Inclusion Criteria:  Age ≥ 18 (or as required by local regulation). Histological or cytological confirmation of unresectable or metastatic solid tumor malignancy harboring a KRAS mutation. No more than 3 prior standard treatments appropriate for tumor type and stage of disease. ECOG performance status ≤ 1. Existence of measurable disease (according to Response evaluation criteria in solid tumors [RECIST v1.1] criteria). Subjects with asymptomatic CNS metastases and/or asymptomatic leptomeningeal carcinomatosis are eligible. Adequate organ function.  Exclusion Criteria:  Major surgery within four weeks of the start of treatment. Previous other cancer requiring treatment within the previous two years. Clinically significant cardiovascular disease. Any of the following cardiac criteria: Mean resting corrected QT interval (QTc) > 470 msec obtained from three ECGs and any factors that increase the risk of QTc prolongation or arrhythmic events Any clinically important abnormalities in rhythm, conduction, or morphology of resting ECG Known clinically significant active infections not controlled with systemic treatment (bacterial, fungal, viral including HIV positivity). Gastrointestinal disease or other malabsorption syndromes that would impact drug absorption. Subjects being treated with or anticipating the need for treatment with strong CYP3A inhibitors or inducers.