as p53, DNMT1 and MYPT1. High expression and correlation with poor prognosis has been reported for KDM1A in several cancer types, such as neuroblastoma, prostate cancer and non small cell lung cancer. Moreover the high expression of KDM1A and its inverse correlation in hematological malignancies, mostly in acute myeloid leukemia, was observed. Furthermore the enzyme has been demonstrated to sustain the in vivo leukemiogenic potential of MLLAF9 expressing leukemia stem cells. In the light of these findings, KDM1A has been increasingly recognized as an attractive therapeutic target in oncology. We have developed a novel series of potent and irreversible KDM1A inhibitors based on tranylcypromine. The compounds were obtained by a versatile and scalable synthetic process which allows a stereoselective synthesis of the trans enantiomers of the cyclopropane ring. Biochemical and biological characterization of these inhibitors, including their transcriptional effect on KDM1A targets and efficacy in reducing colony forming ability in leukemia cells, will be reported, together with ADME and pharmacokinetic properties of selected compounds. Finally, the best inhibitors of the series induced after oral administration a significant survival increase and provided evidences of target modulation in an in vivo murine promyelocytic leukemia model.