Phase I dose escalation study of telatinib, a tyrosine kinase inhibitor of vascular endothelial growth factor receptor 2 and 3, platelet-derived growth factor receptor beta, and c-Kit, in patients with advanced or metastatic solid tumors

Homodimeric peptide radiotracer [68Ga]Ga-NOTA-(TMVP1)2 for VEGFR-3 imaging of cervical cancer patients

PURPOSE

Vascular endothelial growth factor receptor 3 (VEGFR-3) plays a critical role in tumor lymphangiogenesis and metastasis, holding promise as a promising therapeutic target for solid tumors. TMVP1 (LARGR) is a 5-amino acid peptide previously identified in our laboratory from bacterial peptide display system that specifically targets VEGFR-3. Radiolabeled TMVP1 can be used for non-invasive imaging of VEGFR-3 expressing tumors. Homodimeric peptides have better targeting ability than monomeric peptides, and it is worth exploring whether homodimers of TMVP1 ((TMVP1)2) can achieve better imaging effects. This study aimed to explore the peptide properties and tumor assessment value of [68Ga]Ga-labeled (TMVP1)2.

METHODS

In this study, we developed a TMVP1 homodimer that was conjugated with 1,4,7-triazacyclononane-N, N', N″-triacetic acid (NOTA) via tetraethyleneglycol (PEG4) and triglyicine (Gly3) spacer, and labeled with 68Ga, to construct [68Ga]Ga-NOTA-(TMVP1)2. Binding of VEGFR-3 by TMVP1 and (TMVP1)2, respectively, was modeled by molecular docking. The affinity of [68Ga]Ga-NOTA-(TMVP1)2 for VEGFR-3 and its ability to bind to cells were evaluated. MicroPET imaging and biodistribution studies of [68Ga]Ga-NOTA-(TMVP1)2 were performed in subcutaneous C33A cervical cancer xenografts. Five healthy volunteers and eight patients with cervical cancer underwent whole-body PET/CT acquisition 30-45 min after intravenous injection of [68Ga]Ga-NOTA-(TMVP1)2.

RESULTS

Both molecular docking and cellular experiments showed that homodimeric TMVP1 had a higher affinity for VEGFR-3 than monomeric TMVP1. [68Ga]Ga-NOTA-(TMVP1)2 was excreted mainly through the renal route and partly through the liver route. In mice bearing C33A xenografts, [68Ga]Ga-NOTA-(TMVP1)2 specifically localized in the tumor (2.32 ± 0.10% ID/g). Pretreatment of C33A xenograft mice with the unlabeled peptide NOTA-(TMVP1)2 reduced the enrichment of [68Ga]Ga-NOTA-(TMVP1)2 in tumors (0.58 ± 0.01% ID/g). [68Ga]Ga-NOTA-(TMVP1)2 proved to be safe in all healthy volunteers and recruited patients, with no side effects or allergies noted. In cervical cancer patients, a majority of the [18F]-FDG identified lesions (18/22, 81.8%) showed moderate to high signal intensity on [68Ga]Ga-NOTA-(TMVP1)2. SUVmax and SUVmean were 2.32 ± 0.77 and 1.61 ± 0.48, respectively. With normal muscle (gluteus maximus) as background, tumor-to-background ratios were 3.49 ± 1.32 and 3.95 ± 1.64 based on SUVmax and SUVmean, respectively.

CONCLUSION

The favorable characterizations of [68Ga]Ga-NOTA-(TMVP1)2 such as convenient synthesis, high specific activity, and high tumor uptake enable the evaluation of VEGFR-3 in cervical cancer patients and warrant further clinical studies.

TRIAL REGISTRATION

ChiCTR-DOD-17012458. Registered August 23, 2017 (retrospectively registered).

New Cluster Analysis Method for Quantitative Dynamic Contrast-Enhanced MRI Assessing Tumor Heterogeneity Induced by a Tumor-Microenvironmental Ameliorator (E7130) Treatment to a Breast Cancer Mouse Model

BACKGROUND

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can provide insight into tumor perfusion. However, a method that can quantitatively measure the intra-tumor distribution of tumor voxel clusters with a distinct range of K^trans and v_e values remains insufficiently explored.

HYPOTHESIS

Two-dimensional cluster analysis may quantify the distribution of a tumor voxel subregion with a distinct range of K^trans and v_e values in human breast cancer xenografts.

