This is a multicenter, open-label, multiple-dose dose finding and expansion study to evaluate the safety, tolerability, pharmacokinetic(PK) profile, and anti-tumor efficacy of SKB445 for injection in patients with advanced solid tumors.

This is an open-label, dose-escalation, multicenter study to evaluate the safety, tolerability, PK characteristics, immunogenicity, and preliminary anti-tumor activity of SKB445 monotherapy in patients with advanced solid tumors.

Inclusion Criteria:

1. At the time of signing the ICF: age between 18 -75 years, male or female.
2. subjects with histologically or cytologically confirmed locally advanced or metastatic solid tumors who have failed/are intolerant/ineligible to or do not have standard therapy, and have at least one measurable lesion meeting Response Evaluation Criteria in Solid Tumors (RECIST v1.1).
3. Eastern Cooperative Oncology Group (ECOG) score of 0 to 1.
4. Expected survival ≥ 3 months.
5. Subjects with adequate organ and bone marrow function confirmed by laboratory results
6. Subjects of childbearing potential (male or female) must use effective medical contraception during the study
7. Ability to understand and willingness to sign ICF, and will be able to comply with the protocol-specified visits and relevant procedures.

Exclusion Criteria:

1. Has received anti-tumor therapy, including chemotherapy, targeted therapy, tumor immunotherapy, and traditional Chinese medicinal products with anti-tumor indications, within 4 weeks prior to the first dose or within 5 half-lives of known drugs (whichever is shorter).
2. Has had major surgery within 4 weeks prior to the first dose.
3. Has known history of allergy to any component of SKB445 or SKB445.
4. Has a known previous or concurrent other malignancies within 3 years prior to first dose.
5. Presence of active central nervous system (CNS) metastases.
6. Has uncontrolled or severe cardiovascular disease.
7. Has uncontrolled systemic diseases.
8. Has human immunodeficiency virus (HIV) infection; has any active viral hepatitis.
9. Subjects with a known history of psychiatric illness or drug abuse that would preclude the subject from complying with the study.
10. Has prior autologous/allogeneic hematopoietic stem cell transplantation or solid organ transplantation.
11. Has any other conditions such as medical history, treatment and laboratory abnormalities that may confound the study results, interfere with the subject's compliance, or impair the subject's interests, as assessed by the investigator or the sponsor.