Adebrelimab Plus Apatinib for Maintenance Therapy of Extensive Stage Small Cell Lung Cancer

Inclusion Criteria:

1. Participants voluntarily enrolled in this study and signed an informed consent form,were compliant and co-operated with follow-up visits;

2. Age 18 years and above, male and female;

3. Diagnosis of extensive stage small cell lung cancer (ES-SCLC) confirmed by histologyor pathology (according to the American Veterans Lung Cancer Association, VALGstage);

4. ECOG physical condition score is 0-2;

5. Subjects have not received systematic treatment for ES-SCLC in the past (includingchemotherapy, VEGFR inhibitors and immune checkpoint inhibitors, etc.)

6. Patients with limited stage small cell lung cancer (LS-SCLC) who have receivedradiotherapy, chemotherapy or radiochemotherapy require a treatment-free period ofmore than 6 months. Patients with asymptomatic brain metastases are allowed to havecranial radiotherapy during induction chemotherapy;

7. Life expectancy >= 3 months;

8. There must be a measurable target lesion that meets the RECIST 1.1 criteria (CT scanlength of the tumour lesion >10mm);

9. The function of major organs is normal, that is, the following criteria are met.

• Blood routine (not transfused, not using haematopoietic factors and notcorrected with drugs within 14 days): ANC ≥ 1.5 x 109/L; HB ≥ 90 g/L; PLT ≥ 100 × 109/L;

• Biochemical tests: TBIL ≤ 1.5ULN; TBIL ≤ 1.5 ULN; ALT, AST ≤ 2.5 ULN;

• Renal function: Serum creatinine (Cr) ≤ 1.5 x ULN or creatinine clearance ≥ 40mL/min. (apply the standard Cockcroft-Gault formula):

• Coagulation function must meet: INR ≤ 1.5 and APTT ≤ 1.5 ULN;

10. Females of childbearing potential must have a negative serum or urine pregnancy testwithin 72 hours prior to the first dose. Female subjects of childbearing potentialand male subjects whose partner is a female of childbearing potential must agree touse a highly effective method of contraception and breastfeeding for the duration ofthe study up to 90 days after the last administration of study drug. TheInvestigator or his/her designee, in consultation with the subject, will be requiredto confirm that the subject has knowledge of how to properly and consistently usethe contraceptive method;

11. For males, surgical sterilisation or agreement to use a highly effective method ofcontraception for the duration of the trial and for 90 days after the finaladministration of study drug;

12. For female participants, agreement to refrain from breastfeeding for the duration ofthe study or for 180 days after the last dose of study treatment is required.

Exclusion Criteria:

1. Patients with meningeal metastases;

2. Prior treatment with any T-cell co-stimulation or immune checkpoint therapy,including, but not limited to, cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4)inhibitors, PD-1 inhibitors, PD-L1/2 inhibitors, CD137 agonists, or other agentsthat target T cells;

3. Prior treatment with apatinib;

4. Factors affecting oral administration of medications such as inability to swallow,post gastrointestinal resection, chronic diarrhoea, intestinal obstruction;

5. Any active autoimmune disease or history of autoimmune disease (e.g., uveitis,enteritis, hepatitis, pituitary gland inflammation, vasculitis, myocarditis,nephritis, hyperthyroidism, hypothyroidism (may be included after hormonereplacement therapy), tuberculosis); and skin disorders (e.g., vitiligo, psoriasis,or alopecia) in which asthma has been in complete remission in childhood and hasrequired no intervention in adulthood or in which systemic therapy is not required.or alopecia areata) may be included; patients requiring medical intervention withbronchodilators may not be included;

6. Patients with congenital or acquired immune function defects such as humanimmunodeficiency virus (HIV) infection, active hepatitis B (HBV DNA ≥ 500 IU/ml),hepatitis C (hepatitis C antibody positive with HCV-RNA above the lower limit ofdetection of the analytical method), or co-infection with both hepatitis B andhepatitis C;

7. Urine routine suggesting urinary protein ≥ (++), or 24h urine protein amount ≥ 1g orsevere hepatic or renal insufficiency;

8. Subjects requiring systemic therapy with corticosteroids (>10 mg/day of prednisoneor equivalent) or other immunosuppressive agents within 14 days prior to first dose.Inhaled or topical corticosteroids and adrenal hormone replacement therapy at doses > 10 mg/day prednisone efficacy dose are permitted in the absence of activeautoimmune disease;

9. Subjects who have been treated with antitumour vaccines or other antitumour agentswith immunostimulatory effects (interferon, interleukin, thymidine, immune celltherapy, etc.) within 1 month prior to the first dose;

10. Concomitant other malignancies ≤5 years prior to enrolment, except adequatelytreatable carcinoma in situ of the cervix, basal cell or squamous epithelial cellskin cancer, localised prostate cancer after radical surgery, and ductal carcinomain situ after radical surgery;

11. Evidence of previous or current pulmonary fibrosis, interstitial pneumonitis,pneumoconiosis, radiographic pneumonia, drug-induced pneumonia, active pneumoniaconfirmed by imaging, and severely impaired lung function;

12. Uncontrolled hypertension (systolic blood pressure ≥ 140 mmHg or diastolic bloodpressure ≥ 90 mmHg despite optimal pharmacological treatment);

13. Myocardial ischaemia or myocardial infarction of class II or greater, poorlycontrolled arrhythmias (including QTc intervals ≥450 ms in men and ≥470 ms inwomen). Myocardial infarction, New York Heart Association class II or higher heartfailure, uncontrolled angina pectoris, uncontrolled severe ventricular arrhythmia,clinically significant pericardial disease, or electrocardiogram suggestive of acuteischaemia or active pericardial disease, within 6 months prior to enrolment,according to NYHA criteria, class III-IV cardiac insufficiency or cardiac ultrasoundsuggestive of a left ventricular ejection fraction (LVEF) of < 50% conduction systemabnormalities;

14. Complicated severe infection within 4 weeks prior to first dose or unexplained fever >38.5°C during screening/prior to first dose;

15. Major surgery, open biopsy or significant trauma within 28 days prior to enrolment;

16. An arterial/venous thrombotic event within 6 months;

17. A significant risk of coughing up blood, bleeding events, or perforation as assessedby the investigator;

18. Known history of allogeneic organ transplantation or allogeneic haematopoietic stemcell transplantation;

19. Pregnant or lactating women; patients of childbearing potential who are unwilling orunable to use effective contraception;

20. Known hypersensitivity, hypersensitivity or intolerance to adebelizumab, apatinib,chemotherapeutic agents or their excipients;

21. Any condition which, in the opinion of the Investigator, may be detrimental to thesubject or result in the subject's inability to meet or perform the requirements ofthe study.