Liposomal irinotecan + 5-fluorouracil + leucovorin + bevacizumab as second-line therapy in metastatic colorectal cancer (IRIS): A multi-center, single-arm, prospective, phase II study.

195 Background: In patients with advanced colorectal cancer (CRC), the recommended second-line treatment following first-line therapy with oxaliplatin-based regimens is irinotecan-based therapy. Liposomal irinotecan, a novel formulation of traditional irinotecan, has demonstrated potential to enhance efficacy while minimizing toxicity. This study aims to investigate the efficacy and safety of liposomal irinotecan in combination with 5-FU/LV and bevacizumab as a second-line treatment option for metastatic CRC. Methods: This is a multi-center, single-arm, prospective, phase II study. Patients with metastatic CRC who received oxaliplatin-based chemotherapy as first-line treatment were enrolled to receive liposomal irinotecan + 5-fluorouracil + leucovorin + bevacizumab regimen until disease progression and/or unacceptable toxicity. The primary endpoint is objective response rate (ORR), secondary endpoints include disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Results: A total of 50 patients were enrolled from Jan 2024 to Jul 2024 across 6 sites in China. The median age was 56.5 years (range: 30.0-76.0), with 58.0% male and 36.0% ECOG 0. Among the patients, 38.0% had left-sided colon cancer, 24.0% had right-sided colon cancer, and 38.0% had rectal cancer. As of Sept 14, 2024, 39 patients had at least one tumor assessment and 19 patients were still on treatment. ORR and DCR were 20.5% (8/39, 95% CI: 9.3%-36.5%) and 84.6% (33/39, 95% CI: 69.5%-94.1%), respectively. Eleven patients had disease progression and 5 patients died, and the median PFS and OS were not reached. The relative dose intensity of liposomal irinotecan and 5-fluorouracil were 92.8% (range: 23.6%-109.6%) and 89.5% (range: 13.3%-116.8%), respectively. During treatment, 43 (86.0%) patients had at least one adverse event (AE) and 24 (48.0%) had grade 3-4 AE. Most common (≥ 10%) grade 3-4 AEs were neutropenia (20.0%), leukocytopenia (16.0%) and diarrhea (10.0%). No unexpected toxicities observed in this study. Conclusions: These preliminary results reveled that liposomal irinotecan + 5-fluorouracil + leucovorin + bevacizumab after oxaliplatin-based treatment for metastatic CRC was well tolerated with encouraging clinical activity, which warrants further follow up. Clinical trial information: NCT06184698 .