High-dose continuous-infusion ifosfamide in advanced well-differentiated/dedifferentiated liposarcoma.

Background: Liposarcomas represent the most common histological type of soft-tissue sarcomas (STS). Its main subgroups, WD/DD, is known to be poorly sensitive to chemotherapy, with few active agents, i.e., anthracyclines +/- ifosfamide and trabectedin. High-dose ifosfamide (HDIFX >12 g/m2) is active in STS pts pretreated with standard-dose IFX, though with greater toxicity. A prolonged continuous-infusion (ci) through a portable external pump may be an alternative way to administer HDIFX.

Methods: From March 2002 to August 2013, 28 pts (median age =60, range =37-73 yrs) with advanced disease (6 WD and 22 WD/DD) were given ciHDIFX, at the dose of 14 g/m2 as a 14-day continuous infusion every 4 weeks. Twenty-four pts (86%) were previously treated with chemotherapy (19 with anthracyclines and ifosfamide; 4 with anthracycline monotherapy; 1 with trabectedin).

Results: Seven PR (all in DDLPS), 2 minor response (MR) and 11 SD were observed. Of interest, 6 of 9 patients with PR or MR had had SD with the previous therapy with anthracycline plus ifosfamide. The median progression-free survival was 7 months. Most common side effects were mild myelosuppression (anemia G2-3 in 3 pts; G2-3 neutropenia in 3 pts and G4 in 1; G3 thrombocytopenia in 1 pt); nausea (G3 in 3 pts) and fatigue (G3 in 6 pts). One pts had transient G3 confusion.

Conclusions: These data suggest that ciHDIFX is active in WD/DDLPS, even in patients already treated with a combination of anthracyclines plus ifosfamide. In this series, ciHDIFX regimen was better tolerated than HDIFX in published studies.