A prospective phase II single-arm study and predictive factor analysis of irinotecan as third-line treatment in patients with metastatic gastric cancer.

Abstract

Currently, there is no recommended standard third-line chemotherapy for metastatic gastric cancer. In this study, we aimed to evaluate irinotecan's efficacy and safety in treating metastatic gastric cancer after the failure of first- and second-line chemotherapy. Prospective single-arm, two-center, phase II trial. Patients were aged 18-70 years, with histologically confirmed gastric adenocarcinoma and an Eastern Cooperative Oncology Group performance status of 0-1, progressed during or within 3 months following the last administration of second-line chemotherapy and had no other severe hematologic, cardiac, pulmonary, hepatic, or renal functional abnormalities or immunodeficiency diseases. Eligible patients received 28-day cycles of irinotecan (180 mg/m2 intravenously, days 1 and 15) and were assessed according to the RECIST 1.1 criteria every two cycles. Patients who discontinued treatment for any reason were followed up every 2 months until death. The primary endpoint was overall survival (OS), and the secondary endpoints were progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and toxicity. A total of 98 eligible patients were enrolled in this study. In the intention-to-treat population, the median OS was 7.17 months, the median PFS was 3.47 months, and the ORR and DCR were 4.08% and 47.96%, respectively. In the per-protocol population, the median OS was 7.77 months, the median PFS was 3.47 months, and the ORR and DCR were 4.82% and 50.60%, respectively. The incidence of grade 3 or 4 hematological and non-hematological toxicities was 19.4%, and none of the patients died owing to adverse events. Cox regression analysis revealed neutropenia and baseline thrombocyte levels were independently correlated with PFS and OS. Irinotecan monotherapy is an efficient, well-tolerated, and economical third-line treatment for patients with metastatic gastric cancer as a third-line treatment. ClinicalTrials.gov identifier: NCT02662959.