In 2006, SAHA (vorinostat) was first approved by the US Food and Drug Administration (FDA) for the treatment of cancer, restricted to patients with cutaneous T-cell lymphoma (CTCL), as an HDAC inhibitor.643 Romidepsin (Istodax) was the second approved HDAC inhibitor, which was approved in 2009. Here, HDAC9 is linked to primary cutaneous T-cell non-Hodgkin lymphoma.