Phase II study of imatinib in patients with WHO B3 and C thymomas

14665 Background: Compared to other epithelial malignancies, genetic abnormalities are relatively rare in thymomas, they increase with increasing malignant behavior. C-Kit is highly expressed in thymic carcinomas (80%) but infrequent in thymomas. Scanty information is available on the role of C-Kit mutations in thymic carcinomas. Methods: Patients with surgically unresectable WHO B3 or C thymomas were enrolled in this study. Patients had to have performance status 0–2, good organ function and measurable disease. Imatinib was administered at 600 mg PO daily. The dose was increased to 800 mg (400 mg BID) if progression was observed in absence of clinical deterioration or no major response was achieved after two month treatment. Results: 7 patients were recruited at one institution, form June 2005 to August 2006. Two patients had WHO B3 and 5 had C, 2 had Masaoka stage IVA and 5 stage IVB, 4 had PS 2 and 3 PS 1, 6 were male, median age was 67 (range 36–76) and none had associated paraneoplastic syndromes. Th...