Safety, pharmacokinetics, and pharmacodynamics of AMG 102, a fully human hepatocyte growth factor-neutralizing monoclonal antibody, in a first-in-human study of patients with advanced solid tumors

Targeting the hepatocyte growth factor-cMET axis in cancer therapy

The hepatocyte growth factor (HGF) and its receptor, the transmembrane tyrosine kinase cMET, promote cell proliferation, survival, motility, and invasion as well as morphogenic changes that stimulate tissue repair and regeneration in normal cells but can be co-opted during tumor growth. MET overexpression, with or without gene amplification, has been reported in a variety of human cancers, including breast, lung, and GI malignancies. Furthermore, high levels of HGF and/or cMET correlate with poor prognosis in several tumor types, including breast, ovarian, cervical, gastric, head and neck, and non-small-cell lung cancers. Gene amplification and protein overexpression of cMET drive resistance to epidermal growth factor receptor family inhibitors, both in preclinical models and in patients. It is increasingly apparent that the HGF-cMET axis signaling network is complex, and rational combinatorial therapy is needed for optimal clinical efficacy. Better understanding of HGF-cMET axis signaling and the mechanism of action of HGF-cMET inhibitors, along with the identification of biomarkers of response and resistance, will lead to more effective targeting of this pathway for cancer therapy.

Associations between hepatocyte growth factor, c-Met, and basic fibroblast growth factor and survival in endometrial cancer patients

Background:

Hepatocyte growth factor (HGF), c-Met, and basic fibroblast growth factor (bFGF) are molecular markers that contribute to angiogenesis and proliferation in numerous cancers. We assessed the prognostic significance of these factors in tumour and stroma of endometrial cancer (EC) patients (n=211).

Methods:

Immunohistochemistry (IHC) was used to detect tumour and stromal protein expression of the biomarkers. Associations between expression and clinicopathological factors were assessed using Chi-square tests. Kaplan–Meier curves, log-rank tests, and Cox regression were used to summarise associations between biomarker expression and overall survival (OS) and recurrence-free survival (RFS).

Results:

Tumour bFGF was significantly associated with high-grade endometrioid and clear cell histology (P<0.001), advanced stage (P=0.008), positive lymph-node involvement (P=0.002), poor OS (log-rank test, P=0.009), and poor RFS (P<0.001). In multivariable analyses, cases with HGF-positive, stromal bFGF-positive tumours had a lower risk of death compared with cases with HGF-positive, stromal bFGF-negative tumours (hazard ratio (HR): 0.14, 95% CI: 0.03, 0.60). Cases with HGF-positive, bFGF-positive tumours had a higher risk of recurrence compared with cases with negative expression of both markers (HR: 9.88, 95% CI: 2.63, 37.16).

Conclusion:

These IHC data show that tumour and stromal bFGF expression have opposite associations with survival outcomes in EC patients. If confirmed in larger studies, tumour-derived bFGF could be an attractive target in EC therapy.

MET: a promising anticancer therapeutic target

The MET pathway is dysregulated in many human cancers and promotes tumour growth, invasion and dissemination. Abnormalities in MET signalling have been reported to correlate with poor clinical outcomes and drug resistance in patients with cancer. Thus, MET has emerged as an attractive target for cancer therapy. Several MET inhibitors have been introduced into the clinic, and are currently in all phases of clinical trials. In general, initial results from these studies indicate only a modest benefit in unselected populations. In this Review, we discuss current challenges in developing MET inhibitors--including identification of predictive biomarkers--as well as the most-efficient ways to combine these drugs with other targeted agents or with classic chemotherapy or radiotherapy.

Targeting multiple-myeloma-induced immune dysfunction to improve immunotherapy outcomes

Multiple myeloma (MM) is a plasma cell malignancy associated with high levels of monoclonal (M) protein in the blood and/or serum. MM can occur de novo or evolve from benign monoclonal gammopathy of undetermined significance (MGUS). Current translational research into MM focuses on the development of combination therapies directed against molecularly defined targets and that are aimed at achieving durable clinical responses. MM cells have a unique ability to evade immunosurveillance through several mechanisms including, among others, expansion of regulatory T cells (Treg), reduced T-cell cytotoxic activity and responsiveness to IL-2, defects in B-cell immunity, and induction of dendritic cell (DC) dysfunction. Immune defects could be a major cause of failure of the recent immunotherapy trials in MM. This article summarizes our current knowledge on the molecular determinants of immune evasion in patients with MM and highlights how these pathways can be targeted to improve patients' clinical outcome.

