Background: Irinotecan (CPT-11) is a novel antineoplastic agent that takes effect by inhibiting topoisomerase I. The Italian Soft Tissue Sarcoma (STS) Committee performed a multiinstitutional Phase II study to evaluate its effect on STS.
Methods: Over a 2-year period between 2002 and 2004, 32 heavily pretreated patients were administered 60-minute infusions of irinotecan at 20 mg/m2/day, for 5 days a week, for 2 consecutive weeks. The courses were repeated every 4 weeks for at least 2 courses, unless there were signs of toxicity or disease progression. Thirty patients, 13 with peripheral primitive neuroectodermal tumor (PNET), 12 with rhabdomyosarcoma (RMS), 3 with desmoplastic small round cell tumor (DSRCT), and 2 with other STS were evaluable for response.
Results: A total of 79 cycles were delivered. The main regimen-related toxicity was diarrhea, occurring in 58% of cycles with 9 episodes graded as 3 or 4. Grade 3-4 neutropenia was recorded in 10% of cycles. The overall response rate was 23% (2 complete remissions +5 partial remissions of 30 patients), 38% for PNET and 16% for RMS. In addition, 4 minor responses were noted.
Conclusions: As a single agent in the treatment of recurrent and refractory STS, irinotecan administered on a daily x5 x2 schedule revealed a noteworthy response rate in a population of heavily pretreated patients, especially in the subset of patients with PNET. Its hematologic toxicity profile warrants further investigation in association with other myelotoxic agents.
Copyright (c) 2005 American Cancer Society.