Study of Patritumab Deruxtecan Plus Pembrolizumab With Other Anticancer Agents in Participants With High-Risk Early-Stage Triple-Negative or Hormone Receptor-Low Positive/HER-2 Negative Breast Cancer (MK-1022-010, HERTHENA-Breast-03)

Eligibility Criteria

• * Has locally advanced, non-metastatic (M0), breast cancer, defined as any of the following combined primary tumor (T) and regional lymph node (N) staging per current American Joint Committee on Cancer (AJCC) criteria: cT1c, N1-N2; cT2, N0-N2; cT3, N0-N2; or cT4a-d, N0-N2
• * Has centrally confirmed diagnosis of breast cancer that is triple-negative or HR-low+/HER2- breast cancer that will be treated according to the triple-negative breast cancer (TNBC) paradigm
• * Participants who are Hepatitis B surface antigen (HBsAg) positive are eligible if they have received Hepatitis B virus (HBV) antiviral therapy for at least 4 weeks and have undetectable HBV viral load
• * Participants with a history of Hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable
• * Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1 within 28 days prior to allocation/randomization
• * Has left ventricular ejection fraction (LVEF) of ≥50% or ≥ lower limit of normal (LLN) as assessed by echocardiogram (ECHO) or multigate acquisition scan (MUGA) scan
• * Has uncontrolled or significant cardiovascular disease before randomization
• * Has clinically significant corneal disease
• * Has human immunodeficiency virus (HIV) infection with a history of Kaposi sarcoma and/or multicentric Castleman disease
• * Has received prior therapy with an anti-programmed death (PD)-1, anti-PD-L1, or anti-PD-L2 agent, or with an agent directed to another stimulatory or coinhibitory T-cell receptor
• * Has received any prior treatment, including radiation, systemic therapy, and/or definitive surgery for currently diagnosed breast cancer
• * Has received prior treatment with an anti-human epidermal growth factor receptor 3 (HER3) antibody and/or antibody-drug conjugate (ADC) that consists of an exatecan derivative that is a topoisomerase I inhibitor (e.g., trastuzumab deruxtecan)
• * Has metastatic (Stage IV) breast cancer or cN3 nodal involvement
• * Has known additional malignancy that is progressing or has required active treatment within the past 5 years
• * Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis
• * Has a history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease, or where suspected ILD/pneumonitis cannot be ruled out by standard diagnostic assessments
• * Has an active infection requiring systemic therapy
• * Has concurrent active HBV and HCV infection
• * Has clinically severe respiratory compromise resulting from intercurrent pulmonary illness