De novo maintenance therapy with denileukin diftitox (Ontak) in a patient with peripheral T-cell lymphoma is associated with prolonged remission.

Peripheral T-cell lymphoma (PTCL) is an aggressive form of non-Hodgkin's lymphoma (NHL), associated with poor prognosis and without standard approach to treatment. Denileukin diftitox (Ontak) is a synthetic fusion protein combining the receptor-binding domain of interleukin-2 to the enzymatically active portion of diphtheria toxin. While approved for the treatment of cutaneous T-cell lymphoma, it has demonstrated activity in non-Hodgkin's lymphomas of both T-cell and B-cell origin. This report documents the first case of de novo maintenance therapy with denileukin diftitox sustaining an ongoing complete response at the molecular level for 2 years in a patient with PTCL.