Pracinostat (SB939) is an orally bioavailable, small-molecule histone deacetylase (HDAC) inhibitor based on hydroxamic acid with potential anti-tumor activity characterized by favorable physicochemical, pharmaceutical, and pharmacokinetic properties.
Pracinostat selectively inhibits HDAC class I, II, IV without class III and HDAC6 in class IIb,[1] but has no effect on other Zn-binding enzymes, receptors, and ion channels. It accumulates in tumor cells and exerts a continuous inhibition to histone deacetylase, resulting in acetylated histones accumulation, chromatin remodeling, tumor suppressor genes transcription, and ultimately, apoptosis of tumor cells.[2]
Clinical studies suggests that pracinostat has potential best pharmacokinetic properties when compared to other oral HDAC inhibitors.[3] In March 2014, pracinostat has granted Orphan Drug for acute myelocytic leukemia (AML) and for the treatment of T-cell lymphoma by the Food and Drug Administration.