Preclinical evaluation of biomarkers for response monitoring to the MET inhibitor BAY-853474

CONTEXT

The receptor tyrosine kinase MET contributes to a wide range of biological activities, including survival, proliferation, and metastasis, which play an important role in cancer progression. MET is frequently overexpressed or amplified in a range of malignancies. Therefore, MET is an attractive therapeutic target for treatment of cancer. BAY-853474 is a novel specific MET inhibitor highly effective in preclinical tumor models.

OBJECTIVE

For response monitoring in clinical studies, soluble plasma biomarkers are the most convenient and least invasive choice. Therefore, we sought to identify such biomarkers in xenograft models.

RESULTS

We show that BAY-853474 reduces the tumor burden in U87MG glioblastoma, NCI-H1993 nonsmall cell lung cancer, and HS746T gastric cancer xenograft models. We demonstrate that the dose dependence is reflected by inhibition of MET phosphorylation and that the soluble plasma biomarkers hepatocyte growth factor, vascular endothelial growth factor, and interleukin-8 as well as the MET-ectodomain can be used to monitor the tumor size and response to treatment. Clinical samples, however, show only moderately elevated levels of these biomarker candidates in cancer patients even with MET amplification. We, therefore, established an immunohistochemistry (IHC) protocol to detect MET phosphorylation that is suitable to monitor the effect of BAY-853474 in tumor biopsies.

CONCLUSION

IHC-based analysis of target phosphorylation in tumor biopsies is recommended in addition to testing plasma biomarkers for response monitoring.

Novel therapies for metastatic renal cell carcinoma: efforts to expand beyond the VEGF/mTOR signaling paradigm

With six agents approved for metastatic renal cell carcinoma (mRCC) within the past 5 years, there has undoubtedly been progress in treating this disease. However, the goal of cure remains elusive, and the agents nearest approval (i.e., axitinib and tivozanib) abide by the same paradigm as existing drugs (i.e., inhibition of VEGF or mTOR signaling). The current review will focus on investigational agents that diverge from this paradigm. Specifically, novel immunotherapeutic strategies will be discussed, including vaccine therapy, cytotoxic T-lymphocyte antigen 4 (CTLA4) blockade, and programmed death-1 (PD-1) inhibition, as well as novel approaches to angiogenesis inhibition, such as abrogation of Ang/Tie-2 signaling. Pharmacologic strategies to block other potentially relevant signaling pathways, such as fibroblast growth factor receptor or MET inhibition, are also in various stages of development. Although VEGF and mTOR inhibition have dramatically improved outcomes for patients with mRCCs, a surge above the current plateau with these agents will likely require exploring new avenues.

Prognostic and predictive significance of plasma HGF and IL-8 in a phase III trial of chemoradiation with or without tirapazamine in locoregionally advanced head and neck cancer

PURPOSE

Hepatocyte growth factor (HGF) is a hypoxia-induced secreted protein that binds to cMet and regulates interleukin (IL)-8 expression. We evaluated the role of circulating HGF and IL-8 as prognostic and predictive factors for efficacy of tirapazamine (TPZ), a hypoxic cell cytotoxin.

EXPERIMENTAL DESIGN

Patients with stages III to IV head and neck cancer were randomized to receive radiotherapy with cisplatin (CIS) or CIS plus TPZ (TPZ/CIS). Eligibility for the substudy included plasma sample availability for HGF and IL-8 assay by ELISA and no major radiation deviations (N = 498). Analyses included adjustment for major prognostic factors. p16(INK4A) staining (human papillomavirus surrogate) was carried out on available tumors. Thirty-nine patients had hypoxia imaging with (18)F-fluoroazomycin arabinoside ((18)FAZA)-positron emission tomography.

RESULTS

Elevated IL-8 level was associated with worse overall survival (OS) irrespective of treatment. There was an interaction between HGF and treatment arm (P = 0.053); elevated HGF was associated with worse OS in the control but not in the TPZ/CIS arm. Similar trends were observed in analyses restricted to p16(INK4A)-negative patients. Four subgroups defined by high and low HGF/IL-8 levels were examined for TPZ effect; the test for interaction with arm was P = 0.099. TPZ/CIS seemed to be beneficial for patients with high HGF and IL-8 but adverse for low HGF and high IL-8. Only HGF correlated with (18)FAZA tumor standard uptake value.

CONCLUSIONS

IL-8 is an independent prognostic factor irrespective of treatment. There is an interaction between HGF and treatment arm. Certain subgroups based on IL-8/HGF levels seemed to do better with TPZ/CIS while others did worse, highlighting the complexity of hypoxia targeting in unselected patients.

