- Disease-related criteria: Histologically documented adenocarcinoma of the lung; Stage IIIB or Stage IV disease; Biopsy material available for central assessment of programmed death receptor ligand 1 (PD-L1) and mesothelin, consisting of either tumor block or unstained slides of tumor sample (archival tissue, or fresh biopsy if archival tissue is insufficient); (In Phase 2 only) Mesothelin-positive status (greater than 0 percent positive tumor cells), determined at a central laboratory using mesothelin immunohistochemistry (IHC) assay