A Study of CBX 12 in Subjects With Platinum Resistant or Refractory Ovarian Cancer

Inclusion Criteria: * Subjects must have histologically- or cytologically-diagnosed epithelial high-grade serous cancer of the ovary, fallopian tube cancer or primary peritoneum cancer that is refractory to prior therapy and must have platinum-resistant disease defined as: * Subjects who have received only 1 platinum-based chemotherapy regimen for at least 4 cycles of platinum must have disease progression on treatment or occurring ≤ 26 weeks after their last dose of platinum. * Patients who have progressed following a second course of a platinum based regimen. * Subjects may have up to 2 additional systemic regimens for advanced or metastatic disease. Maintenance regimens (e.g., with a PARP inhibitor or bevacizumab) are not considered separate regimens. * Age greater than or equal to 18 years at the time of signing the informed consent form (ICF). * Has measurable disease per RECIST 1.1. * Has provided written informed consent. * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1. * Adequate liver, renal, hematologic, pulmonary and coagulation function. Exclusion Criteria: * Cytotoxic chemotherapy, biologic agent, investigational agent, or radiation therapy within 3 weeks prior to the first dose of CBX-12. * Subjects who are currently receiving any other anticancer or investigational agent(s). * Clinically significant intercurrent disease. * Active human immunodeficiency virus (HIV) infection. * Active hepatitis B or C infection.