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Small-cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers, and is characterized as extremely aggressive, often displaying rapid tumor growth and multiple organ metastases. In addition, the clinical outcome of SCLC patients is poor due to early relapse and acquired resistance to standard chemotherapy treatments. Hence, novel therapeutic strategies for the treatment of SCLC are urgently required. Accordingly, several molecular targeted therapies were evaluated in SCLC; however, they failed to improve the clinical outcome. The receptor tyrosine kinase MET is a receptor for hepatocyte growth factor (HGF), and aberrant activation of HGF/MET signaling is known as one of the crucial mechanisms enabling cancer progression and invasion. Here, we found that the HGF/MET signaling was aberrantly activated in chemoresistant or chemorelapsed SCLC cell lines (SBC-5, DMS273, and DMS273-G3H) by the secretion of HGF and/or MET copy number gain. A cell-based in vitro assay revealed that HGF/MET inhibition, induced either by MET inhibitors (crizotinib and golvatinib), or by siRNA-mediated knockdown of HGF or MET, constrained growth of chemoresistant SCLC cells through the inhibition of ERK and AKT signals. Furthermore, treatment with either crizotinib or golvatinib suppressed the systemic metastasis of SBC-5 cell tumors in natural killer cell-depleted SCID mice, predominantly through cell cycle arrest. These findings reveal the therapeutic potential of targeting the HGF/MET pathway for inhibition, to constrain tumor progression of SCLC cells showing aberrant activation of HGF/MET signaling. We suggest that it would be clinically valuable to further investigate HGF/MET-mediated signaling in SCLC cells.

Almost all cancers show intrinsic and/or evasive resistance to vascular endothelial growth factor (VEGF) inhibitors by multiple mechanisms. Serum angiopoietin-2 (Ang2) level has been proposed as a potential biomarker of VEGF inhibitor response in several cancers. From these clinical observations, the Ang2 and Tie2 (its receptor) axis has been focused on as a promising target. Here, we show a novel strategy to circumvent the resistance by combining multi-tyrosine kinase inhibitors lenvatinib (VEGF receptor, fibroblast growth factor receptor, and RET inhibitor) and golvatinib (E7050; c-Met, Tie2, and EphB4 inhibitor). Tie2 identifies a highly pro-angiogenic macrophage subset, Tie2-expressing macrophages (TEM). Angi-Tie2 and EphB4-EphrinB2 signaling plays critical roles in pericyte-mediated vessel stabilization. In vitro analyses suggested that golvatinib combined with lenvatinib inhibited pericyte-mediated vessel stabilization and TEM differentiation. In thyroid and endometrial cancer models, golvatinib and lenvatinib inhibited pericyte network development and TEM infiltration, resulting in severe perfusion disorder and massive apoptosis. Body weight loss was tolerable, and no macroscopic change was observed. These preclinical studies suggest that modulation of the tumor microenvironment by a strategic and well-tolerated combination of multi-targeting tyrosine kinase inhibitors may sensitize cancer to VEGF inhibitors.

Purpose: Receptor tyrosine kinases c-Met and Ron transduce signals regulating cell migration and matrix invasion. This phase I dose-escalation trial tested golvatinib, a highly potent, small-molecule, ATP-competitive inhibitor of c-Met and multiple members of the Eph receptor family plus c-Kit and Ron. Experimental Design: Patients with advanced solid tumors received golvatinib orally, once daily, continuously. Using a “3+3” design, dosing started at 100 mg once daily, escalating to the maximum tolerated dose (MTD) defined by dose-limiting toxicities. Pharmacokinetic, pharmacodynamic, and preliminary antitumor activity was assessed during dose escalation and in a MTD expansion cohort. Results: Thirty-four patients were treated at six dose levels. The MTD was determined as 400 mg once daily. Three dose-limiting toxicities were observed: grade 3 increased γ-glutamyltransferase and alkaline phosphatase (200 mg), repeated grade 2 fatigue, and grade 3 fatigue (50.0%). Frequent treatment-related adverse events (with incidence >10%) included diarrhea (58.8%), nausea (50%), vomiting (44.1%), fatigue (41.2%), decreased appetite (32.4%), elevated alanine aminotransferase (32.4%), elevated aspartate aminotransferase (20.6%), dry skin (11.8%), and dysgeusia (11.8%). Best overall response was stable disease (median duration 85 days, range 85–237). Pharmacokinetics demonstrated high variability, although maximum plasma concentration and area under the plasma concentration–time curve increased with dose. Soluble urokinase-type plasminogen activator receptor, VEGFR2, c-Met, and angiopoietin-2 levels increased after dose. Posttreatment decrease in either p-c-Met or p-ERK was observed in 3 of 4 paired biopsies at MTD. Conclusions: Golvatinib at the MTD of 400 mg once daily was well tolerated with pharmacodynamic evidence of c-Met target modulation. Clin Cancer Res; 20(24); 6284–94. ©2014 AACR.

