A Study of SGN-STNV in Advanced Solid Tumors

Inclusion Criteria: * Disease indication * Must have disease that is relapsed or refractory or be intolerant to standard-of-care therapies and should have no appropriate standard-of-care therapeutic option. * Non-small cell lung cancer (NSCLC) * HER2 negative breast cancer * Ovarian cancer * Cervical cancer * Endometrial cancer * Esophageal cancer * Gastric cancer and GEJ carcinoma * Colorectal cancer * Exocrine pancreatic adenocarcinoma * Appendiceal adenocarcinoma and pseudomyxoma peritonei of unknown origin * Participants enrolled in the following study parts should have an appropriate tumor site that satisfies the following criteria: * Site has tumor that is not a target lesion and has not been previously irradiated (unless progression has occurred since end of radiotherapy) * Site has tumor that is accessible for a minimally invasive biopsy that does not present a significant risk, AND * Participant must agree to a biopsy as follows * Disease-specific expansion cohorts: pre-treatment biopsy, unless medically infeasible following consultation with the medical monitor * Biology expansion cohort: pretreatment biopsy (required) and additional on-treatment biopsy during Cycle 1 (unless medically infeasible following consultation with the medical monitor) * Measurable disease per the Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) at baseline * An Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1 * Adequate renal, hepatic, and hematologic function Exclusion Criteria * History of another malignancy within 3 years before the first dose of study drug, or any evidence of residual disease from a previously diagnosed malignancy. * Known active central nervous system metastases * Carcinomatous meningitis * Previous receipt of monomethylauristatin E (MMAE)-containing drugs * Pre-existing neuropathy ≥ Grade 2 per the National Cancer Institute's Common Terminology Criteria for Adverse Events (NCI CTCAE) v5.0 * Any uncontrolled ≥ Grade 3 (per the NCI CTCAE, Version 5.0) viral, bacterial, or fungal infection within 2 weeks prior to the first dose of SGN-STNV There are additional inclusion and exclusion criteria. The study center will determine if criteria for participation are met.