Irinotecan plus temozolomide for pediatric relapsed or refractory solid tumors: a retrospective cohort study.

BACKGROUND

Relapsed or refractory pediatric solid tumors carry a poor prognosis, and effective salvage therapies are limited. The combination of irinotecan and temozolomide (IT) has shown promise in early studies, but real‑world data in Chinese pediatric populations are lacking. This study aims to evaluate the efficacy and safety of the IT regimen in children with recurrent or refractory solid tumors.

METHODS

This single‑center retrospective cohort study included 86 pediatric patients with relapsed or refractory malignant solid tumors treated at Beijing Jingdu Children's Hospital (March 2021-March 2025). Inclusion criteria were pathologically confirmed recurrence/progression, adequate organ function, and no prior IT therapy. Patients received irinotecan (50 mg/m2/day, intravenous, days 1-5) and temozolomide (100-150 mg/m2/day, oral, days 1-5) in 21‑day cycles. Tumor response was assessed every two cycles using RECIST 1.1. Primary endpoints were objective response rate (ORR) and progression‑free survival (PFS); secondary endpoints were disease control rate (DCR), overall survival (OS), and safety. Survival was estimated by Kaplan‑Meier with time zero set to IT initiation.

RESULTS

Of 86 patients (median age 7 years, range 1-18 years; 52 neuroblastoma), the median number of prior chemotherapy lines was 3 (range 1-7). ORR was 23.3% [95% confidence interval (CI): 15.1-33.6%] and DCR 52.4% (95% CI: 41.3-63.3%). For neuroblastoma (n=52), ORR was 31.0% (95% CI: 19.5-44.5%) and DCR 67.3% (95% CI: 53.7-78.8%). Median PFS was 5.5 months (95% CI: 3.8-8.1) and median OS 9.8 months (95% CI: 6.5-14.2). The 1‑year OS rate was 36.8% (95% CI: 27.5-49.4%) and 1‑year PFS rate 22.4% (95% CI: 14.7-34.4%). Grade III-IV adverse events included neutropenia (25.2% of cycles), thrombocytopenia (26.0%), diarrhea (3.6%), and liver dysfunction (4.0%). No treatment‑related deaths occurred.

CONCLUSIONS

The IT regimen demonstrates clinical activity and was found to be tolerable in this cohort. These findings are hypothesis‑generating and warrant confirmation in prospective controlled studies.