Efatutazone Dihydrochloride in Treating Patients With Previously Treated Myxoid Liposarcoma That Cannot Be Removed by Surgery

PRIMARY OBJECTIVES: I. To determine the confirmed response rate for efatutazone dihydrochloride (efatutazone) in patients with advanced myxoid liposarcoma whose disease has progressed on at least one prior therapy. SECONDARY OBJECTIVES: I. To assess the progression free survival (PFS), overall survival (OS), and adverse event rates for efatutazone treated patients with advanced myxoid liposarcoma whose disease has progressed on at least one prior therapy. TERTIARY OBJECTIVES: I. To assess the predictive value of peroxisome proliferator-activated receptor (PPAR) and retinoid X receptors (RXR) tumor expression from archived patient tumor samples. II. To assess the predictive value of the expression of PPARgamma-regulated markers of adipocytes differentiation. III. To assess the predictive value of the expression of PPARgamma-regulated cell cycle proteins. IV. To assess the effects of efatutazone treatment on serum adiponectin levels. OUTLINE: Patients receive efatutazone dihydrochloride orally (PO) twice daily (BID) continuously. Courses repeat every 21 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 12 weeks for 2 years and then every 6 months for up to 5 years.