A Study of Escalating Doses of DCDS4501A in Patients With Relapsed or Refractory B-Cell Non-Hodgkins Lymphoma and Chronic Lymphocytic Leukemia and DCDS4501A in Combination With Rituximab in Patients With Relapsed or Refractory B-Cell Non-Hodgkins Lymphoma

Inclusion Criteria:

- Life expectancy of at least 12 weeks

- History of one of the following histologically-documented hematologic malignancy for
which no effective standard therapy exists: indolent non Hodgkin's lymphoma (NHL),
Grade 3b FL, diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma (MCL), or
chronic lymphocytic leukemia (CLL)

- All patients (NHL and B-CLL) must have at least one bi-dimensionally measurable
lesion

- For all men or women of childbearing potential (unless surgically sterile): use of
adequate methods of contraception such as oral contraceptives, intrauterine device,
or barrier method of contraception in conjunction with spermicidal jelly

Exclusion Criteria:

- Prior use of any monoclonal antibody or antibody-drug conjugate within 4 weeks before
Cycle 1, Day 1

- Treatment with radiotherapy, any chemotherapeutic agent, or treatment with any other
investigational anti-cancer agent within 2 weeks prior to Cycle 1, Day 1. Adverse
events from any previous treatments must be resolved or stabilized prior to Cycle 1,
Day 1, except for neuropathy

- Completion of autologous stem cell transplant within 100 days prior to Cycle 1, Day 1

- Prior allogeneic stem cell transplant