To Evaluate the Safety and Tolerability of JSKN003 in Chinese Subjects With Advanced Solid Tumors

1. Subject is at least 18 years old, male or female, and willing to follow the study procedure on the date of signing the informed consent;

2. ECOG score 0 or 1, expected survival ≥12 weeks;

3. Unresectable locally advanced or metastatic solid tumors with pathologic documented confirmation.

4. Measurable lesions at baseline according to RECIST 1.1 criteria; If the subject has only one measurable lesion at baseline, the lesion area must not have received prior radiotherapy or there is evidence of significant progression after the end of radiotherapy.

5. Agrees to provide adequate paraffin sections or fresh tissue specimens of the tumor for testing;

6. Laboratory tests within 7 days or cardiac ultrasound within 28 days prior to the first dose meet the protocol criteria.

7. Adequate washout from prior therapy prior to the first dose.

8. A fertile female subject or a fertile male subject with a+B72 fertile partner agrees to use highly effective contraception (annual failure rate less than 1%) from the time of initial dosing to 180 days after the end of dosing. Pregnancy test results must be negative for fertile female subjects within 7 days prior to initial administration (fertile women are defined as premenopausal women with no recorded tubal ligation or hysterectomy, or women who have been menopausal for less than 1 year);

1. Subjects with untreated active brain metastases or meningeal metastases；

2. Previous history of other primary malignant tumors;

3. Previously received topoisomerase I inhibitor antibody conjugate drug;

4. Has uncontrolled comorbidities as specified by the protocol；

5. Past or current history of interstitial pneumonia/lung disease requiring systemic hormonal therapy, or suspected interstitial pneumonia/lung disease that cannot be ruled out by imaging during screening;

6. Subjects with uncontrolled large serous cavity effusion or moderate to large serous cavity effusion requiring repeated drainage (recurrent within 2 weeks after intervention) such as pleural effusion, pericardial effusion, ascites, bad fluid, etc.;

7. Toxicity of previous antitumor therapy did not return to class 1 as defined by NCI-CTCAE v5.0.

8. Systemic corticosteroids (≥10 mg/ day of prednisone, or equivalent of other corticosteroids) or immunosuppressant therapy were required within 14 days prior to initial administration in this study; 9. Has a history of life-threatening anaphylaxis or known hypersensitivity to any component or excipient in the JSKN003 drug formulation.

10. Previous history of trastuzumab-induced anaphylaxis (grade ≥3), angioedema, or severe hypotension.

11. Subjects with gastrointestinal tumors who are known to have lost 10% or more of their body weight within three months prior to signing the informed consent form.

12. Other conditions that the investigator considers unsuitable to participate in this clinical trial, including but not limited to psychiatric disorders, alcoholism or drug abuse, etc.