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Featured researches published by Ramon V. Tiu.


American Journal of Hematology | 2016

Impact of allogeneic hematopoietic cell transplant in patients with myeloid neoplasms carrying spliceosomal mutations.

Betty K. Hamilton; Valeria Visconte; Xuefei Jia; Ali Tabarroki; Hideki Makishima; Edy Hasrouni; Donna Abounader; Matt Kalaycio; Mikkael A. Sekeres; Ronald Sobecks; Hien Liu; Brian J. Bolwell; Jaroslaw P. Maciejewski; Edward A. Copelan; Ramon V. Tiu

Molecular predictors of outcome are increasingly important in determining optimal therapy for myeloid neoplasms. Mutations in the spliceosomal genes (U2AF1 and SRSF2) predict for poor outcomes in myelodysplastic syndromes (MDS) and related diseases. We investigated the effect of hematopoietic cell transplant (HCT) on the negative prognostic impact of U2AF1 and SRSF2 mutations. In total, 122 patients with MDS (30%), acute myeloid leukemia (51%), myeloproliferative neoplasms (MPN) (11%), and MDS/MPN (8%) receiving a HCT from 2003 to 2012 were evaluated for mutations in U2AF1 and SRSF2 by direct sequencing. Median time of follow up was 24 months (range 0.46–110). SRSF2 mutations were detected in 11 (10%) patients and U2AF1 in 3 (3%) patients. There were no significant differences in baseline characteristics between mutated and wild‐type (WT) patients. Patients carrying SRSF2 and U2AF1 mutations had similar overall survival (P = 0.84), relapse mortality (P = 0.50), and non‐relapse mortality (P = 0.72) compared to WT patients. However, taking into account disease status and cytogenetics in a subset of AML patients, SRSF2 and U2AF1 mutations were associated with worse survival (HR 3.71, P = 0.035). Am. J. Hematol. 91:406–409, 2016.


Clinical Cancer Research | 2017

Mouse PDX Trial Suggests Synergy of concurrent Inhibition of RAF and EGFR in Colorectal Cancer with BRAF or KRAS mutations

Yung Mae M. Yao; Gregory P. Donoho; Philip W. Iversen; Youyan Zhang; Robert D. Van Horn; Amelie Forest; Ruslan D. Novosiadly; Yue Webster; Philip J. Ebert; Steven M. Bray; Jason C. Ting; Amit Aggarwal; James Robert Henry; Ramon V. Tiu; Gregory D. Plowman; Sheng Bin Peng

Purpose: To evaluate the antitumor efficacy of cetuximab in combination with LSN3074753, an analog of LY3009120 and pan-RAF inhibitor in 79 colorectal cancer patient-derived xenograft (PDX) models. Experimental Design: Seventy-nine well-characterized colorectal cancer PDX models were employed to conduct a single mouse per treatment group (n = 1) trial. Results: Consistent with clinical results, cetuximab was efficacious in wild-type KRAS and BRAF PDX models, with an overall response rate of 6.3% and disease control rate (DCR) of 20.3%. LSN3074753 was active in a small subset of PDX models that harbored KRAS or BRAF mutations. However, the combination treatment displayed the enhanced antitumor activity with DCR of 35.4%. Statistical analysis revealed that BRAF and KRAS mutations were the best predictors of the combinatorial activity and were significantly associated with synergistic effect with a P value of 0.01 compared with cetuximab alone. In 12 models with BRAF mutations, the combination therapy resulted in a DCR of 41.7%, whereas either monotherapy had a DCR of 8.3%. Among 44 KRAS mutation models, cetuximab or LSN3074753 monotherapy resulted in a DCR of 13.6% or 11.4%, respectively, and the combination therapy increased DCR to 34.1%. Molecular analysis suggests that EGFR activation is a potential feedback and resistant mechanism of pan-RAF inhibition. Conclusions: MAPK and EGFR pathway activations are two major molecular hallmarks of colorectal cancer. This mouse PDX trial recapitulated clinical results of cetuximab. Concurrent EGFR and RAF inhibition demonstrated synergistic antitumor activity for colorectal cancer PDX models with a KRAS or BRAF mutation. Clin Cancer Res; 23(18); 5547–60. ©2017 AACR.