STUDY TYPE

Prospective longitudinal study.

ANIMAL MODEL

Twenty-two female athymic nude mice with MCF-7 xenograft, treated with E7130, a tumor-microenvironmental ameliorator, or saline.

FIELD STRENGTH/SEQUENCE

9.4 Tesla, turbo rapid acquisition with relaxation enhancement, and spoiled gradient-echo sequences.

ASSESSMENT

We performed two-dimensional k-means clustering to identify tumor voxel clusters with a distinct range of K^trans and v_e values on Days 0, 2, and 5 after treatment, calculated the ratio of the number of tumor voxels in each cluster to the total number of tumor voxels, and measured the normalized distances defined as the ratio of the distance between each tumor voxel and the nearest tumor margin to a tumor radius.

STATISTICAL TESTS

Unpaired t-tests, Dunnett's multiple comparison tests, and Chi-squared test were used.

RESULTS

The largest and second largest clusters constituted 44.4% and 27.5% of all tumor voxels with cluster centroid values of K^trans at 0.040 min^-1 and 0.116 min^-1 , and v_e at 0.131 and 0.201, respectively. At baseline (Day 0), the average normalized distances for the largest and second largest clusters were 0.33 and 0.24, respectively. E7130-treated group showed the normalized distance of the initial largest cluster decreasing to 0.25, while that of the second largest cluster increasing to 0.31. Saline-treated group showed no change.

DATA CONCLUSION

A two-dimensional cluster analysis might quantify the spatial distribution of a tumor subregion with a distinct range of K^trans and v_e values.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 1.

Sorafenib-associated hand-foot skin reaction: practical advice on diagnosis, mechanism, prevention, and management

Introduction: Sorafenib is a multitargeted tyrosine kinase inhibitor, which has been mainly used in the treatment of advanced hepatocellular carcinoma and renal cancer. However, hand-foot skin reaction (HFSR), as one of the most common adverse reactions, have hindered its long-term clinical application. At present, the mechanism of its occurrence has not been clearly studied and it leads to the lack of effective means of intervention. This article reviews known mechanism and management methods of HFSR caused by sorafenib.Areas covered: The author reviews HFSR caused by the treatment of sorafenib including the mechanism and management. English language reports located through PubMed are reviewed.Expert opinion: There are some conjectures about the mechanism of HFSR. However, the mechanism of HFSR induced by sorafenib is still unclear at present. In the absence of understanding the mechanism of HFSR, the most common method for clinical treatment of sorafenib-induced HFSR is dose down-regulation or discontinuation of treatment, which affects efficacy and even survival. Future research should focus on the mechanism of HFSR to find out new ways for prevention. Precautionary measures before the occurrence of HFSR can also be studied in the future.

KIT as a therapeutic target for non-oncological diseases

KIT is a receptor tyrosine kinase that after binding to its ligand stem cell factor activates signaling cascades linked to biological processes such as proliferation, differentiation, migration and cell survival. Based on studies performed on SCF and/or KIT mutant animals that presented anemia, sterility, and/or pigmentation disorders, KIT signaling was mainly considered to be involved in the regulation of hematopoiesis, gametogenesis, and melanogenesis. More recently, novel animal models and ameliorated cellular and molecular techniques have led to the discovery of a widen repertoire of tissue compartments and functions that are being modulated by KIT. This is the case for the lung, heart, nervous system, gastrointestinal tract, pancreas, kidney, liver, and bone. For this reason, the tyrosine kinase inhibitors that were originally developed for the treatment of hemato-oncological diseases are being currently investigated for the treatment of non-oncological disorders such as asthma, rheumatoid arthritis, and alzheimer's disease, among others. The beneficial effects of some of these tyrosine kinase inhibitors have been proven to depend on KIT inhibition. This review will focus on KIT expression and regulation in healthy and pathologic conditions other than cancer. Moreover, advances in the development of anti-KIT therapies, including tyrosine kinase inhibitors, and their application will be discussed.

