A Study to Investigate Atezolizumab and Chemotherapy Compared With Placebo and Chemotherapy in the Neoadjuvant Setting in Participants With Early Stage Triple Negative Breast Cancer

Inclusion criteria:

Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
Histologically documented TNBC (negative human epidermal growth factor receptor 2 [HER2], estrogen receptor [ER], and progesterone receptor [PgR] status)
Confirmed tumor programmed death-ligand 1 (PD-L1) evaluation as documented through central testing of a representative tumor tissue specimen
Primary breast tumor size of greater than (>) 2 centimeters (cm) by at least one radiographic or clinical measurement
Stage at presentation: cT2-cT4, cN0-cN3, cM0
Participant agreement to undergo appropriate surgical management including axillary lymph node surgery and partial or total mastectomy after completion of neoadjuvant treatment
Baseline left ventricular ejection fraction (LVEF) greater than or equal to (>=) 53 percent (%) measured by echocardiogram (ECHO) or multiple-gated acquisition (MUGA) scans
Adequate hematologic and end-organ function
Representative formalin-fixed, paraffin-embedded (FFPE) tumor specimen in paraffin blocks (preferred) or at least 20 unstained slides, with an associated pathology report documenting ER, PgR, and HER2 negativity
For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods, and agreement to refrain from donating eggs
For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures and agreement to refrain from donating sperm
Women who are not postmenopausal or have undergone a sterilization procedure must have a negative serum pregnancy test result within 14 days prior to initiation of study drug

Exclusion criteria:

Prior history of invasive breast cancer
Stage 4 (metastatic) breast cancer
Prior systemic therapy for treatment and prevention of breast cancer
Previous therapy with anthracyclines or taxanes for any malignancy
History of ductal carcinoma in situ (DCIS), except for participants treated exclusively with mastectomy >5 years prior to diagnosis of current breast cancer
History of pleomorphic lobular carcinoma in situ (LCIS), except for participants surgically managed >5 years prior to diagnosis of current breast cancer
Bilateral breast cancer
Undergone incisional and/or excisional biopsy of primary tumor and/or axillary lymph nodes
Axillary lymph node dissection prior to initiation of neoadjuvant therapy
History of other malignancy within 5 years prior to screening, with the exception of those with a negligible risk of metastasis or death
Cardiopulmonary dysfunction
History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins
Known hypersensitivity to biopharmaceuticals produced in Chinese hamster ovary cells
Known allergy or hypersensitivity to the components of the formulations of atezolizumab, nab-paclitaxel, cyclophosphamide, or doxorubicin, filgrastim or pegfilgrastim
Active or history of autoimmune disease or immune deficiency diseases except history of autoimmune-related hypothyroidism, controlled Type 1 diabetes mellitus, and dermatologic manifestations of eczema, psoriasis, lichen simplex chronicus, or vitiligo (e.g., participants with psoriatic arthritis are excluded)
History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest computed tomography (CT) scan. History of radiation pneumonitis in the radiation field (fibrosis) is permitted
Positive human immunodeficiency virus (HIV) test at screening
Active hepatitis B and hepatitis C virus infection
Active tuberculosis
Severe infections within 4 weeks prior to initiation of study treatment, including but not limited to hospitalization for complications of infection, bacteremia, or severe pneumonia
Treatment with therapeutic oral or IV antibiotics within 2 weeks prior to initiation of study treatment, except prophylactic antibiotics
Major surgical procedure within 4 weeks prior to initiation of study treatment or anticipation of need for a major surgical procedure during the course of the study
Prior allogeneic stem cell or solid organ transplantation
Administration of a live attenuated vaccine within 4 weeks prior to initiation of study treatment or anticipation of need for such a vaccine during the study
Any other disease, metabolic dysfunction, physical examination finding, 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 render the participant at high risk from treatment complications
Prior treatment with cluster of differentiation 137 (CD137) agonists or immune checkpoint-blockade therapies, including anti-cluster of differentiation 40 (anti-CD40), anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4), anti-programmed death-1 (anti-PD-1), and anti-PD-L1 therapeutic antibodies
Treatment with systemic immunostimulatory agents within 4 weeks or 5 half-lives of the drug, whichever is longer, prior to initiation of study treatment
Treatment with systemic immunosuppressive medications within 2 weeks prior to initiation of study treatment or anticipation of need for systemic immunosuppressive medications during the study
History of cerebrovascular accident within 12 months prior to randomization
Pregnant or lactating, or intending to become pregnant during the study