The purpose of this study is to assess the safety, tolerability, and efficacy of CBX-12 in female subjects with platinum resistant or refractory ovarian cancer at 2 doses; 125 mg/m2 every 21 days or 100 mg/m2 every 21 days.

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.