A Study of AK138D1 Alone or in Combination With Ivonescimab in Advanced Breast Cancer

Inclusion Criteria:

1. The subject must sign the written informed consent form (ICF) voluntarily;
2. At enrollment, aged ≥ 18 to ≤ 75 years, both males and females are eligible;
3. ECOG performance status score of 0 or 1;
4. Has a life expectancy of ≥ 3 months;
5. At least 1 measurable lesion as per RECIST v1.1 that is suitable for repeated accurate measurement.
6. Adequate organ function.

Exclusion Criteria:

1. Concomitant participation in another clinical study, unless it is a non-interventional clinical study or the follow-up period of an interventional study;
2. Presence of active central nervous system (CNS) metastases.
3. Live vaccines or attenuated live vaccines administered within 4 weeks prior to the first dose, or planned to be administered during the study; use of inactivated vaccines is allowed;
4. Untreated subjects with active hepatitis B or active hepatitis C;
5. Known active pulmonary tuberculosis (TB); subjects with suspected active TB must undergo appropriate clinical assessment to rule out the presence of active disease;
6. Known active syphilis infection;
7. Subjects with known allergy to any component of any study drug; and with a history of known severe hypersensitivity reactions to other monoclonal antibodies;
8. Other reasons for ineligibility as evaluated by the investigator.