Telatinib Is an Effective Targeted Therapy for Pseudomyogenic Hemangioendothelioma

Purpose: Pseudomyogenic hemangioendothelioma (PHE) is an extremely rare locally aggressive neoplasm with endothelial differentiation, which often presents with multiple lesions. These tumors have characteristic SERPINE1-FOSB fusions. We report a 17 years old patient with advanced unresectable PHE with a durable complete remission to the multi-tyrosine kinase inhibitor telatinib. The aim of this study was to generate an in vitro model for PHE, to study the functional consequences of SERPINE1-FOSB in endothelial cells, and its interaction with telatinib, to biologically substantiate the complete response to telatinib.Experimental Design: As the fusion results in overexpression of a truncated form of FOSB, we overexpressed truncated FOSB in normal endothelial cells.Results: Truncated FOSB significantly affected tumor growth in three-dimensional (3D) on matrigel with increased and sustained sprouting. Moreover, truncated FOSB acted as an active transcription factor capable to regulate its own transcription, as well as to upregulate PDGFRA and FLT1 expression (four-fold). Telatinib decreased proliferation and tumor growth in 3D and induced apoptosis. As expected, telatinib blocked VEGF signaling as phosphorylation of ERK was abolished. Interestingly, in FOSB overexpressing cells, telatinib specifically affected PDGFRA, FLT1, and FLT4 signaling and downregulated SERPINE1, thereby affecting the self-regulation of the fusion gene.Conclusions: We provide a biological substantiation of a complete clinical remission that was seen in a patient with PHE, showing that telatinib indirectly interferes with the self-regulated expression of the fusion product. Thus, telatinib or any other currently available VEGFR1-4/PDGFRA inhibitor could be a highly specific treatment option for patients with multifocal unresectable PHE. Clin Cancer Res; 24(11); 2678-87. ©2018 AACR.

Uterine sarcoma part III-Targeted therapy: The Taiwan Association of Gynecology (TAG) systematic review

Uterine sarcoma is a very aggressive and highly lethal disease. Even after a comprehensive staging surgery or en block cytoreduction surgery followed by multimodality therapy (often chemotherapy and/or radiation therapy), many patients relapse or present with distant metastases, and finally die of diseases. The worst outcome of uterine sarcomas is partly because of their rarity, unknown etiology, and highly divergent genetic aberration. Uterine sarcomas are often classified into four distinct subtypes, including uterine leiomyosarcoma, low-grade uterine endometrial stromal sarcoma, high-grade uterine endometrial stromal sarcoma, and undifferentiated uterine sarcoma. Currently, evidence from tumor biology found that these tumors showed alternation and/or mutation of genomes and the intracellular signal pathway. In addition, some preclinical studies showed promising results for targeting receptor tyrosine kinase signaling, phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway, various kinds of growth factor pathways, Wnt/beta-catenin signaling pathway, transforming growth factor β/bone morphogenetic protein signal pathway, aurora kinase A, MDM2 proto-oncogene, histone deacetylases, sex hormone receptors, certain types of oncoproteins, and/or loss of tumor suppressor genes. The current review is attempted to summarize the recurrent advance of targeted therapy for uterine sarcomas.

Multikinase Inhibitor-Induced Hand-Foot Skin Reaction: A Review of Clinical Presentation, Pathogenesis, and Management

Multikinase inhibitors (MKIs) are targeted cancer therapies designed to inhibit multiple tyrosine kinase pathways responsible for tumor proliferation, growth, and survival. These agents are more able to target cancer cells and possess better safety profiles than conventional chemotherapies. However, MKIs can produce significant cutaneous adverse events, hand-foot skin reaction (HFSR) being the most clinically significant. Although not life threatening, HFSR can lead to MKI dose modification, interruption, or termination, potentially limiting the anti-tumor effect. This article summarizes the current knowledge concerning the epidemiology, clinical presentation, pathogenesis, histopathology, prognostic implication, and current evidence-based prophylactic and reactive treatment options for MKI-induced HFSR. Its high incidence and significant impact on the quality of life emphasizes the great need to understand the pathogenesis and improve management of this condition.

Molecular targeted therapy in gastric cancer

Gastric cancer is one of the most common malignant tumors in China. Traditional treatments such as surgery, radiotherapy and chemotherapy not only have side effects, but the treatment efficiency is also poor. Molecular targeted therapy, due to its high efficiency, low toxicity, and high orientation, has been widely used in the treatment of gastric cancer. Targets applied in molecular targeted therapy of gastric cancer are mainly related to the cytokine and receptors that contribute to gastric cancer cell growth, including epidermal growth factor and its receptors, vascular endothelial growth factor and its receptors, epithelial cell adhesion molecules, insulin-like growth factor and its receptors, and molecules related to the cell cycle. This review focuses on molecular targeted treatment in gastric cancer.

