A Study on the Efficacy of Disitamab Vedotin in Advanced HER2-positive Paget's Disease.

RC48 at a dosage of 2mg/kg administered intravenously every 3 weeks (ivgtt q3w) is continued until disease progression, with the allowance for treatment discontinuation due to disease progression, death, intolerable toxicity, withdrawal of informed consent, initiation of new antineoplastic therapy, or other reasons specified in the protocol, with the earliest occurring event taking precedence. Alternatively, the study investigator may determine the need to discontinue treatment.