Here we report a patient with chemo-refractory PTCL, status post 2 cycles of CHOP-21, 2 cycles of DHAP, and 1 cycle of DexaBEAM, who achieved a remarkably long lasting CR (39 months) after treatment with the novel HDAC inhibitor, belinostat. The gene discussed is HDAC9; the disease is mature T-cell and NK-cell non-Hodgkin lymphoma.