Randomized Phase II Clinical Study of Liposomal Irinotecan or Etoposide Combined With Carboplatin and Serplulimab as First-line Treatment for Extensive Stage Small Cell Lung Cancer

Lung cancer is a malignant tumor with high incidence and mortality in China and the world, among which small cell lung cancer (SCLC) accounts for 13% to 17% of lung cancer, and about 250,000 patients are diagnosed with SCLC every year in the world, and nearly 200,000 people die from it. Due to the high degree of malignancy of SCLC, it is easy to develop distant metastasis in the early stage, and most of the patients are diagnosed in the late stage with poor prognosis. Although SCLC is sensitive to chemotherapy and radiotherapy and has a high remission rate after initial treatment, it is prone to secondary drug resistance and relapse. SCLC is a low-differentiated, high-grade neuroendocrine tumor that can be classified into limited-stage and extensive stage (ES-SCLC). Etoposide combined with cisplatin (EP regimen) or carboplatin (EC regimen), irinotecan combined with cisplatin (IP regimen) or carboplatin (IC regimen) are the basis of standard first-line therapy for ES-SCLC. Immunocombined chemotherapy has also become the first-line standard treatment for ES-SCLC, among which serplulimab + etoposide + carboplatin is recommended by CSCO guidelines for first-line treatment. Liposomal irinotecan is irinotecan encapsulated by liposomes, which has advantages in safety. The study is expected to achieve good efficacy, improve the quality of life and prolong the survival of patients by combining the immune drug serplulimab on the basis of IC regimen. After replacing ordinary irinotecan with liposomal irinotecan, this study aims to compare the efficacy and safety of liposomal irinotecan + carboplatin + serplulimab with the first-line standard regimen (etoposide + carboplatin + serplulimab) in patients with extensive stage small-cell lung cancer, providing a better basis for clinical use.

Trial design: This is a multicenter, open-label, non-comparative, randomized Phase II clinical study. Sixty patients with extensive stage small cell lung cancer were expected to be enrolled and randomly assigned 1:1 to either liposomal irinotecan + carboplatin + serplulimab or etoposide + carboplatin + serplulimab for treatment. The study included a screening period (within 28 days), a treatment period (4 cycles planned), and a follow-up period (safety follow-up and PFS follow-up). Subjects signed informed consent and underwent baseline examination during the screening period. Patients who met the inclusion and exclusion criteria entered the treatment period. All subjects completed relevant examinations specified in the protocol during treatment to observe safety, tolerability and efficacy. The same subject received only one dosing schedule during the study. After the treatment period, the follow-up period was entered.

Treatment regimen: Cohort 1: Liposomal irinotecan: 50mg/m2, ivgtt, d1; Carboplatin AUC=5, ivgtt, d1; Serplulimab: 4.5mg/kg, ivgtt, d1; The drug was administered once every three weeks for a total of 4 cycles. After 4 cycles, serplulimab is maintained until disease progression or toxicity becomes intolerable. Cohort 2: Etoposide: 100 mg/m2, ivgtt, d1-3; Carboplatin AUC=5, ivgtt, d1; Serplulimab: 4.5mg/kg, ivgtt, d1; The drug was administered once every three weeks for a total of 4 cycles. After 4 cycles, serplulimab is maintained until disease progression or toxicity becomes intolerable.

Endpoint: Primary endpoint: Progression-free survival (PFS). Secondary endpoints: Objective response rate (ORR), disease control rate (DCR), overall survival (OS), and outcome in brain metastases (PFS).

Safety endpoints: Incidence and severity of hematologic and nonhematologic adverse events (NCI-CTCAE5.0).