A Study of SC-007 in Subjects With Advanced Cancer

Inclusion Criteria: * Histologically or cytologically confirmed advanced metastatic or unresectable advanced colorectal cancer (CRC) or gastric cancer that is relapsed, refractory, or progressive after: * CRC: at least 2 prior systemic regimens in the metastatic setting, and as appropriate in patients whose tumors are microsatellite instability-high (MSI-H), pembrolizumab as well. * Gastric cancer (including gastric and EGJ cancers): at least 2 prior systemic regimens in adjuvant, advanced, or metastatic setting and, as appropriate, a human epidermal growth factor receptor 2 (HER2) targeted agent. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Adequate hematologic, hepatic, and renal function. Exclusion Criteria: * Any significant medical condition that, in the opinion of the investigator or sponsor, may place the participant at undue risk from the study. * Has electrocardiogram (ECG) abnormalities that make QT interval corrected (QTc) evaluation difficult. * Prior exposure to a pyrrolobenzodiazepine or indolinobenzodiazepine based drug.