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Amplification or overexpression of the FGFR family of receptor tyrosine kinases occurs in a significant proportion of gastric cancers. Regorafenib is a multikinase inhibitor of angiogenic and oncogenic kinases, including FGFR, which showed activity in the randomized phase II INTEGRATE clinical trial in advanced gastric cancer. There are currently no biomarkers that predict response to this agent, and whether regorafenib is preferentially active in FGFR-driven cancers is unknown. Through screening 25 gastric cancer cell lines, we identified five cell lines that were exquisitely sensitive to regorafenib, four of which harbored amplification or overexpression of FGFR family members. These four cell lines were also sensitive to the FGFR-specific inhibitors, BGJ398, erdafitinib, and TAS-120. Regorafenib inhibited FGFR-driven MAPK signaling in these cell lines, and knockdown studies confirmed their dependence on specific FGFRs for proliferation. In the INTEGRATE trial cohort, amplification or overexpression of FGFRs 1–4 was detected in 8%–19% of cases, however, this was not associated with improved progression-free survival and no objective responses were observed in these cases. Further preclinical analyses revealed FGFR-driven gastric cancer cell lines rapidly reactivate MAPK/ERK signaling in response to FGFR inhibition, which may underlie the limited clinical response to regorafenib. Importantly, combination treatment with an FGFR and MEK inhibitor delayed MAPK/ERK reactivation and synergistically inhibited proliferation of FGFR-driven gastric cancer cell lines. These findings suggest that upfront combinatorial inhibition of FGFR and MEK may represent a more effective treatment strategy for FGFR-driven gastric cancers.

Background: Less than 5% of patients with metastatic pancreatic cancer survive to 5 years and there have been no major improvements in outcomes over the last 20 years. The use of treatments targeted according to the molecular phenotype of individual tumours may result in improved response and survival compared to standard therapy. Methods: The IMPaCT trial is a multidisciplinary collaboration between the AGITG, NHMRC Clinical Trials Centre, Sydney Catalyst, and the Kinghorn Cancer Centre at Garvan Institute of Medical Research, which houses the Australian Pancreatic Cancer Genome Initiative (APGI). Patients who have available sequence data will be screened for actionable molecular phenotypes and randomized 1:1 to receive standard therapy (gemcitabine) or personalized treatment. Recruitment to the IMPaCT trial is based on the following defined molecular phenotypes: HER2/neu overexpression: personalized treatment with gemcitabine + trastuzumab; BRCA1, BRCA2, and PALB2 mutations: personalized treatment with 5-FU and mitomycin C; Kras wildtype: personalized treatment with gemcitabine + erlotinib. The study will be conducted in two parts: an initial 20 patient pilot trial across 4 Australian sites assessing feasibility, followed by an additional 70 patients to assess progression (90 patients in total). The pilot study is now open and active. Results: The novel trial design involves personalized treatment, where therapies are assigned based on a defined molecular phenotype, in a standard care setting. Stratifying randomization for individual molecular signatures will provide evidence, albeit in small numbers, for confirmation in a larger Phase III trial and broader clinical applicability. Additionally, the study offers the opportunity to explore a number of unique tertiary/correlative objectives, including the planned examination of circulating DNA as a surrogate of survival. Conclusion: The IMPaCT trial exemplifies a strong collaboration between basic scientists, clinicians and clinical trial investigators to illustrate the promises and challenges facing the development and successful testing of personalized therapeutic strategies. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A75. Citation Format: Lorraine Chantrill, Amber Johns, Adnan Nagrial, Venessa Chin, Angela Chou, Mark Pinese, Scott Mead, Val Gebski, Katrin Sjoquist, Chee Lee, Sonia Yip, Danielle Miller, Lucille Sebastian, Ray Asghari, Sandra Harvey, Nick Pavlakis, Sanjay Mukhedkar, Peter Grimison, David Miller, John Pearson, Nicola Waddell, Sean Grimmond, John Simes, Andrew Biankin. The IMPaCT trial: Individualised Molecular Pancreatic Cancer Therapy. A pilot, randomized, open label Phase II trial assessing first line treatment with gemcitabine or personalized treatment based on tumour molecular signature in patients with metastatic pancreatic cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A75.