Cancer Research | 2017

Abstract 4973: Discovery of LY3214996, a selective and novel ERK1/2 inhibitor with potent antitumor activities in cancer models with MAPK pathway alterations

Shripad V. Bhagwat; William Thomas Mcmillen; Shufen Cai; Baohui Zhao; Matthew Whitesell; Lisa Kindler; Robert Flack; Wenjuan Wu; Karen L. Huss; Bryan D. Anderson; Xiu-Juan Yuan; Susan Jaken; Denis J. McCann; Brian Michael Mathes; Andrew J. Dropsey; Jason Manro; Jennie L. Walgren; Eunice Yuen; Xueqian Gong; Michael J. Rodriguez; Jianping Huang; Ramon V. Tiu; Sajan Joseph; Sheng-Bin Peng

The RAS/MAPK pathway is dysregulated in approximately 30% of human cancers, and the extracellular-signal-regulated kinases (ERK1 and ERK2) serves as key central nodes within this pathway. The feasibility and clinical impact of targeting the RAS/MAPK pathway has been demonstrated by the therapeutic success of BRAF and MEK inhibitors in BRAF V600E/K metastatic melanoma. However, resistance develops frequently through reactivation of the pathway. Therefore, simultaneous targeting of multiple effectors such as RAF, MEK and ERK in this pathway, offers a potential for enhanced efficacy while delaying and overcoming resistance. LY3214996 is a highly selective inhibitor of ERK1 and ERK2, with IC50 of 5 nM for both enzymes in biochemical assays. It potently inhibits cellular phospho-RSK1 in BRAF and RAS mutant cancer cell lines. In an unbiased tumor cell panel sensitivity profiling for inhibition of cell proliferation, tumor cells with MAPK pathway alterations including BRAF, NRAS or KRAS mutation are generally sensitivity to LY3214996. In tumor xenograft models, LY3214996 inhibits PD biomarker phospho-p90RSK1 in tumors and the PD effects are correlated with compound exposures and anti-tumor activities. LY3214996 shows either similar or superior anti-tumor activity as compared to other published ERK inhibitors in BRAF or RAS mutant cell lines and xenograft models. Oral administration of single-agent LY3214996 significantly inhibits tumor growth in vivo and is well tolerated in BRAF or NRAS mutant melanoma, BRAF or KRAS mutant colorectal, lung and pancreatic cancer xenografts or PDX models. Therefore, LY3214996 can be tailored for treatment of cancers with MAPK pathway alteration. In addition, LY3214996 has anti-tumor activity in a vemurafenib-resistant A375 melanoma xenograft model due to MAPK reactivation, may have potential for treatment of melanoma patients who have failed BRAF therapies. More importantly, LY3214996 can be combined with investigational and approved agents in preclinical models, particularly KRAS mutant models. Combination treatment of LY3214996 and CDK4/6 inhibitor abemaciclib was well tolerated and results in potent tumor growth inhibition or regression in multiple in vivo cancer models, including KRAS mutant colorectal and non-small cell lung cancers. Here, we first report the preclinical characterization of LY3214996, a novel small molecule ERK1/2 inhibitor currently in Phase I clinical trials in patients with advanced and metastatic cancers (NCT02857270). Citation Format: Shripad V. Bhagwat, William T. McMillen, Shufen Cai, Baohui Zhao, Matthew Whitesell, Lisa Kindler, Robert S. Flack, Wenjuan Wu, Karen Huss, Bryan Anderson, Xiu-Juan Yuan, Susan Jaken, Denis McCann, Brian Mathes, Andrew J. Dropsey, Jason Manro, Jennie Walgren, Eunice Yuen, Xueqian Gong, Michael J. Rodriguez, Jianping Huang, Ramon V. Tiu, Sajan Joseph, Sheng-Bin Peng. Discovery of LY3214996, a selective and novel ERK1/2 inhibitor with potent antitumor activities in cancer models with MAPK pathway alterations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4973. doi:10.1158/1538-7445.AM2017-4973


Oncogene | 2018

RAF inhibitor LY3009120 sensitizes RAS or BRAF mutant cancer to CDK4/6 inhibition by abemaciclib via superior inhibition of phospho-RB and suppression of cyclin D1

