Pilot study of daily ifosfamide 1 g/m2 until grade III granulocytopenia as second-line chemotherapy for anthracycline-pretreated advanced soft tissue sarcoma.

Background And Aims: Second-line chemotherapy regimens for advanced soft tissue sarcomas after treatment failure or tumor relapse following anthracyclines are still investigational. The aim of the present study was to assess the activity of ifosfamide with a new schedule for patients with advanced soft tissue sarcoma failing to achieve remission or relapsing following anthracycline-containing regimens; it was attempted to individualize dosages and prevent excessive toxicity.

Study Design: A second-line chemotherapy regimen of ifosfamide 1 g/m2 daily, with drug withdrawal until the next cycle upon appearance of grade III granulocytopenia, was administered to 21 patients with advanced soft tissue sarcoma. All patients failed to achieve remission or relapsed following a first-line high-dose anthracycline regimen (epirubicin 180 mg/m2 or zorubicin 600 mg/m2 per cycle). The cycles were repeated every four weeks.

Results: The median number of cycles applied was three (range, 1-15). The ifosfamide dosage reached was 4-13 g/m2 per cycle, median 5 g/m2. A complete response was achieved in 1/21 patient (5%), no partial responses were observed, 4/21 patients (20%) had stable disease, and 16/21 (75%) had progressive disease. No difference in response and stable disease rates was observed between responders and non-responders to first-line chemotherapy. No difference in the ifosfamide dose reached was noted between patients receiving second-line chemotherapy directly following first-line therapy and those with a time interval between first- and second-line chemotherapy. The granulocytopenia grade III nadir lasted for a median of one day (range, 1-3) and other toxicities including hematological toxicity were mild and infrequent.

Conclusions: In view of the swift regeneration from grade III granulocytopenia, continuation of the study with granulocytopenia grade IV as a limiting factor for ifosfamide dose escalation seems feasible, with the prospect of better efficacy without excessive toxicity.