4117 Background: The multikinase inhibitor sorafenib is standard of care for pts with advanced HCC. Tivantinib, an oral, selective MET inhibitor, demonstrated synergistic antitumor activity when combined with sorafenib in several tumor models. The phase 1 dose-escalation study assessed the safety profile of tivantinib plus sorafenib in pts with advanced solid tumors. Methods: Endpoints were safety, the recommended phase 2 dose (RP2D) of tivantinib plus sorafenib, and antitumor activity. Dose escalation previously established the RP2D as tivantinib 360 mg twice daily (BID) plus sorafenib 400 mg BID. Extension cohorts enrolled ≤ 20 pts each with HCC or other tumors. Patients were treated until disease progression or unacceptable toxicity. After a safety review in HCC pts in other studies and a report of febrile neutropenia in this study, the tivantinib dose for newly enrolled pts was reduced to 240 mg BID. Results: 20 pts with HCC (mean age, 62 yr; Child-Pugh [CP] A [n = 14], or CP B [n = 6]) were treated a...