KEYNOTE-603: This study evaluates how safe, tolerable and effective a drug called mRNA-4157 when given in combination with other treatments or by itself in individuals with solid cancers.A Phase 1, Open-Label, Multicenter Study to Assess the Safety, Tolerability, and Immunogenicity of mRNA-4157 Alone and in Combination in Participants With Solid Tumors

Inclusion

• Parts A, A2, and D: Participants must be clinically disease-free at study entry (that is, participants in the adjuvant setting).
  
  
• Part B: Participants must have one of the histologically- or cytologically-confirmed unresectable (locally advanced or metastatic) protocol-specified solid malignancies, have measurable disease at study entry defined by RECIST 1.1., and be considered suitable for treatment with pembrolizumab; in this study pembrolizumab will be considered an investigational study drug.
  
  
• Part C: Participants must have one of the histologically- or cytologically confirmed unresectable (locally advanced or metastatic) protocol-specified solid malignancies, must not have received prior anti-programmed cell death protein 1 (PD-1)/programmed death -ligand 1 (PD-L1) therapy, and must have measurable disease at study entry defined by RECIST 1.1.
  
  
• Part A2: Participants with histologically confirmed PDAC who have undergone complete macroscopic resection(that is, R0 - no cancer cells within 1 mm of all resection margins or R1 - cancer cells present within 1 mm of one or more resection margins) who had no evidence of metastatic disease with adequate recovery from surgery to receive adjuvant therapy.
  
  
• Parts E1 and E2: Participants with untreated histologically/cytologically confirmed Stage II-IIIB NSCLC (per AJCC version 8) that is considered resectable of non-squamous (adenocarcinoma only) or squamous cell carcinoma histology, absence of major associated pathologies that increase the surgery risk to an unacceptable level, must have a tumor tissue sample available for NGS and PD-L1 IHC testing as defined in the Laboratory Manual.
  
  
• Part E3: Participants with untreated, locally advanced surgically resectable, histologically/cytologically confirmed, gastric/GEJ adenocarcinoma, as defined by a primary lesion that is T3 or greater or with the presence of any positive clinical nodes (N+) and without evidence of metastatic disease, measurable disease according to RECIST version 1.1, absence of major associated pathologies that increase the surgery risk to an unacceptable level, must have a tumor tissue sample available for NGS and PD-L1 IHC testing as defined in the Laboratory Manual.
  
  
• Part D: Participants with completely resected Stage II, III or IV cutaneous melanoma.
  
  
• Parts A, A2, and D: Participants must have a formalin-fixed paraffin embedded (FFPE) tumor sample available (for example, from their prior surgery) that is suitable for the next generation sequencing (NGS) required for this study.
  
  
• Parts B and C: Participants must have at least 1 lesion amenable to the mandatory fresh tumor biopsy at study entry.
  
  
• Participants must have resolution of toxic effect(s) (as specified in the protocol) from prior therapy to Grade 1 or less.
  
  
• Participant is willing to use an adequate method of contraception for the course of the study through 120 days after the last dose of study drug (male and female participants of childbearing potential), or for a specified time after the last dose of SoC chemotherapy per SoC product labeling, whichever is later.
  
  
• Participants with Performance Scale (PS) of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) PS.