A Study of SGN-ALPV in Advanced Solid Tumors

Inclusion Criteria: * Participants must have one of the following histologically or cytologically confirmed metastatic or unresectable solid tumor types: * Parts A and B * Ovarian cancer * Endometrial cancer * Non-small cell lung cancer (NSCLC) * Gastric cancer, including gastroesophageal junction (GEJ) carcinoma * Cervical cancer * Malignant testicular germ cell tumor (GCT), except for pure teratomas * Malignant ovarian GCT, except for pure teratomas * Malignant extragonadal GCT except for pure teratomas or tumors with primaries arising from CNS * Part C * High-grade serous ovarian cancer (HGSOC): Participants must have HGSOC which has progressed or relapsed within 6 months after previous platinum containing chemotherapy, received 2 to 4 prior anticancer lines of therapy, and at least 1 line of therapy in the platinum-resistant setting. If eligible at least 1 line of therapy must have contained bevacizumab or a biosimilar to bevacizumab. * Endometrial Cancer: Participants must have unresectable locally advance or metastatic endometrial carcinoma and have had at least 1 prior line of therapy. * NSCLC: Participants must have unresectable locally advanced or metastatic NSCLC and have received platinum-based therapy and a PD-(L)1 inhibitor. * Gastric cancer or GEJ carcinoma: Participants must have unresectable locally advanced or metastatic gastric cancer or GEJ carcinoma and have received prior platinum and fluoropyrimidine -based chemotherapy * Participants enrolled in the following study parts should have an appropriate tumor site and agree to a biopsy * Part B dose and schedule optimization cohorts and Part C disease-specific expansion cohorts: pretreatment biopsy, unless clinically infeasible following consultation with the medical monitor. * Part C biology expansion cohort: pretreatment biopsy (required), on-treatment biopsy during Cycle 1 (unless clinically infeasible following consultation with the medical monitor) * Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1 * Measurable disease per the RECIST v1.1 at baseline Exclusion Criteria: * History of another malignancy within 3 years of first dose of study treatment or any evidence of residual disease from a previously diagnosed malignancy. Exceptions are malignancies with a negligible risk of metastasis or death. * Known active central nervous system metastases. * Previous receipt of an MMAE-containing agent or an agent targeting ALPP or ALPPL2. * Pre-existing neuropathy ≥ Grade 2 per National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 5.0