Vascular endothelial growth factor receptor (VEGFR) inhibitors are approved for the treatment of several tumor types; however, some tumors show intrinsic resistance to VEGFR inhibitors, and some patients develop acquired resistance to these inhibitors. Therefore, a strategy to overcome VEGFR inhibitor resistance is urgently required. Recent reports suggest that activation of the hepatocyte growth factor (HGF) pathway through its cognate receptor, Met, contributes to VEGFR inhibitor resistance. Here, we explored the effect of the HGF/Met signaling pathway and its inhibitors on resistance to lenvatinib, a VEGFR inhibitor. In in vitro experiments, addition of VEGF plus HGF enhanced cell growth and tube formation of HUVECs when compared with stimulation by either factor alone. Lenvatinib potently inhibited the growth of HUVECs induced by VEGF alone, but cells induced by VEGF plus HGF showed lenvatinib resistance. This HGF-induced resistance was cancelled when the Met inhibitor, golvatinib, was added with lenvatinib. Conditioned medium from tumor cells producing high amounts of HGF also conferred resistance to inhibition by lenvatinib. In s.c. xenograft models based on various tumor cell lines with high HGF expression, treatment with lenvatinib alone showed weak antitumor effects, but treatment with lenvatinib plus golvatinib showed synergistic antitumor effects, accompanied by decreased tumor vessel density. These results suggest that HGF from tumor cells confers resistance to tumor endothelial cells against VEGFR inhibitors, and that combination therapy using VEGFR inhibitors with Met inhibitors may be effective for overcoming resistance to VEGFR inhibitors. Further evaluation in clinical trials is warranted.

Although vascular endothelial growth factor (VEGF) inhibitors provide significant clinical benefit, they often require dose reductions or even withdrawals due to their severe toxicities. Furthermore, almost all cancers show intrinsic and/or evasive resistance to VEGF inhibitors by multiple mechanisms. Serum angiopoietin-2 (Ang2) level has been proposed as a potential biomarker of VEGF inhibitor response in several cancers. Response to lenvatinib (E7080; VEGFR1-3 inhibitor) is also reported to correlate with low Ang2 level in differentiated thyroid cancer and endometrial cancer. From these clinical observations, Ang2 and its receptor Tie2 has been focused as promising targets. Here, we demonstrated mechanisms of resistance induced by Ang2 and a novel strategy to circumvent the resistance by combination of multi-tyrosine kinase inhibitors (TKIs), lenvatinib and golvatinib (E7050; c-Met, Tie2, EphB4 inhibitor). Tie2 defines a highly pro-angiogenic macrophage subset, Tie2-expressing macrophage (TEM). Ang-Tie2 and EphB4-EphrinB2 signaling play critical roles in pericyte-mediated vessel stabilization. Ectopic expression of Ang2 in thyroid cancer conferred resistance to lenvatinib and enhanced pericyte-associated endothelial network development and TEM infiltration. In vitro analyses suggested that golvatinib/lenvatinib combination inhibited pericyte-mediated vessel stabilization and TEM differentiation. In thyroid and endometrial cancer models, golvatinib/lenvatinib combination inhibited pericyte network development and TEM infiltration, resulting in severe perfusion disorder and massive apoptosis. Body weight loss was tolerable in mice, and no macroscopic change was observed. These results suggest that modulation of tumor microenvironment by strategic and well-tolerated combination of multi-targeting TKIs sensitizes cancer to VEGF inhibitors, which warrants further clinical investigation to determine the clinical benefit of anti-angiogenesis cancer therapy. Citation Format: Youya Nakazawa, Satoshi Kawano, Junji Matsui, Yasuhiro Funahashi, Osamu Tohyama, Hiroki Muto, Takayuki Nakagawa, Tomohiro Matsushima. Maximizing the efficacy of anti-angiogenesis cancer therapy: A multi-targeting strategy by tyrosine kinase inhibitors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2980. doi:10.1158/1538-7445.AM2014-2980

