Phase II study of imatinib mesylate in chemotherapy refractory germ cell tumors expressing KIT

Objective: This phase II study was conducted to determine the activity of imatinib (gleevec) in heavily pretreated patients with KIT-positive metastatic germ cell tumor. Materials and Methods: From June 2002 through April 2005, 18 patients with refractory germ cell tumors were tested for KIT expression by immunohistochemistry. All patients screened were deemed to be incurable with further standard chemotherapy or surgery. Six patients were eligible and treated with imatinib 600 mg/d orally. Results: There were no complete or partial remissions. Five of 6 patients had progressive disease and 1 patient had stable disease with a > 50% decline in serum alpha-fetoprotein for 3 months before developing further progression. Conclusion: In this small sample size, there was no evidence of significant antitumor activity of imatinib in patients with KIT-positive refractory germ cell tumors.