A novel classification of lung cancer into molecular subtypes

The remarkably heterogeneous nature of lung cancer has become more apparent over the last decade. In general, advanced lung cancer is an aggressive malignancy with a poor prognosis. The discovery of multiple molecular mechanisms underlying the development, progression, and prognosis of lung cancer, however, has created new opportunities for targeted therapy and improved outcome. In this paper, we define "molecular subtypes" of lung cancer based on specific actionable genetic aberrations. Each subtype is associated with molecular tests that define the subtype and drugs that may potentially treat it. We hope this paper will be a useful guide to clinicians and researchers alike by assisting in therapy decision making and acting as a platform for further study. In this new era of cancer treatment, the 'one-size-fits-all' paradigm is being forcibly pushed aside-allowing for more effective, personalized oncologic care to emerge.

Nanobodies targeting the hepatocyte growth factor: potential new drugs for molecular cancer therapy

Hepatocyte growth factor (HGF) and its receptor c-Met are associated with increased aggressiveness of tumors and poor prognostic outcome of patients with cancer. Here, we report the development and characterization of therapeutic anti-HGF (αHGF)-Nanobodies and their potential for positron emission tomographic (PET) imaging to assess HGF expression in vivo. Two αHGF-Nanobodies designated 1E2 and 6E10 were identified, characterized, and molecularly fused to an albumin-binding Nanobody unit (Alb8) to obtain serum half-life extension. The resulting Nanobody formats were radiolabeled with the positron emitter zirconium-89 ((89)Zr, t(1/2;) = 78 hours), administered to nude mice bearing U87 MG glioblastoma xenografts, and their biodistribution was assessed. In addition, their therapeutic effect was evaluated in the same animal model at doses of 10, 30, or 100 μg per mouse. The (89)Zr-Nanobodies showed similar biodistribution with selective tumor targeting. For example, 1E2-Alb8 showed decreased blood levels of 12.6%ID/g ± 0.6%ID/g, 7.2%ID/g ± 1.0%ID/g, 3.4%ID/g ± 0.3%ID/g, and 0.3%ID/g ± 0.1%ID/g at 1, 2, 3, and 7 days after injection, whereas tumor uptake levels remained relatively stable at these time points: 7.8%ID/g ± 1.1%ID/g, 8.9%ID/g ± 1.0%ID/g, 8.7%ID/g ± 1.5%ID/g, and 7.2%ID/g ±1.6%ID/g. Uptake in normal tissues was lower than in tumor, except for kidneys. In a therapy study, all Nanobody-treated mice showed tumor growth delay compared with the control saline group. In the 100-μg group, four of six mice were cured after treatment with 1E2-Alb8 and 73 days follow-up, and three of six mice when treated with 6E10-Alb8. These results provide evidence that Nanobodies 1E2-Alb8 and 6E10-Alb8 have potential for therapy and PET imaging of HGF-expressing tumors.

Novel targeted therapies in head and neck cancer

INTRODUCTION

Molecularly targeted therapy, with the potential for increased selectivity and fewer adverse effects, hold promise in the treatment of HNSCC.

AREAS COVERED

Targeted agents for HNSCC expected to improve the effectiveness of current therapy including HER family, Src-family kinase, cell cycle, MET, AKT, HDAC, PARP, COX inhibitors and antiangiogenesis.

EXPERT OPINION

Epidermal growth factor receptor inhibitors are established in HNSCC and the need now is to find biomarkers for sensitivity to better select patients. Moreover, other pathway inhibitors hold significant promise and are being tested in clinical trials. Angiogenesis inhibition is likely to yield only modest efficacy alone but may augment existing standards. Lastly, one clinical arena where targeted therapies may find secure purchase is in the adjuvant or prevention setting where minimal or preneoplastic disease can be affected by inhibition of a single or few targets.

Cell surface receptors in malignant glioma

Despite advances in surgery, radiation, and chemotherapy, malignant gliomas are still highly lethal tumors. Traditional treatments that rely on nonspecific, cytotoxic approaches have a marginal impact on patient survival. However, recent advances in the molecular cancer biology underlying glioma pathogenesis have revealed that abnormalities in common cell surface receptors, including receptor tyrosine kinase and other cytokines, mediate the abnormal cellular signal pathways and aggressive biological behavior among the majority of these tumors. Some cell surface receptors have been targeted by novel agents in preclinical and clinical development. Such cancer-specific targeted agents might offer the promise of improved cancer control without substantial toxicity. Here, we review these common cell surface receptors with clinical significance for malignant glioma and discuss the molecular characteristics, pathological significance, and potential therapeutic application of these cell surface receptors. We also summarize the clinical trials of drugs targeting these cell surface receptors in malignant glioma patients.

