Inclusion Criteria:

1. Patient has histologically proven DLBCL, which may represent de novo DLBCL or DLBCL
arising from transformed follicular lymphoma or chronic lymphocytic leukemia.

2. Patient has relapsed or refractory CD20-positive disease following previous
first-line systemic chemotherapy. Patients who have failed to achieve complete
remission with previous chemotherapy are defined as refractory, and those who
relapsed after an initial complete remission are classified as having relapsed. A
biopsy must be performed to confirm diagnosis of relapsed disease. Tumor tissue
within 6 months of Day 1 of Cycle 1 of study treatment will be used for the central
review.

3. Patient has at least 1 measurable tumor mass (greater than 1.5 cm in the longest
dimension, or 1.1 to 1.5 cm in the longest dimension, and greater than 1.0 cm in the
shortest axis) that has not previously been irradiated or has grown since previous
irradiation

Exclusion Criteria:

1. Patient has allergies or hypersensitivity to murine, chimeric, human, or humanized
proteins.

2. Patient has had prior allogeneic or ASCT.

3. Patient has received any other anticancer therapy within 28 days before Day 1 of
Cycle 1 of study treatment and more than 1 prior line of chemotherapy, with the
exception of having received the last dose of rituximab within 6 months before Day 1
of Cycle 1 of study treatment if they have undergone prior treatment with rituximab.