Current trends in the development of histone deacetylase inhibitors: a review of recent patent applications.

Histone deacetylases (HDACs) have become an important target for the treatment of cancer and other diseases. Currently, more than ten HDAC inhibitors have entered clinical studies and two of them have already reached the market. The hydroxamic acid derivative SAHA (also known as vorinostat or Zolinza®) and the cyclic depsipeptide FK228 (romidepsin or Istodax®) have gained approval from the US FDA for the treatment of cutaneous T-cell lymphoma. Nevertheless, there has been a continuous effort aimed at discovering a new generation of clinical candidates with improved pharmaceutical properties. This review provides a summary of the most recent patents published from mid-2009 to mid-2011.