Zhiqiang Du¹, Sean Caenepeel², Yuqing Shen³, Karen Rex⁴, Yanni Zhang⁵, En-tzu Tang³, Ouhong Wang³, Wenge Zhong³, Hui Zhou³, Jacqueline Huang³,  Eric Huang³, Liaoyuan Hu³, Angela Coxon⁶, Mingqiang Zhang³

¹R&D, Amgen, ²Oncology Research, AmgenInc., Thousand Oaks, CA, USA, ³Amgen Biopharmaceutical Research & Development (Shanghai) Co., Ltd, ⁴Oncology Research, AmgenInc, ⁵Amgen Biopharmaceutical Research & Development (Shanghai) Co., Ltd, Amgen Biopharmaceutical Research & Development (Shanghai) Co., Ltd, ⁶Oncology Research, AmgenInc.,

Objective: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide. Aberrant hepatocyte growth factor/MET signaling has been implicated in hepato carcinogenesis, suggesting that MET may serve as an attractive therapeutic target in HCC. The purpose of this study was to investigate the anti-tumor activity in vitro and in vivo of AMG 337, a potent and highly selective small molecule MET kinase inhibitor, in preclinical models of HCC. Method: The anti-proliferative activity of AMG 337 was evaluated across a panel of 40 HCC cell lines in a72-hour viability assay. Daily oral administration of AMG 337 at doses of 3, 10and 30mg/kg was used to evaluate the in vivo anti-tumor activity of AMG 337 in two patient-derived mouse xenograft (PDX) models of HCC, LI0612 and LI1078. Effects on MET signaling were assessed by western blot analysis of downstream effector proteins including p-GAB1, p-AKT and p-ERK. MET protein levels and gene copy number for both PDX models and a subset of HCC cell lines were assessed by immuno-histochemistry (IHC; Dako) and fluorescence in situhybridization(FISH; Dako), respectively. High MET expression was defined as the presence of any tumor cells with membrane staining at 3+ intensity. MET amplification was defined as MET: CEN-7 ratio >2.0 or MET SNP array log2 copy number >2.5. Result: AMG 337 displayed potent anti-proliferative activity in two of 40 HCC cell lines (MHCC97H and HCCLM3) (IC50 0.015 µM and 0.025 µM, respectively); both cell lines were amplified for MET (MET/CEN-7>2.0) and showed high MET expression (3+ IHC). AMG 337 potently inhibited p-MET in all cell lines with detectable levels of total MET. However, dose-dependent inhibition of p-GAB1, p-AKT and p-ERK was limited to those cell lines that were sensitive to AMG 337 in viability assays. AMG 337 significantly inhibited tumor growth at all doses tested (P<0.001) in the MET-amplified and MET-high expressing HCC PDX model LI0612. However, AMG 337 had no effect on tumor growth in the non-MET–amplified and MET-low expressing HCC PDX model LI1078. Analysis of The Cancer Genome Atlas (TCGA) data identified four of164(2.4%) HCC tumor samples with MET amplification (https://tcga-data.nci.nih.gov/tcga), representing a patient population with potential to derive clinical benefit from AMG 337. Conclusion: These preclinical studies show that the efficacy of AMG 337 in HCC was highly associated with MET amplification. AMG 337 represents a promising, novel clinical therapeutic strategy for targeting HCC with a dependence on the MET pathway.

Key Words: MET