A Study of ZN-c3 in Subjects With High-Grade Serous Ovarian, Fallopian Tube or Primary Peritoneal Cancer

Open to people ages 18 years and up

1. Age ≥18 years
2. High-grade serous ovarian cancer
3. Prior therapy:
   1. Subjects must have platinum-resistant disease
   2. One to 4 prior lines or regimens are allowed (1 to 5 prior lines are permitted in part 1b)
   3. Prior bevacizumab treatment is required
4. Measurable disease per RECIST Version 1.1.
5. Adequate hematologic and organ function

1. Any of the following treatment interventions within the specified time frame prior to C1D1:
   1. Major surgery within 28 days
   2. Any chemotherapy or targeted tumor therapy within 14 days or 5 half-lives (whichever is shorter);
   3. Radiation therapy within 21 days;
   4. Autologous or allogeneic stem cell transplant within 3 months.
   5. Current use of any other investigational drug therapy <28 days or 5 half-lives (whichever is shorter).
2. Prior therapy with ZN-c3 or any other WEE1 inhibitor, ATR inhibitor, or CHK1/2 inhibitor.
3. A serious illness or medical condition(s) including, but not limited to: Any evidence of bowel obstruction as determined by air/fluid levels on computed tomography (CT) scan, recent hospitalization for bowel obstruction within 3 months prior to C1 D1, or recurrent paracentesis or thoracentesis within 6 weeks prior to C1 D1.