Protein-intrinsic and signaling network-based sources of resistance to EGFR- and ErbB family-targeted therapies in head and neck cancer

Agents targeting EGFR and related ErbB family proteins are valuable therapies for the treatment of many cancers. For some tumor types, including squamous cell carcinomas of the head and neck (SCCHN), antibodies targeting EGFR were the first protein-directed agents to show clinical benefit, and remain a standard component of clinical strategies for management of the disease. Nevertheless, many patients display either intrinsic or acquired resistance to these drugs; hence, major research goals are to better understand the underlying causes of resistance, and to develop new therapeutic strategies that boost the impact of EGFR/ErbB inhibitors. In this review, we first summarize current standard use of EGFR inhibitors in the context of SCCHN, and described new agents targeting EGFR currently moving through pre-clinical and clinical development. We then discuss how changes in other transmembrane receptors, including IGF1R, c-Met, and TGF-β, can confer resistance to EGFR-targeted inhibitors, and discuss new agents targeting these proteins. Moving downstream, we discuss critical EGFR-dependent effectors, including PLC-γ; PI3K and PTEN; SHC, GRB2, and RAS and the STAT proteins, as factors in resistance to EGFR-directed inhibitors and as alternative targets of therapeutic inhibition. We summarize alternative sources of resistance among cellular changes that target EGFR itself, through regulation of ligand availability, post-translational modification of EGFR, availability of EGFR partners for hetero-dimerization and control of EGFR intracellular trafficking for recycling versus degradation. Finally, we discuss new strategies to identify effective therapeutic combinations involving EGFR-targeted inhibitors, in the context of new system level data becoming available for analysis of individual tumors.

Future directions in the evaluation of c-MET-driven malignancies

The c-MET (mesenchymal-epithelial transition factor) receptor tyrosine kinase is an exciting novel drug target in view of its key role in oncogenesis, as well as its association with disease prognosis in a number of malignancies. Several drugs targeting c-MET are currently showing promise in clinical trials and will hopefully validate positive observations from preclinical studies. The potential efficacy of these different therapeutic agents is expected to be influenced by the mechanism of aberrant hepatocyte growth factor (HGF)/c-MET signaling pathway activation in a particular cancer, but presents a promising strategy for cancer treatment either as a single agent or as part of a combination therapeutic approach. However, there is an ongoing need to improve and accelerate the transition of preclinical research into improved therapeutic strategies for patients with cancer. The main challenges facing the development of HGF/c-MET-targeted agents for cancer treatment include the discovery of rationally designed anticancer drugs and combination strategies, as well as the validation of predictive biomarkers. This paper discusses these issues, with a particular focus on future directions in the evaluation of c-MET-driven malignancies.

A novel kinase inhibitor, INCB28060, blocks c-MET-dependent signaling, neoplastic activities, and cross-talk with EGFR and HER-3

PURPOSE

The c-MET receptor tyrosine kinase plays important roles in the formation, progression, and dissemination of human cancer and presents an attractive therapeutic target. This study describes the preclinical characterization of INCB28060, a novel inhibitor of c-MET kinase.

EXPERIMENTAL DESIGN

Studies were conducted using a series of in vitro and in vivo biochemical and biological experiments.

RESULTS

INCB28060 exhibits picomolar enzymatic potency and is highly specific for c-MET with more than 10,000-fold selectivity over a large panel of human kinases. This inhibitor potently blocks c-MET phosphorylation and activation of its key downstream effectors in c-MET-dependent tumor cell lines. As a result, INCB28060 potently inhibits c-MET-dependent tumor cell proliferation and migration and effectively induces apoptosis in vitro. Oral dosing of INCB28060 results in time- and dose-dependent inhibition of c-MET phosphorylation and tumor growth in c-MET-driven mouse tumor models, and the inhibitor is well tolerated at doses that achieve complete tumor inhibition. In a further exploration of potential interactions between c-MET and other signaling pathways, we found that activated c-MET positively regulates the activity of epidermal growth factor receptors (EGFR) and HER-3, as well as expression of their ligands. These effects are reversed with INCB28060 treatment. Finally, we confirmed that circulating hepatocyte growth factor levels are significantly elevated in patients with various cancers.

CONCLUSIONS

Activated c-MET has pleiotropic effects on multiple cancer-promoting signaling pathways and may play a critical role in driving tumor cell growth and survival. INCB28060 is a potent and selective c-MET kinase inhibitor that may have therapeutic potential in cancer treatment.

