Phase I-II, FIH, TROP2 ADC, Advanced Unresectable/Metastatic Solid Tumors, Refractory to Standard Therapies (KL264-01)

This is an open label, Phase I-II, first in human (FIH) study for SKB264 as monotherapy in patients who have locally advanced unresectable or metastatic solid tumor that is refractory to all standard therapies. TROP2 (trophoblast antigen 2) assessments will not be performed prior to enrollment but it will be assessed retrospectively. Confirmation of TROP2 (trophoblast antigen 2) expression by immunohistology or other means is not required, but the Sponsor will request fresh tumor biopsy or tissue specimens from archived materials for determination of TROP2 (trophoblast antigen 2) expression retrospectively. The patient must be, in the judgment of the investigator, an appropriate candidate for experimental therapy whose tumor is refractory to standard therapies. Patients will receive study drug as a single IV infusion at the prescribed dose level at each administration. Cycles will continue until disease progression or unacceptable toxicity. The study is divided into 2 parts (Phase I and Phase II).