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)