This study is a single-arm, open-label, multicenter Phase IIa trial designed to evaluate the efficacy, safety, and pharmacokinetic profile of BRY812 for Injection in patients with LIV-1-positive advanced gynecological malignancies. The study comprises two cohorts. For Cohort 1 (ovarian cancer), a Simon's two-stage design is adopted. In the first stage, 13 evaluable subjects will be enrolled. If fewer than 3 subjects achieve an objective response among these 13, enrollment in this cohort will be terminated. Otherwise, the cohort will proceed to the second stage, and additional 23 evaluable subjects will be enrolled, bringing the total to 36. If at least 10 out of the 36 evaluable subjects achieve an objective response, the cohort will be considered worthy of further investigation. Cohort 2 (endometrial cancer and ovarian clear cell carcinoma) plans to enroll approximately 20 subjects in a single stage.