Receptor-tyrosine-kinase-targeted therapies for head and neck cancer

Molecular therapeutics for treating epidermal growth factor receptor-(EGFR-) expressing cancers are a specific method for treating cancers compared to general cell loss with standard cytotoxic therapeutics. However, the finding that resistance to such therapy is common in clinical trials now dampens the initial enthusiasm over this targeted treatment. Yet an improved molecular understanding of other receptor tyrosine kinases known to be active in cancer has revealed a rich network of cross-talk between receptor pathways with a key finding of common downstream signaling pathways. Such cross talk may represent a key mechanism for resistance to EGFR-directed therapy. Here we review the interplay between EGFR and Met and the type 1 insulin-like growth factor receptor (IGF-1R) tyrosine kinases, as well as their contribution to anti-EGFR therapeutic resistance in the context of squamous cell cancer of the head and neck, a tumor known to be primarily driven by EGFR-related oncogenic signals.

Antibodies in oncology

Monoclonal antibodies (mAbs) have become one of the largest classes of new therapeutic agents approved for use in oncology, and have revolutionised the treatment of many human malignancies. Clinically useful mAbs can function through several different mechanisms, including inhibition of tumour-related signalling, induction of apoptosis, inhibition of angiogenesis, enhancing host immune response against cancer and targeted delivery of payloads (such as toxins, cytotoxic agents or radioisotopes) to the tumour site. The increasing knowledge of key molecules and cellular pathways involved in tumour induction and progression has led to a rise in the proportion of therapeutic mAbs entering clinical trials. These mAbs consist of various conventional or recombinant, murine, humanised, chimeric or fully human and fusion constructs. In this review, we provide an overview of mAbs approved for use in clinical oncology and those currently in clinical development. We also discuss the mechanisms of action of anti-cancer mAbs, as well as the antigen targets recognised by these antibodies.

Light-dark oscillations in the lung transcriptome: implications for lung homeostasis, repair, metabolism, disease, and drug action

Diurnal-nocturnal, or circadian-like, rhythms are 24-h variations in biological processes, evolved for the efficient functioning of living organisms. Such oscillations and their regulation in many peripheral tissues are still unclear. In this study, we used Affymetrix gene chips in a rich time-series experiment involving 54 animals killed at 18 time points within the 24-h cycle to examine light-dark cycle patterns of gene expression in rat lungs. Data mining identified 646 genes (represented by 1,006 probe sets) showing robust oscillations in expression in lung that were parsed into 8 distinct temporal clusters. Surprisingly, more than two-thirds of the probe sets showing cyclic expression peaked during the animal's light/inactive period. Six core clock genes and nine clock-related genes showed rhythmic oscillations in their expression in lung. Many of the genes that peaked during the inactive period included genes related to extracellular matrix, cytoskeleton, and protein processing and trafficking, which appear to be mainly involved in the repair and remodeling of the organ. Genes coding for growth factor ligands and their receptors, which play important roles in maintaining normal lung function, also showed rhythmic expression. In addition, genes involved in the metabolism and transport of endogenous compounds, xenobiotics, and therapeutic drugs, along with genes that are biomarkers or potential therapeutic targets for many lung diseases, also exhibited 24-h cyclic oscillations, suggesting an important role for such rhythms in regulating various aspects of the physiology and pathophysiology of lung.

Identification of a therapeutic strategy targeting amplified FGF19 in liver cancer by Oncogenomic screening

We screened 124 genes that are amplified in human hepatocellular carcinoma (HCC) using a mouse hepatoblast model and identified 18 tumor-promoting genes, including CCND1 and its neighbor on 11q13.3, FGF19. Although it is widely assumed that CCND1 is the main driving oncogene of this common amplicon (15% frequency in HCC), both forward-transformation assays and RNAi-mediated inhibition in human HCC cells established that FGF19 is an equally important driver gene in HCC. Furthermore, clonal growth and tumorigenicity of HCC cells harboring the 11q13.3 amplicon were selectively inhibited by RNAi-mediated knockdown of CCND1 or FGF19, as well as by an anti-FGF19 antibody. These results show that 11q13.3 amplification could be an effective biomarker for patients most likely to respond to anti-FGF19 therapy.

A phase II study evaluating the efficacy and safety of AMG 102 (rilotumumab) in patients with recurrent glioblastoma

