Amrubicin monotherapy for patients with extrapulmonary neuroendocrine carcinoma after platinum-based chemotherapy

Purpose: Extrapulmonary neuroendocrine carcinomas (EPNEC) are rarely observed and are associated with poor outcomes. Based on the clinicopathological similarity, treatment used for small cell lung carcinoma has also been employed for EPNEC, but the response to such therapy has not been well examined. The goal of this study was to investigate amrubicin (AMR) monotherapy as a salvage therapy for EPNEC arising from digestive organs. Methods: Patients with EPNEC of the digestive organs who had prior platinum-based chemotherapy and were subsequently treated with AMR between July 2005 and December 2013 at any one of four institutions were retrospectively examined to characterize the safety and efficacy of AMR. Results: Thirteen patients (ten males, three females; median age 64 years) were examined. Primary cancer sites included stomach (n = 6), rectum (n = 3), esophagus (n = 2), liver (n = 1) and pancreas (n = 1). Prior irinotecan- and etoposide-containing chemotherapies were used in ten and six patients, respectively. Median initial dose of AMR was 40 mg/m²/day for three consecutive days, and median of treatment cycles was 4 (range 1-9). The objective response rate (ORR) was 38.5 %. Median progression-free survival (PFS) and overall survival (OS) were 107 (range 22-275) and 215 days (range 71-535), respectively. Common severe adverse events (grade 3/4) were neutropenia (84.6 %) and febrile neutropenia (30.8 %). Patient with longer platinum-free interval (>90 days) exhibited longer PFS and OS than those with shorter platinum-free interval (190 vs. 63 days and 348 vs. 145 days, respectively). Conclusions: AMR showed evidence of clinical activity and safety when used for the treatment of EPNEC. It might be especially useful for populations with sensitive relapse.