Veltuzumab and Milatuzumab in Treating Patients With Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Inclusion Criteria:

* Histologically confirmed B-cell non-Hodgkin lymphoma (NHL), including any of the following:

  * Marginal zone lymphoma
  * Waldenstrom macroglobulinemia (lymphoplasmacytic lymphoma)
  * Follicular lymphoma
  * Mantle cell lymphoma
* Relapsed or refractory disease after ≥ 1 prior therapy
* Patients with rituximab-refractory disease (defined as having less than a partial response to the prior rituximab-containing regimen) or rituximab-sensitive disease (defined as having a complete response or partial response to the last rituximab-containing regimen \[provided it has been ≥ 3 months since the last dose of rituximab\]) are eligible.
* Age \>18 years.
* Eastern Cooperative Oncology Group (ECOG)performance status 0-2.
* Patients must have normal organ and marrow function as defined below:

  * Absolute neutrophil count ≥ 1000/μL
  * Platelets ≥ 75,000/μL
  * Total bilirubin ≤ 2.0 X institutional upper limit of normal
  * AST(SGOT)/ALT(SGPT) ≤ 2.5 X institutional upper limit of normal
  * Creatinine ≤ 2.0 mg/dL
* Patients who have relapsed after stem cell transplant are eligible for this trial.
* Patients with active Hepatitis B infection are not eligible.
* Non-pregnant and non-nursing. Women of child bearing potential and men must agree to use contraception prior to study entry and for duration of study participation.
* Must possess the ability to understand and the willingness to sign a written informed consent document.

Phase II

-Must have measurable disease, defined as at least one lesion that can be accurately measured in at least one dimension \>10 mm or in the case of Waldenstrom's macroglobulinemia, the presence of an IgM paraprotein level 2x the upper limit of normal.

Exclusion Criteria:

* Must be recovered from all toxicities from prior therapy or radiation (excluding alopecia).
* No known CNS lymphoma.
* History of documented human anti-globulin antibodies.
* No uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations.
* HIV-positive patients.
* Pregnant women.
* Patients with secondary malignancies with exception of non-melanomatous skin cancers.