Search

Association of NR1I3 haplotype with TTP (Supplementary Online only). CAT/CAT carriers, median TTP 1.92 months vs 6.21 months for CAT/â^' or â^'/â^' carriers.

Purpose: This phase I/II single-arm study evaluated the safety, pharmacokinetics, pharmacodynamics, and activity of foretinib, an oral multikinase inhibitor of MET, ROS, RON, AXL, TIE-2, and VEGFR2, in the first-line setting in advanced hepatocellular carcinoma patients.Experimental Design: In the phase I part, advanced hepatocellular carcinoma patients were dose escalated on foretinib (30–60 mg) every day using the standard 3+3 design. Once the maximum tolerated dose (MTD) was determined, an additional 32 patients were dosed at the MTD in the phase II expansion cohort for assessment of efficacy and safety. Exploratory analyses were conducted to assess potential biomarkers that might correlate with clinical efficacy and survival.Results: The MTD of foretinib was established as 30 mg every day. The most frequent adverse events were hypertension, decreased appetite, ascites, and pyrexia. When dosed at 30 mg every day in the first-line setting, foretinib demonstrated promising antitumor activity. According to the modified mRECIST, the objective response rate was 22.9%, the disease stabilization rate 82.9%, and the median duration of response 7.6 months. The median time to progression was 4.2 months and the median overall survival (OS) was 15.7 months. Fifteen candidate biomarkers whose levels in the circulation were significantly altered in response to foretinib treatment were elucidated. Multivariate analyses identified IL6 and IL8 as independent predictors of OS.Conclusions: Foretinib demonstrated promising antitumor activity and good tolerability in the first-line setting in Asian advanced hepatocellular carcinoma patients. Baseline plasma levels of IL6 or IL8 might predict the response to foretinib. Clin Cancer Res; 23(10); 2405–13. ©2016 AACR.

Table S1: Summary of pharmacokinetic parameters (days 1 and 15); Table S2: Significant changes in circulating biomarkers from baseline; Table S3: Multivariate models for selected covariates, Overall Survival.

Ruxolitinib cream demonstrated safety and efficacy over 8 weeks in two double-blind phase 3 atopic dermatitis studies (NCT03745638/NCT03745651).Evaluate long-term safety (LTS) and disease control with ruxolitinib cream.Patients initially randomized to twice-daily 0.75%/1.5% ruxolitinib cream maintained their regimen during the 44-week LTS period (as-needed treatment). Patients on vehicle were rerandomized (1:1) at Week 8 to either ruxolitinib cream strength. Safety and disease control (Investigator's Global Assessment [IGA] score 0/1 and affected body surface area [BSA]) were assessed.Over 52 weeks, adverse events (AEs) were reported in 67.4%/62.6%/53.5%/57.6% of patients in 0.75%/1.5% ruxolitinib cream/vehicle to 0.75% ruxolitinib cream/vehicle to 1.5% ruxolitinib cream groups (n=426/446/101/99). Most common AEs were upper respiratory tract infection (10.3%/11.4%/5.9%/7.1%) and nasopharyngitis (8.9%/9.9%/7.9%/14.1%). Most AEs were considered unrelated to treatment. Application site reactions were infrequent (3.8%/1.8%/1.0%/1.0%). Disease control was achieved throughout the LTS; 74.1%-77.8% of patients had IGA 0/1 at Week 52, and mean affected BSA was low (1.4%-1.8%).LTS had no control treatment.During 44 weeks of as-needed treatment, ruxolitinib cream demonstrated effective disease control and tolerability; low ruxolitinib plasma concentrations alongside safety findings reflecting known risk factors suggest physiologically meaningful systemic Janus kinase inhibition is highly unlikely.

Purpose Camrelizumab inhibits PD-1 in non-clinical models and showed typical non-clinical pharmacokinetic (PK) and safety profiles for an IgG4 monoclonal antibody. We report results from the First-in-Human Phase 1 trial of camrelizumab in Australian population.

[This corrects the article DOI: 10.1371/journal.pone.0054014.].

