The study will be conducted in two parts. The first part is efficacy exploration and the second part is efficacy verification. During the course of efficacy exploration, 33 subjects will be enrolled to preliminarily evaluate the safety and efficacy of MRG002. The second part will be adjusted according to the result of the first part. 29 subjects are planned to be enrolled. Considering the dropout rate of 10%, approximately 33 subjects are planned to be enrolled. A total of 66 subjects are planned to be enrolled in efficacy exploration and verification.
The objective of this study is to assess the safety, efficacy, pharmacokinetics, and immunogenicity of MRG002 in patients with HER2-low locally advanced or metastatic BC.