This phase II study evaluated the efficacy and safety of AMG 102 (rilotumumab), a fully human monoclonal antibody against hepatocyte growth factor/scatter factor (HGF/SF), in patients with recurrent glioblastoma (GBM). Patients with histologically confirmed, measurable recurrent GBM or gliosarcoma (World Health Organization grade 4) and ≤3 relapses or prior systemic therapies received AMG 102 (10 or 20 mg/kg) by infusion every 2 weeks. The primary endpoint was best confirmed objective response rate (central assessment) per Macdonald criteria. Of the 61 patients who enrolled, 60 received AMG 102. Twenty-nine patients (48%) had previously received bevacizumab. There were no objective responses per central assessment, but 1 patient had an objective response per investigator assessment. Median overall survival (95% CI) in the 10- and 20-mg/kg cohorts was 6.5 months (4.1-9.8) and 5.4 months (3.4-11.4), respectively, and progression-free survival (PFS) per central assessment was 4.1 weeks (4.0-4.1) and 4.3 weeks (4.1-8.1), respectively. PFS was similar among patients who had previously received bevacizumab compared with bevacizumab-naive patients. The most common adverse events were fatigue (38%), headache (33%), and peripheral edema (23%). AMG 102 serum concentrations increased approximately dose-proportionally with 2-fold accumulation at steady state. Plasma total HGF/SF and soluble c-Met concentrations increased 12.05- and 1.12-fold, respectively, from baseline during AMG 102 treatment. AMG 102 monotherapy at doses up to 20 mg/kg was not associated with significant antitumor activity in heavily pretreated patients with recurrent GBM.

Detection of hepatocyte growth factor (HGF) ligand-c-MET receptor activation in formalin-fixed paraffin embedded specimens by a novel proximity assay

Aberrant activation of membrane receptors frequently occurs in human carcinomas. Detection of phosphorylated receptors is commonly used as an indicator of receptor activation in formalin-fixed paraffin embedded (FFPE) tumor specimens. FFPE is a standard method of specimen preparation used in the histological analysis of solid tumors. Due to variability in FFPE preparations and the labile nature of protein phosphorylation, measurements of phospho-proteins are unreliable and create ambiguities in clinical interpretation. Here, we describe an alternative, novel approach to measure receptor activation by detecting and quantifying ligand-receptor complexes in FFPE specimens. We used hepatocyte growth factor (HGF)-c-MET as our model ligand-receptor system. HGF is the only known ligand of the c-MET tyrosine kinase receptor and HGF binding triggers c-MET phosphorylation. Novel antibody proximity-based assays were developed and used to detect and quantify total c-MET, total HGF, and HGF-c-MET ligand-receptor interactions in FFPE cell line and tumor tissue. In glioma cells, autocrine activation of c-MET by HGF-c-MET increased basal levels of c-MET phosphorylation at tyrosine (Tyr) 1003. Furthermore, HGF-c-MET activation in glioma cell lines was verified by Surface Protein-Protein Interaction by Crosslinking ELISA (SPPICE) assay in corresponding soluble cell lysates. Finally, we profiled levels ofc-MET, HGF, and HGF-c-MET complexes in FFPE specimens of human Non-Small Cell Lung Cancer (NSCLC), Gastric Cancer, Head and Neck Squamous Cell, and Head and Neck Non-Squamous Cell carcinomas. This report describes a novel approach for the detection and quantification of ligand-receptor interactions that can be widely applied to measure receptor activation in FFPE preclinical models and archived FFPE human tissue specimens.

Radioimmunotherapy of solid tumors: searching for the right target

Radioimmunotherapy of solid tumors remains a challenge despite the tremendous success of ⁹⁰Y ibritumomab tiuxetan (Zevalin) and ¹³¹I Tositumomab (Bexxar) in treating non-Hodgkin's lymphoma. For a variety of reasons, clinical trials of radiolabeled antibodies against solid tumors have not led to responses equivalent to those seen against lymphoma. In contrast, promising responses have been observed with unlabeled antibodies that target solid tumor receptors associated with cellular signaling pathways. These observations suggest that anti-tumor efficacy of the carrier antibody might be critical to achieving clinical responses. Here, we review and compare tumor antigens targeted by radiolabeled antibodies and unlabeled antibodies used in immunotherapy. The review shows that the trend for radiolabeled antibodies under pre-clinical development is to also target antigens associated with signaling pathways that are essential for the growth and survival of the tumor.

A phase II study of the efficacy and safety of AMG 102 in patients with metastatic renal cell carcinoma

OBJECTIVE

• To evaluate the efficacy and safety of single-agent AMG 102, an investigational, fully human monoclonal antibody to hepatocyte growth factor/scatter factor (HGF/SF), in renal cell carcinoma (RCC).

PATIENTS AND METHODS

• This open-label phase II study included patients ≥ 18 years old with histologically confirmed, advanced or metastatic RCC (mRCC) and Eastern Cooperative Oncology Group performance status 0 to 2. AMG 102 was administered i.v. at 10 or 20 mg/kg once every 2 weeks. • A two-stage design was used at each dose level and the primary endpoint was objective best confirmed response (by Response Evaluation Criteria in Solid Tumours) at any time.