Purpose Camrelizumab inhibits PD-1 in non-clinical models and showed typical non-clinical pharmacokinetic (PK) and safety profiles for an IgG4 monoclonal antibody. We report results from the First-in-Human Phase 1 trial of camrelizumab in Australian population. Methods Camrelizumab was administered to patients with advanced solid tumors who had failed standard therapies. In the dose-escalation phase (n=23), camrelizumab was administered intravenously at 1 mg/kg, 3 mg/kg, 6 mg/kg, and 10 mg/kg every 2 weeks. In dose expansion (n=26), camrelizumab was given at 200 mg or 600 mg every 4 weeks. Results Two dose-limiting toxicities were observed during dose escalation: transaminase elevation and diarrhea (both grade 3). Overall, treatment-related adverse events were consistent with the expected toxicity profile of immune checkpoint inhibition, with the striking exception of the dose-related development of angiomatous skin lesions characterized as reactive cutaneous capillary endothelial proliferation. The PK profile showed a dose-progressive increase in half-life from 3 days at 1 mg/kg to 7 days at 10 mg/kg. Moreover, receptor occupancy assays showed a PD-1 occupancy of >50% in most patients out to 28 days post-dose. The objective response rate was 15.2% (95% CI 6.3–28.9). Conclusion Camrelizumab has manageable toxicity and encouraging preliminary antitumor activity in advanced solid tumors in Australia. Clinical Trial Registration ClinicalTrials.gov Identifier: NCT02492789.

Foretinib is a multikinase inhibitor that inhibits multiple receptor tyrosine kinases, including MET and VEGFR, with the potential for treatment of solid tumors. Hepatocellular carcinoma (HCC) pathogenesis is associated with overexpression of MET, and physiologic changes in the livers of HCC patients may decrease CYP3A isozyme-mediated metabolism of foretinib. A population pharmacokinetic model of foretinib was developed to explore the effect of tumor type, formulation, and other covariates. Data from 1 HCC study in Asia and 3 non-HCC studies in the United States with varying foretinib regimens and formulations were used for analysis. A 2-compartment model with a linear first-order absorption and elimination and lag time in absorption adequately described foretinib pharmacokinetics in 132 advanced non-HCC and HCC patients and identified an effect of formulations on bioavailability. The bisphosphate salt capsules and freebase tablets had a relative bioavailability 37% and 20% higher, respectively, than the solution formulation. HCC patients had ≈19.6% lower mean clearance (70.14 L/h), ≈16% lower mean volume of distribution (1725.6 L), and higher dose-normalized exposure compared with non-HCC patients. This could be a result of differences in metabolism in HCC patients, body weight, or activity of CYP3A isozymes between Asian and Western cancer patients.

Purpose: This phase I/II single-arm study evaluated the safety, pharmacokinetics, pharmacodynamics, and activity of foretinib, an oral multikinase inhibitor of MET, ROS, RON, AXL, TIE-2, and VEGFR2, in the first-line setting in advanced hepatocellular carcinoma patients. Experimental Design: In the phase I part, advanced hepatocellular carcinoma patients were dose escalated on foretinib (30–60 mg) every day using the standard 3+3 design. Once the maximum tolerated dose (MTD) was determined, an additional 32 patients were dosed at the MTD in the phase II expansion cohort for assessment of efficacy and safety. Exploratory analyses were conducted to assess potential biomarkers that might correlate with clinical efficacy and survival. Results: The MTD of foretinib was established as 30 mg every day. The most frequent adverse events were hypertension, decreased appetite, ascites, and pyrexia. When dosed at 30 mg every day in the first-line setting, foretinib demonstrated promising antitumor activity. According to the modified mRECIST, the objective response rate was 22.9%, the disease stabilization rate 82.9%, and the median duration of response 7.6 months. The median time to progression was 4.2 months and the median overall survival (OS) was 15.7 months. Fifteen candidate biomarkers whose levels in the circulation were significantly altered in response to foretinib treatment were elucidated. Multivariate analyses identified IL6 and IL8 as independent predictors of OS. Conclusions: Foretinib demonstrated promising antitumor activity and good tolerability in the first-line setting in Asian advanced hepatocellular carcinoma patients. Baseline plasma levels of IL6 or IL8 might predict the response to foretinib. Clin Cancer Res; 23(10); 2405–13. ©2016 AACR.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, a member of the family of acyl-condensing enzymes, catalyzes the first committed step in the mevalonate pathway and is a potential target for novel antibiotics and cholesterol-lowering agents. The Staphylococcus aureus mvaS gene product (43.2 kDa) was overexpressed in Escherichia coli, purified to homogeneity, and shown biochemically to be an HMG-CoA synthase. The crystal structure of the full-length enzyme was determined at 2.0-A resolution, representing the first structure of an HMG-CoA synthase from any organism. HMG-CoA synthase forms a homodimer. The monomer, however, contains an important core structure of two similar alpha/beta motifs, a fold that is completely conserved among acyl-condensing enzymes. This common fold provides a scaffold for a catalytic triad made up of Cys, His, and Asn required by these enzymes. In addition, a crystal structure of HMG-CoA synthase with acetoacetyl-CoA was determined at 2.5-A resolution. Together, these structures provide the structural basis for an understanding of the mechanism of HMG-CoA synthase.

