In a randomized trial of denileukin diftitox (ONTAK) for the treatment of cutaneous T-cell lymphoma (CTCL), a type of non-Hodgkin lymphoma that begins in the skin, patients who received the drug survived without progression of their disease for a median of more than 2 years, compared with just over 4 months for patients who received a placebo. Results from the trial, sponsored by Eisai, the pharmaceutical company that manufactures the drug, were reported March 8, 2010, in the Journal of Clinical Oncology.
Denileukin diftitox (DD) consists of a toxin derived from the diphtheria bacterium attached to human interleukin 2 (IL-2), a protein produced by the immune system. The IL-2 binds preferentially to CTCL cells, delivering the toxin to the tumors.
An international group of researchers led by H. Miles Prince, M.D., of the University of Melbourne, Australia, enrolled 144 patients who had received three or fewer prior treatments for CTCL into the trial. Participants received one of two different doses of DD (either 9 micrograms or 18 micrograms per kilogram of body weight per day) or a placebo.
Each course of treatment consisted of once-daily infusions for 5 days followed by 16 days of rest, for up to eight courses (approximately 6 months). Treatment stopped if a patient’s disease progressed or if they experienced unacceptable side effects.
Overall response rates (either complete or partial tumor regression) were 49.1 percent in the group receiving the higher dose of DD, 37.8 percent in the group receiving the lower dose, and 15.9 percent in the placebo group. Patients receiving the higher dose of DD had a 73 percent reduction in the risk of disease progression or death compared with patients receiving the placebo. More patients receiving DD reported side effects, though the incidence of serious toxic effects was relatively low in all treatment arms.