Temozolomide in resistant or relapsed pediatric solid tumors

Purpose: We report the off-label study aimed at investigating the use of temozolomide (TMZ) as single agent in relapsed or resistant pediatric solid tumors. The drug was administered at the dose of 215 mg/m(2)/day x 5 days or 180 mg/m(2)/day x 5 days in patients with prior craniospinal irradiation (CSI) or autologous bone marrow transplantation (ABMT). Patients and Methods: Fifty two patients, median age 127.6 months, with resistant or relapsed solid tumors were enrolled. Tumor types were: neuroblastoma (NB; n = 17), medulloblastoma (MB; 8), brain stem glioma (BSG; 8), extraosseous Ewing's sarcoma/peripheral neuroectodermal tumor (EOES; 4), Ewing's sarcoma (ES; 4), anaplastic astrocytoma (AA; 3), rhabdomyosarcoma (RMS; 2), ependymoma (EP; 2), cerebral primitive neuroectodermal tumor (cPNET; 2), hepatocarcinoma (HC; 1), and osteosarcoma (OS; 1). All patients were pre-treated. Two outpatient courses were administered, with a median of 4.8 courses/pt. Results: Objective response-rate (CR+PR+MR) in our series was 13.4% (1.9% CR, 3.8% PR, and 7.7% MR), SD occurred in 38.4% of patients and 48% had PD. The median survival was 7.8 months (range 1-37) and median time to progression was 3.4 months (range 1-20); these data were significantly correlated with histology and previous nitrosureas administration in multivariate analysis. Haematological toxicity grade 3-4 (mainly thrombocytopenia) was observed in 21.4% of administered courses, nausea was reported in 3.1% and respiratory distress in 0.7%. Conclusion: Oral TMZ was well tolerated in children with resistant or relapsed solid tumors and showed activity in NB and CNS tumours refractory to standard chemotherapy.