2003) . In a large analysis of 975 newly diagnosed Ewing’s sarcoma patients enrolled in trials from 1979 to 1993, the 5-year recurrence free survival (RFS) for patients with primary metastatic disease (n=179) was 22%, which was significantly worse than localized disease (p<.0001) (Cotterill, Ahrens et al. 2000). Although the SEER data survival for metastatic disease has improved (5-year survival of 39%) with “current” standard of care it is achieved at the cost of an increased toxicity profile (Esiashvili, Goodman et al. 2008). Second or greater line therapy regimens only show temporary benefit with dismal survival outcome. 1.2 Relapsed and Refractory Ewing’s sarcoma Thirty to forty percent (30-40%) of Ewing’s sarcoma patients who present with localized disease, and 60-80% presenting with primary metastatic disease, will experience relapse or progression at a median time to relapse of 1.3 years (Ozaki, Hillmann et al. 1996, Bacci, Picci et al.