A phase I study of imatinib mesylate and paclitaxel in patients with advanced (stage IIIC/IV) or recurrent uterine papillary serous carcinoma (UPSC)

16025 Background: Uterine serous carcinoma (USC) is a rare, aggressive uterine tumor biologically distinct from typical endometrial cancers. Imatinib mesylate (IM)-associated kinases (kit, abl, PDGFR-B) are overexpressed and activated in most tumors from patients (pts) with USC. Single agent paclitaxel (TAX) has a good response rate but short duration of response in pts with USC. The purpose of this study was to determine the maximum tolerated dose (MTD) and dose limiting toxicity (DLT) of escalated doses of IM with a fixed dose of TAX. Methods: Pts with newly diagnosed (stage IIIC/IV) or recurrent USC were eligible (pts were required to have tumors that expressed at least one of the IM-targeted kinases by immunohistochemistry). Measurable disease was not required. TAX was administered at 175 mg/m2 every three weeks. One dose reduction to 135 mg/m2 was allowed. IM was given daily (400 mg, 500 mg or 600 mg). A 3+3 design was implemented. Pts with measurable disease were treated until progression or treatme...