Randomized Phase III Study of Irinotecan Plus Cisplatin Versus Etoposide Plus Cisplatin for Completely Resected High-Grade Neuroendocrine Carcinoma of the Lung: JCOG1205/1206.

Abstract

To verify the superiority of irinotecan plus cisplatin over etoposide plus cisplatin as postoperative adjuvant chemotherapy for patients with pathologic stage I-IIIA, completely resected, high-grade neuroendocrine carcinoma (HGNEC) of the lung. This was a randomized, open-label, phase III study on patients with completely resected stage I-IIIA HGNEC of the lung. They were randomly assigned to receive either etoposide (100 mg/m², days 1-3) plus cisplatin (80 mg/m², day 1) or irinotecan (60 mg/m², days 1, 8, 15) plus cisplatin (60 mg/m², day 1) up to four cycles. The primary end point was relapse-free survival (RFS) in the intention-to-treat population. This trial was registered with the Japan Registry of Clinical Trials (jRCTs031180216). Between April 2013 and October 2018, 221 patients were enrolled (etoposide plus cisplatin arm, 111 patients; irinotecan plus cisplatin arm, 110 patients). In the second interim analysis, early termination of the trial was recommended because of futility. At a median follow-up of 24.1 months, the 3-year RFS was 65.4% for etoposide plus cisplatin and 69.0% for irinotecan plus cisplatin, with a hazard ratio of 1.076 (95% CI, 0.666 to 1.738; one-sided log-rank <i>P</i> = .619). Grade 3-4 adverse events were more frequent in the etoposide plus cisplatin arm, with febrile neutropenia (20% of 109 patients <i>v</i> 4% of 107 patients) and neutropenia (97% <i>v</i> 36%) being the most common. Meanwhile, grade 3-4 anorexia (6% <i>v</i> 11%) and diarrhea (1% <i>v</i> 8%) were more frequently observed in the irinotecan plus cisplatin arm. Irinotecan plus cisplatin is not superior to etoposide plus cisplatin for improving RFS in patients with completely resected HGNEC; thus, etoposide plus cisplatin remains the standard treatment.