Metronomic Trabectedin, Gemcitabine, and Dacarbazine for Soft Tissue Sarcoma

Inclusion Criteria: * Male or Female ≥ 18 years of age * Pathologically confirmed diagnosis of locally advanced, unresectable or metastatic leiomyosarcoma * Previously treated patient with measurable disease by RECIST v1.1 * ECOG performance status ≤ 2 * Life expectancy of at least 3 months * Acceptable liver function: Bilirubin \< 1.5 times upper limit of normal (ULN; except subjects with Gilbert Syndrome who must have a total bilirubin level \< 3.0 ULN); AST (SGOT), ALT (SGPT) and alk phos \< 2.5 x ULN (\< 5 x ULN if liver metastases present) * Acceptable renal function: Creatinine \< 1.5 times ULN and creatinine clearance \> 60 ml/min using the Crockroft-Gault formula * Acceptable hematologic status: ANC \>1000 cells/μL; Platelet count \>100,000/μL; Hemoglobin \> 9.0 g/dL * INR and PT \< 1.5 ULN unless taking anti-coagulation, in which case PT, INR and aPTT must be within therapeutic range of intended use of anticoagulants * Ability to understand the purposes and risks of the study and has signed and dated a written informed consent form approved by the Investigator's IRB/Ethics Committee * Willingness to comply with all study procedures and availability for the duration of the study * All women of childbearing potential must have a negative urine or serum pregnancy test within 72 hours of enrollment. If urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required; all subjects must agree to use highly effective means of contraception (surgical sterilization or the use of barrier contraception with either a condom or diaphragm in conjunction with spermicidal gel or an IUD) with their partner from entry into the study through 5 months for women and 7 months for men after the last dose. Exclusion Criteria: * Currently receiving treatment with another investigational device or drug study, or \<14 days since ending treatment with another investigational device or drug study(s). * Subject has known sensitivity to trabectedin, gemcitabine or dacarbazine. * Female subject is pregnant or breast-feeding or planning to become pregnant during study treatment and through 3 months after the last dose of trabectedin, gemcitabine or dacarbazine. * Female subject of childbearing potential who is unwilling to use acceptable method(s) of effective contraception during study treatment and through 3 months after the last dose of trabectedin, gemcitabine or dacarbazine. * Sexually active subjects and their partners unwilling to use male or female latex condom