Ovarian Cancer Clinical Trials

• Sign and date the tissue prescreening ICF, prior to HER2 central testing. Sign and date the Main ICF, prior to the start of any trial- specific qualification procedures. Consent to optional PGx prior to any PGx procedures.

• \*For participants in the safety run-in phase, a safety run-in ICF needs to be signed and dated prior to the start of any trial-specific qualification procedures.

• Adults ≥18 years of age on the day of signing the ICF. Follow local regulatory requirements if the legal age of consent for trial participation is \>18 years old.

• Has histologically confirmed diagnosis of epithelial high-grade ovarian, fallopian tube or primary peritoneal carcinoma per local assessment (including but not limiting to serous, endometrioid, clear cell, carcinosarcoma, mucinous).

• Is newly diagnosed FIGO Stage III or IV.

• Has HER2 expression per 2016 ASCO-CAP gastric cancer IHC scoring (3+/2+/1+) guidelines1 by prospective central testing.

• \*For participants in the safety run-in phase, HER2 expression assessed by either local (require using ASCO-CAP gastric cancer IHC scoring \[IHC 3+/2+/1+\] guidelines) or central assessment (if available) is acceptable. Submission of the pathology report is required for participants enrolled based on local HER2 IHC results.

• Has adequate tumor tissue sample available for assessment of HER2 by central laboratory. Tumor tissue block or sufficient tissue slides are required for HER2 testing and retrospective HRD status determination.

• \*Participants in the safety run-in phase who are enrolled based on local HER2 IHC results are recommended to provide tumor tissue sample from the same specimen for central assessment.

• Has a local HRD or BRCA test result available. Participants with BRCA-wildtype will have a local HRD test results, as applicable.

• Has received up to 6 cycles of standard of care bevacizumab in combination with frontline platinum- based chemotherapy as per approved indication and clinical guidelines and is eligible to continue single agent bevacizumab maintenance per standard of care and investigator discretion.