This is a Phase 1, multicenter, open-label, dose-escalation study of DMUC4064A administered by intravenous (IV) infusion every three weeks (q3w) to cancer participants. The study will employ a traditional 3 + 3 dose escalation design to determine the maximum tolerated dose (MTD) of DMUC4064A against platinum-resistant ovarian cancer. Once a q3w recommended Phase 2 dose (RP2D) is identified, two expansion cohorts (one in platinum-resistant ovarian cancer and another in unresectable pancreatic cancer) may be evaluated to further characterize the safety and activity in these populations.