Peripheral T-cell lymphomas (PTCL) are rare but markedly aggressive forms of
non-Hodgkin's lymphoma (NHL). They carry a poor prognosis, with current therapeutic approach being generally ineffective. The most employed first-line treatment is CHOP (
cyclophosphamide,
doxorubicin,
vincristine, and
prednisone), which still results in high rates of relapses.
Denileukin diftitox is a fusion
protein combining the cytotoxic portion of the
diphtheria toxin and the receptor-binding domain of the
interleukin-2 (IL-2) molecule, thereby targeting cells expressing the
IL-2 receptor, including both T-cell and
B-cell lymphomas. It has been approved for the treatment of
cutaneous T-cell lymphomas, and it has documented activity in PTCL both as a single agent and as part of combination
therapy. This report documents three cases of PTCL where
denileukin diftitox has been used as long-term maintenance
therapy after complete remission was achieved. While the overall survival rate of patients with advanced stage, refractory PTCL is generally poor (with median overall survival of 5.5 months), the three patients described in this report are all experiencing an ongoing complete remission for more than four years.