PURPOSE: The Children's Oncology Group conducted a phase II trial of
21-day continuous infusion topotecan to determine the response rate in
pediatric patients with recurrent or refractory malignant solid tumors.
PROCEDURE: Patients with Ewing sarcoma family of tumors (ESFT),
osteosarcoma (OS), soft tissue sarcomas (STS), medulloblastoma
(MB)/primitive neuroectodermal tumor (PNET), astrocytoma, or
neuroblastoma (NB) recurrent or refractory to conventional therapy,
measurable disease, and adequate organ function were treated with
topotecan 0.3 mg/m(2)/day by continuous intravenous infusion for 21
consecutive days, followed by 7 days without therapy prior to response
assessment. RESULTS: Fifty-five patients were enrolled; two were
ineligible, two were removed from protocol therapy prior to evaluation
for response, and one was inevaluable for response, leaving 53 and 50
patients evaluable for toxicity and response, respectively. Objective
responses were seen in 2/20 patients with ESFT (both partial responses,
4 and 19 courses), 0/10 OS patients, and 0/12 STS patients. There were
insufficient patients enrolled to determine the response rate for the
MB/PNET, astrocytoma, and NB strata. The most common Grade 3 or 4
toxicities during the first course of therapy were thrombocytopenia
(12/53), neutropenia (8/53), and fatigue (7/53). CONCLUSION:
Intravenous topotecan by 21-day continuous infusion is tolerable in
pediatric patients with recurrent or refractory solid tumors. Limited
activity was seen in ESFT and further development of this topotecan
schedule as a single agent is not warranted. Pediatr Blood Cancer (c)
2006 Wiley-Liss, Inc.

PMID: 16435380 [PubMed – as supplied by publisher]