PIM inhibition in MET addicted tumors

abstracts

Annals of Oncology

1967P

Triple MET/SRC/PIM inhibition in MET addicted tumors

I. Attili1, L. Bonanno2, J.P. Bracht3, J. Berenguer3, C. Codony-Servat4, J. Codony-Servat5, M. Ito4, P.F. Conte1, J.J. Cui6, N. Karachaliou7, R. Rosell8 1 Surgery Oncology and Gastroenterology, Universit a degli Studi di Padova, Padua, Italy, 2 Medical Oncology 2, Istituto Oncologico Veneto IRCCS, Padua, Italy, 3IþD, Pangaea onOncology, Barcelona, Spain, 4Laboratory of Oncology - Pangaea Oncology, Quir Dexeus University Institute, Barcelona, Spain, 5Laboratory, Pangaea Oncology, Barcelona, Spain, 6Oncology, TP Therapeutics, Inc., San Diego, CA, USA, 7RD Clinical Oncology, Merck KgaA, Darmstadt, Germany, 8Laboratory of Cellular and Molecular Biology, Institut for Healh Sciences Germans Trias i Pujol, Badalona, Spain

Officer / Board of Directors: Merck KgaA. All other authors have declared no conflicts of interest.

1968P

Bioactivation of napabucasin triggers reactive oxygen species– mediated cancer cell death

F.E.M. Froeling1, I.I.C. Chio2, M.A. Yao1, M. Lucito1, P. Alagesan1, J. Li3, A-Y. Chang3, Y. Park1, H.A. Rogoff3, D.A. Tuveson1, J.D. Watson4 1 Lustgarten Foundation Pancreatic Cancer Research Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA, 2Institute for Cancer Genetics, Columbia University, New York, NY, USA, 3Translational Research Team, Boston Biomedical Inc, Cambridge, MA, USA, 4Cancer Center, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA Background: Napabucasin (2-acetylfuro-1,4-naphthoquinone) is a small molecule currently being clinically evaluated in several different cancer types. It has mostly been recognized for its ability to inhibit STAT3-mediated gene expression with activity against bulk tumor cells, as well as cancer stem cells. However, based on its chemical structure, we hypothesized that napabucasin is a substrate for reduction by NAD(P)H:quinone oxidoreductase-1 (NQO1) and therefore may exert its anti-cancer effect through redox cycling, resulting in reactive oxygen species (ROS) production and cell death. Methods: Binding of napabucasin to NQO1, as well as other oxidoreductases, was measured. Pancreatic cancer cell lines and xenografts were treated with napabucasin, and cell survival, ROS generation, glutathione to glutathione disulfide (GSH:GSSG) ratios and changes in STAT3 signaling were assayed. Genetic knockout or pharmacological inhibition with dicoumarol was used to evaluate the dependency on NQO1 in vitro and in vivo. Results: Napabucasin was found to bind with high affinity to NQO1 and to a lesser degree to cytochrome P450 oxidoreductase (POR). Differential cytotoxic effects were

Volume 30 | Supplement 5 | October 2019

employment: Boston Biomedical, Inc.. H.A. Rogoff: Full / Part-time employment: Boston Biomedical, Inc.. J.D. Watson: Advisory / Consultancy, The consultancy occured in the past: Boston Biomedical, Inc. All other authors have declared no conflicts of interest.

1969P

Targeting NRG1-fusions in multiple tumour types: Afatinib as a novel potential treatment option

S.V. Liu1, M. Duruisseaux2, K. Tolba3, E. Branden4, Y. Goto5, B.A. Weinberg6, D.J. Renouf7, R.C. Doebele8, C. Heining9, R.F. Schlenk10, P.K. Cheema11, J. Cadranel12, M.R. Jones13, A.E. Drilon14, D. Trombetta15, L.A. Muscarella15, A. Cseh16, F. Solca17, J.J. Laskin7 1 Division of Medical Oncology, Georgetown University, Washington, DC, USA, 2 Department of Respiratory Medicine, Hospices Civils de Lyon Cancer Institute, Universite´ Claude Bernard Lyon 1; UMR INSERM 1052 CNRS 5286 CRCL, Lyon, France, 3 Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA, 4 Department of Respiratory Medicine, G€ avle Hospital, G€ avle, Sweden, 5Department of Thoracic Oncology, National Cancer Center Hospital, Tokyo, Japan, 6Division of Hematology and Oncology, Georgetown University Medical Center, Washington, DC, USA, 7Division of Medical Oncology, Department of Medicine, University of British Columbia, BC Cancer, Vancouver, BC, Canada, 8Department of Medicine, University of Colorado Cancer Center, Aurora, CO, USA, 9Department of Translational Medical Oncology, National Center for Tumor Diseases Dresden, Dresden, Germany, 10NCT Trial Center, National Center of Tumor Diseases Heidelberg, University Hospital and German Cancer Research Center, Heidelberg, Germany, 11Faculty of Medicine, William Osler Health System, University of Toronto, Toronto, ON, Canada, 12Department of Pneumology, Assistance Publique Hoˆpitaux de Paris, Hoˆpital Tenon and Sorbonne Universite´, Paris, France, 13Precision Oncology, Bioinformatic Business Area, Qiagen Inc., Redwood City, CA, USA, 14Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 15Laboratory of Oncology, Fondazione IRCCS Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo, Foggia, Italy, 16Department of Medical Affairs, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria, 17 Department of Pharmacology, Boehringer Ingelheim RCV GmbH & Co. KG, Vienna, Austria Background: Neuregulin 1 (NRG1) is a growth factor that binds HER3/4 and activates ErbB signalling pathways. NRG1 fusions function as oncogenic drivers and represent a potential therapeutic target across tumour types. Afatinib, an ErbB-family blocker, may be a treatment option for some patients (pts) with NRG1 fusion-positive (NRG1þ) tumours, as supported by preclinical evidence and published case reports (Table). Methods: We report clinico-pathological and molecular characteristics of seven previously unreported cases of afatinib-treated NRG1þ tumours. Results: Pt 1, 70 yo female, never-smoker with pan-wildtype, non-mucinous lung adenocarcinoma (ADC) received 15th-line afatinib for 24 mos (PR). An NRG1 fusion was subsequently identified. The pt was re-challenged with afatinib (PR, 3 mos) before switching to atezolizumab (PD). Pt 2, 66 yo female, never-smoker with metastatic (m) non-mucinous lung ADC. CD74-NRG1 fusion was identified, and 5th-line afatinib initiated. PR is ongoing after 14 mos. Pt 3, 68 yo male, >20 pack-yr smoking history with non-mucinous lung ADC. SDC4-NRG1 fusion was identified and 2nd-line afatinib initiated. Best response: SD, 4 mos. Pt 4, 43 yo female, non-smoker with advanced invasive mucinous lung ADC. CD74-NRG1 fusion was identified and 3rd-line afatinib initiated; PR is ongoing. Pt 5, 69 yo male, with KRAS-mutated m-colorectal cancer. Following a right hemicolectomy and liver/lung metastasectomies, a novel POMKNRG1 fusion was detected and afatinib initiated (SD, 4 mos; treatment ongoing). Pts 6 and 7, male (54 & 59 yo) with KRAS WT, m-pancreatic cancers. Following PD on chemotherapy, APP-NRG1 and ATP1B1-NRG1 fusions, respectively, were detected and afatinib initiated. Pt 6 had a PR for 5 mos; treatment ongoing. Pt 7 had a PR for 5.5 mos. Conclusions: These findings add to a growing body of evidence suggesting that afatinib is a potential treatment option for pts with NRG1þ tumours. Prospective study is ongoing in the Drug Rediscovery Protocol trial (DRUP; NCT02925234).