MBL-II-141, a chromone derivative, enhances irinotecan (CPT-11) anticancer efficiency in ABCG2-positive xenografts

ABCG2 is responsible for the multidrug resistance (MDR) phenotype, and strongly modulates cancer outcomes. Its high expression at a number of physiological barriers, including blood-brain and intestinal barriers, impacts on drug pharmacokinetics parameters. We characterized MBL-II-141, a specific and potent ABCG2 inhibitor. Combination of 10 mg/kg MBL-II-141 with the anticancer agent CPT-11 completely blocked the growth of 90% freshly implanted ABCG2-positive tumors. Moreover, the same combination slowed the growth of already established tumors. As required for preclinical development, we defined the main pharmacokinetics parameters of MBL-II-141 and its influence on the kinetics of CPT-11 and its active metabolite SN-38 in mice. MBL-II-141 distribution into the brain occurred at a low, but detectable, level. Interestingly, preliminary data suggested that MBL-II-141 is well tolerated (at 50 mg/kg) and absorbed upon force-feeding. MBL-II-141 induced a potent sensitization of ABCG2-positive xenografts to CPT-11 through in vivo ABCG2 inhibition. MBL-II-141 strongly increased CPT-11 levels in the brain, and therefore would be a valuable agent to improve drug distribution into the brain to efficiently treat aggressive gliomas. Safety and other pharmacological data strongly support the reglementary preclinical development of MBL-II-141.

Mammalian drug efflux transporters of the ATP binding cassette (ABC) family in multidrug resistance: A review of the past decade

Multidrug resistance (MDR) is a serious phenomenon employed by cancer cells which hampers the success of cancer pharmacotherapy. One of the common mechanisms of MDR is the overexpression of ATP-binding cassette (ABC) efflux transporters in cancer cells such as P-glycoprotein (P-gp/ABCB1), multidrug resistance-associated protein 2 (MRP2/ABCC2), and breast cancer resistance protein (BCRP/ABCG2) that limits the prolonged and effective use of chemotherapeutic drugs. Researchers have found that developing inhibitors of ABC efflux transporters as chemosensitizers could overcome MDR. But the clinical trials have shown that most of these chemosensitizers are merely toxic and only show limited or no benefits to cancer patients, thus new inhibitors are being explored. Recent findings also suggest that efflux pumps of the ABC transporter family are subject to epigenetic gene regulation. In this review, we summarize recent findings of the role of ABC efflux transporters in MDR.

Investigational therapies up to Phase II which target PDGF receptors: potential anti-cancer therapeutics

INTRODUCTION

The platelet-derived growth factor receptor (PDGFR) pathway has important functions in cell growth and, by overexpression or mutation, could also be a driver for tumor development. Moreover, PDGFR is expressed in a tumoral microenvironment and could promote tumorigenesis. With these biological considerations, the PDGFR pathway could be an interesting target for therapeutics. Currently, there are many molecules under development that target the PDGFR pathway in different types of cancer.

AREAS COVERED

In this review, the authors report the different molecules under development, as well as those approved albeit briefly, which inhibit the PDGFR pathway. Furthermore, the authors summarize their specificities, their toxicities, and their development.

EXPERT OPINION

Currently, most PDGFR kinase inhibitors are multikinase inhibitors and therefore do not simply target the PDGFR pathway. The development of more specific PDGFR inhibitors could improve drug efficacy. Moreover, selecting tumors harboring mutations or amplifications of PDGFR could improve outcomes associated with the use of these molecules. The authors believe that new technologies, such as kinome arrays or pharmacologic assays, could be of benefit to understanding resistance mechanisms and develop more selective PDGFR inhibitors.

The modulation of ABC transporter-mediated multidrug resistance in cancer: a review of the past decade

ATP-binding cassette (ABC) transporters represent one of the largest and oldest families of membrane proteins in all extant phyla from prokaryotes to humans, which couple the energy derived from ATP hydrolysis essentially to translocate, among various substrates, toxic compounds across the membrane. The fundamental functions of these multiple transporter proteins include: (1) conserved mechanisms related to nutrition and pathogenesis in bacteria, (2) spore formation in fungi, and (3) signal transduction, protein secretion and antigen presentation in eukaryotes. Moreover, one of the major causes of multidrug resistance (MDR) and chemotherapeutic failure in cancer therapy is believed to be the ABC transporter-mediated active efflux of a multitude of structurally and mechanistically distinct cytotoxic compounds across membranes. It has been postulated that ABC transporter inhibitors known as chemosensitizers may be used in combination with standard chemotherapeutic agents to enhance their therapeutic efficacy. The current paper reviews the advance in the past decade in this important domain of cancer chemoresistance and summarizes the development of new compounds and the re-evaluation of compounds originally designed for other targets as transport inhibitors of ATP-dependent drug efflux pumps.

