Inclusion Criteria:

- Dose escalation cohorts: subjects with diagnosis of CD22-positive Non-Hodgkin's
Lymphoma (NHL) who have had at least 1 prior anticancer treatment, including prior
treatment with rituximab and chemotherapy.

- Expanded maximum tolerated dose (MTD) confirmation and preliminary efficacy cohorts:
subjects with diagnosis of CD22-positive NHL who have had at least 1 prior anticancer
treatment, including prior treatment with rituximab and chemotherapy or newly
diagnosed subjects who are not candidates for anthracycline-based therapy.

- At least 1 measurable disease lesion that is > 1 cm in the longest transverse
diameter, with a product of the diameters > 2.25 cm2 by CT or magnetic resonance
imaging (MRI).

Exclusion Criteria:

- Candidate for potentially curative therapy such as stem cell transplantation.

- Prior allogeneic hematopoietic stem cell transplantation (HSCT).

- Prior autologous transplantation, radioimmunotherapy, or other anti CD22
immunotherapy <= 6 months before the first dose of investigational product.

- More than 3 previous combination chemotherapy (2 or more cytotoxics) anticancer
regimens.