Dose Escalation and Pharmacokinetic Study of High-Dose Chemotherapy with Treosulfan and Autologous Peripheral Blood Stem Cell Transplantation in Patients with Advanced Malignancies 1

A Phase I dose escalation and pharmacokinetic study of the alkylating cytotoxic agent treosulfan was conducted to evaluate the maximum tolerated dose and the dose-limiting toxicities in patients with advanced malignancies rescued by autologous peripheral blood stem cell transplantation. Twenty-two patients (15 ovarian and 7 other carcinomas/ lymphomas) with a median age of 48 years were treated with 28 high-dose courses. Treosulfan was infused ove r 2 h at escalating doses from 20 to 56 g/m , and pharmacokinetic parameters were analyzed. At 56 g/m, three of six patients experienced dose-limiting toxicities: diarrhea grade III/IV in three patients; mucositis/stomatitis grade III in one patient; toxic epidermal necrolysis in one patient; and grade III acidosis in one patient. Other low-grade side effects, including erythema, pain, fatigue, and nausea/vomiting, were recorded. Two patients died within 4 weeks after treatment because of rapid tumor progression and fungal infection, respectively. Plasma half-life, distribution volume, and renal elimination of treosulfan were independent of dose, whereas the increase in area under the curve was linear up to 56 g/m treosulfan. The maximum tolerated dose of high-dose treosulfan is 47 g/m. A split-dose or continuous infusion regimen is recommended for future high-dose trials. In consideration of antineoplastic activity and limited organ toxicity, inclusion of high-dose treosulfan in combination protocols with autologous peripheral blood stem cell transplantation seems worthwhile.