A Phase I/II Study of a 72‐h Continuous Infusion of Etoposide in Advanced Soft Tissue Sarcoma

Abstract

Purpose. The study was performed to assess the antitumour activity and toxicity of a 72-h continuous infusion of single-agent etoposide as second-line treatment for patients with locally advanced or metastatic soft tissue sarcoma (STS), following reports of substantial activity using this schedule of etoposide administration as first-line treatment in combination with ifosfamide. Patients/method. This was an open phase I/II trial performed at a single institution in patients with metastatic or locally advanced STS who had failed first-line treatment with doxorubicin + ifosfamide combination chemotherapy or, less commonly, single-agent treatment with doxorubicin or ifosfamide. Etoposide was given as a continuous intravenous infusion over 72 h. The starting dose level was 200 mg m-2 day-1 × 3 escalating in 10% steps in cohorts of three patients until dose-limiting toxicity was encountered. Results. Seventeen patients were treated, median age 47 years (range 26–71 years). No responses were seen in 16 assessable patients despite etoposide levels in the cotoxic range. The steady-state plasma concentration exceeded 8 μg ml−1 in all patients and in patients treated at ≥ 600 mg m −2 the mean steady-state level was 14.4 μg ml −1. The median event-free survival was 6 weeks (95% confidence interval (CI) 3.31–8.69) and the overall survival 16 weeks (95% CI 9.28–22.72). The maximum tolerated dose in this pretreated patient group was 200 mg mm-2 day-1 × 3. The dose-limiting toxicity was myelosuppression. Discussion. Etoposide given by 72-h infusion is inactive as second-line chemotherapy in STS. It is associated with significant toxicity when given in these doses, in this patient group.