Vascular endothelial growth factor receptor (VEGFR) inhibitors are approved for the treatment of several types of tumors, however, some tumor shows intrinsic resistance to VEGFR inhibitors. In addition, patients initially responding develop acquired resistance to VEGFR inhibitors after varying periods of time. Thus it is urgent to develop strategy to overcome anti-VEGF therapy resistance. Hepatocyte growth factor (HGF)/Met signaling is activated in various types of tumors. Recently, it is reported that HGF/Met signaling contributes to resistance to tyrosine kinase inhibitors such as EGFR, BRAF, ALK inhibitors. This suggests that Met inhibitors may be promising in treating HGF/Met activated anti-VEGF therapy-resistant tumors. We have identified lenvatinib (E7080) as a highly-potent VEGFR inhibitor and phase III trial is ongoing in thyroid cancer. Lenvatinib inhibited the growth of HUVEC induced by VEGF, however, addition of HGF to HUVEC conferred resistance to lenvatinib. This resistance was cancelled by the addition of golvatinib (E7050) which is identified as a potent Met/EphB4 inhibitor and phase I trial of the lenvatinib/golvatinib combination therapy is ongoing. In mouse models bearing various tumor cell lines expressing VEGF and HGF, treatment with lenvatinib alone demonstrated only moderate antitumor activity, however, combination with golvatinib demonstrated synergistic antitumor activity with decrease of tumor vessel density. Furthermore, it is reported that EphB4 has critical roles in tumor vessel development and maturation. Our unique in vitro assay systems, endothelial cells/pericyte 2D co-culture assay and endothelial cells/pericyte 3D co-culture sprouting assay, suggested that EphB4 inhibitory activity of golvatinib disrupted anti-VEGF therapy-resistant tumor vascular in the combination with lenvatinib. Together, these data demonstrated that combination therapy with golvatinib may be promising to overcome anti-VEGF therapy resistance. Citation Format: Satoshi Kawano, Takayuki Nakagawa, Yuya Nakazawa, Yoshiaki Sato, Tomohiro Matsushima, Yasuhiro Funahashi. Combination of VEGFR inhibitor lenvatinib (E7080) and Met/EphB4 inhibitor golvatinib (E7050) overcomes VEGFR inhibitor-resistant tumor vascular. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1619. doi:10.1158/1538-7445.AM2013-1619

Background Golvatinib is a highly potent, small-molecule ATP-competitive inhibitor of the c-Met receptor tyrosine kinase and multiple members of the Eph receptor family as well as c-Kit and Ron, based on isolated kinase assays. Golvatinib showed preclinical evidence of anti-tumor activity. Two phase 1 studies were conducted: a once daily (QD) dosing study in UK and a twice daily (BID) dosing study in JP to evaluate the MTD, safety, PK, PD and preliminary activity. Methods Golvatinib was administered orally, QD or BID, continuously to patients with advanced solid tumors. Blood samples for PK and PD analysis were collected at multiple time-points. Tumor tissues were collected pre- and post-cycle 1 for PD analysis in an expanded MTD cohort. Results 34 patients were treated at 6 QD doses levels (100, 200, 270, 360, 450 and 400 mg QD) and 16 patients were treated at 4 BID doses levels (50, 100, 200 and 300 mg BID). In the QD dosing, 3 DLTs occurred: Gr3 GGT and alkaline phosphatase (n = 1; 200 mg QD) and repeated Gr2 (n = 1) and Gr3 (n = 1) fatigue, both at 450 mg QD. In the BID dosing, one DLT (Gr3 ALT) and one equivalent DLT (Gr2 vomiting, nausea and anorexia) occurred, both at 300 mg BID. The MTDs were determined to be 400 mg QD and 200 mg BID. Frequently occurring AEs (of which, all ≤G3) across both dosing regimens (n = 50) were fatigue 58% (G3: 10%), nausea 56% (G3: 2%), diarrhea 54%, vomiting 48%, decreased appetite 48% (G3: 8%), ALT increase 44% (G3: 2%) and AST increase 32%. Best response included 6 SDs (>84 days) and 4 SDs (>84 days) in the QD and the BID dosing, respectively. PK showed high variability and plasma concentration increased with dose. The Cmax was reached at a median time of 2–4 h, and declined with a t1/2 of ∼40 h. Plasma PD analysis showed a significant increase in soluble c-Met levels after golvatinib treatment. Tumour tissue PD analysis in five patients at 400 mg QD demonstrated a baseline elevated MET gene copy number, with c-Met over-expression and post-treatment decline phospho (p)-c-Met expression in 1 patient, post-treatment decline in p-c-Met in the second patient, and post-treatment decline in p-ERK in the third patient. Conclusions The MTD of golvatinib was achieved at 400 mg QD and 200 mg BID. Preliminary PD analysis demonstrated evidence of c-Met target modulation. QD dosing was selected for further evaluation of golvatinib in phase 2 studies.