RESULTS

• Sixty-one patients with mRCC enrolled and received AMG 102 (40 at 10 mg/kg; 21 at 20 mg/kg). Overall, 70.5% were men, median age was 59 years (range, 39 to 84 years), and 92% had received previous anti-vascular endothelial growth factor therapy. RCC histologies were: clear cell (75.4%), papillary (11.5%), chromophobe (4.9%) and unclassified (8.2%). • One confirmed partial response occurred at 10 mg/kg, maintained for over 2.5 years; 26 patients (43%) had stable disease, 10 (16%) for ≥ 32 weeks. The median profression-free survival was 3.7 months at 10 mg/kg and 2.0 months at 20 mg/kg. The commonest adverse events were oedema (45.9%), fatigue (37.7%) and nausea (27.9%). Grade 3 or 4 adverse events occurred in 33% of patients, the most common being oedema (9.8%). • Baseline levels of plasma HGF/SF and soluble c-Met as well as archival-tumour c-Met did not correlate with measures of efficacy.

CONCLUSION

• Single-agent AMG 102 was tolerable, but it is unclear if AMG 102 was growth inhibitory in this population of patients with mRCC.

Serum hepatocyte growth factor levels and the effects of antidepressants in panic disorder

Previous animal studies have suggested that hepatocyte growth factor (HGF) could be associated with depression- and anxiety-related behaviors. Our aim was to relate serum HGF levels with State-Trait Anxiety Inventory (STAI), Profile of Mood State (POMS), and Revised NEO Personality Inventory (NEO-PI-R) scores in patients with panic disorder (with or without agoraphobia) and healthy controls. We examined 67 patients with panic disorders and 97 controls. Patients were split into two groups according to whether they exhibited a 50% improvement in test scores (good/high response group: n = 26) or not (poor/low response group: n = 41). In both healthy control and panic disorder individuals, there were no significant associations between HGF serum levels and STAI or NEO-PI-R scores. However, there was a significant correlation between serum HGF levels and fatigue in healthy control subjects in as scored by POMS testing. HGF concentration in the good/high response group was significantly elevated compared to both the low/poor response group (p < 0.01) and the control group (p < 0.01). HGF levels in the poor response group did not differ from the control group (p = 0.48). These results indicate that increased serum HGF levels might be a requirement for antidepressant efficacy in patients with panic disorders.

Potential therapeutics specific to c-MET/RON receptor tyrosine kinases for molecular targeting in cancer therapy

Products of proto-oncogenes c-MET and RON belong to a subfamily of receptor tyrosine kinases that contribute significantly to tumorigenic progression. In primary tumors, altered c-MET/RON expression transduces signals regulating invasive growth that is characterized by cell migration and matrix invasion. These pathogenic features provide the basis for targeting c-MET/RON in cancer therapy. In the last decade, various approaches have been investigated to suppress c-MET/RON-transduced oncogenesis. Among the therapeutics developed, monoclonal antibodies (mAbs) and small-molecule inhibitors (SMIs) have emerged as promising candidates. The mechanism of these therapeutic candidates is the disruption of tumor dependency on c-MET/RON signals for survival. The mAbs specific to hepatocyte growth factor (AMG102) and c-MET (MetMAb) are both humanized and able to block c-MET signaling, leading to inhibition of tumor cell proliferation in vitro and inhibition of tumor growth in xenograft models. The mAb AMG102 neutralizes hepatocyte growth factor and enhances the cytotoxicity of various chemotherapeutics to tumors in vivo. AMG102 is currently in phase II clinical trials for patients with advanced solid tumors. IMC-41A40 and Zt/f2 are RON-specific mAbs that down-regulate RON expression and inhibit ligand-induced phosphorylation. Both mAbs inhibit tumor growth in mice mediated by colon and pancreatic cancer cells. SMIs specific to c-MET (ARQ107 and PF-02341066) are in various phases of clinical trials. Therapeutic efficacy has also been observed with dual inhibitors such as Compound I, which is specific to c-MET/RON. However, a potential issue is the emergence of acquired resistance to these inhibitors. Clearly, development of c-MET/RON therapeutics provides opportunities and challenges for combating cancer in the future.

Radiosensitization of glioma cells by modulation of Met signalling with the hepatocyte growth factor neutralizing antibody, AMG102

