• Males or females, ≥ 18 years of age

• Part 1: documented B cell NHL (any subtype except Burkitt lymphoma, Waldenström macroglobulinemia, chronic lymphocytic leukemia); previously confirmed CD19-positive if feasible

• Part 2: documented B cell NHL (subtypes to be determined); confirmed CD19-positive; possible expansion cohorts may include:

∙ Diffuse large B cell lymphoma (including germinal center B cell type, activated B cell type)

‣ Follicular lymphoma (including duodenal-type follicular lymphoma)

‣ Mantle cell lymphoma

‣ B cell lymphomas not specified

• If B cell NHL subtype likely to have bone marrow involvement must be willing to undergo bone marrow biopsy in the event of an on-study complete response to confirm response

• NHL that is relapsed, refractory to, or intolerant of existing therapy(ies) with known curative potential, or for which no standard therapy is available; must have received at least 2 prior lines of systemic therapy

• Must be in need of systemic treatment and not require immediate cytoreductive therapy

• Part 1: measurable or non-measurable disease

• Part 2: measurable disease according to The Revised Criteria/Lugano Classification

• Part 1: screening tumor biopsy requested, but optional; Part 2: patient must agree to screening tumor biopsy

⁃ ECOG performance status 0 or 1; anticipated life expectancy ≥ 10 weeks

⁃ Women of childbearing potential and fertile men agreeing to use two effective methods of contraception (including a highly effective method of contraception); women beginning 2 weeks prior to the first dose, men beginning prior to the first dose, and both continuing until 8 months after the last dose of study drug; male patients must also agree to refrain from sperm donation during this period.

⁃ Ability to understand and give written informed consent