Results of randomised studies of the EORTC Soft Tissue and Bone Sarcoma Group (STBSG) with two different ifosfamide regimens in first- and second-line chemotherapy in advanced soft tissue sarcoma patients

Abstract

The aim of this phase II study was to evaluate the efficacy and toxicity of two regimens of ifosfamide in metastatic soft tissue sarcoma patients given as first- and second-line chemotherapy. Two different schedules of ifosfamide were investigated in a randomised manner: Ifosfamide was given either at a dose of 5 g/m2 over 24 h (5 g/m2/1 day), every 3 weeks or at a dose of 3 g/m2 per day, administered over 4 h on three consecutive days (3 g/m2/3 days), every 3 weeks. Both schedules were given as first-line or second-line chemotherapy. A total of 182 patients was entered, 103 in first- and 79 in second-line, of whom 8 patients were ineligible, 5 in the first- and 3 in the second-line study. Most patients had a leiomyosarcoma, 46 of the 98 in the first-line and 34 of the 76 in the second-line. The two study arms were well balanced in both the first- and second-lines with respect to sex, age and performance status. In first-line treatment, 5 g/m2/1 day yielded five partial responses (PR) (Response Rate (RR) 10%), versus 12 PR (RR 25%) for the 3 g/m2/3 days. As second-line treatment, the 24-h infusion yielded: one CR and one PR (RR 6%) and the 3-day schedule one CR and two PR (RR 8%). Survival did not differ between the two regimens. The major World Health Organization (WHO) grade 3 and 4 toxicities encountered were: leucopenia in 19% of all courses in the first-line and 32% in the second-line with the 5 g/m2/1 day, while for the 3 g/m2/3 days schedule the rates were 57 and 63% respectively. Grade 3 or 4 infections were seen in 4% of patients treated with 5 g/m2/1 day first-line and 10% of patients given 3 g/m2/3 days, both as first- and second-lines. No such infections were seen in patients receiving 5 g/m2/1 day as second line treatment. In advanced soft-tissue sarcomas in the first-line, ifosfamide 3 g/m2, given over 4 h on three consecutive days, is an active regimen with acceptable toxicity while the 5 g/m2 over 24 hours schedule resulted in a disappointing response rate.