An initial open-label, phase II study of 131 patients with R/R PTCL (53% PTCL-NOS, 21% AITL, 16% ALK-negative ALCL) yielded an ORR of 25% and CR of 14.6% when treated with single-agent romidepsin. This evidence concerns the gene ALK and angioimmunoblastic T-cell lymphoma.