Tuberculosis remains a global health problem, and programs dedicated to discovery of novel compounds against Mycobacterium tuberculosis require robust assays for high-throughput screening of chemical and natural product libraries. Enzymes involved in the biosynthesis of mycolic acids, vital components of the mycobacterial cell wall, have received much attention as potential drug targets. KasA and KasB, examples of the beta-ketoacyl-acyl carrier protein synthase I/II (KASI/II) class of condensing enzymes of the M. tuberculosis fatty acid synthase II system have been the focus of several studies designed to biochemically characterize these enzymes. Whilst robust methods have been developed for FabH-like proteins, fast and sensitive assays for high-throughput screening of KASI/II enzymes have not been available. Here we report the development of a direct scintillation proximity assay (SPA) for the KASI/II enzymes, KasA and KasB. The SPA was more sensitive than existing assays, as shown by its ability to measure activity using less enzyme than other assay formats, and the SPA was validated using the known KAS inhibitor thiolactomycin. In addition, the KasA and KasB SPA was adapted for use with Staphylococcus aureus FabF to show the versatility of this assay format to KAS enzymes from other pathogenic organisms.

Mycolic acids are vital components of the Mycobacterium tuberculosis cell wall, and enzymes involved in their formation represent attractive targets for the discovery of novel anti-tuberculosis agents. Biosynthesis of the fatty acyl chains of mycolic acids involves two fatty acid synthetic systems, the multifunctional polypeptide fatty acid synthase I (FASI), which performs de novo fatty acid synthesis, and the dissociated FASII system, which consists of monofunctional enzymes, and acyl carrier protein (ACP) and elongates FASI products to long chain mycolic acid precursors. In this study, we present the initial characterization of purified KasA and KasB, two beta-ketoacyl-ACP synthase (KAS) enzymes of the M. tuberculosis FASII system. KasA and KasB were expressed in E. coli and purified by affinity chromatography. Both enzymes showed activity typical of bacterial KASs, condensing an acyl-ACP with malonyl-ACP. Consistent with the proposed role of FASII in mycolic acid synthesis, analysis of various acyl-ACP substrates indicated KasA and KasB had higher specificity for long chain acyl-ACPs containing at least 16 carbons. Activity of KasA and KasB increased with use of M. tuberculosis AcpM, suggesting that structural differences between AcpM and E. coli ACP may affect their recognition by the enzymes. Both enzymes were sensitive to KAS inhibitors cerulenin and thiolactomycin. These results represent important steps in characterizing KasA and KasB as targets for antimycobacterial drug discovery.

Mycolic acids are generated in Mycobacterium tuberculosis as a result of the interaction of two fatty acid biosynthetic systems: the multifunctional polypeptide, FASI, in which the acyl carrier protein (ACP) domain forms an integral part of the polypeptide, and the dissociated FASII system, which is composed of monofunctional enzymes and a discrete ACP (AcpM). In order to characterize enzymes of the FASII system, large amounts of AcpM are required to generate substrates such as holo-AcpM, malonyl-AcpM and acyl-AcpM. The M. tuberculosis acpM gene was overexpressed in Escherichia coli and AcpM purified, yielding approximately 15-20 mg/l of culture. Analysis of AcpM by mass spectrometry, N-terminal sequencing, amino acid analysis, and gas chromatography indicated the presence of three species, apo-, holo-, and acyl-AcpM, the former comprising up to 65% of the total pool. The apo-AcpM was purified away from the in vivo generated holo- and acyl-forms, which were inseparable and heterogeneous with respect to acyl chain lengths. Once purified, we were able to convert apo-AcpM into holo- and acyl-forms. These procedures provide the means for the preparation of the large quantities of AcpM and derivatives needed for characterization of the purified enzymes of the mycobacterial FASII system.

