Pazopanib Hydrochloride and Topotecan Hydrochloride in Treating Patients With Metastatic Soft Tissue and Bone Sarcomas

PRIMARY OBJECTIVES: I. To determine progression free rate at week 12 for patients with soft tissue sarcoma (STS) treated with pazopanib (pazopanib hydrochloride) plus oral topotecan (topotecan hydrochloride). SECONDARY OBJECTIVES: I. To determine the overall response rate for patients with STS treated with combination pazopanib and topotecan. II. To determine the clinical benefit rate (complete response \[CR\] + partial response \[PR\] + stable disease \[SD\]) for patients with STS treated with combination pazopanib and topotecan. III. To determine median progression-free rate (PFR) for patients with STS treated with combination pazopanib and topotecan. IV. To evaluate overall survival (OS) for patients with STS treated with combination pazopanib and topotecan. V. To assess safety and tolerability for patients treated with combination pazopanib and topotecan. VI. To estimate the PFR for patients with osteosarcoma treated with combination pazopanib and topotecan. VII. To estimate the PFR for patients with liposarcoma treated with combination pazopanib and topotecan. TERTIARY OBJECTIVES: I. To estimate the correlation of PFR and OS to levels of soluble vascular endothelial growth factor receptor 2 (sVEGFR2) and phosphatidylinositol-glycan biosynthesis class F (PIGF). OUTLINE: Patients receive pazopanib hydrochloride orally (PO) once daily (QD) on days 1-28 and topotecan hydrochloride PO on days 1, 8, and 15. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity or until discontinuation per patient preference or physician recommendation. After completion of study treatment, patients are followed up every 6 months for 2 or 5 years.