Study to Evaluate D-1553 in Subjects With Lung Cancer

Inclusion Criteria: * Subject with histologically proven, locally advanced, unresectable and/or metastatic NSCLC for which no standard treatment is available or the subject is refractory to or intolerant of existing standard treatment. * Subject has KRasG12C mutation in tumor tissue or other biospecimens containing cancer cells or DNA. Historical, local laboratory result (up to 5 years prior to this study) can be used for Phase 1 subjects. Phase 2 subjects must be tested for KRasG12C mutation by a central laboratory. * Subject has measurable disease according to RECIST, v1.1 Exclusion Criteria: * Subject with unstable or progressive central nervous system (CNS) metastases. * Subjects with clinically significant cardiovascular disease * Subject with interstitial lung disease (ILD) or any active systemic infection including but not limited to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. * Subject has impaired gastrointestinal (GI) function or GI diseases that may significantly alter the absorption or metabolism of oral medications. * Subject is pregnant or lactating.