Inclusion Criteria:

- Histologically confirmed CD19-positive non-Hodgkin's B-cell lymphoma, relapsed or
refractory after standard treatments, with no curative option with conventional
therapy

- ECOG performance status 0 to 2

Exclusion Criteria:

- Burkitt's lymphoma, Lymphoblastic lymphoma, Chronic lymphocytic leukemia (Small
lymphocytic lymphoma may be included)

- Chemotherapy or radiation therapy or other investigational agents within 4 weeks
prior to entering the study

- Previous radioimmunotherapy within 12 weeks

- Known intolerance to infused protein products or maytansinoids

- Poor kidney, liver and bone marrow functions

- Any serious active disease or co-morbid condition, which in the opinion of the
principle investigator, will interfere with the safety or with compliance with the
study

- Pregnant or breast-feeding women

- Patient with reproductive potential without effective birth control methods

The above information is not intended to contain all considerations relevant to a
patient's potential participation in a clinical trial.