Phase II trial of ifosfamide in combination with sorafenib in patients with advanced soft tissue sarcoma: A Spanish Group for Research on Sarcomas (GEIS) study.

Abstract

10523 Background: Recent studies suggest that VEGFR inhibition could play a role in the treatment of soft tissue sarcoma (STS). Prior studies by our group showed that the combination of ifosfamide with sorafenib resulted in preclinical additive activity and that was feasible and safe in the phase I trial. Methods: Patients (pts) with advanced STS, previously treated with doxorubicin, no prior ifosfamide, ECOG PS 0-2, and adequate hematological, renal and hepatic function, were enrolled in this multicenter phase II study, receiving sorafenib 400 mg bid po continuously and ifosfamide 2 g/m2 iv for 3 days together with mesna 400 mg/m2 every 3 weeks. The primary endpoint was progression-free rate (PFR) at 3 months. A one-sample binomial design was used (PFR P0=40%, P1=60%, α=0.10, β=0.20), requiring at least 19 of 35 pts free of progression at 3 months to be considered positive. Results: From September 09 to March 12, 35 pts were enrolled at 11 centers. Median age was 55 (18-73). PS: 0-13, 1-18; 2-4 pts. Histologic types were: LMS 12, Lipo 6, SS 5, MPNST 2, other 10 pts. . The median number of cycles administered per patient was 4. PFR at 3 months was 67%, with 23 pts being free of progression at 3 months. Median progression-free survival was 4.8 months (95% CI, 1.9-6.3) and median overall survival was 16.2 months. PR was achieved in 17% pts. Most common grade 3-4 toxicities were asthenia (25%), hand-foot syndrome (11%) and neutropenia (20%) resulting in 3 episodes of neutropenic fever. Other common toxicities (G1-4) included emesis (34%), rash (22%), diarrhea (34%), hypertension (11%) and mucositis (9%). Conclusions: The combination of ifosfamide and sorafenib is active and has acceptable toxicity in pts with doxorubicin pretreated STS. The PFR at 3 months might exceed the expected with ifosfamide alone warranting further investigation. Clinical trial information: EudraCT: 2007-002176-34.