Gemcitabine and Docetaxel in Combination With Pazopanib (Gem/Doce/Pzb) for the Neoadjuvant Treatment of Soft Tissue Sarcoma (STS)

Inclusion Criteria: * Patients must have histologically or cytologically confirmed extremity only, ≥8 cm, high grade STS (MPNST, MFH/UPS, LMS) at MSKCC or locally for participating sites. * Subjects must have only localized disease that is potentially amenable to definitive resection. * The first 15 MSKCC patients on the Phase II portion of the protocol must undergo either an open incisional or core tumor biopsy prior to the initiation of therapy. * Patients must have measurable disease by RECIST 1.1, defined as at least one lesion that can be accurately measured in at least one dimension (longest diameter to be recorded) as \>20 mm with conventional techniques or as \>10 mm with spiral CT scan. See Section 10 for the evaluation of measurable disease. * Age \>18 years. ECOG performance status 0 or 1. * Patients must have normal organ and marrow function as defined below (ULN indicates institutional upper limit of normal): Absolute neutrophil count (ANC) ≥1.5 X 109/L Hemoglobin ≥9 g/dL (5.6 mmol/L) Platelets ≥100 X 109/L International normalized ratio (INR) ≤1.2 X ULN Activated partial thromboplastin time (aPTT)≤1.2 X ULN Total bilirubin ≤1.5 X ULN Alanine amino, transferase (ALT) and Aspartate aminotransferase (AST) ≤2.5 X ULN Serum creatinine ≤1.5 mg/dL (133 μmol/L) Or, if serum creatinine, \>1.5 mg/dL: Calculated creatinine clearance (ClCR) ≥30 mL/min to ≥50 mL/min Urine Protein to Creatinine Ratio (UPC; appropriate appendix) \<1 Or, 24-hour urine protein \<1g * Patients must not have current evidence of another malignancy. * Pazopanib, gemcitabine and docetaxel all carry category D (positive evidence of risk) pregnancy status. For this reason women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) during therapy and for at least 8 weeks after completion of therapy and have pregnancy testing prior to study entry and after two cycles of treatment. Should a woman become pregnant or suspect she is pregnant while participating in this study, she must inform her treating physician immediately. Exclusion Criteria: * Patients who have had major surgery 4 weeks prior to entering the study, or those who have not recovered from adverse events to ≤ NCI CTC AE Grade 1, associated with surgery. Excluded from such considerations are surgical changes not expected to improve, e.g. removal of muscle tissue. * Patients must not have had been treated previously with radiation, chemotherapy or other anti-cancer agent for the current disease. * History of allergic reactions or hypersensitivity reactions attributed to compounds of similar chemical or biologic composition to pazopanib, gemcitabine, docetaxel or other agents used in the study. * Patients with a contraindication to MRIs. * Patients who required concomitant treatment with medications that are known to be inhibitors or strong inducers of isoenzyme CYP3A4, CYP2C8, and CYP2D6 unless the drugs are medically necessary and no substitutes are available. If there are no acceptable substitutes, special precautions should be taken in these patients. Similarly, co-administration with CYP3A inhibitors (e.g. Ergot derivatives, Neuroleptics, Antiarrhythmics, Immune modulators and miscellaneous agents such quetiapine, risperidone, clozapine, atomoxetine, and inducers (e.g. Glucocorticoids, Anticonvulsants, HIV antivirals, Antibiotics, miscellaneous agents such as St. John's Wort, modafinil, pioglitazone, troglitazone, simvastatin, should also be avoided if possible, or otherwise subject to caution (e.g. increased frequency of safety monitoring). Strong CYP3A4 inhibitors are PROHIBITED within 14 days prior to the first dose of pazopanib including: Antibiotics, HIV protease inhibitors, Antifungals and Antidepressants * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, including HIV, active hepatitis B or C, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, poorly controlled diabetes or psychiatric illness/social situations that would limit compliance with study requirements. Hepatitis B and C will be screened for in all patients prior to initiating treatment via hepatitis B serologic markers, that is, HBsAg, HBs Ab, HBc Ab and Hep C Antibody. If patients have positive serologic markers, viral load markers (HBV-DNA and Hepatitis C RNA-PCR) will be performed during screening to confirm disease as well as screening for hepatitis C via quantitative RNA-PCR. * Pregnant women and women who are breast-feeding. * HIV -positive patients on combination antiretroviral therapy due to the potential for pharmacokinetic interactions with pazopanib. * Patients with significant respiratory compromise or an active and unexplained pneumonitis given that these patients would have an increased risk of pneumonitis from gemcitabine, and would also confuse the evaluation of pneumonitis on the trial * Clinically significant gastrointestinal abnormalities that may increase the risk for gastrointestinal bleeding including, but not limited to: Active peptic ulcer disease * Inflammatory bowel disease (e.g. ulcerative colitis, Crohn's disease), or other gastrointestinal conditions with increased risk of perforation * History of abdominal fistula, gastrointestinal perforation, or intra-abdominal * abscess within 28 days prior to beginning study treatment Active diarrhea of any grade * Clinically significant gastrointestinal abnormalities that may affect absorption of investigational product including, but not limited to: * Malabsorption syndrome * Major resection of the stomach or small bowel * History of any one or more of the following cardiovascular conditions within the past 6 months: Cardiac angioplasty or stenting Myocardial infarction Unstable angina Coronary artery bypass graft surgery Symptomatic peripheral vascular disease * History of cerebrovascular accident including transient ischemic attack (TIA), pulmonary embolism or untreated deep venous thrombosis (DVT) within the past 6 months. * Note: Subjects with recent DVT who have been treated with therapeutic anticoagulating agents for at least 6 weeks are eligible * Corrected QT interval (QTc) ≥ 450 msecs using Bazett's formula (append formula); for subjects with bundle branch block (BBB), QTc ≥480 msecs using Bazett's formula.) * Poorly controlled hypertension, defined as systolic blood pressure (SBP) of ≥140 mmHg or diastolic blood pressure (DBP) of ≥ 90mmHg. * Note: Initiation or adjustment of antihypertensive medication(s) is permitted prior to study entry. History of Class III or IV congestive heart failure, as defined by the New York Heart Association Classification of Congestive Heart Failure \[see Appendix D for description\] * Evidence of active bleeding or bleeding diathesis * Administration of any non-oncologic investigational drug within 30 days or 5 half lives whichever is longer prior to receiving the first dose of study treatment.