S-H Chen; Xueqian Gong; Youyan Zhang; R D Van Horn; Tinggui Yin; Lysiane Huber; Teresa F. Burke; J Manro; Philip W. Iversen; Wenjuan Wu; Shripad V. Bhagwat; Richard P. Beckmann; Ramon V. Tiu; Sean Buchanan; S-B Peng

KRAS, NRAS and BRAF mutations are among the most important oncogenic drivers in many major cancer types, such as melanoma, lung, colorectal and pancreatic cancer. There is currently no effective therapy for the treatment of RAS mutant cancers. LY3009120, a pan-RAF and RAF dimer inhibitor advanced to clinical study has been shown to inhibit both RAS and BRAF mutant cell proliferation in vitro and xenograft tumor growth in vivo. Abemaciclib, a CDK4/6-selective inhibitor, is currently in phase III studies for ER-positive breast cancer and KRAS mutant lung cancer. In this study, we found that combinatory treatment with LY3009120 and abemaciclib synergistically inhibited proliferation of tumor cells in vitro and led to tumor growth regression in xenograft models with a KRAS, NRAS or BRAF mutation at the doses of two drugs that were well tolerated in combination. Further in vitro screen in 328 tumor cell lines revealed that tumor cells with KRAS, NRAS or BRAF mutation, or cyclin D activation are more sensitive, whereas tumor cells with PTEN, PIK3CA, PIK3R1 or retinoblastoma (Rb) mutation are more resistant to this combination treatment. Molecular analysis revealed that abemaciclib alone inhibited Rb phosphorylation partially and caused an increase of cyclin D1. The combinatory treatment cooperatively demonstrated more complete inhibition of Rb phosphorylation, and LY3009120 suppressed the cyclin D1 upregulation mediated by abemaciclib. These results were further verified by CDK4/6 siRNA knockdown. Importantly, the more complete phospho-Rb inhibition and cyclin D1 suppression by LY3009120 and abemaciclib combination led to more significant cell cycle G0/G1 arrest of tumor cells. These preclinical findings suggest that combined inhibition of RAF and d-cyclin-dependent kinases might provide an effective approach to treat patients with tumors harboring mutations in RAS or RAF genes.


Clinical Cancer Research | 2018

Phase I Study of LY2940680, a Smo Antagonist, in Patients with Advanced Cancer Including Treatment-Naïve and Previously Treated Basal Cell Carcinoma

Johanna C. Bendell; Valérie André; Alan Ho; Ragini R. Kudchadkar; Michael R. Migden; Jeffrey R. Infante; Ramon V. Tiu; Celine Pitou; Trevor Tucker; Les H. Brail; Daniel D. Von Hoff

Purpose: The purpose of this study was to determine a recommended phase II dose and schedule of LY2940680 (taladegib) for safe administration to patients with locally advanced/metastatic cancer. Experimental Design: This was a phase I, multicenter, open-label study of oral LY2940680. The maximum tolerable dose (MTD) was determined using a 3+3 design, the dose was confirmed, and then treatment-naïve and previously hedgehog (Hh)-inhibitor–treated patients with basal cell carcinoma (BCC) were enrolled. Results: Eighty-four patients were treated (dose escalation, n = 25; dose confirmation, n = 19; and BCC dose expansion, n = 40). Common treatment-emergent adverse events were dysgeusia [41 (48.8%)], fatigue [40 (47.6%)], nausea [38 (45.2%)], and muscle spasms [34 (40.5%)]. Four patients experienced events (3 were grade 3; 1 was grade 2) that were considered dose-limiting toxicities (DLT). The MTD was determined to be 400 mg because of DLTs and dose reductions. Pharmacokinetic analyses showed no clear relationship between exposure and toxicity. Analysis of Gli1 mRNA from skin biopsies from unaffected areas suggested that all doses were biologically active [inhibition median of 92.3% (80.9% to 95.7%)]. All clinical responses (per RECIST 1.1) were in patients with BCC (n = 47); the overall and estimated response rate was 46.8% (95% confidence interval, 32.1%–61.9%). Responses were observed in patients previously treated with Hh therapy (11/31) and in Hh treatment–naïve (11/16) patients. Conclusions: LY2940680 treatment resulted in an acceptable safety profile in patients with advanced/metastatic cancer. Clinical responses were observed in patients with locally advanced/metastatic BCC who were previously treated with Hh therapy and in Hh treatment–naïve patients. Clin Cancer Res; 24(9); 2082–91. ©2018 AACR.


