Regorafenib (R) in advanced solitary fibrous tumor (SFT): Results from an exploratory phase II clinical study.

11558 Background: R showed antitumor activity in a PDX model of dedifferentiated SFT (D-SFT), inducing a superior tumour growth inhibition than with other antiangiogenic agents (A), such as pazopanib (P) and axitinib (A). The efficacy of P and A in patients (pts) with advanced typical- (T-)/ malignant- (M-)SFT has been already confirmed in phase 2 clinical trials, but not in D-SFT. An exploratory phase 2 study was designed to investigate the...