Multitarget inhibitors derived from crosstalk mechanism involving VEGFR2

Seven VEGFR small-molecule inhibitors have been approved by the US FDA as anticancer drugs, which confirms the therapeutic value of angiogenesis inhibitors. However, much more evidence indicates that VEGFR inhibition alone is usually not sufficient to block the tumor progress. The potential of some agents targeting VEGFR owes partially to the simultaneous inhibition of additional targets in other signaling pathways. In this review, the crosstalk between VEGFR2 and the additional targets in other signaling pathways, such as EGFR, MET, FGFR, PDGFR, c-Kit, Raf, PI3K and HDAC, and the synergistic effects derived from multitarget activities against these crosstalks are discussed. We also briefly describe the multitarget inhibitors in clinical trials or reported in the literature and patents under the different multitarget categories involving VEGFR2.

Vascular effects, efficacy and safety of nintedanib in patients with advanced, refractory colorectal cancer: a prospective phase I subanalysis

BACKGROUND

Nintedanib is a potent, oral angiokinase inhibitor that targets VEGF, PDGF and FGF signalling, as well as RET and Flt3. The maximum tolerated dose of nintedanib was evaluated in a phase I study of treatment-refractory patients with advanced solid tumours. In this preplanned subanalysis, the effect of nintedanib on the tumour vasculature, along with efficacy and safety, was assessed in 30 patients with colorectal cancer (CRC).

METHODS

Patients with advanced CRC who had failed conventional treatment, or for whom no therapy of proven efficacy existed, were treated with nintedanib ranging from 50-450 mg once-daily (n = 14) or 150-250 mg twice-daily (n = 16) for 28 days. After a 1-week rest, further courses were permitted in the absence of progression or undue toxicity. The primary objective was the effect on the tumour vasculature using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and expressed as the initial area under the DCE-MRI contrast agent concentration-time curve after 60 seconds (iAUC60) or the volume transfer constant between blood plasma and extravascular extracellular space (Ktrans).

RESULTS

Patients received a median of 4.0 courses (range: 1-13). Among 21 evaluable patients, 14 (67%) had a ≥40% reduction from baseline in Ktrans and 13 (62%) had a ≥40% decrease from baseline in iAUC60, representing clinically relevant effects on tumour blood flow and permeability, respectively. A ≥40% reduction from baseline in Ktrans was positively associated with non-progressive tumour status (Fisher's exact: p = 0.0032). One patient achieved a partial response at 250 mg twice-daily and 24 (80%) achieved stable disease lasting ≥8 weeks. Time to tumour progression (TTP) at 4 months was 26% and median TTP was 72.5 days (95% confidence interval: 65-114). Common drug-related adverse events (AEs) included nausea (67%), vomiting (53%) and diarrhoea (40%); three patients experienced drug-related AEs ≥ grade 3. Four patients treated with nintedanib once-daily had an alanine aminotransferase and/or aspartate aminotransferase increase ≥ grade 3. No increases > grade 2 were seen in the twice-daily group.

CONCLUSIONS

Nintedanib modulates tumour blood flow and permeability in patients with advanced, refractory CRC, while achieving antitumour activity and maintaining an acceptable safety profile.

Lymphangiosarcoma of the scalp

BACKGROUND

Lymphangiosarcoma is a rare, aggressive malignancy that originates from the endothelial cells lining lymphatic vessels and carries an extremely poor prognosis. Its clinical and histologic features are often indistinguishable from angiosarcoma.

OBJECTIVE

We sought to better characterize the clinical and histologic features of lymphangiosarcoma.

METHODS

Case report and review of the literature.

RESULTS

A number of immunohistochemical markers, including Von Willebrand factor, Ulex europaeus agglutinin 1, CD31, VEGFR-3, D2-40, Prox-1, can be used to help differentiate lymphatic from vascular tissue.

CONCLUSIONS

Recent characterization of several new biologic markers has allowed greater differentiation between these tumors and may provide new therapeutic targets for treatment.

