10026 Background: Potential IM cardiotoxicity has not been evaluated in patients with GIST or other sarcomas. CHF has been reported in leukemia pts on IM. Objectives: To determine the incidence of CHF in GIST and other sarcoma pts receiving IM. Methods: From our clinical trial database we reviewed all Grade III/IV potential cardiac adverse events (PCAEs) including dyspnea, dyspnea on exertion, chest pain, edema, pleural effusion, ascites, cardiac ischemia, and arrhythmia. Results: 219 pts were enrolled on clinical trials with IM from Dec 27, 2000 to May 11, 2006. 18 pts (8.22%) were identified as having PCAEs. The median age was 65.5 yrs (range, 21 to 88 yrs) and 7 were women. Their diagnoses were advanced GIST (13 of 125 pts, 10.40 %), primary GIST (4 of 48 pts, 8.33 %), or osteosarcoma (1 of 46 sarcoma pts, 2.17%). The osteosarcoma pt had received prior anthracycline therapy. The median time from start of IM to a PCAE was 173.5 days (11 to 1,568 days). IM dose at the time of the PCAE was 400 mg/d in 10 pts, 600 mg/d in 4 pts, and 800 mg/d in 4 pts. 13 pts had a past medical history of risk factors for coronary artery disease (CAD) or established heart disease: diabetes (4 pts, 22.22%), hypertension (9 pts, 50%), CAD (2 pts, 11.11%), hypertrophic obstructive cardiomyopathy (1 pt, 5.56%), peripheral vascular disease (2 pts, 11.11%), hyperlipidemia (3 pts, 16.67%) or arrhythmia (1 pts, 5.56%). None of these patients had evidence of pulmonary vascular congestion by chest film. 8 pts had an ECHO or MUGA scan at the time of the PCAE, and 1 of them had documented low ejection fraction; in only 2 of these 8 pts was there an ECHO prior to IM (LVEF >50% in both). The single pt with LVEF<50% at the time of the PCAE had prior a history of hypertension, multi-vessel CAD and coronary artery bypass grafting 12 years prior to the PCAE. All of the pts continued IM therapy with dose adjustments and toxicity-specific management with no further complications. Conclusions: Pts who develop PCAEs on IM should be treated with diuretics, ACE-inhibitors, and beta-blockers with continuation of IM as clinically indicated. CHF in sarcoma patients treated with IM is rare and was observed in only one elderly patient with known prior cardiac disease. No significant financial relationships to disclose.