A Safety and Pharmacology Study of Atezolizumab (MPDL3280A) Administered With Obinutuzumab or Tazemetostat in Participants With Relapsed/Refractory Follicular Lymphoma and Diffuse Large B-cell Lymphoma

Inclusion Criteria:

- Histologically documented, CD20-positive, relapsed or refractory (defined as having
relapsed within 6 months to the previous treatment) FL or DLBCL (including primary
mediastinal large B-cell lymphoma [PMLBCL])

- Bone marrow biopsy at screening (unless it was performed within 3 months prior to
screening)

- Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2

- Life expectancy greater than or equal to (>=) 12 weeks

- Has a QT interval corrected by Fridericia's formula (QTcF) less than or equal to (<=)
480 milliseconds (msec)

- At least one bi-dimensionally measurable nodal lesion >1.5 cm in its longest diameter
by computed tomography (CT) scan or MRI, as defined by the Lugano Classification

- Adequate hematologic and end-organ function

- Archival tumor tissue

- For women of childbearing potential: agreement to remain abstinent (refrain from
heterosexual intercourse) or use contraceptive methods that result in a failure rate
of < 1% per year during the treatment period and for at least 90 days after the last
dose of atezolizumab or 18 months after the last dose of obinutuzumab, whichever is
longer

- For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use
contraceptive measures and agreement to refrain from donating sperm

Exclusion Criteria:

- Known central nervous system lymphoma, leptomeningeal lymphoma, or histologic evidence
of transformation from an indolent lymphoma to a high-grade or DLBCL

- Grade 3b FL, small lymphocytic lymphoma (SLL), or Waldenström's macroglobulinemia (WM)
or other lymphoma subtypes except as stated in the inclusion criteria

- Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent
drainage procedures (once monthly or more frequently); participants with indwelling
catheters are eligible

- Uncontrolled hypercalcemia or symptomatic hypercalcemia requiring continued use of
bisphosphonate therapy or denosumab

- History of severe allergic or anaphylactic reactions to monoclonal antibody therapy

- Has had prior exposure to tazemetostat or other inhibitor(s) of enhancer of zeste
homolog 2 (EZH2)

- Regular treatment with corticosteroids within the 2 or 4 weeks prior to the start of
Cycle 1, unless administered for indications other than non-Hodgkin's lymphoma at a
dose equivalent to < 30 mg/day prednisone/prednisolone

- Pregnant and lactating women

- History of autoimmune disease

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

- Participants with prior allogeneic bone marrow transplantation or prior solid organ
transplantation

- History of idiopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitis
obliterans), drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active
pneumonitis per chest CT scan at screening. History of radiation pneumonitis in the
radiation field (fibrosis) is allowed

- Positive test for Human Immunodeficiency Virus (HIV)

- History of chronic hepatitis B infection or positive test results for active or
chronic hepatitis B or hepatitis C

- Significant cardiovascular disease, such as cardiac disease (New York Heart
Association Class II or greater), myocardial infarction within the previous 3 months,
unstable arrhythmias, or unstable angina

- Hypersensitivity or prior treatment with obinutuzumab

- Fludarabine or Campath within 12 months prior to study entry

- Prior treatment with CD137 agonists or immune checkpoint blockade therapies, including
anti-CTLA4, anti-PD-1, and anti-PD-L1 therapeutic antibodies

- Treatment with systemic immunostimulatory agents (including but not limited to
interferon, interleukin-2) within 6 weeks or 5 half-lives of the drug, whichever is
shorter, prior to Cycle 1, Day 1

- Treatment with systemic immunosuppressive medications, including but not limited to
prednisone, cyclophosphamide, azathioprine, methotrexate, thalidomide, and anti-tumor
necrosis factor (anti-TNF) agents within 2 weeks prior to Cycle 1, Day 1; inhaled
corticosteroids and mineralocorticoids are allowed

- Participants with active tuberculosis (TB) will be excluded from the clinical trial