Tandem thiotepa with autologous hematopoietic cell rescue in patients with recurrent, refractory, or poor prognosis solid tumor malignancies

Abstract Background: The purpose of this study was to determine the feasibility and tolerability of tandem courses of high‐dose thiotepa with autologous hematopoietic cell rescue (AHCR) in patients with recurrent, refractory solid tumors who were ineligible for a single course of high‐dose therapy due to greater than minimal residual disease. Patients with decreased hearing or poor renal function were eligible. Procedure: Thiotepa was administered intravenously at a dose of 200 mg/m 2 /day (6.67 mg/kg/day) daily for 3 days followed by AHCR. A second course of thiotepa was given 4 weeks later provided blood counts recovered sufficiently without evidence of tumor progression. Results: Fifty‐eight patients received 96 courses. Thirty‐eight (65%) patients received two courses of therapy. Twenty‐seven courses (28%) were administered completely in the outpatient setting. A toxic mortality rate of 3.4% was observed. Five of 26 patients with medulloblastoma were alive at a median of 35 months, whereas 21 patients died at a median of 11.7 months. Four of five patients with central nervous system germ cell tumors (CNS GCT) were alive 68–103 months following AHCR. Conclusions: Two cycles of high‐dose thiotepa with AHCR were well tolerated even in these heavily pretreated patients. This therapy may provide prolonged survival in patients with recurrent malignant brain tumors, particularly medulloblastoma and CNS GCT.