Inclusion Criteria:
1. Subjects voluntarily agree to participate in the study and sign the Informed Consent Form (ICF).
2. 18 to 80 years of age at the time of signature of the ICF, without gender limitation.
3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
4. Life expectancy of ≥ 3 months as assessed by the investigator.
5. Women and men of childbearing potential must be advised and agree to practice effective methods of contraception during the study.
6. Understand study requirements, and willing and able to comply with arrangements of study and follow-up procedures.
7. Adequate Bone Marrow Reserve and Organ Functions.
8. Subjects must have measurable disease according to RECIST (version 1.1).
9. Histologically or cytologically confirmed advanced malignant solid tumors.
10. For non-urothelial carcinoma patients enrolled in the dose expansion study: Subjects must have a positive expression of Nectin-4 in their tumor samples as confirmed by the central laboratory.
11. Subjects are willing to follow study procedures.
Exclusion Criteria:
1. History of other malignancy(ies) within 3 years before signing the ICF, except for non-melanoma skin cancer, cervical carcinoma in situ, or other malignant tumors that are considered to have been cured.
2. Any anticancer therapy, including any investigational drug, within 2 weeks before the first dose of the study drug.
3. Uncontrolled central nervous system metastases.
4. Prior treatment with Nectin-4-targeting anti-cancer therapy.
5. Preexisting treatment-related toxicity Grade ≥ 2 (except alopecia).
6. Preexisting Grade ≥ 2 (as per CTCAE v5.0) sensory or motor neuropathy.
7. Major surgery within 4 weeks prior to the first dose of the study drug.
8. History of interstitial lung disease (ILD), preexisting ILD, or the suspected ILD that cannot be ruled out by imaging examination at screening.
9. Preexisting active keratitis or corneal ulcerations.
10. Preexisting serious dermatological diseases, or having experienced serious skin toxicities during the prior anti-cancer treatment (e.g., Stevens-Johnson syndrome, toxic Epidermal Necrolysis, etc.).
11. Currently receiving systemic antimicrobial treatment for active infection (viral, bacterial, or fungal) at the time of first dose of study drug, or fever within 14 days prior to the first dose of the study drug.
12. History of uncontrolled diabetes mellitus.
13. History of thromboembolic events and bleeding disorders ≤ 6 months (e.g.,deep vein thrombosis (DVT) or pulmonary embolism ( PE)) prior to the first dose of the study drug.
14. Positive results of virus serology tests.
15. History of serious cardiovascular and cerebrovascular diseases, including but not limited to:
1. Serious cardiac arrhythmias or conduction abnormalities, such as ventricular arrhythmia require treatment, and grade 2 or 3 atrioventricular block.
2. QTc prolongation to \>450 milliseconds (ms) in males and \>470 ms in females based on ECG.
3. Acute coronary syndrome, congestive heart failure, aortic dissection, stroke, or transient ischemic attack (TIA) within 6 months prior to the first dose of the study drug.
4. New myocardial infarction or unstable angina within 6 months before the first dose of the study drug.
5. Uncontrolled hypertension.
16. Require ongoing therapy with a medication that is a strong inhibitor or inducer of the cytochrome P450 3A4 (CYP3A4) enzymes.
17. Known sensitivity to any of the ingredients of the investigational product.
