A Study Of Blinatumomab For The Treatment Of Relapsed Or Refractory Indolent Non-Hodgkin Lymphoma

Inclusion Criteria: * Subjects must have histologically determined B cell NHL that is relapsed or primary refractory after initial therapy. * Follicular Lymphoma of any grade * Marginal zone lymphoma (extranodal, nodal, or splenic). Patients with gastric MALT must have progressed after H. Pylori therapy and radiation. Patients with splenic MZL must have prior splenectomy. * At least 1 prior line of chemoimmunotherapy if primary refractory or relapsed with in one year. Subjects who respond to initial therapy for greater than one year must have had at least 2 prior lines of therapy including one line with chemoimmunotherapy including an anti-CD20 monoclonal antibody * Measurable disease that has not been previously irradiated on PET-CT of at least 1.5cm, * Age ≥18 years. * ECOG performance status ≤2 ( see Appendix A) * Participants must have adequate organ and marrow function as defined below: * absolute neutrophil count ≥750/mcL * platelets ≥75,000/mcL * total bilirubin \< 2.0 x upper limit of normal (ULN) * AST(SGOT)/ALT(SGPT) ≤2.5 × institutional upper limit of normal or 5 X ULN * if due to lymphoma infiltration * creatinine 2.0 X ULN OR * creatinine clearance ≥50 mL/min/1.73 m2 for participants with creatinine levels above 2.0 X ULN . * Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Participants who have had chemotherapy within 3 weeks, rituximab or obinutuzumab within 4 weeks, or radioimmunotherapy within 6 weeks prior to entering the study, or those who have not recovered from adverse events due to agents administered more than 3 weeks earlier. Subjects actively progressing within that window who have recovered from toxicities of prior therapy are also eligible. * Autologous stem cell transplantation within 12 weeks prior to study entry * Prior allogeneic transplant * Therapeutic doses of corticosteroids within 14 days prior to study entry, defined as \>20mg/day pf prednisone, or equivalent. Topical and/or inhaled steroids are permitted. * Participants who are receiving any other investigational agents. * Participants with known brain metastases should be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction that would confound the evaluation of neurologic and other adverse events. * History of allergic reactions attributed to compounds of similar chemical or biologic composition to blinatumomab * Subjects with known HIV infection * Pregnant or lactating subjects. * Chronic infection with hepatitis B or hepatitis C virus * History of or current relevant CNS pathology such as epilepsy, seizure, paresis,aphasia, apoplexia, severe brain injuries, cerebellar disease, organic brain syndrome, psychosis * Prior history of another malignancy (except for non-melanoma skin cancer, in situ cervical or breast cancer, or localized prostate cancer) unless disease free for at least one year and felt at low risk of relapse by treating physician. * Uncontrolled intercurrent illness including, but not limited to, ongoing or uncontrolled systemic fungal, bacterial, viral, or other infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.