The hepatocyte growth factor (HGF)/Met signalling pathway is up-regulated in many cancers, with downstream mediators playing a role in DNA double strand break repair. Previous studies have shown increased radiosensitization of tumours through modulation of Met signalling by genetic methods. We investigated the effects of the anti-HGF monoclonal antibody, AMG102, on the response to ionizing radiation in a model of glioblastoma multiforme in vitro and in vivo. Radiosensitivity was evaluated in vitro in the U-87 MG human glioma cell line. Met activation was measured by Western blot, and the effect on survival following radiation was evaluated by clonogenic assay. Mechanism of cell death was evaluated by apoptosis and mitotic catastrophe assays. DNA damage was quantitated by γH2AX foci and neutral comet assay. Growth kinetics of subcutaneous tumours was used to assess the effects of AMG102 on in vivo tumour radiosensitivity. AMG102 inhibited Met activation after irradiation. An enhancement of radiation cell killing was shown with no toxicity using drug alone. Retention of γH2AX foci at 6 and 24 hrs following the drug/radiation combination indicated an inhibition of DNA repair following radiation, and comet assay confirmed DNA damage persisting over the same duration. At 48 and 72 hrs following radiation, a significant increase of cells undergoing mitotic catastrophe was seen in the drug/radiation treated cells. Growth of subcutaneous tumours was slowed in combination treated mice, with an effect that was greater than additive for each modality individually. Modulation of Met signalling with AMG102 may prove a novel radiation sensitizing strategy. Our data indicate that DNA repair processes downstream of Met are impaired leading to increased cell death through mitotic catastrophe.

A phase Ib study of AMG 102 in combination with bevacizumab or motesanib in patients with advanced solid tumors

PURPOSE

This phase Ib study evaluated the safety, pharmacokinetics, pharmacodynamics, and antitumor activity of AMG 102, a fully human monoclonal antibody against hepatocyte growth factor/scatter factor (HGF/SF), in combination with bevacizumab or motesanib in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

Patients with treatment-refractory advanced solid tumors were sequentially enrolled into four cohorts (3, 10, or 20 mg/kg AMG 102 plus 10 mg/kg bevacizumab i.v. every 2 weeks, or 3 mg/kg AMG 102 i.v. every 2 weeks plus 75 mg motesanib orally once daily).

RESULTS

Fourteen patients were enrolled and received AMG 102. The combination of AMG 102 with bevacizumab (n = 12) seemed to have acceptable toxicity. The number of patients (n = 2) who received AMG 102 plus motesanib was insufficient to adequately assess safety. No dose-limiting toxicities were reported. Enrollment in the motesanib cohort was suspended because of reports of cholecystitis in other motesanib studies. Treatment-emergent adverse events among patients receiving AMG 102 plus bevacizumab were generally mild and included fatigue (75%), nausea (58%), constipation (42%), and peripheral edema (42%). No anti-AMG 102 antibodies were detected. Bevacizumab did not seem to affect AMG 102 pharmacokinetics. Circulating total HGF/SF increased from baseline throughout the study. Eight of 10 evaluable patients had reductions in tumor dimensions, and stable disease at > or =8, > or =16, and > or =24 weeks occurred in 9, 7, and 4 patients, respectively. Progression-free survival ranged from 7.9 to 121.9 weeks.

CONCLUSIONS

AMG 102 in combination with bevacizumab was well tolerated. Further evaluation of AMG 102 in combination with antiangiogenic agents is warranted.

Biochemical characterization of AMG 102: a neutralizing, fully human monoclonal antibody to human and nonhuman primate hepatocyte growth factor

AMG 102 is a fully human monoclonal antibody that selectively targets and neutralizes hepatocyte growth factor/scatter factor (HGF/SF). A detailed biochemical and functional characterization of AMG 102 was done to support its clinical development for the treatment of cancers dependent on signaling through the HGF/SF:c-Met pathway. In competitive equilibrium binding experiments, AMG 102 bound to human and cynomolgus monkey HGF with affinities of approximately 19 pmol/L and 41 pmol/L, respectively. However, AMG 102 did not detect mouse or rabbit HGF on immunoblots. Immunoprecipitation experiments showed that AMG 102 preferentially bound to the mature, active form of HGF, and incubation of AMG 102/HGF complexes with kallikrein protease indicated that AMG 102 had no apparent effect on proteolytic processing of the inactive HGF precursor. AMG 102 inhibited human and cynomolgus monkey HGF-induced c-Met autophosphorylation in PC3 cells with IC(50) values of 0.12 nmol/L and 0.24 nmol/L, respectively. AMG 102 also inhibited cynomolgus monkey HGF-induced migration of human MDA-MB-435 cells but not rat HGF-induced migration of mouse 4T1 cells. Epitope-mapping studies of recombinant HGF molecules comprising human/mouse chimeras and human-to-mouse amino acid substitutions showed that amino acid residues near the NH(2)-terminus of the beta-chain are critical for AMG 102 binding. Bound AMG 102 protected one trypsin protease cleavage site near the NH(2)-terminus of the beta-chain of human HGF, further substantiating the importance of this region for AMG 102 binding. Currently, AMG 102 is in phase II clinical trials in a variety of solid tumor indications. Mol Cancer Ther; 9(2); 400-9.