The aroA gene (Escherichia coli nomenclature) encoding 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase from the gram-positive pathogen Streptococcus pneumoniae has been identified, cloned and overexpressed in E. coli, and the enzyme purified to homogeneity. It was shown to catalyze a reversible conversion of shikimate 3-phosphate (S3P) and phosphoenolpyruvate (PEP) to EPSP and inorganic phosphate. Activation by univalent cations was observed in the forward reaction, with NH+4, Rb+ and K+ exerting the greatest effects. Km(PEP) was lowered by increasing [NH+4] and [K+], whereas Km(S3P) rose with increasing [K+], but fell with increasing [NH+4]. Increasing [NH+4] and [K+] resulted in an overall increase in kcat. Glyphosate (GLP) was found to be a competitive inhibitor with PEP, but the potency of inhibition was profoundly affected by [NH+4] and [K+]. For example, increasing [NH+4] and [K+] reduced Ki(GLP versus PEP) up to 600-fold. In the reverse reaction, the enzyme catalysis was less sensitive to univalent cations. Our analysis included univalent cation concentrations comparable with those found in bacterial cells. Therefore, the observed effects of these metal ions are more likely to reflect the physiological behavior of EPSP synthase and also add to our understanding of how to inhibit this enzyme in the host organism. As there is a much evidence to suggest that EPSP synthase is essential for bacterial survival, its discovery in the serious gram-positive pathogen S. pneumoniae and its inhibition by GLP indicate its potential as a broad-spectrum antibacterial target.

Purpose The receptors for hepatocyte and vascular endothelial cell growth factors (MET and VEGFR2, respectively) are critical oncogenic mediators in gastric adenocarcinoma. The purpose is to examine the safety and efficacy of foretinib, an oral multikinase inhibitor targeting MET, RON, AXL, TIE-2, and VEGFR2 receptors, for the treatment of metastatic gastric adenocarcinoma. Patients and Methods Foretinib safety and tolerability, and objective response rate (ORR) were evaluated in patients using intermittent (240 mg/day, for 5 days every 2 weeks) or daily (80 mg/day) dosing schedules. Thirty evaluable patients were required to achieve alpha = 0.10 and beta = 0.2 to test the alternative hypothesis that single-agent foretinib would result in an ORR of ≥25%. Up to 10 additional patients could be enrolled to ensure at least eight with MET amplification. Correlative studies included tumor MET amplification, MET signaling, pharmacokinetics and plasma biomarkers of foretinib activity. Results From March 2007 until October 2009, 74 patients were enrolled; 74% male; median age, 61 years (range, 25–88); 93% had received prior therapy. Best response was stable disease (SD) in 10 (23%) patients receiving intermittent dosing and five (20%) receiving daily dosing; SD duration was 1.9–7.2 months (median 3.2 months). Of 67 patients with tumor samples, 3 had MET amplification, one of whom had SD. Treatment-related adverse events occurred in 91% of patients. Rates of hypertension (35% vs. 15%) and elevated aspartate aminotransferase (23% vs. 8%) were higher with intermittent dosing. In both patients with high baseline tumor phospho-MET (pMET), the pMET:total MET protein ratio decreased with foretinib treatment. Conclusion These results indicate that few gastric carcinomas are driven solely by MET and VEGFR2, and underscore the diverse molecular oncogenesis of this disease. Despite evidence of MET inhibition by foretinib, single-agent foretinib lacked efficacy in unselected patients with metastatic gastric cancer. Trial Registration ClinicalTrials.gov NCT00725712

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase, a member of the family of acyl-condensing enzymes, catalyzes the first committed step in the mevalonate pathway and is a potential target for novel antibiotics and cholesterol-lowering agents. The Staphylococcus aureus mvaS gene product (43.2 kDa) was overexpressed in Escherichia coli, purified to homogeneity, and shown biochemically to be an HMG-CoA synthase. The crystal structure of the full-length enzyme was determined at 2.0-A resolution, representing the first structure of an HMG-CoA synthase from any organism. HMG-CoA synthase forms a homodimer. The monomer, however, contains an important core structure of two similar alpha/beta motifs, a fold that is completely conserved among acyl-condensing enzymes. This common fold provides a scaffold for a catalytic triad made up of Cys, His, and Asn required by these enzymes. In addition, a crystal structure of HMG-CoA synthase with acetoacetyl-CoA was determined at 2.5-A resolution. Together, these structures provide the structural basis for an understanding of the mechanism of HMG-CoA synthase.

