STREAM: A randomized discontinuation, blinded, placebo-controlled phase II study of sorafenib (S) treatment of chemonaïve patients (pts) with metastatic uveal melanoma (MUM).

9511Background: There is no established systemic treatment for pts with MUM. The STREAM study evaluated the efficacy of the oral multikinase inhibitor S in chemonaive pts with MUM with the primary endpoint progression-free survival (PFS). Methods: During the initial 56d run-in period all pts received oral S 400 mg bid with concomitant monitoring by magnetic resonance imaging including diffusion weighted imaging (DWI-MRI). Pts with partial remission (PR) on d56 according to RECIST 1.1 were further treated with open-label S and monitored, pts with progressive disease (PD) were taken off study, and pts with stable disease (SD) were randomly assigned to blinded S or placebo (P) and were further monitored every 8 wks and unblinded in case of PD. Pts on S were taken off study and pts on P were offered S with further monitoring. Results: Altogether, 118 (79.2%) of 149 pts entering the run-in period were evaluable for response on d56. Two pts had PR (1.7%), 78 pts had SD (66.1%) and 38 pts had PD (32.2%), respect...