Molecular Cancer Therapeutics | 2015

Abstract B32: LY2940680, a hedgehog (Hh) pathway inhibitor, demonstrates anti-tumor activity in patients with advanced basal cell carcinoma (BCC)

Johanna C. Bendell; Valérie André; Alan Ho; Ragini R. Kudchadkar; Michael R. Migden; Jeffrey R. Infante; Ramon V. Tiu; Celine Pitou; Trevor Tucker; Les H. Brail; Daniel D. Von Hoff

We previously reported interim dose escalation results from this multi-center, open-label Phase 1 clinical trial (NCT01226485) (Bendell et al, EJC 2012). Here, we report the final aggregate safety results and the anti-tumor activity demonstrated by LY2940680, a novel Hh pathway inhibitor, in locally advanced (la) and metastatic (m) BCC. Methods: The primary objective of this study was to determine a recommended Phase 2 dose and regimen of LY2940680 that could be safely administered to patients with advanced cancer, including BCC. Patients deemed eligible for experimental therapy were enrolled in the study and dosed once daily (QD) for 28 day cycles until discontinuation. The maximum tolerated dose (MTD) was determined using a 3+3 dose escalation design. Based on initial anti-tumor activity, a cohort of la/m BCC patients was enrolled. Safety, PK/PD, and tumor response data were collected and analyzed. Results: A total of 84 advanced cancer patients were dosed, including 47 patients with la/m BCC. Median age was 62.5 years (range: 29-89). Advanced cancer patients received escalating doses ranging from 50 mg to 600 mg QD resulting in a MTD of 400 mg QD. The most commonly reported treatment-emergent adverse events (TEAE) possibly related to study drug (>20%) were dysgeusia (Gr 1-2: 46.4%, Gr 3: 2.4%), fatigue (Gr 1-2: 44.0%, Gr 3: 3.6%), nausea (Gr 1-2: 42.9%, Gr 3: 2.4%), muscle spasms (Gr 1-2: 35.7%, Gr 3: 4.8%), decreased appetite (Gr 1-2: 35.7%, Gr 3: 0%), vomiting (Gr 1-2: 29.7%, Gr 3: 2.4%), alopecia (Gr 1-2: 33.3%, Gr 3: 0%), and weight decrease (Gr 1-2: 26.2%, Gr 3: 1.2%). PK analysis showed no clear relationship between exposure (PK) and toxicity. PD marker analysis of Gli-1 mRNA from unaffected skin biopsies suggested all doses were biologically active (inhibition median of 91.7% with interquartile range (80.9-95.7%) in all patients with available pre- and post-treatment biopsies). The most common reasons for treatment discontinuation were progression of disease (n = 43), adverse event (n = 10) and withdrawal by subject (n = 10). All reported clinical responses (per RECIST 1.1) were in patients with la/m BCC. Overall response rate (ORR) for patients with la/m BCC (n = 47) was 46.8% (95% CI: 32.1-61.9%) and clinical benefit rate (CR+PR+SD) was 93.6% (95% CI: 82.5-98.7%). The median duration of response was estimated at 10.2 months (95% CI: 5.6- not estimable). Responses were observed in patients who were Hh treatment naive (11/16) but also in patients who previously failed Hh therapy (11/31). Conclusion: LY2940680 treatment resulted in an acceptable safety profile in patients with advanced cancer including la/m BCC. Clinical responses were observed in la/m BCC patients naive to Hh inhibitor treatment and also in those who had failed treatment with other Hh inhibitor agents. This phase 1 study supports further clinical development of LY2940680 in advanced BCC and potentially in other malignancies Citation Information: Bendell J. et al. European Journal of Cancer (EJC) 2012 48(6 Suppl) Abstract 594. Citation Format: Johanna Bendell, Valerie Andre, Alan Ho, Ragini Kudchadkar, Michael Migden, Jeffrey Infante, Ramon Tiu, Celine Pitou, Trevor Tucker, Les Brail, Daniel Von Hoff. LY2940680, a hedgehog (Hh) pathway inhibitor, demonstrates anti-tumor activity in patients with advanced basal cell carcinoma (BCC). [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B32.


