A Trial of Pembrolizumab With Chemotherapy or Chemoradiotherapy in Participants From India With Different Types of Cancer (MK-3475-G44/KEYNOTE-G44)

Cohort 1:

• The participant must have a histologically or cytologically confirmed diagnosis of locally advanced unresectable or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma, with locally confirmed programmed death-ligand 1 (PD-L1) CPS ≥1.
• Has locally confirmed human epidermal growth factor receptor 2 (HER2) negative cancer.

Cohort 2:

- Has a histologically confirmed diagnosis of advanced (metastatic) and/or unresectable (locally advanced) biliary tract cancer (BTC) (intra or extrahepatic cholangiocarcinoma or gallbladder cancer).

Cohort 3:

• Has high-risk locally advanced cervical cancer.
• Has histologically confirmed squamous cell carcinoma, adenocarcinoma, or adenosquamous carcinoma of the cervix.

All Cohorts:

• If hepatitis B surface antigen (HBsAg)-positive, has undetectable hepatitis B virus (HBV) viral load and has received HBV antiviral therapy for at least 4 weeks and will continue it.
• If history of hepatitis C virus (HCV) infection, has undetectable HCV viral load.

Exclusion Criteria:

Cohort 1:

• Has squamous cell or undifferentiated gastric cancer.
• Has had previous therapy for locally advanced, unresectable or metastatic gastric/GEJ cancer.
• Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis.
• Has had major surgery, open biopsy, or significant traumatic injury within 28 days prior to first dose of study.
• Had active hemoptysis (bright red blood of at least 0.5 teaspoon) within 3 weeks or tumor bleeding within 2 weeks prior to the first dose of study intervention.

Cohort 2:

• Has ampullary cancer.
• Has small cell cancer, neuroendocrine tumors, lymphoma, sarcoma, mixed tumor histology, and/or mucinous cystic neoplasms.
• Has had previous systemic therapy for advanced (metastatic) or unresectable (locally advanced) BTC (intra or extrahepatic cholangiocarcinoma or gallbladder cancer), with the exception of neoadjuvant/adjuvant therapy, which is allowed.
• Has known active CNS metastases and/or carcinomatous meningitis.
• Had active hemoptysis (bright red blood of at least 0.5 teaspoon) within 3 weeks or tumor bleeding within 2 weeks prior to the first dose of study intervention.

Cohort 3:

- Has undergone a previous hysterectomy defined as removal of the entire uterus or will have a hysterectomy as part of their initial cervical cancer therapy.

All Cohorts:

• Has hypokalemia.
• Has hypomagnesemia.
• Has hypocalcemia.
• Received prior therapy with an anti-programmed cell death protein 1 (PD-1), anti-PD-L1, or anti-programmed death-ligand 2 (PD-L2) agent, or with an agent directed to another stimulatory or coinhibitory T-cell receptor.
• Has active autoimmune disease that has required systemic treatment in the past 2 years.
• Has history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or current pneumonitis/interstitial lung disease.
• Has a known additional invasive malignancy that is progressing or has required active treatment within the past 3 years.
• Has history of human immunodeficiency virus (HIV) infection.
• Has known active tuberculosis.
• Has not adequately recovered from major surgery or is having ongoing surgical complications.