A Study to Evaluate the Safety and Efficacy of Mosunetuzumab (BTCT4465A) in Combination With Polatuzumab Vedotin in B-Cell Non-Hodgkin Lymphoma

Key Inclusion Criteria:

- ECOG PS of 0, 1, or 2

- Histologically confirmed FL or DLBCL

- Must have received at least one prior systemic treatment regimen containing an
anti-CD20−directed therapy for DLBCL or FL

- Relapsed to prior regimen(s) after having a documented history of response (complete
response [CR], CR unconfirmed [CRu], or partial response [PR]) of >/= 6 months in
duration from completion of regimen(s); or, refractory to any prior regimen, defined
as no response to the prior therapy, or progression within 6 months of completion of
the last dose of therapy

- Measurable disease, defined as at least one bi-dimensionally measurable nodal lesion,
defined as > 1.5 cm in its longest dimension, or at least one bi-dimensionally
measurable extranodal lesion, defined as > 1.0 cm in its longest dimension

- Adequate hematologic, renal, and hepatic function

Key Exclusion Criteria:

- Prior treatment with mosunetuzumab or other CD20-directed bispecific antibodies

- Prior treatment with polatuzumab vedotin

- Current > Grade 1 peripheral neuropathy

- Prior use of any monoclonal antibody, radioimmunoconjugate or antibody-drug conjugate
(ADC) within 4 weeks before first dose of study treatment

- Treatment with any chemotherapeutic agent, or treatment with any other anti-cancer
agent (investigational or otherwise) within 4 weeks or 5 half-lives of the drug,
whichever is shorter, prior to first dose of study treatment

- Treatment with radiotherapy within 2 weeks prior to the first dose of study treatment

- Autologous stem-cell transplantation (SCT) within 100 days prior to first study
treatment administration

- Prior treatment with chimeric antigen receptor T-cell (CAR-T) therapy within 30 days
before first study treatment administration

- Prior allogeneic SCT

- Prior solid organ transplantation

- Patients with history of confirmed progressive multifocal leukoencephalopathy (PML)

- Current or past history of central nervous system (CNS) lymphoma or CNS disease

- History of autoimmune disease