Phase 1, Safety and Tolerability Study of XmAb541 in Advanced Solid Tumors

Key Inclusion Criteria: * Age ≥ 18 years. For subjects with GCTs, age ≥15 years * CLDN6+ tumor * Histological or cytological documentation of locally advanced, recurrent, or metastatic ovarian, fallopian tube, or peritoneal cancer, adenocarcinoma of the endometrium (endometrial cancer, uterine cancer, or carcinoma of the uterine corpus), GCT * Have documented progressive disease (PD) on standard-of-care therapies appropriate for the specific tumor type; have exhausted therapies with a survival benefit or the standard therapy has no survival benefit or proven to be ineffective, intolerable, or subject is not a candidate for such available therapy. * Eastern Cooperative Oncology Group performance status of 0-2 * Life expectancy ≥ 3 months * Adequate liver, kidney, and bone marrow function Key Exclusion Criteria: * Prior exposure to a CLDN6 targeting product * Ovarian cancer that is platinum refractory, or has rapid progression on most recent prior ≥ second line systemic anticancer therapy * Have known active central nervous system metastases and/or carcinomatous meningitis. Patients with treated brain metastases may participate, provided they are radiologically stable. * Active known or suspected autoimmune disease * Have any condition requiring systemic treatment with corticosteroids, prednisone equivalents, or other immunosuppressive medications within 14 days prior to first dose of study drug * Clinically significant cardiovascular, pulmonary or gastrointestinal disease * Positive test for hepatitis C RNA * Positive test for hepatitis B surface antigen or hepatitis B core antibody (hBcAb)