Continuing vs Intermittent Trabectedin in Patients With Advanced Soft Tissue Sarcoma

Inclusion Criteria (for the selection part): * Inoperable or metastatic soft tissue sarcoma and/or uterine sarcoma * Measurable lesions (RECIST 1.1) * Performance status ≤ 2 * Age ≥ 18 * Normal hematological parameters (polynuclear neutrophils ≥ 1500, hemoglobin level ≥ 9 g/dl, platelets counts ≥ 100,000) * Adequate biological parameters : * Adequate hepatic function (bilirubin ≤ ULN , SGPT/ALT and SGOT/AST ≤ 2.5 x ULN) * Alkaline phosphatases ≤ 2.5 x ULN, If Alkaline phosphatases ≥ 2.5 ULN, hepatic isoenzymes 5-nucleotidases or GGT tests must be performed; hepatic isoenzymes 5- nucleotidases and/or GGT must be within the normal range * Albumin ≥ 25 g/L * Adequate renal function : Serum creatinine ≤ 1.5 x ULN * Creatine phosphokinase ≤ 2.5 x ULN * Adequate central venous access * Pregnant or lactating women or men of reproductive potential must use effective contraceptive methods * Patient covered by government health insurance * Information sheet given to the patient (Patient information sheet 1) Exclusion Criteria (for the selection part): * Patients that have received more than one regimen of chemotherapy for metastatic or inoperable soft tissue or uterine sarcoma, after the failure/intolerance of doxorubicin and ifosfamide. Maintenance treatment does not count as treatment line * The following histological subtypes : GIST, rhabdomyosarcoma, aggressive fibromatosis, desmoïd tumour, PNET, carcinosarcoma, and all bone sarcomas * Single tumour in an irradiated region * Other malignant tumour over the past five years (except basal cell carcinoma or cervical carcinoma in situ adequately treated) * Currently active bacterial or fungus infection (\> grade 2 CTC \[CTCAE\] Version 4.02). Known HIV1, HIV2, hepatitis B or hepatitis C infections * Presence of known leptomeningeal or brain metastasis * Patients unable to receive corticotherapy * Any circumstance that could jeopardise compliance or proper follow-up during the trial * Pregnant or nursing women Inclusion Criteria (for the randomized part): * Patient registered in the selection part * Stable tumour or objective response (CR + PR) after 6 Trabectedin (Yondelis®) cycles, according to local assessment * Available copies of thoraco-abdominal and pelvic scan performed prior to the first cycle and after the sixth cycle * Performance status ≤ 2 * Patients receiving at least 1 mg/m²/3 weeks of Trabectedin at the time of the sixth cycle * Normal hematological parameters (polynuclear neutrophils ≥ 1500, hemoglobin level ≥ 9 g/dl, platelets counts ≥ 100,000) * Adequate biological parameters : * Adequate hepatic function (bilirubin ≤ ULN , SGPT/ALT and SGOT/AST ≤ 2.5 x ULN) * Alkaline phosphatases ≤ 2.5 x ULN, If Alkaline phosphatases ≥ 2.5 ULN, hepatic isoenzymes 5-nucleotidases or GGT tests must be performed; hepatic isoenzymes 5- nucleotidases and/or GGT must be within the normal range * Albumin ≥ 25 g/L * Adequate renal function : Serum creatinine ≤ 1.5 x ULN * Creatine phosphokinase (CPK) ≤ 2.5 x ULN * Adequate central venous access * Pregnant or lactating women or men of reproductive potential must use effective contraceptive methods * Informed consent form signed by the patient or the patient's legal representative (patient information sheet 2 and informed consent) Exclusion Criteria (for the randomized part): * Tumour progression (according to RECIST 1.1) during the first six Yondelis cycles * Non-availability of baseline scans prior to the first cycle and following the sixth cycle * Currently active bacterial or fungus infection (\> grade 2 CTC \[CTCAE\] Version 4.02). Known HIV1, HIV2, hepatitis B or hepatitis C infections * Presence of known leptomeningeal or brain metastasis * Creatinine clearance less than 30 ml/min * Patients unable to receive corticotherapy * Any circumstance that could jeopardise compliance or proper follow-up during the trial * Pregnant or nursing women * Hypersensitivity to Trabectedin or any excipient in prior cycles