Camrelizumab Plus Nab-Paclitaxel and Carboplatin as First-Line Treatment for Extensive-Stage Small-Cell Lung Cancer (ES-SCLC): A Phase II Trial

Background: Immunotherapy (PD-1/PD-L1 antibody) combined with platinum-based chemotherapy has been established as the standard first-line treatment for extensive-stage small-cell lung cancer (ES-SCLC). Our previous study showed that nab-paclitaxel had promising efficacy as later line setting in ES-SCLC. This phase 2 trial aimed to evaluate the efficacy and safety of camrelizumab (PD-1 antibody) plus nab-paclitaxel and carboplatin as first-line treatment for ES-SCLC.Methods: Inclusion criteria included aged 18-75 years, histologically or cytologically confirmed ES-SCLC, ECOG performance status 0-1, no previous systematic treatment. Patients received 4~6 cycles of camrelizumab (200mg, D1, q3w) combined with nab-paclitaxel (230mg/m2, D1, q3w) plus carboplatin (AUC= 5, D1, q3w), followed by maintenance therapy with camrelizumab until disease progression or intolerable toxicity. The primary endpoint was 6-month progression-free survival (PFS) rate. Secondary endpoints included PFS, overall survival (OS), objective response rate (ORR), disease control rate (DCR) and safety.Results: From March 31, 2021 to December 14, 2022, a total of 60 patients were enrolled. All patients were included in the safety and efficacy analysis population. The 6-month PFS rate was 52.2% (95% CI: 39.8-68.5%) and the median PFS was 7.1 months (95% CI: 5.5–9.7 months). The median OS was 18.1 months (95% CI: 12.9–not reached months) and the 1-year OS rate was 68.4% (95% CI: 56.8-82.3%). The confirmed ORR was 73.3% (95% CI: 60.3-83.9%) and DCR was 93.3% (95% CI: 83.8-98.2%). The most common grade 3 or higher treatment-related adverse events (TRAEs) included neutrophil count decreased (31.7%), white blood cell count decreased (15.0%), platelet count decreased (13.3%), gamma-glutamyltransferase increased (10.0%) and blood bilirubin increased (10.0%). No unexpected adverse events were observed.Conclusion: Camrelizumab plus nab-paclitaxel and carboplatin demonstrated promising efficacy and a manageable safety profile as first-line treatment for ES-SCLC, which warranted further validation.Trial Registration: ClinicalTrials.gov identifier: NCT04790539.Funding: This study was funded by Jiangsu Hengrui Pharmaceuticals Co., Ltd. This study was supported by Shanghai Rising-Star Program (No. 23QA1408000). This study was supported in part by The Fujian Research and Training Grants for Young and Middle-aged Leaders in Healthcare (to XC).Declaration of Interest: The authors declare that they have no competing interests.Ethical Approval: This study was approved by the Ethics Committee of Shanghai Pulmonary Hospital (approval ID: L20- 446-1), and the study was conducted in accordance with the Declaration of Helsinki. All participants provided written informed consent upon enrollment.