The UDP-N-acetylenolpyruvylglucosamine reductase (MurB) from a Gram-positive pathogen, Streptococcus pneumoniae, was identified and characterized. The enzyme from S. pneumoniae shows 31% identity with the MurB protein from Escherichia coli, and contains the catalytic residues, substrate-binding residues and FAD-binding motif identified previously in the E. coli protein. The gene was cloned into the pET28a+ expression vector, and the 34.5kDa protein that it encodes was overexpressed in E. coli strain BL21(DE3) to 30% of total cell protein. The majority of the protein was found to be insoluble. A variety of methods were used to increase the amount of soluble protein to 10%. This was then purified to near homogeneity in a two-step process. The absorption spectrum of the purified protein indicated it to be a flavoprotein, like its E. coli homologue, with a characteristic absorption at 463nm. The enzyme was shown to be active, reducing UDP-N-acetylglucosamine enolpyruvate with the concomitant oxidation of NADPH, and was characterized kinetically with respect to its two substrates. The enzyme showed properties similar to those of its E. coli counterpart, being activated by univalent cations and being subject to substrate inhibition. The characterization of an important cell wall biosynthesis enzyme from a Gram-positive pathogen provides a good starting point for the discovery of antibacterial agents against MurB.

Human papillomavirus type 6b (HPV-6b) is one of the most common causes of human genital warts, an important sexually transmitted disease. Discovery of antiviral therapies for this condition has been hampered by the inability to propagate the virus using standard tissue culture techniques and through difficulties in expressing sufficient recombinant viral proteins in vitro. Replication of papillomavirus DNA requires two viral proteins, E1 and E2. In an effort to establish assays to discover compounds active against this virus, we have co-expressed HPV-6b E1 and E2 proteins in insect cells. We demonstrate that the two proteins form a heteromeric complex which can be purified by sequence-specific DNA affinity chromatography. We also demonstrate that the complex has both E1-associated ATPase and ATP-dependent DNA helicase activity and report further characterization of these functions.

4108 Background: Hepatocyte growth factor (HGF)/MET signalling plays a pivotal role in tumor cell proliferation, migration and invasion in HCC and circulating levels of HGF correlate with poor prognosis. This phase I/II trial (MET111645) evaluated foretinib, an oral multikinase inhibitor targeting MET, RON, AXL, TIE-2 and VEGFR, as first-line therapy in Asian advanced-HCC patients. Methods: Asian patients with measurable, unresectable/metastatic HCC, no prior sorafenib or other multi-kinase inhibitors, ECOG PS 0-1, adequate organ function and Child-Pugh grade A were recruited. The phase I was a standard 3+3 dose escalation design with a phase II cohort expansion. The primary endpoint was safety and tolerability at the maximum tolerated dose (MTD) and the secondary endpoints included antitumor activity (objective response rate [ORR], disease stabilization rate [DSR; confirmed CR/PR or SD for at least 12 weeks], and time to progression [TTP] evaluated by central review according to modified RECIST), and overall survival (OS) at the MTD, plus pharmacokinetics (PK). Results: Thirteen patients were enrolled in phase I. Two dose-limiting toxicities (DLT) (renal failure, proteinuria) were observed at 45 mg once daily (QD) but no DLTs were observed at 30 mg QD. Thus, the MTD was determined to be 30 mg QD. A further 32 patients were enrolled at the MTD, for a study total of 39 patients treated at 30 mg QD. The most common AEs, independent of causality,were hypertension (36%), decreased appetite (23%), and pyrexia (21%). The most common SAEs were hepatic encephalopathy (10%) and ascites (8%). Two patients discontinued foretinib due to AEs. No dose reductions were reported. Thirty-eight patients were evaluable for efficacy. The ORR was 24% (95% CI 11-40), DSR 79% (95% CI; 63-90), and the median TTP was 4.2 months (95% CI 2.7-7.5). Mature OS data will be presented. Mean steady-state exposures (AUC/Cmax) were comparable after administration of foretinib at 30 and 45 mg. Conclusions: Foretinib has an acceptable safety, tolerability, and PK profile in an Asian HCC population. It has demonstrated promising antitumor activity that warrants further testing in a randomized setting.

