This study is testing a drug called azenosertib (ZN-c3) for people who have certain types of cancer that don't respond to a common treatment called platinum. These cancers include high-grade serous ovarian, fallopian tube, or primary peritoneal cancer. Azenosertib is a medicine that tries to stop cancer cells from fixing themselves, so they die. The study has two parts: the first part is finished, and the second part is for people whose cancer cells have a special protein called Cyclin E1.

People can join if they are 18 or older, have the right type of cancer, and have had some other treatments before. They should not have had the cancer come back right after platinum treatment or have certain health issues that could make the study unsafe for them.

• The study involves taking a new drug and requires tumor testing.
• You must have tried other treatments before joining.
• Make sure you can safely stop any interfering medications or supplements before starting.