Treatment of peripheral T-cell lymphoma: are we data driven or driving the data?

Peripheral T-cell lymphomas (PTCL) are a group of uncommon and heterogeneous malignancies arising from a postthymic or mature T-lymphocyte. The treatment of PTCL remains a challenging endeavor. Compared with the more common aggressive B-cell lymphomas, more patients with PTCL will be refractory to initial therapy and those who achieve responses often will have shorter progression-free survival. Despite retrospective data that suggest that anthracycline-based multiagent chemotherapy regimens may not provide a benefit compared with nonanthracycline regimens, nonanthracycline-based regimens, with the notable exception of L-asparaginase regimens for extranodal NK/T-cell lymphoma, have been disappointing so far. Based on phase II evidence and subset analyses available, we believe that the addition of etoposide to standard regimens and consolidation of first remissions with autologous stem cell transplantation (autoSCT) provides the best outcome in patients with PTCL and currently use CHOEP followed by ASCT for eligible patients with the common PTCL subtype: PTCL-NOS, AITL, and ALK negative ALCL. For those with ALK-positive ALCL standard CHOP or CHOEP is appropriate with consideration of ASCT only for those with high-risk disease. Other strategies to incorporate additional agents, such as with dose-adjusted EPOCH or sequential CHOP-ICE regimens are logical options; however, they lack the supporting literature of CHOEP. Whereas the above recommendation is our current off-protocol approach, with the possible exception of low risk ALK positive ALCL, none of these choices is supported by strong enough data to supplant a well-conceived clinical trial as the truly preferred strategy in PTCL. The novel agents, romidepsin, pralatrexate, and brentuximab vedotin, are currently approved in the relapsed/refractory setting. These agents are being studied as additions or substitutions for other agents in up-front multiagent chemotherapy regimens. In the relapsed/refractory setting, both pralatrexate and romidepsin remain well-studied choices with some patients achieving a response with durability. Clinical trials of new agents in PTCL continue to be a valuable option and an important part of routine patient management as progressive disease often is seen. Lastly, we believe patients with relapsed/refractory PTCL should be considered for allogeneic stem cell transplantation if a suitable response is demonstrated and a willing donor is available.