Signal Transduction via the hepatocyte growth factor (HGF)/Met receptor kinase pathway is critical for normal embryogenesis and adult homeostasis, and aberrant HGF/Met signaling contributes to tumorigenesis and metastasis in many prevalent forms of cancer. By defining the basic molecular mechanisms of pathway activation at the target cell surface, we hope to develop novel strategies to antagonize oncogenic signaling as well as methods to assess pathway status in cancer patients. These methods may help identify those most likely to benefit from HGF/Met targeted therapies and help monitor treatment response. Distinct domains of HGF bind to the Met receptor tyrosine kinase and to cell-surface heparan sulfate (HS) proteoglycans. The latter are widely expressed, structurally diverse biopolymers that modulate many important protein-protein interactions, but their importance in eliciting HGF biological responses is controversial. We have identified basic (positively charged) amino acid residues in HGF that form the primary binding site for (negatively charged) HS proteoglycans. HS binding by these residues increases the affinity of ligand-receptor binding and, with HS polymers of sufficient length, facilitates ligand oligomerization. Ligand oligomerization, in turn, controls Met kinase activation, cell motility and proliferation under normal conditions. Opposite (negative) charge amino acid substitutions at these critical HS binding residues in HGF can mimic bound HS in promoting high affinity receptor binding, but antagonize the binding of long HS polymers on the cell surface, thereby antagonizing ligand oligomerization and its consequences. Engineering these substitutions in the context of a short HGF isoform containing only the primary HS and Met binding domains yields a potent and selective competitive inhibitor of oncogenic HGF signaling in vivo. These findings further define the role of HS in growth factor signaling and reveal a novel strategy for antagonist development that may be applicable to other HS-binding growth factors. The Met receptor kinase is among many transmembrane proteins that are proteolytically released from the cell surface by a process known as ectodomain shedding. Consistent with the concept that Met ectodomain shedding is a normal physiological process, we found that healthy human volunteers (n > 100) display soluble Met (sMet) plasma concentrations in the range of 100 - 300 ng/ml and urinary sMet concentrations that are approximately 1000-fold lower. We hypothesized that aberrantly high Met expression, a frequent occurrence in many forms of cancer, and/or dysregulated proteolytic activity, another common feature of aggressive malignancies, could lead to increased ectodomain shedding and that sMet levels could be a useful biomarker of tumorigenesis, tumor progression and overall tumor burden. In prior studies we found that increased Met shedding correlated with malignancy in several cell lines, and that urinary sMet levels were significantly elevated in metastatic prostate cancer patients relative to those with organ-confined cancer or no evidence of disease. In an ongoing investigation of sMet as a diagnostic and/or prognostic biomarker of bladder cancer, the mean urinary sMet level among 150 patients with pathologically confirmed disease was significantly higher than that obtained from a group of 50 individuals with no evidence of disease, whether mean values were normalized to urine creatinine concentration or not (two-tailed Mann-Whitney t-test p-value We have also measured plasma sMet levels in patients participating in a phase II clinical trial of Foretinib (formerly GSK1363089/XL880), a small molecule multikinase inhibitor targeting Met and vascular endothelial cell growth factor-2 (VEGFR-2) Axl and Ron, designed to evaluate the safety and efficacy of 2 dosing schedules (continuous daily dosing and intermittent 5 days on/9 days off dosing) of foretinib as a single therapeutic agent in patients with metastatic gastric carcinoma (GC). Plasma sMet concentrations, as well as plasma VEGF-A, HGF and soluble VEGFR-2 (sVEGFR-2) levels were measured before and during treatment with foretinib to measure potential pharmacodynamic (PD) effects and/or the modulation by foretinib of Met and VEGFR-2 pathways. Marker changes from baseline were analyzed at days 5, 15, 29 and 47 using analysis of variance and their relationships with plasma concentrations of foretinib (PK) and clinical outcome (sum of longest diameter [SLD] of tumor as a surrogate for tumor shrinkage, progression-free survival [PFS], and RECIST) were also examined. In GC patients on the intermittent dosing schedule, plasma sMet and VEGF-A concentrations tended to increase during the treatment periods compared with the drug holidays, suggestive of a direct short-term drug effect on sMet and VEGF-A levels. Although mean tumor burden did not change significantly from baseline to week 8, plasma levels of sMet and VEGF-A correlated positively with the change in SLD over this period, suggesting that the increases of sMet and VEGF-A may be reflective of increased GC tumor burden. Citation Format: Fabiola Cecchi, Deborah Pajalunga, Brian McNeil, Daniel Rabe, Andrew Fowler, Yuan Liu, C. Robert Gagnon, Howard Kallender, Manish A. Shah, Robert Getzenberg, Mark Schoenberg, Anne-Marie Martin, Ramaprasad Srinivasan, W. Marston Linehan, R Andrew Byrd, Donald P. Bottaro. Oncogenic signal transduction via the hepatocyte growth factor/Met receptor kinase pathway [abstract]. In: Proceedings of the AACR 101st Annual Meeting 2010; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr SY23-03