doi:10.1093/annonc/mdz268 | v791

Downloaded from https://academic.oup.com/annonc/article-abstract/30/Supplement_5/mdz268.094/5577149 by guest on 24 October 2019

Background: MET addicted tumors are known to show very short response to single MET inhibition. In MET addicted cells, MET inhibition leads to activation of proviral integration site for Moloney murine leukemia virus-1 (PIM1). PIM1 and SRC can regulate the expression of receptor tyrosine kinases (RTKs), potentially being responsible of resistance to MET inhibition. We previously showed that the dual inhibition of MET and PIM1 with class I MET inhibitors and the pan-PIM inhibitor AZD1208, as well as MET and SRC (with dasatinib), is synergistic in MET addicted cell lines. Methods: We evaluated the activity of class I and class II MET inhibitors, MET/SRC/ CSF1R inhibitor TPX-02226 and pan-PIM inhibitors AZD1208 and PIM447 in four MET addicted cell lines: 2 MET amplified lung cancer cell lines (EBC1 and H1993), 1 MET exon 14 mutant cell line (Hs746T) and 1 MET exon 7-8 splicing variant cell line (E98). We assessed the effect of the dual inhibition of MET and PIM, and the triple inhibition of MET, SRC and PIM in cell viability by combining the TPX-02226 with the pan-PIM inhibitors. Results: All cell lines were sensitive to class I-II MET inhibitors (IC50s in nM range) except for cabozantinib in H1993. Only the MET amplified cell lines were sensitive to TPX-02226. All cell lines were resistant to PIM inhibition. The combination of class I MET inhibitors with PIM447 showed stronger synergism in the MET amplified cell lines, compared to the combination with AZD1208. Class I-II MET inhibitors and PIM inhibitor combination showed only additive effect in exon 7-8 cell line E98, while the combination of TPX-02226 and PIM447 was strongly synergistic. Conclusions: We identified potential role of PIM inhibition in MET amplified tumors. Even though single agent TPX-02226, AZD1208 or PIM447 showed no activity and dual MET/PIM inhibition showed only additive effect, the triple inhibition of MET, SRC and PIM was strongly effective in MET exon 7-8 splicing variant, suggesting a crucial role of SRC-PIM interaction in this still not well recognized MET addicted tumor. Further investigation on this triple inhibition is ongoing in MET addicted cell lines and role of co-presence of MET and PIM1 and/or SRC alterations in tumor samples. Legal entity responsible for the study: IGTP, Germans Trias i Pujol Research Institute, Badalona, Barcelona, Spain. Funding: Fundaci o Obra Social “La Caixa”. Disclosure: J.J. Cui: Leadership role, Officer / Board of Directors: TP Therapeutics. N. Karachaliou:

observed, where NQO1-expressing cells in particular were highly sensitive. Treatment resulted in significant induction of ROS with reduced GSH:GSSG ratios, increased DNA damage and an NQO1-dependent decrease in STAT3 phosphorylation. Cells with low or no baseline NQO1 expression also produced ROS in response to napabucasin treatment, albeit to a lesser degree, through the one-electron reductase POR. Conclusions: Napabucasin is bioactivated by oxidoreductases, in particular NQO1 and to a lesser extent POR, resulting in futile redox cycling and generation of cytotoxic levels of ROS. The increase in ROS has multiple intracellular effects, one of which is a reduction in STAT3 signaling, ultimately resulting in cell death. Legal entity responsible for the study: The authors. Funding: Lustgarten Foundation, National Institutes of Health, Donaldson Charitable Trust, Boston Biomedical Inc. Disclosure: J. Li: Full / Part-time employment: Boston Biomedical, Inc. A. Chang: Full / Part-time