Cancer Research | 2017

Abstract 3231: Identifying high quality, potent and selective pyrimidinylthienopyrrolone inhibitors of ERK1/2 kinase: LY3214996

Gaiying Zhao; William Thomas Mcmillen; Shufen Cai; Baohui Zhao; Matthew Whitesell; Wenjuan Wu; Karen L. Huss; Bryan D. Anderson; Xiu-Juan Yuan; Susan Jaken; Lisa Kindler; Robert Flack; Denis J. McCann; Brian Michael Mathes; Andrew J. Dropsey; Jennie L. Walgren; Eunice Yuen; Jason Manro; Xueqian Gong; Guillermo S. Cortez; Johnathan Alexander Mclean; Michael J. Rodriguez; Ramon V. Tiu; Shripad V. Bhagwat; Sajan Joseph

The ERK/MAPK pathway plays a central role in the regulation of critical cellular processes and is activated in more than 30% of human cancers. While targeting upstream nodes with RAF and MEK inhibitors has proven effective clinically, resistance frequently develops through reactivation of the pathway. ERK inhibitors have the potential to address resistance caused by ERK reactivation. Herein, a potent, selective small molecule ERK1/2 inhibitor is described. LY3214996 possesses an optimal balance of potency (hERK1 IC50 5 nM, hERK2 IC50 5nM, pRSK IC50 0.43 µM), solubility (FaSSIF solubility at pH 6.5 0.133 µM), PK properties (dog, AUCoral 23800 nM*hr, CL 12.1 mL/min/kg, bioavailability 75.4%), IVTI (TED50 =16 mg/kg pRSK1) and demonstrated significant in vivo efficacy in several human cancer xenograft models. LY3214996 is currently undergoing early clinical evaluation. Citation Format: Gaiying Zhao, William T. McMillen, Shufen Cai, Baohui Zhao, Matthew Whitesell, Wenjuan Wu, Karen Huss, Bryan Anderson, Xiu-Juan Yuan, Susan Jaken, Lisa Kindler, Robert S. Flack, Denis McCann, Brian Mathes, Andrew J. Dropsey, Jennie Walgren, Eunice Yuen, Jason Manro, Xueqian Gong, Guillermo Cortez, Johnathan McLean, Michael J. Rodriguez, Ramon V. Tiu, Shripad V. Bhagwat, Sajan Joseph. Identifying high quality, potent and selective pyrimidinylthienopyrrolone inhibitors of ERK1/2 kinase: LY3214996 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3231. doi:10.1158/1538-7445.AM2017-3231


Cancer Research | 2017

Abstract 317: Combination of a novel ERK1/2 inhibitor (LY3214996) with CDK4 and CDK6 inhibitor (abemaciclib) enhances antitumor efficacy in KRAS mutant non-small cell lung cancer (NSCLC)

Wenjuan Wu; Shripad V. Bhagwat; Constance King; Susan E. Pratt; Xueqian Gong; Julie Stewart; Bonita D. Jones; Robert Flack; Richard Beckman; Beverly L. Falcon; Jason Manro; William Thomas Mcmillen; Ramon V. Tiu; Sheng-Bin Peng; Christoph Reinhard; Sajan Joseph; Sean Buchanan

