Inclusion Criteria:  Histologically confirmed diagnosis of a solid tumor malignancy with KRAS G12C mutation (phase 1b must be either Non-Small Cell Lung Cancer or Colorectal Cancer) Unresectable or metastatic disease No available treatment with curative intent Adequate organ function  Exclusion Criteria:  History of intestinal disease, inflammatory bowel disease, major gastric surgery, or other gastrointestinal conditions likely to alter absorption of study treatment or result in inability to swallow Other active cancer Cardiac abnormalities