A Phase 1b Study of Atezolizumab in Combination With Erlotinib or Alectinib in Participants With Non-Small Cell Lung Cancer (NSCLC)

Inclusion Criteria:

- Histologically or cytologically documented, locally advanced or metastatic NSCLC.

- Participants in Stage 1 (Safety Evaluation) receiving erlotinib: No limit to the
number of prior therapies (except for EGFR TKIs).

- Participants in Stage 2 (Expansion) receiving erlotinib: i) sensitizing mutation in
the EGFR gene and ii) consent to collection of tumor tissue samples before, during,
and after treatment for biopsy and PD biomarker analyses.

- Participants receiving alectinib in either Stage 1 or Stage 2: must be ALK positive as
assessed by Food and Drug Administration (FDA) approved test and must not have
received prior treatment for their advanced NSCLC.

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

- Life expectancy of at least 12 weeks.

- Measurable disease, as defined by RECIST Version 1.1 (v1.1).

- Adequate hematologic and end-organ function.

- Use of highly effective contraception (as defined by protocol) and until 5 months
after the last dose of atezolizumab and for 3 months after the last dose of alectinib
or for 2 weeks after the last dose of erlotinib, whichever is longer; Males must also
refrain from sperm donatation during this same time period. Participants must not be
pregnant or breastfeeding.

- Archival tumor tissue specimen meeting protocol specifications or the participant will
be offered the option of a pre-treatment biopsy to obtain adequate tissue sample.

Exclusion Criteria:

- For participants receiving erlotinib group: prior treatment with any EGFR
mutant-targeting TKI

- Any approved anticancer therapy, including chemotherapy, or hormonal therapy (except
hormone-replacement therapy or oral contraceptives) within 3 weeks of first dose.

- Treatment with any other test drug or participation in another clinical trial within
28 days of enrollment.

- Known symptomatic central nervous system (CNS) metastases. Participants with a history
of treated or untreated asymptomatic CNS metastases may be eligible.

- Leptomeningeal disease.

- Uncontrolled tumor-related pain.

- Uncontrolled pleural effusion, pericardial effusion, or ascites requiring drainage at
least once monthly.

- High levels of calcium requiring bisphosphonate therapy or denosumab.

- Malignancies other than NSCLC within 5 years prior to enrollment, with the exception
of those with a negligible risk of metastasis or death (such as adequately treated
carcinoma in-situ of the cervix, basal or squamous cell skin cancer, localized
prostate cancer, or ductal carcinoma in situ).

- History of severe allergic, anaphylactic, or other reactions to chimeric or humanized
antibodies or fusion proteins.

- Known hypersensitivity to biopharmaceuticals produced in Chinese hamster ovary cells
or any component of the atezolizumab formulation.

- History of autoimmune disease.

- Participants with prior bone marrow or solid organ transplantation.

- History of lung inflammation or disease.

- Serum albumin less than (<) 2.5 grams per deciliter (g/dL).

- Positive for Human Immunodeficiency Virus (HIV).

- Liver disease.

- Current or active tuberculosis, hepatitis B, or hepatitis C.

- Participants with past or resolved hepatitis B virus (HBV) infection are eligible;
participants positive for hepatitis C virus (HCV) antibody are eligible only if
polymerase chain reaction (PCR) is negative for HCV Riboxy Nucleic Acid (RNA).

- Signs or symptoms of infection within 2 weeks prior to first dosing.

- Received therapeutic oral or IV antibiotics within 2 weeks prior to first dosing.

- Significant cardiovascular disease.

- Major surgical procedure other than for diagnosis within 28 days prior to first dosing
or during the course of the study.

- Administration of a live, attenuated vaccine within 4 weeks before first dosing or
during the study.

- Any other diseases, metabolic dysfunction, physical examination finding, or clinical
laboratory finding that may reasonably prevent the participant from participating.

- Hypersensitivity to erlotinib or alectinib or to any of the excipients.

- Any significant ophthalmologic abnormality. The use of contact lenses is not
recommended during the study.

- For participants receiving alectinib: baseline Fridericias corrected QT interval
(QTcF) greater than (>) 470 milliseconds (ms) or symptomatic bradycardia.

- Prior treatment with CD137 agonists or immune checkpoint blockade therapies.

- Treatment with systemic immunostimulatory agents within 6 weeks or five half-lives of
the drug, whichever is shorter, prior to first dosing.

- Treatment with systemic immunosuppressive medications within 2 weeks prior to first
dosing (inhaled corticosteroids and mineralocorticoids are allowed).

- Participants who received acute, low-dose systemic immunosuppressant medication or a
one-time pulse dose of systemic immunosuppressant medication are elgible for study
after discussion and approval by the Medical Monitor.