Foretinib (formerly GSK1363089) is a small molecule multikinase inhibitor which includes inhibition of MET and VEGFR2. The ongoing phase II study, MET111643, is evaluating the safety and efficacy of 2 dosing schedules (continuous daily dosing and intermittent 5 days on/9 days off dosing) of foretinib as a single agent in pts with metastatic GC. An additional component of the study is to collect patient plasma samples before and during treatment with foretinib, to explore the potential pharmacodynamic effect and/or the modulation by foretinib of MET and VEGFR2. Plasma samples were collected from 42 pts on the intermittent 5 days on/9 off foretinib schedule at baseline and prior to dosing on days 5, 15, 29, and 47. The plasma levels of sMET, HGF, sVEGFR2, and VEGFA were measured using the Meso Scale Discovery platform (MSD). These marker changes from baseline were analyzed at each time point using analysis of variance and their relationships with plasma concentrations of foretinib (PK) and clinical outcome (progression free survival [PFS] and RECIST response) were also examined. Statistically significant increases from baseline of sMET at days 5, 15, 29, and 47 (p Changes in sMET, VEGFA, and sVEGFR2 levels were observed for both intermittent and daily dosing schedules in the gastric cancer study. Although SLD at 8 weeks did not change significantly from baseline in the GC study, plasma levels of sMET and VEGFA correlated positively with the week 8 magnitude of SLD. Hence plasma levels of sMET and VEGFA may reflect biological changes following foretinib treatment. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B210.

Summary Background Foretinib is a small-molecule, oral multikinase inhibitor primarily targeting the mesenchymal epithelial transition (MET) factor receptor, and the vascular endothelial growth factor receptor 2. We conducted a phase II study to evaluate the single-agent activity and tolerability of foretinib in patients with recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN). Methods An open-label, single-arm, multicenter trial employing a Simon 2-stage design was conducted with a total of 41 patients planned for the study. One or more responses in the first 14 patients were required in order to progress to the second stage. Foretinib was administered as 240 mg orally for 5 consecutive days of a 14-day treatment cycle (5/9 schedule) to patients with recurrent and/or metastatic SCCHN. Results Fourteen patients were enrolled. The study did not meet criteria for continuing to the second stage. A maximum of 30 cycles were administered (median = 4.0). Fifty percent of patients (7/14) showed stable disease (SD), 43 % of patients (6/14) experienced tumor shrinkage and two patients had prolonged disease stabilization for ≥13 months. The most common adverse events were fatigue, constipation and hypertension, which were manageable with additional medication or adjustments to the dosing schedule. Conclusion Foretinib 240 mg on a 5/9 schedule was generally well tolerated. SD was the best-observed outcome, with minor tumor shrinkage detected in nearly half of all patients. The efficacy results, prolonged disease stabilization and tolerable side-effect profile, support further investigation, possibly in combination with other targeted agents or cytotoxic chemotherapy for SCCHN. Electronic supplementary material The online version of this article (doi:10.1007/s10637-012-9861-3) contains supplementary material, which is available to authorized users.