Study to Assess if ABP798 is Safe & Effective in Treating Non Hodgkin Lymphoma Compared to Rituximab

Inclusion Criteria:

Males and females 18 years of age and older
Histological confirmed (by lymph node or extranodal region biopsy), Grade 1, 2, or 3a follicular B-cell NHL expressing CD20 within 12 months before randomization

Stage 2, 3, or 4 (per Cotswold's Modification of Ann Arbor Staging System) with measurable disease (per International Working Group)

subjects must have a baseline scan (computed tomography [CT]) of the neck (if palpable lymph node > 1.0 cm), chest, abdomen, and pelvis to assess disease burden within 6 weeks before randomization
subjects must have had a baseline bone marrow biopsy within 12 months before randomization. Previously confirmed positive bone marrow involvement does not need to be repeated for purposes of screening.

Low tumor burden based on the Groupe d'Etudes des Lymphomes Folliculaires (GELF) criteria

largest nodal or extranodal mass ≤ 7 cm
no more than 3 nodal sites with diameter > 3 cm
no splenomegaly > 16cm by CT scan and no symptomatic splenomegaly
no significant pleural or peritoneal serous effusions by CT
lactate dehydrogenase ≤ upper limit of normal (ULN)
no B symptoms (night sweats, fever [temperature > 38°C], weight loss > 10% in the previous 6 months)

Exclusion Criteria:

Diffuse large cell component and/or Grade 3b follicular NHL
History or known presence of central nervous system metastases
Malignancy other than NHL within 5 years (except treated in-situ cervical cancer, or squamous or basal cell carcinoma of the skin)
Recent infection requiring a course of systemic anti-infective agents that was completed ≤ 7 days before randomization (with the exception of uncomplicated urinary tract infection)
Other investigational procedures that can impact the study data, results, or patient safety while participating in this study are excluded; participation in observational studies is allowed.
Subject is currently enrolled in or has not yet completed at least 30 days or 5 half-lives (whichever is longer) since ending other investigational device or drug study(s), including vaccines, or subject is receiving other investigational agent(s)
Previous use of either commercially available or investigational chemotherapy, biological, or immunological therapy for NHL (including rituximab or biosimilar rituximab, or other anti-CD20 treatments)
Systemic corticosteroid use within 3 months before randomization (inhaled are allowable)