327 Background: Pts with aHCC and CPB liver status are often excluded from clinical trials of novel therapies due to their poor prognosis (Greten British J Cancer 2005). Historical overall survival (OS) for these pts when treated with sorafenib (SOR) has ranged ≈3–5 mo in retrospective or descriptive studies (Abou-Alfa Gastrointest Cancer Res 2011; Da Fonseca Mol Clin Oncol 2015; Pressiani Ann Oncol 2013; Chiu Cancer 2012); thus, novel treatment options are needed for these pts. The PD-1 inhibitor NIVO is approved in the US, Canada, and elsewhere, most recently Australia, for SOR-treated pts with aHCC based on results from CheckMate-040 (NCT01658878) (El-Khoueiry Lancet 2017). Here we report data from the CPB cohort of CheckMate-040, the first prospective study of immunotherapy in this pt group. Methods: Pts with CPB (B7–B8) aHCC who were SOR-naïve (n = 25) or -experienced (n = 24) received NIVO 240 mg IV for 30 min Q2W until unacceptable toxicity or disease progression. Primary endpoints were objective response rate (ORR) (investigator assessed [INV], RECIST v1.1) and duration of response (DOR). Safety was assessed in all treated pts using NCI CTCAE v4.0. Results: Of 49 analyzed pts, 28 (57.1%) had vascular invasion or extrahepatic spread. During a follow-up range of 6–18 mo, INV ORR was 10.2% with 5 pts responding; disease control rate (DCR) was 55.1%. Median (m) time to response was 2.7 mo and mDOR was 9.9 mo; 2 pts had ongoing responses at data cutoff. The mOS was 7.6 mo (mOS follow-up was 7.4 mo); mOS in SOR-naïve and -treated pts was 9.8 and 7.3 mo, respectively. Treatment-related adverse events (TRAEs) were reported in 25 (51%) pts; 4 (8.2%) pts had select hepatic TRAEs. TRAEs led to discontinuation in 2 pts (4.1%). NIVO safety profile in these pts appeared comparable to cohorts of pts with CPA aHCC. Comparison data for pts with CPA aHCC and extended follow-up for pts with CPB aHCC will be presented. Conclusions: Encouraging DCR and durable responses were observed in pts with CPB aHCC treated with NIVO. AEs were manageable and did not lead to higher discontinuation compared with pts with CPA aHCC. NIVO showed promising efficacy and tolerability compared with historical data, supporting further investigation. Clinical trial information: NCT01658878.

Sorafenib, systemic treatment for advanced hepatocellular carcinoma (HCC), and regorafenib, novel second line treatment after sorafenib failure, have efficacy limited by evasive mechanisms of acquired-drug resistance. BCL-2 proteins participate in the response to tyrosine kinase inhibitors; however, their role in HCC therapy with sorafenib/regorafenib remains uncertain. BH3-mimetic ABT-263 (navitoclax) enhanced sorafenib activity, inducing cell death via a mitochondrial caspase-dependent mechanism, after BCL-xL/BCL-2 inhibition. Sorafenib-resistant hepatoma cells (HepG2R and Hep3BR) exhibited altered mRNA expression of BCL-2 and other anti-apoptotic family members, such as MCL-1, priming drug-resistant cancer cells to death by BH3-mimetics. ABT-263 restored sorafenib efficacy in sorafenib-resistant cell lines and HCC mouse models. Moreover, in mice xenografts from patient-derived BCLC9 cells, better tumor response to sorafenib was associated to higher changes in the BCL-2 mRNA pattern. HCC non-treated patients displayed altered BCL-2, MCL-1 and BCL-xL mRNA levels respect to adjacent non-tumoral biopsies and an increased BCL-2/MCL-1 ratio, predictive of navitoclax efficacy. Moreover, regorafenib administration also modified the BCL-2/MCL-1 ratio and navitoclax sensitized hepatoma cells to regorafenib by a mitochondrial caspase-dependent mechanism. In conclusion, sorafenib/regorafenib response is determined by BCL-2 proteins, while increased BCL-2/MCL-1 ratio in HCC sensitizes drug resistant-tumors against ABT-263 co-administration. Thus, changes in the BCL-2 profile, altered in HCC patients, could help to follow-up sorafenib efficacy, allowing patient selection for combined therapy with BH3-mimetics or early switch them to second line therapy.

4000 Background: Tivantinib (T), a selective, oral MET inhibitor, improved overall survival (OS) and progression-free survival (PFS) versus placebo (P) in a phase II study in MET-High HCC pts. Methods: This randomized, placebo-controlled phase III trial (NCT01755767) enrolled pts with: advanced HCC; Child Pugh A; ECOG PS ≤1; adequate bone marrow, liver, kidney functions; no liver transplant; radiographic disease progression (PD) after or intolerance to sorafenib; tumor MET-High (MET ≥2+ in ≥50% of tumor cells) by centralized immunohistochemistry. Pts were randomly assigned 2:1 to oral T or P, stratified by vascular invasion (VI), extrahepatic spread (ES), AFP ( < / > 200ng/mL), treated until PD or unacceptable toxicity. Response (RECIST 1.1) was evaluated by CT / MRI every 8 weeks. Primary endpoint of OS and secondary endpoints including PFS and safety were assessed in the intent-to-treat (ITT) population. Results: From Dec 2012 to Dec 2015, 1209 pts were consented in Australia, the Americas, Europe, New Zealand: 589 MET-High, 43 initially randomized at the dose of 240mg BID, then reduced due to high neutropenia rate, 340 randomized at 120mg BID: 226 to T, 114 to P (ITT population). Characteristics of pts were balanced between arms: 306 (90%) male; median age: 67; PS 0: 207 (61%); VI: 117 (34%); ES: 197 (58%); AFP ≤200: 195 (57%); radiographic PD on sorafenib: 275 (81%). Median OS (95% CI) was 8.4 months (m) (6.8-10.0) in T, 9.1 m (7.3-10.4) in P, HR = 0.97 (0.75-1.25), P = 0.81. Median PFS (95% CI) was 2.1 m (1.9-3.0) in T, 2.0 m (1.9-3.6) in P, HR = 0.96 (0.75-1.22), P = 0.72. No OS difference was seen in pts with VI (HR 1.19, 0.79-1.79), ES (HR 1.09, 0.78-1.52), AFP > 200ng/mL (HR 1.00, 0.71-1.41). Grade (G) > 3 AEs were 55.6% in T, 55.3% in P. In T, most common G > 3 AEs were ascites (7.1%), general deterioration (5.8%), anemia (4.9%); most common serious AE was general deterioration (4.9%). Deaths within 30 days of last dose were 22.1% on T vs 15.8% on P (most common causes: general deterioration 3.5%, hepatic failure 2.6%). Conclusion: Tivantinib at the 120mg BID dose did not improve OS or PFS over placebo in patients with advanced MET-High HCC who failed previous treatment with sorafenib. Clinical trial information: NCT01755767.