Telatinib reverses chemotherapeutic multidrug resistance mediated by ABCG2 efflux transporter in vitro and in vivo

Multidrug resistance (MDR) is a phenomenon where cancer cells become simultaneously resistant to anticancer drugs with different structures and mechanisms of action. MDR has been shown to be associated with overexpression of ATP-binding cassette (ABC) transporters. Here, we report that telatinib, a small molecule tyrosine kinase inhibitor, enhances the anticancer activity of ABCG2 substrate anticancer drugs by inhibiting ABCG2 efflux transporter activity. Co-incubation of ABCG2-overexpressing drug resistant cell lines with telatinib and ABCG2 substrate anticancer drugs significantly reduced cellular viability, whereas telatinib alone did not significantly affect drug sensitive and drug resistant cell lines. Telatinib at 1 μM did not significantly alter the expression of ABCG2 in ABCG2-overexpressing cell lines. Telatinib at 1 μM significantly enhanced the intracellular accumulation of [(3)H]-mitoxantrone (MX) in ABCG2-overexpressing cell lines. In addition, telatinib at 1 μM significantly reduced the rate of [(3)H]-MX efflux from ABCG2-overexpressing cells. Furthermore, telatinib significantly inhibited ABCG2-mediated transport of [(3)H]-E₂17βG in ABCG2 overexpressing membrane vesicles. Telatinib stimulated the ATPase activity of ABCG2 in a concentration-dependent manner, indicating that telatinib might be a substrate of ABCG2. Binding interactions of telatinib were found to be in transmembrane region of homology modeled human ABCG2. In addition, telatinib (15 mg/kg) with doxorubicin (1.8 mg/kg) significantly decreased the growth rate and tumor size of ABCG2 overexpressing tumors in a xenograft nude mouse model. These results, provided that they can be translated to humans, suggesting that telatinib, in combination with specific ABCG2 substrate drugs may be useful in treating tumors that overexpress ABCG2.

Tivozanib for the treatment of metastatic renal cancer

Tyrosine kinase inhibitors have revolutionized the treatment of metastatic renal cell carcinoma (RCC). Drugs such as sorafenib, sunitinib and pazopanib act on the VEGF receptor pathway, but they can also inhibit other kinases, resulting in off-target toxicities. Tivozanib was developed due to its potency and selectivity against VEGF receptors 1-3. It has a favorable pharmacokinetic profile after oral administration and a long plasma half-life. In the Phase III TIVO-1 trial, it demonstrated a higher response rate and longer progression-free survival than sorafenib with a better side-effect profile. It is currently awaiting approval to be used in the first-line treatment of metastatic RCC. An early-phase trial has also shown its tolerability at full dose when given with the mTOR inhibitor temsirolimus, suggesting its potential in combination treatment. This article examines tivozanib from its laboratory to clinical development, as well as its relevance and future role in the treatment of RCC in the era of the tyrosine kinase inhibitors.

Immunohistochemical analysis on potential new molecular targets for esophageal cancer

Despite multimodal therapeutic options, esophageal cancer is still among the most deadly malignancies. In the past decade, targeted therapy has shown great potential in other cancers, but data on esophageal carcinoma are still rare. Five potential new molecular targets in esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC) were investigated for their expression characteristics: vascular endothelial growth factor receptor (VEGFR)-3, human epidermal growth factor receptor-2, stem cell growth factor receptor, tissue inhibitors of metalloproteinase (TIMP)-4 and TIMP-3. One hundred seventy-one EAC and ESCC tissue samples obtained from patients undergoing esophagectomy from 2000 to 2008 were included. Clinical data were evaluated retrospectively. Immunohistochemical staining was performed using tumor tissue with and without neoadjuvant treatment and healthy tissue. For samples without neoadjuvant treatment, expression of all targets was higher in tumor tissue than in healthy tissue except for VEGFR-3 (>98% expression in both tissues). For TIMP-4, TIMP-3 and stem cell growth factor receptor, trends to higher expression in tumor tissue were also found in EAC and ESCC that had received neoadjuvant treatment. Using Matched-pair analysis, we compared target expression in tumor tissue with and without neoadjuvant treatment. Only TIMP-3 had significantly lower expression in neoadjuvant treated tumor tissue (EAC: P = 0.059, ESCC: P = 0.006). TIMP-4, TIMP-3 and VEGFR-3 appear to qualify for targeted therapy in esophageal cancer because of their high expression in neoplastic tissue. TIMP-3 appears to be downregulated in neoadjuvantly treated esophageal cancer, and VEGFR-3 shows high expression in healthy mucosa leading to severe side effects by molecular targeting. Thus, TIMP-4 seems the most promising target.

