Overview

The goal of this clinical trial is to learn about the efficacy and safety of trastuzumab emtansine (T-DM1) in the treatment of patients with advanced HER2-positive breast cancer after TKIs or HP therapy. The main questions it aims to answer are:

• The objective response rate of patients receiving T-DM1 therapy with advanced HER2-positive breast cancer after TKIs or HP therapy.
• The adverse events and prognosis of patients with advanced HER2-positive breast cancer who receive the T-DM1 therapy.
• Changes of anti-tumor immunity during T-DM1 therapy in patients with advanced HER2-positive breast cancer.

Participants will receive T-DM1 treatment (3.6mg/kg, d1/21, IVD) until progressive diseases or intolerable adverse effects occurs.

Eligibility

Inclusion Criteria:-

• Medically stable on the basis of physical examination, medical history, vital signs and 12-lead electrocardiogram (ECG) performed at screening
• Clinical diagnosis of systemic lupus erythematosus (SLE) for more than or equal to (\>=) 24 weeks prior to screening according to european league against rheumatism/american college of rheumatology (EULAR/ACR) classification criteria
• Must have a systemic lupus erythematosus disease activity index 2000 (SLEDAI-2K) score \>= 6 and a clinical SLEDAI-2K \>= 4 at screening, AND a clinical SLEDAI-2K score \>= 4 points at Week 0, excluding points attributed to "lupus headache," "alopecia," and "organic brain syndrome"
• Participants of childbearing potential must have a negative serum beta human chorionic gonadotropin (β-hCG) test at screening and a negative urine (β- hCG) test at Week 0 prior to randomization
• Has at least 1 BILAG-2004 A score or 2 BILAG-2004 B scores observed at screening

Exclusion Criteria:

• History of severe, progressive and/or uncontrolled hepatic, gastrointestinal, renal, pulmonary, cardiovascular, psychiatric, neurological or musculoskeletal disorder, hypertension, and/or any other medical or uncontrolled autoimmune disorder (s) or clinically significant abnormalities in screening laboratory
• Any unstable or progressive manifestation of SLE that is likely to warrant escalation in therapy beyond permitted background medications
• Confirmed or suspected clinical immunodeficiency syndrome not related to treatment of SLE or has a family history of congenital or hereditary immunodeficiency unless confirmed absent in the participant
• Has shown a previous severe immediate hypersensitivity reaction, such as anaphylaxis, to therapeutic proteins
• Suspected or known allergies, hypersensitivity, or intolerance to nipocalimab or its excipients, or excipients used in the placebo formulation