ACY-1215 (Rocilinostat) is an orally-available, hydroxamic acid-based, selective inhibitor of HDAC6 and HDAC8 with IC50 values of 5 nM and 100 nM, respectively. ACY-1215 is12-, 10-, and 11-fold less active against HDAC1, HDAC2, and HDAC3, respecitvely, and has minimal activity (IC50 > 1 uM) against HDAC4, HDAC5, HDAC7, HDAC9, HDAC11, Sirtuin1 and Sirtuin2. [1]

To demonstrate ACY-1215 selectivity for HDAC6, MM.1S cells were cultured with increasing doses of ACY-1215 for 6 hours. Dose-dependent increased acetylated a-tubulin was observed at low doses (0.62 uM) with no effect on histone acetylation.

ACY-1215 has been shown to work synergistically with bortezomib in multiple myeloma models.