A Study of RO7198457 (Personalized Cancer Vaccine [PCV]) as a Single Agent and in Combination With Atezolizumab in Participants With Locally Advanced or Metastatic Tumors

Inclusion Criteria:

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

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

- Adequate hematologic and end-organ function

- Measured or calculated creatinine clearance >=50 milliliters per minute (mL/min) on
the basis of the Cockcroft-Gault glomerular filtration rate estimation

Cancer-Specific Inclusion Criteria:

- Participants with histologic documentation of locally advanced, recurrent, or
metastatic incurable malignancy that has progressed after at least one available
standard therapy; or for whom standard therapy has proven to be ineffective or
intolerable, or is considered inappropriate; or for whom a clinical trial of an
investigational agent is a recognized standard of care

- Participants with confirmed availability of representative tumor specimens in
formalin-fixed, paraffin-embedded (FFPE) blocks (preferred), or sectioned tissue

- Participants with measurable disease per RECIST v1.1

Additional Inclusion Criteria for Participants Who Backfill Cleared Cohorts of Phase 1a and
Phase 1b:

- Backfill cohort enrollment may be limited to participants whose tumors have PD-L1
(programmed death-ligand 1) and/or different levels of cluster of differentiation 8
(CD8) expression, as defined by the Sponsor

- Backfill enrollment in Phase Ib may be managed such that approximately half of the
patients in each backfill cohort will not have been trated with prior immune
checkpoint inhibitors (anti-PD-L1/PD-1 [programmed death-1] and/or cytotoxic
T-lymphocyte-associated protein 4 [CTLA-4]), except for those patients with tumor
indications where cancer immunotherapy (CIT) is approved as treatment by local
regulatory authorities

Additional Inclusion Criteria for Participants in Each Indication-Specific
Exploration/Expansion Cohort of Phase 1b:

- NSCLC Cohorts (CIT-Naïve): Participants with histologically confirmed incurable,
advanced NSCLC not previously treated with anti-PD−L1/PD-1 and/or with anti-CTLA−4
(investigational or approved), for whom a clinical trial of an investigational agent
in combination with an anti-PD−L1/PD-1 antibody is considered an acceptable treatment
option (if CIT [including anti-PD−L1/PD-1 agents] is approved as treatment for NSCLC
by local regulatory authorities).

- NSCLC Cohort (CIT-Treated): Participants with histologically confirmed incurable,
advanced NSCLC previously treated with anti-PD-L1/PD-1 with or without anti-CTLA-4
(investigational or approved)

- Triple negative breast cancer (TNBC) Cohort: Participants with histologically
confirmed incurable, advanced estrogen receptor (ER)-negative, progesterone
receptor-negative, and human epidermal growth factor receptor 2 (HER2)-negative
adenocarcinoma of the breast (triple-negative) not previously treated with
anti-PD-L1/PD-1 and/or anti-CTLA-4 (investigational or approved)

- Colorectal cancer (CRC) Cohort: Participants with histologically confirmed incurable,
advanced adenocarcinoma of the colon or rectum not previously treated with
anti-PD-L1/PD-1 and/or anti-CTLA-4 (investigational or approved)

- Head and neck squamous cell carcinoma (HNSCC) Cohort: Participants with histologically
confirmed inoperable, locally advanced or metastatic, recurrent, or persistent HNSCC
(oral cavity, oropharynx, hypopharnyx, or larynx) not amenable to curative therapy not
previously treated with anti-PD-L1/PD-1 and/or anti-CTLA-4 (investigational or
approved)

- Urothelial carcinoma (UC) Cohort (CIT-Naïve): Participants with histologically
confirmed incurable, advanced transitional cell carcinoma of the urothelium including
renal pelvis, ureters, urinary bladder, and urethra, not previously treated with
anti-PD-L1/PD-1 with or without anti-CTLA-4 (investigational or approved), for whom a
clinical trial of an investigational agent in combination with an anti-PD−L1 antibody
is considered an acceptable treatment option, if CIT (including anti-PD−L1/PD-1
agents) is approved as treatment for UC by local regulatory authorities

- UC Cohort (CIT-Treated): Participants with histologically confirmed incurable advanced
transitional cell carcinoma of the urothelium (including renal pelvis, ureters,
urinary bladder, and urethra) previously treated with anti-PD-L1/PD-1 with or without
anti-CTLA-4 (investigational or approved)

- Renal cell carcinoma (RCC) Cohort: Participants with histologically confirmed
incurable, advanced RCC with component of clear cell histology and/or component of
sarcomatoid histology not previously treated with anti-PD-L1/PD-1 and/or anti-CTLA-4
(investigational or approved)

- Melanoma Cohort: Participants with histologically confirmed incurable, advanced
melanoma not previously treated with anti-PD-L1/PD-1 and/or anti-CTLA-4
(investigational or approved) in the metastatic setting

Additional Inclusion Criteria for Participants in the Serial-Biopsy Expansion Cohort of
Phase 1b:

- Participants with locally advanced or metastatic solid tumors.

- Participants must have accessible lesion(s) that permit a total of two to three
biopsies (pretreatment and on-treatment) or one biopsy (on-treatment, if archival
tissue can be submitted in place of a pre-treatment biopsy) without unacceptable risk
of a significant procedural complication. RECIST lesions should not be biopsied.

