Low Dose Mosunetuzumab for the Treatment of Patients With Indolent B-Cell Lymphoma

Inclusion Criteria: * 18 years or older at time of signing informed consent * Capable of understanding and providing written informed consent * Histologically confirmed indolent B-cell non-Hodgkin lymphoma with no prior therapy for lymphoma. (Prior peptide-based therapeutic vaccines are allowed.) Eligible histologies include: * Follicular lymphoma (grade 1-2 or 3A) * Marginal zone lymphoma * Ann Arbor stage II-IV disease * No prior therapy for lymphoma * Have low-tumor burden disease, defined by Groupe D'Etude des Lymphomes Folliculaires (GELF) criteria: * Nodal or extranodal tumor mass \< 7 cm * Involvement of less than 3 nodal sites with a diameter \> 3 cm * No systemic or B symptoms * No splenomegaly \> 16 cm by imaging * No local risk of vital organ compression * No pleural or peritoneal serous effusions * No leukemic phase (\> 5,0000/ uL circulating lymphocytes) * No significant cytopenias defined as platelets \< 100,000/uL, hemoglobin \< 10 g/dL, or absolute neutrophil count (ANC) \< 1500/ uL * Have measurable nodal disease, including at least 1 disease site measuring at least 1.5 cm in longest dimension on CT or fludeoxyglucose F-18 (FDG)-PET, or a FDG-avid extranodal measurable site measuring at least 1.0 cm in longest dimension. Measurable disease also includes spleen size more than 13 cm in vertical length * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 * Creatinine clearance ≥ 50 mL/min calculated by Cockcroft-Gault equa…