ARTEMIS-008：HS-20093 Compared With Topotecan in Subjects With Relapsed Small Cell Lung Cancer

Inclusion Criteria:

1. Male or female subjects ≥18 years of age.

2. Histologically or cytologically confirmed SCLC.

3. Subjects who progressed on or after first-line platinum-based regimens.

4. Has at least 1 measurable lesion as defined per RECIST 1.1.

5. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.

6. Minimum life expectancy of more than 12 weeks.

7. Females subjects must not be pregnant at screening or have evidence ofnon-childbearing potential.

8. Men or women should be using adequate contraceptive measures throughout the study.

9. Subject has provided informed consent/assent prior to initiation of any studyspecific activities/procedures.

Exclusion Criteria:

1. Combined SCLC, any previous diagnosis of transformed SCLC or SCLC that hastransformed to NSCLC.

2. Chemotherapy-free interval ≤30 days.

3. Has received prior treatment with anti-B7 homologue 3 (B7-H3) targeted agents.

4. Has received prior treatment with topoisomerase I inhibitor, including ADC thatconsists of topoisomerase I inhibitor.

5. Has inadequate washout period before randomization as specified in the protocol.

6. Untreated or symptomatic brain metastases with exceptions defined in the protocol.

7. Unresolved toxicity from prior anti-tumor therapy, defined as not having resolved toCommon Terminology Criteria for Adverse Events (CTCAE) version 5.0 grade 1 withexceptions defined in the protocol.

8. History of other malignancy with exceptions defined in the protocol.

9. Inadequate bone marrow reserve or organ dysfunction.

10. Evidence of cardiovascular risks.

11. Severe, uncontrolled or active cardiovascular diseases.

12. Severe or uncontrolled diabetes.

13. Severe or uncontrolled high blood pressure.

14. Clinically significant bleeding or obvious bleeding tendency within 1 month beforerandomization.

15. Severe arterial or venous thromboembolic events within 3 months prior torandomization.

16. Severe infections within 4 weeks before randomization.

17. Receiving systemic corticosteroid therapy within 30 days prior to randomization withexceptions defined in the protocol.

18. The presence of active infectious diseases before randomization.

19. Current hepatic encephalopathy, hepatorenal syndrome, or Child-Pugh Grade B or moresevere cirrhosis.

20. History of interstitial lung disease, immunotherapy-induced pneumonitis, clinicallymoderate or severe pulmonary disease.

21. History of severe neuropathy or mental disorders.

22. Female subjects of childbearing potential; female subjects who are breastfeeding orwho plan to breastfeed while on study; female subjects planning to become pregnantwhile on study.

23. Vaccination or hypersensitivity of any level within 4 weeks before randomization.

24. History of severe hypersensitivity reaction, severe infusion reaction or allergy torecombinant human or mouse derived proteins.

25. Hypersensitivity to any ingredient of HS-20093, DNA topoisomerase I inhibitor orregimens of Topotecan.