Inclusion Criteria:

* Histologically or cytologically confirmed soft tissue sarcoma

* Unresectable disease
* Locally advanced or metastatic disease
* The following tumor types are not allowed:

* Embryonal and alveolar rhabdomyosarcoma
* Gastrointestinal stromal tumor
* Alveolar soft part sarcoma
* Clear cell sarcoma
* Measurable disease, defined as ≥ 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT scan
* No more than 1 prior therapy for sarcoma
* No known brain metastases
* ECOG performance status (PS) 0-2 OR Karnofsky PS 60-100%
* ANC ≥ 1,500/µL
* Platelet count ≥ 100,000/µL
* Leukocytes ≥ 3,000/µL
* Total bilirubin ≤ upper limit of normal(ULN)
* AST and ALT ≤ 2.5 times ULN
* Creatinine ≤ 1.5 times ULN OR creatinine clearance ≥ 60 mL/min
* Fasting serum glucose \< 120 mg/dL OR below ULN
* LVEF ≥ 50% by MUGA scan
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception during and for 3 months after the last dose of anti-IGF-1R recombinant monoclonal antibody IMC-A12
* No history of allergic reactions attributed to compounds of similar chemical or biological composition to anti-IGF-1R recombinant monoclonal antibody IMC-A12
* No poorly controlled diabetes mellitus

* Patients with a history of diabetes mellitus are eligible provided their blood glucose is within normal range and they are on a stable dietary or therapeutic regimen for this condition
* No concurrent uncontrolled illness including, but not limited to, any of the following:

* Ongoing or active infection
* Symptomatic congestive heart failure
* Unstable angina pectoris
* Cardiac arrhythmia
* Psychiatric illness or social situation that would preclude compliance with study requirements
* No other concurrent investigational or commercial agents or therapies
* Recovered from all prior therapy
* More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C)
* More than 4 weeks since prior major surgery, hormonal therapy (other than replacement), or hormonal therapy

* No prior radiotherapy to the heart, mediastinum, or chest wall
* No prior anthracycline therapy or anti-IGF-1R therapy