Irinotecan for pediatric solid tumors: the Memorial Sloan-Kettering experience

Irinotecan is a novel antineoplastic agent that works by inhibiting the enzyme, topoisomerase 1. Although not extensively studied in children, preclinical studies and several phase I trials indicate activity against a variety of relapsed solid tumors when administered on a protracted schedule. This report describes an institutional experience with irinotecan for the treatment of pediatric solid tumors.

Twenty-two heavily pretreated children with multiply relapsed tumors were treated with courses of irinotecan at 20 mg/m2 per day for 10 days [(every day x 5) x 2].

Of the 19 patients evaluable for response, four achieved an objective response, including two complete responses and one partial response among four patients with rhabdomyosarcoma and one additional patient with an undifferentiated sarcoma with rhabdomyoblastic features, and one patient with a fibrosarcoma had stable disease. Among three patients with non-Hodgkin lymphoma, one achieved a partial response and one had stable disease. Diarrhea was the most commonly observed toxicity.

Irinotecan appears to have promising single-agent activity, particularly against rhabdomyosarcoma. with minimal hematopoietic toxicity, making it ideal for further evaluation in patients at high risk with newly diagnosed disease, particularly in combination with other active agents with nonoverlapping toxicities.