SHR-A1811 Versus Investigator's Chemotherapy in Recurrent/Metastatic Breast Cancer Clinical Trial

Inclusion criteria

• Low-HER2 expression defined as IHC 2+/ISH- or IHC 1+ (ISH- or untested).
• HR-positive breast cancer with at least one endocrine therapy and disease progression was judged by the investigator to no longer benefit from endocrine therapy.
• Has been treated with 0 to 1 prior lines of chemotherapy in the metastatic setting.
• Has documented radiologic progression (during or after most recent treatment).
• Has at least 1 protocol-defined measurable lesion.
• Has protocol-defined adequate cardiac, bone marrow, renal, hepatic and blood clotting functions.
• Fertile women (WOCBP) subjects agreed to use highly effective contraception and not to breastfeed from the time of study screening until 7 months after receiving the last study medication; a fertile woman must have a negative serum pregnancy test result within 7 days prior to the first treatment.

Exclusion criteria

• Has known active central nervous system (CNS) metastases. Subjects with previously treated brain metastases may participate provided they are stable.
• A history of human immunodeficiency virus (HIV) infection is known, or has an active autoimmune disease.
• History of interstitial lung disease or pneumonia requiring oral or intravenous steroids.
• Has moderate or severe cardiovascular disease.
• Active HBV(hepatitis B) or HCV (Hepatitis C virus)-infected subjects.
• Any other malignancies within 5 years except for those with negligible risk of metastasis or death.