A Multicenter, Phase II Study of ONTAK (Denileukin Diftitox) in Patients With Previously-Treated Chronic Lymphocytic Leukemia

Inclusion Criteria:

- Patients with B-cell Chronic Lymphocytic Leukemia, Rai Stage 0-II with indication for
treatment by NCI Working Group Criteria or Rai Stage III or IV.

- Patients must have received at least one prior purine analogue-based chemotherapy
regimen.

- ECOG Performance Status of 0, 1, or 2.

- Female patients cannot be pregnant and must use birth control during the course of
the study and for three weeks after the study ends.

Exclusion Criteria:

- Prior treatment with ONTAK (DAB389IL-2) or DAB486IL-2.

- Received any therapy for CLL within 35 days prior to study entry.