Abstract
BACKGROUND: Patients with primary refractory and relapsed neuroblastoma have a poor prognosis since safe and effective chemotherapies for these patients are currently limited. The development of new chemotherapy regimens for these patients is imperative to improve survival outcomes. METHODS: We retrospectively analyzed 40 patients with refractory (n = 36) or relapsed (n = 4) neuroblastoma who received irinotecan, etoposide, and carboplatin (IREC) as a second-line treatment. We evaluated their therapeutic response and the toxicity of IREC. We also assessed the impact of UGT1A1 gene polymorphisms, which are involved in irinotecan metabolism, on outcomes and toxicity. RESULTS: A total of 112 cycles of IREC were administered to 40 patients with a median of 2 cycles per patient (range, 1-9). Six (15%) patients (UGT1A1 wild-type [n = 2] and heterozygous [n = 4]) showed objective responses, including partial response (n = 1), tumor shrinkage (n = 4), and improved findings on their MIBG scan (n = 1). Grade 4 neutropenia, grade 4 leukopenia, and grades 3-4 gastrointestinal toxicity were observed in 110 (98%), 88 (79%), and 3 (3%) cycles, respectively. There was no IREC-related mortality. Patients with UGT1A1 polymorphisms showed a higher frequency of grade 4 leukopenia, but these patients did not have increased treatment-related mortality or non-hematologic toxicity. CONCLUSIONS: IREC showed an objective response rate of 15% including 1 case with partial response. IREC was well tolerated regardless of UGT1A1 genotype. This study suggests that IREC is a promising second-line chemotherapy for refractory or relapsed neuroblastoma.