Dose Escalation Trial of Denileukin Diftitox (Ontak) Post Autologous Transplantation

The primary goal of this study is to determine the feasibility and safety of giving two
doses of denileukin diftitox (DD) at days 0 and 21 post autologous stem cell transplantation
in a dose escalation fashion. Secondary goals include evaluating the the effect of DD on the
number and percentage of T-regs in the peripheral blood post transplant at each dose level,
the effect of DD on T cell (CD4/CD8) reconstitution post transplant at each dose level and
determining the time to engraftment: absolute neutrophil count (>0.5 x 10^9/L for 3
consecutive days), and platelet (>20X 10^9/L for 3 consecutive days).

The hypothesis for the study is based on the ability of DD to deplete T-regs and
subsequently enhance the immune reconstitution and reverse post transplant lymphopenia. This
may indirectly enhance the efficacy of autologous transplantation and reduce disease
relapse.