Emerging therapies in relapsed and refractory peripheral T-cell lymphoma

The peripheral T-cell lymphomas (PTCLs) account for 5% to 10% of all non-Hodgkin lymphomas. In the up-front setting, approximately one-quarter of patients experience a long-term remission. In the setting of relapsed and refractory disease, the median progression-free survival and overall survival are reported to be only 3.7 and 6.5 months, respectively. Unfortunately, the molecular and genetic characterization of PTCL has lagged well behind that of the B-cell lymphomas, although several recent experiences are shedding light on the remarkable molecular heterogeneity that has come to define these diverse diseases. The need to identify new active drugs for patients with PTCL has been addressed in part over the last several years, as 4 drugs have now been approved by the US Food and Drug Administration for patients with relapsed or refractory disease, and a plethora of new studies exploring novel combinations have begun to emerge. More advanced techniques in molecular biology, such as next-generation sequencing, gene expression profiling, and comparative genomic hybridization, have helped identify subtleties among subtypes and potentially identify new targets. Many of these recent clinical advances have been based on the recognition that PTCL is a disease that may be broadly characterized by gross epigenetic dysregulation with sensitivity to histone deacetylase inhibitors. In this report, we discuss emerging new therapies in relapsed and refractory PTCL and try to place these new findings in the evolving biological understanding of the disease.