Inclusion Criteria:  Participants must be able to provide an archived tumor sample Histologically or cytologically confirmed advanced colorectal cancer, advanced small intestinal cancer and advanced appendiceal cancer with KRAS p.G12C mutation Must have received at least 1 prior standard therapy Must have at least 1 measurable lesion per RECIST v1.1 Must have adequate organ function Must be able to swallow and retain orally administered medication  Exclusion Criteria:  Has brain metastases, except if treated and no evidence of radiographic progression or hemorrhage for at least 28 days Active infection requiring systemic treatment within 14 days Active HIV, HBV or HCV Any severe and/or uncontrolled medical conditions LVEF<50% assessed by ECHO QT interval >470 msec