521PA randomized, phase II study comparing irinotecan versus amrubicin as maintenance therapy after first-line induction therapy for extensive disease small cell lung cancer (HOT1401/NJLCG1401)

Abstract Background Cisplatin plus irinotecan (PI) regimen is used for patients with extensive disease (ED)-SCLC. Amrubicin is mainly used for relapsed SCLC. HOT1401/NJLCG1401 trial, open-label randomized phase II trials was designed to assess the benefit of maintenance therapy in patients with ED-SCLC who responded induction therapy. Methods Eligible patients were aged 20-74 years; had histologically or cytologically confirmed, ED-SCLC. After induction therapy PI (P: 60mg/m2 on day 1, I: 60mg/m2 on days 1, 8, 15, every 4 weeks for 4 cycles), patients who attained CR, PR and SD were randomized to either maintenance irinotecan (I: 60mg/m2 on days 1, 8, every 3 weeks) or amrubicin (A: 35 mg/m2 on days 1-3 every 3 weeks). The primary endpoint is 6-months PFS rate. Results A total of 34 patients were enrolled from 2014 to 2017. Twenty patients had disease progression or incomplete of induction chemotherapy, finally 14 (41.1%) patients were randomly assigned to receive irinotecan (n = 7) and amrubicin (n = 7). This study was terminated prematurely because of low patient accrual. Of the evaluable patients (n = 34) the overall objective response rate was 73%, median progression free survival was 5.7 months (95% CI: 3.6 -11.8), and median overall survival was 20.1 months (95% CI: 13.7-NR). Six months PFS rate was 47 % (95%CI: 31.4-63.2). Sub group analysis showed the patients receive maintenance group showed longer PFS and OS than those without (15.8 months and 3.5 months, respectively p  Conclusions Maintenance therapy of irinotecan or amrubicin after induction therapy was well tolerated. Some patients might be effective for maintenance therapy. Clinical trial identification UMIN 000013882. Legal entity responsible for the study HOT/NJLCG. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.