ERK1/2, a key downstream effector of RAS mutations, is involved in the signaling network which drives cell proliferation, survival, metastasis and cancer resistance to drug treatment (including MEK and BRAF inhibitors). Lung cancer is a leading cause of cancer death worldwide. KRAS mutation present in up to 30% of NSCLC patients is associated with a poor prognosis and represents an unmet medical need. In KRAS mutant NSCLC, enhanced ERK activation cooperates with dysregulation of the cell cycle checkpoint (e.g., cyclin D, CDK4 and CDK6 complex), and contributes to tumor progression; thus, the simultaneous inhibition of ERK and the CDK4/6 pathway is hypothesized to augment tumor growth inhibition. LY3214996, a novel and highly selective small molecule inhibitor of ERK1 and ERK2, is currently in phase I clinical trial and has been shown to inhibit cell proliferation in RAS or BRAF mutant tumor cells in vitro and xenograft tumor growth in vivo. Abemaciclib, a CDK4 and CDK6-selective inhibitor is currently in phase III studies for ER positive breast cancer and KRAS mutant NSCLC. In this study we explore the potential efficacy of combined inhibition of ERK1/2 and CDK4 and CDK6 in KRAS mutant NSCLC. The combination of LY3214996 and abemaciclib synergistically inhibited cell proliferation in 85% of KRAS mutant cells in an unbiased NSCLC panel. Combination treatment with LY3214996 and abemaciclib significantly decreased levels of phospho- p90RSK, phospho-Rb, phospho-S6 and Ki67; and synergistically inhibited cell proliferation and survival in KRAS mutant NSCLC cell lines including NCI-H2122 (G-12C), A549 (G-12S) and NCI-H441 (G-12V). Subsequent in vivo studies showed that the combination treatment with LY3214996 and abemaciclib was well tolerated and led to more robust tumor growth inhibition or regression in all KRAS mutant NSCLC xenograft models (H2122, A549 and H441) compared with either single agent treatment (p≤0.002). Furthermore, in xenograft tumors the combination of LY3214996 and abemaciclib resulted in more significant reduction of phospho-p90RSK, phospho-Rb, phospho-S6 and Ki67 in H2122 tumors compared with either single agent. Overall, the combined inhibition of ERK1/2 and CDK4 and CDK6 was tolerated and enhanced antitumor efficacy in several KRAS mutant NSCLC preclinical models. These data support the feasibility of combining ERK inhibitor LY3214996 with CDK4 and CDK6 inhibitor abemaciclib as a promising strategy for the treatment of KRAS mutant NSCLC patients, and provides the rationale for the combination study in the on-going phase I LY3214996 clinic trial (NCT02857270). Citation Format: Wenjuan Wu, Shripad V. Bhagwat, Constance King, Susan Pratt, Xueqian Gong, Julie Stewart, Bonita Jones, Robert Flack, Richard Beckman, Beverly Falcon, Jason Manro, William T. McMillen, Ramon V. Tiu, Sheng-Bin Peng, Christoph Reinhard, Sajan Joseph, Sean Buchanan. Combination of a novel ERK1/2 inhibitor (LY3214996) with CDK4 and CDK6 inhibitor (abemaciclib) enhances antitumor efficacy in KRAS mutant non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 317. doi:10.1158/1538-7445.AM2017-317


Cancer Research | 2016

Abstract 930: Combined inhibition of pan-RAF and VEGFR-2 mediates antitumor activity in KRAS mutant non-small cell lung cancer (NSCLC) through enhanced inhibition of tumor angiogenesis and growth

Wenjuan Wu; Julie Stewart; Constance King; Bonita D. Jones; Robert Flack; Susan E. Pratt; Randi Berryman; Michelle Swearingen; Diane M. Bodenmiller; Xi Lin; Mark T. Uhlik; Beverly L. Falcon; Anthony S. Fischl; Jason Manro; Ramon V. Tiu; Sudhakar Chintharlapalli; Bronislaw Pytowski; Shripad V. Bhagwat; Sean Buchanan; Sheng-Bin Peng

