Study of Anti-CEACAM5 ADC M9140 in Participants With Advanced Solid Tumors (PROCEADE PanTumor)

Required: CEACAM5 high expression (IHC ≥ 2+ in ≥ 50% of tumor cells) (IHC ≥ 2+ in ≥ 50% of tumor cells)

Participants in Part A with CEACAM5high GC/GEJC (defined as IHC ≥ 2+ staining in ≥ 50% of tumor cells)

Required: CEACAM5 low expression (IHC ≥ 2+ in < 50% of tumor cells) (IHC ≥ 2+ in < 50% of tumor cells)

Participants in Part B with CEACAM5low GC/GEJC (defined as IHC ≥ 2+ staining in less than (<) 50% of tumor cells)

Required: CEACAM5 high expression (IHC ≥ 2+ in ≥ 50% of tumor cells) (IHC ≥ 2+ in ≥ 50% of tumor cells)

All participants will be screened using an IHC test to define CEACAM5 expression. Only participants with CEACAM5high expressing tumors will be eligible [PDAC]

Allowed: EGFR mutation

Participants in Part B with CEACAM5 high known EGFR mutated tumors as assessed according to local clinical practice

Must have received: systemic therapy (fluoropyrimidine, platinum agent) — advanced/metastatic

progressed after systemic therapies for the advanced/metastatic stage that must have included (provided there is no medical contraindication and these agents are locally approved and available) a fluoropyrimidine and a platinum agent

Must have received: immune checkpoint inhibitor — advanced/metastatic

an Immune checkpoint inhibitors (ICI) for participants with a known microsatellite instability-high (MSI-H) status or participants whose tumor express PD-L1 with a CPS greater than or equal (>=) 1

Must have received: systemic therapy (FOLFIRINOX regimen, NALIRIFNOX regimen, Nab-paclitaxel/gemcitabine regimen) — advanced/metastatic

progressed after systemic therapies for the advanced metastatic stage that must have included (provided there is no medical contraindications, and these agents are locally approved and available; FOLFIRINOX regimen or NALIRIFNOX regimen or Nab-paclitaxel/gemcitabine regimen

Cannot have received: topoisomerase inhibitor (irinotecan)

Participants with prior therapy with irinotecan