Background: Chemotherapy given by continuous infusion may have different toxicity profiles and different degrees of therapeutic efficacy than when given by bolus administration. The potential therapeutic benefits of continuous infusion chemotherapy and the advantages of outpatient treatment led us to study a continuous infusion of ifosfamide with mesna and oral etoposide.
Methods: The authors performed a Phase I-II trial in which 9 g/m2 ifosfamide was administered for 6 days and 10.5 g/m2 mesna was administered for 7 days, both by continuous infusion, in combination with 50 mg/m2/d oral etoposide for 8 days in 21 patients with sarcomas or other solid tumors. Courses were repeated every 28 days.
Results: A total of 65 treatment cycles were given. Only six patients required hospitalization for treatment, all because of an initial poor performance status, and most carried out normal activities on an ambulatory basis. Treatment was stopped during the first course in five patients because of central nervous system toxicity, each with a poor pretreatment performance status; neurologic recovery was complete in each patient. The dose of etoposide was decreased by 20% in 11 patients and unchanged in 7 following the first treatment. Hematologic toxicity was predominantly manifested by leukopenia. An absolute neutrophil count less than 500 neutrophils/microliters occurred in 22 of 50 cycles; thrombocytopenia (platelets less than 100,000/microliters) was seen in two patients, requiring platelet transfusion in one. Neutropenic fevers occurred in 13 of 65 cycles; in 4 of these, cultures demonstrated a bacterial infection. Nausea and vomiting were mild. Objective responses occurred in 6 of 16 patients with soft tissue sarcomas (6 partial responses [PR]) (95% confidence interval, 15-65%), and 3 of 5 bone sarcomas, all of whom had been previously treated with doxorubicin and dacarbazine.
Conclusions: The authors concluded that ifosfamide and mesna given by ambulatory continuous intravenous infusion with wearable pump systems in combination with oral etoposide was well tolerated and showed substantial anti-tumor activity. This combination represents a rational therapeutic approach to patients with advanced soft tissue sarcomas and may have application to other malignancies.