Exclusion Criteria:

- Known clinically significant liver disease, including active viral, alcoholic, or
other hepatitis, cirrhosis, and inherited liver disease or current alcohol abuse

- Major surgical procedure within 28 days prior to Cycle 1, Day 1, or anticipation of
need for a major surgical procedure during the course of the study

- Any other diseases, metabolic dysfunction, physical examination finding, and/or
clinical laboratory finding giving reasonable suspicion of a disease or condition that
contraindicates the use of an investigational drug or that may affect the
interpretation of the results or may render the participant at high risk from
treatment complications

- Previous splenectomy

- Known primary immunodeficiencies, either cellular (e.g., DiGeorge syndrome, T-negative
severe combined immunodeficiency [SCID]) or combined T- and B-cell immunodeficiencies
(e.g., T- and B-negative SCID, Wiskott Aldrich syndrome, ataxia telangiectasia, common
variable immunodeficiency)

- Any medical condition or abnormality in clinical laboratory tests that, in the
investigator's judgment, precludes the participant's safe participation in and
completion of the study Cancer-Specific Exclusion Criteria

- Any anti-cancer therapy, whether investigational or approved, including chemotherapy,
hormonal therapy, and/or radiotherapy, within 3 weeks prior to initiation of study
treatment, with the exceptions as mentioned in the protocol

- Eligibility based on prior treatment with CIT depends on the mechanistic class of the
drug and the cohort for which the participant is being considered, as described below.
In addition, all criteria pertaining to adverse events attributed to prior cancer
therapies must be met

All Cohorts (Dose-Escalation in Phase 1a and Dose-Escalation, Backfill, and Expansion in
Phase 1b):

- Prior neoantigen-specific or whole-tumor cancer vaccines are not allowed, with the
exception as specified in protocol

- Prior treatment with cytokines is allowed provided that at least 6 weeks or 5
half-lives of the drug, whichever is shorter, have elapsed between the last dose and
the proposed Cycle 1, Day 1

- Prior treatment with immune checkpoint inhibitors, immunomodulatory monoclonal
antibody (mAbs), and/or mAb-derived therapies is allowed provided that at least 6
weeks (Phase 1a) or 3 weeks (Phase 1b) have elapsed between the last dose and the
proposed Cycle 1, Day 1, with the exceptions as specified in protocol

Dose-Exploration/Expansion Cohorts in Phase 1b:

- In the NSCLC CIT-Treated exploration cohort in Phase 1b, the most recent systemic
treatment should have been anti-PD−L1/PD-1 and/or anti-CTLA-4 as monotherapy or in
combination

- In the NSCLC CIT-Naïve expansion cohort in Phase 1b, prior treatment with
anti-PD−L1/PD-1 and/or anti-CTLA-4 (investigational or approved) is not allowed

- Prior treatment with immunomodulators, including toll-like receptor (TLR) agonists,
inhibitors of indoleamine 2,3-dioxygenase (IDO)/ tryptophan-2,3-dioxygenase (TDO), or
agonists of OX40, is allowed provided that at least 5 half-lives of the drug or a
minimum of 3 weeks have elapsed between the last dose of the prior treatment and the
proposed Cycle 1, Day 1, with the exception as specified in protocol

- Any history of an immune-related Grade 4 adverse event attributed to prior CIT (other
than endocrinopathy managed with replacement therapy or asymptomatic elevation of
serum amylase or lipase)

- Any history of an immune-related Grade 3 adverse event attributed to prior CIT (other
than hypothyroidism managed with replacement therapy) that resulted in permanent
discontinuation of the prior immunotherapeutic agent and/or occurred less than or
equal to (<=) 6 months prior to Cycle 1 Day 1

- Adverse events from prior anti-cancer therapy that have not resolved to Grade <=1
except for alopecia, vitiligo, or endocrinopathy managed with replacement therapy

- All immune-related adverse events related to prior CIT (other than endocrinopathy
managed with replacement therapy or stable vitiligo) must have resolved completely to
baseline

- Primary central nervous system (CNS) malignancy, untreated CNS metastases, or active
CNS metastases (progressing or requiring corticosteroids for symptomatic control)

- Leptomeningeal disease

- Uncontrolled tumor-related pain

- Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent
drainage procedures

- Malignancies other than disease under study within 5 years prior to Cycle 1, Day 1,
with the exception of those with a negligible risk of metastasis or death

- Uncontrolled hypercalcemia

- Participant has spinal cord compression not definitively treated with surgery and/or
radiation or previously diagnosed and treated spinal cord compression without evidence
that disease has been clinically stable for >=2 weeks prior to screening

Treatment-Specific Exclusion Criteria:

- History of autoimmune disease with caveats as specified in protocol

- Treatment with monoamine oxidase inhibitors (MAOIs) within 3 weeks prior to Cycle 1,
Day 1

- Treatment with systemic immunosuppressive medications within 2 weeks prior to Cycle 1,
Day 1

- History of idiopathic pulmonary fibrosis, pneumonitis, organizing pneumonia, or
evidence of active pneumonitis on screening chest computed tomography (CT) scan

- Positive test for human immunodeficiency virus (HIV) infection

- Active hepatitis B, hepatitis C

- Known active or latent tuberculosis infection

- Severe infections within 4 weeks prior to Cycle 1, Day 1

- Recent infections not meeting the criteria for severe infections within 2 weeks prior
to Cycle 1, Day 1

- Prior allogeneic bone marrow transplantation or prior solid organ transplantation

- Administration of a live, attenuated vaccine within 4 weeks before Cycle 1, Day 1 or
anticipation that such a live attenuated vaccine will be required during the study

- Known hypersensitivity to the active substance or to any of the excipients in the
vaccine

- Phase 1b and crossover only: History of severe allergic, anaphylactic, or other
hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins;
Known hypersensitivity to Chinese Hamster Ovary (CHO)-cell products; Allergy or
hypersensitivity to components of the atezolizumab formulation