A Phase 1 Study to Evaluate the Safety, Efficacy, and Pharmacokinetics of YL201 in Advanced Solid Tumors

Inclusion Criteria:

1. Informed of the study before the start of the study and voluntarily sign theirname and date on the informed consent form (ICF).

2. Subjects will be enrolled in the dose-escalation phase: Advanced solid tumors,like NPC, SCLC and etc.

3. Subjects will be enrolled in the dose-expansion phase: NPC, SCLC, NSCLC andother advanced cancer.

4. According to the Response Evaluation Criteria in Solid Tumors (RECIST) v1.1,there must be at least one extracranial measurable lesion.

5. Archived or fresh tumor tissue samples can be provided. 6) Within 7 days beforethe first dose, organ and bone marrow functions must meet the requirements.

6. Eastern Cooperative Oncology Group performance status (ECOG PS) score of 0 or 1by the United States of America standards.

7. Female subjects of childbearing potential must agree to use highly effectivecontraception measures from screening throughout the duration of the study andfor at least 6 months after the last dose of the study drug. Male subjects mustagree to use highly effective contraception measures from screening throughoutthe duration of the study and for at least 6 months after the last dose of thestudy drug.

8. Subjects with expected survival ≥ 3 months. 10) Capable and willing to complywith the study protocol's scheduled visits and procedures.

Exclusion Criteria:

1. Suitable for local radical treatment. 2) Previous Drug therapy targeting B7H3.

2. Previous Drug therapy with topoisomerase I inhibitors or ADCs composed oftopoisomerase I inhibitors.

3. Prior treatment with anti-PD-(L)1, other immune checkpoint inhibitors, immunecheckpoint agonists, or immunocellular therapies and other therapies targetingtumor immunity mechanisms.

4. Toxicity from previous anticancer treatments has not resolved. 6) Concurrentenrollment in another clinical study. 7) Inadequate washout period for prioranticancer treatment before the first dose of study drug.

5. Underwent major surgery (excluding diagnostic surgery) or suffered serioustrauma.

6. Received allogeneic stem cell or solid organ transplant. 10) Active autoimmunediseases requiring systemic treatment. 11) Received systemic steroids. 12)Metastases to meninges or carcinomatous meningitis. 13) Brain metastasis orspinal cord compression. 14) Uncontrolled or clinically significantcardiovascular disease. 15) Clinically significant concomitant pulmonarydisease. 16) With uncontrolled third-space fluid. 17) History ofgastrointestinal perforation and / or fistula within 6 months prior to thefirst dose.

7. Serious Infection prior to the first dose. 19) Known human immunodeficiencyvirus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) infection.

8. Any other primary malignancy before the first dose of study drug. 21) A historyof severe hypersensitivity reactions to the investigational product, inactiveingredients in the formulation, or other monoclonal antibodies.

9. Women who are breastfeeding or pregnant as confirmed by pregnancy testsperformed within 3 days before the first dose.

10. Any illness, medical condition, organ system dysfunction, or social situation.