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 (PT) or international normalized ratio (INR) = 1.5 mg/dL: calculated creatinine clearance (ClCR) >= 30 mL/min
• Urine protein to creatinine ratio (UPC) = 1, then a 24-hour urine protein must be assessed; subjects must have a 24-hour urine protein value = 1 year and be greater than 45 years in age, OR, in questionable cases, have a follicle stimulating hormone (FSH) value > 40 mIU/mL and an estradiol value = 1 year and be greater than 45 years of age OR have had documented evidence of menopause based on FSH and estradiol concentrations prior to initiation of HRT
• Childbearing potential, including any female who has had a negative serum pregnancy test within 7 days prior to the first dose of study treatment, preferably as close to the first dose as possible, and agrees to use adequate contraception; defined as follows:
• Complete abstinence from sexual intercourse for 14 days before exposure to investigational product, through the dosing period, and for at least 21 days after the last dose of investigational product
• Oral contraceptive, either combined or progesterone alone
• Injectable progesterone
• Implants of levonorgestrel
• Estrogenic vaginal ring
• Percutaneous contraceptive patches
• Intrauterine device (IUD) or intrauterine system (IUS) with a documented failure rate of less than 1% per year
• Male partner sterilization (vasectomy with documentation of azoospermia) prior to the female subject's entry into the study, and this male is the sole partner for that subject
• Double barrier method: condom and an occlusive cap (diaphragm or cervical/vault caps) with a vaginal spermicidal agent (foam/gel/film/cream/suppository)
• Female subjects who are lactating should discontinue nursing prior to the first dose of study drug and should refrain from nursing throughout the treatment period and for 14 days following the last dose of study drug

Exclusion Criteria

• Prior malignancy; note: subjects who have had another malignancy and have been disease-free for > 3 years, or subjects with a history of completely resected non-melanomatous skin carcinoma, successfully treated in situ carcinoma, or successfully treated superficial bladder cancer are eligible.
• History or clinical evidence of central nervous system (CNS) metastases or leptomeningeal carcinomatosis, except for individuals who have previously-treated CNS metastases, are asymptomatic, and have had no requirement for steroids or anti-seizure medication for 6 months prior to first dose of study drug; scre