Lung cancer is the leading cause of cancer death worldwide. MAPK activation via KRAS mutation is present in up to 30% of lung cancer patients. NSCLC patients with KRAS mutation is associated with poor prognosis and represents an unmet medical need. LY3009120, a pan-RAF and RAF dimer inhibitor which is in phase I clinical trial, was previously demonstrated to have anti-tumor activities in BRAF or RAS mutant tumor cells in vitro and in vivo. Ramucirumab, a fully-human antagonist monoclonal antibody to human VEGFR-2 was recently approved as an anti-angiogenic treatment for several cancer indications including second-line NSCLC. Combination strategies in cancer including targeting both tumor cells and the surrounding stroma cells have been shown to be effective in various disease subtypes. In this study, the combination effect of LSN3074753 (a surrogate and an analogue of LY3009120) with VEGFR-2 inhibitor DC101 (a monoclonal antibody specific for murine VEGFR-2 and a surrogate for ramucirumab) were evaluated in KRAS mutant NSCLC models, including NCI-H2122 (G-12C), A549 (G-12S) and NCI-H441 (G-12V). LSN3074753 treatment alone resulted in 66.9% and 82.4% tumor growth inhibition in H2122 and A549 xenograft tumors, respectively; and 41.4% tumor regression in H441 xenograft tumors. DC101 treatment alone resulted in 64.5%, 75% and 102.2% tumor growth inhibition in H2122, A549 and H441, respectively. The combination of LSN3074753 and DC101 led to more significant tumor growth inhibition (87.2% of tumor growth inhibition for H2122, p Citation Format: Wenjuan Wu, Julie Stewart, Constance King, Bonita Jones, Robert Flack, Susan Pratt, Randi Berryman, Michelle Swearingen, Diane Bodenmiller, Xi Lin, Mark Uhlik, Beverly Falcon, Anthony Fischl, Jason Manro, Ramon Tiu, Sudhakar Chintharlapalli, Bronislaw Pytowski, Shripad V. Bhagwat, Sean Buchanan, Sheng-Bin Peng. Combined inhibition of pan-RAF and VEGFR-2 mediates antitumor activity in KRAS mutant non-small cell lung cancer (NSCLC) through enhanced inhibition of tumor angiogenesis and growth. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 930.


Cancer Research | 2016

Abstract 282: Pan-RAF inhibitor LY3009120 sensitizes RAS or BRAF mutant cancer to CDK4 and 6 inhibition by abemaciclib via superior inhibition of phospho-RB and suppression of cyclin D1

Shih-Hsun Chen; Youyan Zhang; Robert D. Van Horn; Tinggui Yin; Lysiane Huber; Teresa F. Burke; Xueqian Gong; Wenjuan Wu; Shripad V. Bhagwat; Sean Buchanan; Richard P. Beckmann; Ramon V. Tiu; Sheng-Bin Peng

KRAS, NRAS and BRAF mutations are among the most important oncogenic drivers in many major cancer types, including melanoma, lung, colorectal, and pancreatic cancer. There is currently no effective therapy for the treatment of RAS mutant cancers. LY3009120, a pan-RAF and RAF dimer inhibitor currently in phase I clinical trial, has been shown to inhibit cell proliferation of RAS- or BRAF-mutant tumor cells in vitro and xenograft tumor growth in vivo. An unbiased screen for compounds that synergize with LY3009120 in RAS/BRAF mutant cancers identified inhibitors of CDK4 among the top hits. In this study, we found that combined inhibition of RAF and CDK4 and 6 by LY3009120 and abemaciclib cooperatively reduced viability of tumor cells with KRAS, NRAS or BRAF mutation in vitro. In animal models, the LY3009120 and abemaciclib combination exhibited synergistic regression of tumor growth in multiple xenograft models with KRAS, NRAS, or BRAF mutation. Molecular mechanistic analysis revealed that pan-RAF inhibitor treatment suppressed the cyclin D1 upregulation which was mediated through CDK4 and CDK6 inhibition by abemaciclib, and the combination treatment cooperatively demonstrated more complete inhibition of RB phosphorylation. These results were further verified by CDK4 and CDK6 siRNA knockdown and another CDK4 and CDK6 selective inhibitor palbociclib. Importantly, the more complete phospho-RB inhibition and cyclin D1 suppression by LY3009120 and abemaciclib combinational treatment led to more significant cell cycle G0/G1 arrest and apoptosis of tumor cells. These preclinical findings suggest that the combinational inhibition of RAF and CDK4 and CDK6 signaling by LY3009120 and abemaciclib is synergistic and should be further studied compared to single agents in the treatment of cancer in patients with KRAS, NRAS or BRAF mutations. Citation Format: Shih-Hsun Chen, Youyan Zhang, Robert D. Van Horn, Tinggui Yin, Lysiane Huber, Teresa F. Burke, Xueqian Gong, Wenjuan Wu, Shripad Bhagwat, Sean Buchanan, Richard P. Beckmann, Ramon V. Tiu, Sheng-Bin Peng. Pan-RAF inhibitor LY3009120 sensitizes RAS or BRAF mutant cancer to CDK4 and 6 inhibition by abemaciclib via superior inhibition of phospho-RB and suppression of cyclin D1. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 282.

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