Inclusion Criteria:  Subjects ≥18 years of age Pathologically documented, locally-advanced or metastatic solid malignancy with NRAS or KRAS mutation At least one target lesion that can be measured per RECIST version 1.1 Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Adequate organ function (bone marrow, hepatic, renal, cardiovascular) Documented disease progression despite appropriate prior standard therapies or subjects for whom no standard therapy exists for their tumor type and disease stage Reproductive criteria (as defined in the protocol)  Exclusion Criteria:  Subjects with symptomatic central nervous system (CNS) metastases History of another primary malignancy, with the exception of locally excised nonmelanoma skin cancer and carcinoma in situ of uterine cervix Known active hepatitis B infection or hepatitis C infection Known pre-existing interstitial lung disease Known diagnosis of human immunodeficiency virus (HIV) infection History or current evidence/risk of retinal vein occlusion (RVO) or central serous retinopathy; or known risk factors for RVO or central serous retinopathy Any severe and/or uncontrolled medical conditions or other conditions that, in the opinion of the Investigator, Sponsor, or contract research organization, could affect the subject's participation in the study Impaired cardiac function or clinically significant cardiac diseases Previous treatment with RAS or MEK targeting agents Chemotherapy, biologic therapy, immunotherapy, radiotherapy, or investigational agents within 5 half-lives or within 4 weeks (whichever is longer) prior to administration of the first dose of study treatment