Gemcitabine With or Without Pazopanib in Treating Patients With Refractory Soft Tissue Sarcoma

Inclusion Criteria: * Subjects must provide written informed consent prior to performance of study-specific procedures or assessments, and must be willing to comply with treatment and follow-up; procedures conducted as part of the subject's routine clinical management (e.g., blood count, imaging study) and obtained prior to signing of informed consent may be utilized for screening or baseline purposes provided these procedures are conducted as specified in the protocol * Histologically confirmed diagnosis of metastatic or unresectable soft tissue sarcoma, excluding gastrointestinal stromal tumors, Kaposi's sarcoma, Ewing's family of tumors, and embryonal or alveolar rhabdomyosarcoma * Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 * Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 * Patients must have received at least one, but not more than three, systemic regimens for treatment of metastatic soft tissue sarcoma; patients must have had a prior anthracycline in the neoadjuvant, adjuvant, or metastatic setting unless medically inappropriate for the patient * Neoadjuvant or adjuvant therapy will not count towards prior treatment for metastatic disease, unless the patient relapsed within 2 years of completing such therapy. * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L * Hemoglobin \>= 8 g/dL; subjects may not have had a transfusion within 7 days of screening assessment * Platelets \>= 100 x 10\^9/L * Prothrombin time (P…