This is a multi-center, open-label, Phase 1 clinical study of ZG006 in the US for the treatment of subjects with small cell lung cancer who have failed or are intolerant to available standard treatment. During the dose escalation stage, a standard "3+3" design will be used to assess the MTD/ recommended dose for the subsequent studies.

Inclusion Criteria:

• Small cell lung cancer (SCLC), who failed or intolerant to available standard treatments;
• Tissue sample positive for DLL3 expression;
• Life expectancy ≥ 3 months;
• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1;
• Female and Male patients must agree to use a reliable form of contraception during the study treatment period and for at least 6 months after the last dose of the study drug.

Exclusion Criteria:

• Patients having received any of the following treatments:

  • Chemotherapy, biotherapy, endocrine therapy (except for hormone replacement), and biological targeted medicines ≤ 4 weeks before the study entry. Local palliative radiotherapy and a small molecule targeted therapy ≤ 2 weeks (or 5 half-lives, whichever is longer) before the study entry;
  • Systemic immunosuppressive medications, such as corticosteroid (doses > 10 mg/day prednisone or equivalent dose) within 14 days prior to the study entry;
  • Use of any vaccines against viral infections (COVID-19, influenza, varicella, etc.) within 4 weeks of study entry;

• Patients received any blood transfusion, EPO, G-CSF, albumin infusion and renal replacement therapy within 14 days prior to study entry;

• A history of severe, life-threatening immune-mediated adverse events or infusion-related reactions during previous anti-tumor immunotherapy, including events that led to permanent discontinuation of treatment;

• Active infection (such as acute bacterial infection, tuberculosis, active hepatitis B/C, active syphilis, or active human immunodeficiency virus infection);

• Known allergy to other mAbs or any antibody excipients; the history of a severe allergic reaction, anaphylactoid or other hypersensitivity reactions to humanized antibodies or fusion proteins;

• A female who is pregnant or nursing;

• Patients were deemed unsuitable for participating in the study by the investigator for any reason.