SS-208 is reported as an isotype selective inhibitor of histone deacetylase 6 (HDAC6) [2
]. It has been developed for potential to treat advanced melanoma. SS-208 has been designed to provide improved HDAC6 selectivity compared to ricolinostat
which both exhibit unfavourable levels of HDAC1 inhibition.
Selective pharmacological inhibition or genetic abrogation of HDAC6 modulates immune checkpoint activity by downregulating the expression of PD-L1 via
the recruitment and activation of STAT3 [1
]. The antitumour activity of SS-208 in vivo
is primarily mediated by activation of immune cells and an anti-tumour immune response in the tumour microenvironment.