PHASE I/II STUDY OF TAC-EXPRESSING ADULT T-CELL LEUKEMIA (ATL) WITH YTTRIUM-90 (90Y)-RADIOLABELED HUMANIZED ANTI-TAC AND CALCIUM-DTPA

OBJECTIVES:

• Determine the maximum tolerated dose of yttrium Y 90 daclizumab (90Y daclizumab) when combined with pentetic acid calcium in adults with Tac-expressing T-cell leukemia.
• Determine the therapeutic efficacy and toxicity of this regimen in these patients.
• Monitor patients treated on this regimen for circulating infused antibody (free and labeled) and for the serum concentration of soluble interleukin-2 receptor.
• Evaluate, in a preliminary manner, the immunogenicity of daclizumab.
• Determine the effect of 90Y daclizumab on various components of the circulating cellular immune system.
• Determine whether there is additional urinary excretion of yttrium Y 90 when compared to that observed previously in patients treated without pentetic acid calcium.

OUTLINE: This is a dose escalation study of yttrium Y 90 daclizumab (90Y daclizumab).

Patients receive 90Y daclizumab IV over 2 hours on day 1 and a fixed dose of pentetic acid calcium IV over 5 hours for 3 days. Treatment repeats every 6 weeks for a maximum of 9 courses in the absence of disease progression or circulating antibodies to humanized anti-Tac.

Cohorts of 3-6 patients receive escalating doses of 90Y daclizumab until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 6 patients experience dose limiting toxicities. Additional patients are treated at the MTD.