Study of SC-003 Alone and in Combination With ABBV-181 in Subjects With Platinum-Resistant/Refractory Ovarian Cancer

Inclusion Criteria: * Histologically or cytologically confirmed ovarian epithelial cancer * Evidence of progressive disease (PD) on or within 6 months of a platinum (cisplatin or carboplatin) regimen: at least 1 prior regimen must have contained a platinum-taxane combination * Measurable disease as defined by RECIST 1.1 * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 * Fresh or archived tumor tissue sample available for target expression analysis. \[Phase 1b only: Subjects' tumor tissue must test positive for target expression.\] * Adequate hematologic and organ function as confirmed by laboratory values * At least 3 weeks between last systemic chemotherapy and planned start of study treatment (4 weeks for prior investigational drugs, immunotherapy, radiotherapy, or biologics) for ovarian cancer * At least 3 weeks between major surgery and planned start of study treatment; major incisions must have healed Exclusion Criteria: * History of prior malignancy, with the exception of the following: malignancy treated with curative intent and with no evidence of active disease present for more than 3 years prior to screening and felt to be at low risk for recurrence by treating physician; or adequately treated lentigo maligna melanoma without current evidence of disease or adequately controlled non-melanomatous skin cancer; or adequately treated cervical carcinoma in situ without current evidence of disease. * Uncontrolled infection requiring systemic antibiotics/antivirals/antifungals * Evidence of complete or partial bowel obstruction * Patients requiring IV hydration or parenteral nutrition * Positive pregnancy test in females of child-bearing potential or pregnant or currently breastfeeding * Known hypersensitivity to any component of study drug including potential subjects with a history of major immunologic reaction to any IgG-containing agent * Inability to tolerate premedication with dexamethasone * Uncontrolled cardiac disease, or myocardial infarction within the last 12 months, or left ventricular ejection fraction (LVEF) \< 50%, or QTcF interval \> 470 msec * Class II, III or IV heart failure as defined by the NYHA functional class system * Positive serology for hepatitis B or C, or known human immunodeficiency virus infection (HIV) * Previous treatment with a pyrrolobenzodiazepine (PBD)-based drug Additional exclusion criteria for the SC-003 and ABBV-181 combination treatment regimen: * History of inflammatory bowel disease * Active autoimmune disease, with exceptions of psoriasis not requiring systemic treatment, vitiligo, type 1 diabetes mellitus and hypothyroidism * History of primary immunodeficiency, allogeneic bone marrow transplantation, solid organ transplantation, or previous clinical diagnosis of tuberculosis * History of immune-mediated pneumonitis * Current or prior use of immunosuppressive medication within 14 days prior to the first dose of study treatment