Efficacy and safety of liposomal irinotecan combined with cadonilimab as second-line treatment for extensive-stage small cell lung cancer (ES-SCLC): A prospective, single arm phase II clinical study.

e20104 Background: ES-SCLC proliferates rapidly and has a poor prognosis. 60% -70% of SCLC patients (pts) are diagnosed as ES-SCLC. At present, the available treatment options for second-line treatment of ES-SCLC are relatively limited. Liposomal irinotecan, as a new drug delivery system, offers enhanced tumor targeting, prolonged drug release, reduced adverse events, and improved cellular affinity. The results of previous study suggest that liposomal irinotecan exhibited promising clinical efficacy and manageable safety profiles in pts with relapsed SCLC. In addition, immune checkpoint inhibitors have shown strong activity on ES-NCLC. This study aims to explore the efficacy and safety of liposomal irinotecan and cadonilimab in second-line ES-SCLC. Methods: This is a prospective, single center phase II clinical study (ChiCTR2400087003) that enrolled ES-SCLC pts who had previously received first-line treatment. Eligible pts received 4-6 cycles of combination therapy with liposomal irinotecan (70mg/m 2 , Q3W) and cadonilimab (10mg/kg, Q3W), followed by maintenance therapy with cadonilimab (not exceeding 1 year). The primary endpoint was objective response rate (ORR, RECIST 1.1), while the secondary endpoints included disease control rate (DCR, RECIST 1.1), progression free survival (PFS), 1-year overall survival rate (1y-OS rate), and safety. Results: As of January 8, 2025, a total of 13 pts (median age, 64; male, 84.6%, 11/13) with previously treated ES-SCLC have been enrolled. Among them, 7 pts (53.8%) with ECOG of 1, over half had a history of smoking (69.2%, 9/13), 12 pts (92.3%) with clinical stage IV, 8 pts (61.5%) with lymph node metastasis, 5 pts (38.5%) with liver metastasis, 5 pts (38.5%) with brain metastasis, 2 pts (15.4%) with bone metastasis, and 1 pts (7.7%) with adrenal metastasis, respectively. In terms of efficacy, among the 12 evaluable pts, there were 6 pts (50.0%) with the best therapeutic effect for PR, 6 pts (50.0%) with SD; the ORR and DCR were 50.0 and 100.0%, respectively. The median PFS and the median OS has not yet been reached. With regard to safety, 76.9% (10/13) of pts observed adverse events (AEs), with the common AEs being diarrhea (53.8%, 7/13), white blood cell count decreased (53.8%, 7/13), and anemia (23.1%, 3/13). The incidence of grade 3 adverse events was 15.4% (2/13), including grade 3 diarrhea. Conclusions: The preliminary results indicate that the combination of liposomal irinotecan and cadonilimab as a second-line treatment for ES-SCLC shows potential efficacy and tolerable safety, and is worthy of further exploration and research. Clinical trial information: ChiCTR2400087003 .