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

PURPOSE: 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.

METHODS

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).

RESULTS

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 P = .619). Grade 3-4 adverse events were more frequent in the etoposide plus cisplatin arm, with febrile neutropenia (20% of 109 patients v 4% of 107 patients) and neutropenia (97% v 36%) being the most common. Meanwhile, grade 3-4 anorexia (6% v 11%) and diarrhea (1% v 8%) were more frequently observed in the irinotecan plus cisplatin arm.

CONCLUSION

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.