Abstract only 10020 Background: There is no standard of care for both rare sarcomas. Regarding, the important vascularization of EHE and SFT, we explored the activity/toxicity of So in pts with these sarcomas. Methods: We conducted a multicenter one-step phase II trial of So (800 mg/d). The primary endpoint was the 9-months progression-free rate (9-PFR). According to EORTC criteria, So is considered as promising drug if 6-PFR≥14%. All pts have had documented progressive disease at entry. Results: 20 pts (15 EHE & 5 SFT) were enrolled from June 2009 to February 2011 in the 8 participating institutions. 12 men and 8 women. Median age was 57. The most common primaries were superficial trunk (8 cases) and liver (4 cases). PS were 0 in 10 cases, 1 in 7 cases and 2 in 3 cases. 16 pts had metastasic disease , especially in lung (15), liver (6) and bone (4). Eight pts received prior chemotherapy (Doxorubicin : n= 8 cases and taxane : n =3). The median So treatment duration was 124 days. 9 pts experienced grade-3 toxicities; the most frequent grade-3 toxic events were hand foot syndrome (5 pts), myalgia (1), stomatitis (1), anorexia (1), diarrhea (1) and arterial hypertension (1).Because of this toxicity, treatment discontinuation was necessary in 6 cases and dose reduction was necessary in 5 pts. The 9-PFR was 6/18 (33.3% 11.5-55.1). The 2, 4 and 6 PFR were 15/18 (83.3%), 8/18 (44.4%) and 7/18 (38.8) respectively We observed 2 partial responses lasting 2 and 9 months in 2 pts with EHE. Analysis of the predictive value of circulating pre-angiogenetic biomarkers is ongoing. Conclusions: According to the STBSG-EORTC criteria (3-PFR≥40% & 6-PFR≥14%), So is a promising drug for EHE and SFT pts. Further trials is needed, especially a discontinuation randomized trial.