Regression of extranodal natural killer/T-cell lymphoma, nasal type with denileukin diftitox (Ontak) and bexarotene (Targretin): report of a case.

Denileukin diftitox (Ontak) is a fusion protein comprising a diphtheria toxin and an interleukin (IL)-2 moiety that specifically targets CD25 (IL-2 receptor)-positive tumour cells. We report a patient with rapidly progressive Epstein-Barr virus-positive nasal type extranodal natural killer/T-cell lymphoma (extranodal NKTCL), treated with a combination of denileukin diftitox (Ontak) and oral bexarotene (Targretin). A significant regression of the cutaneous tumours was observed already after the first cycle of denileukin diftitox and was maintained for a period of 5 months with monthly cycles of denileukin diftitox. The treatment was well tolerated. Following this response the patient decided to stop the treatment. He was then followed by his oncologist and lost from dermatological follow-up. Shortly after treatment withdrawal the disease progressed and the patient received one cycle of doxorubicin (Caelyx). He died from septic shock syndrome 2 months later. To our knowledge this is the first case of extranodal NKTCL treated with denileukin diftitox and bexarotene. A striking, albeit transient, response occurred with this therapy. Combination treatment with denileukin diftitox and bexarotene should be further assessed in this aggressive type of cutaneous lymphoma.