LC-ESI-MS/MS determination of simotinib, a novel epidermal growth factor receptor tyrosine kinase inhibitor: application to a pharmacokinetic study

Simotinib is a novel epidermal growth factor receptor tyrosine kinase inhibitor. This study presented a sensitive and specific liquid chromatography-electrospray ionization-mass spectrometry method using erlotinib as internal standard for the determination of simotinib in human plasma. The method involved a simple liquid-liquid extraction using diethyl ether. The analytes were separated with isocratic gradient elution on an Agilent TC-C18 column (4.6 × 150 mm, 5 μm). Mass spectrometric detector equipped with electrospray ionization source was carried out in the mode of multiple reaction monitoring (MRM). The monitored transitions were m/z 501.2→182.1 for simotinib and m/z 394.4→278.1 for erlotinib. The calibration curve of simotinib was established over the range of 2.058-3000 μg L(-1) (r(2)=0.9924). The intra- and inter-day precisions were all less than 10%, and all the biases were not more than 7%. This validated method was then successfully applied to a pharmacokinetic study involving twelve healthy Chinese volunteers. The mean Cmax and Tmax for simotinib were 254.79±98.30 μg L(-1) and 1.71±0.48 h, respectively. Plasma concentrations declined with a t1/2 of 5.37±2.32 h. AUC0-t and AUC0→∞ values obtained were 1262.59±501.41 μg L(-1) h and 1329.95±517.42 μg L(-1) h, respectively.

Blastic leukaemias (AML): a biologist's view

Acute myeloblastic leukaemia is characterised by the extreme clonal proliferation of haematopoietic precursor cells with abnormal or arrested differentiation. Chemotherapy of acute leukaemia is channelled towards the reduction and eradication of leukaemic cells. However, relapse is generally assumed to occur in residual host cells, which are refractory to or elude therapy. The cancer stem cell hypothesis has gained considerable importance in recent years and could interpret this behaviour. This persuasive theory states that cells within a tumour are organised in a hierarchy similar to that of normal tissues and are maintained by a small subset of cells responsible for tumour dormancy. These cells, defined as 'tumour initiating cells' (TICs), possess several properties of normal tissue stem cells. Recently, the TICs associated with AML have been shown to comprise distinct, hierarchically arranged classes similar to those observed for haematopoietic stem cells. We know now that the growth and survival of blasts in AML are driven by the same growth factors that stimulate normal cells. Furthermore, direct evidence of the role of membrane stem cell factor and its receptor c-Kit in cell-cell interactions and cell survival in primary AML blasts have been provided, defining the importance of juxtacrine stimulation. Inhibition of c-Kit signalling induces combinations of cell death: autophagy (compensatory mechanism towards survival) and apoptosis. While recent work confirmed that c-Kit inhibitors reduce cancer cell proliferation, it also demonstrated that future inappropriate prescriptions could cause normal tissue deterioration. The purpose of this paper was to review some of the salient features of leukaemic blasts in support of the proposal that research into neoplasia be increased. Rather than presenting the details of various studies, I have attempted to indicate general areas in which work has been done or is in progress. It is hoped that this survey of the subject will demonstrate a variety of opportunities for additional research in human neoplasia.

Evolution of clinical trial design in early drug development: systematic review of expansion cohort use in single-agent phase I cancer trials

PURPOSE

To evaluate the use and objectives of expansion cohorts in phase I cancer trials and to explore trial characteristics associated with their use.

METHODS

We performed a systematic review of MEDLINE and EMBASE, limiting studies to single-agent phase I trials recruiting adults and published after 2006. Eligibility assessment and data extraction were performed by two reviewers. Data were assessed descriptively, and associations were tested by univariable and multivariable logistic regression.

RESULTS

We identified 611 unique phase I cancer trials, of which 149 (24%) included an expansion cohort. The trials were significantly more likely to use an expansion cohort if they were published more recently, were multicenter, or evaluated a noncytotoxic agent. Objectives of the expansion cohort were reported in 74% of trials. In these trials, safety (80%), efficacy (45%), pharmacokinetics (28%), pharmacodynamics (23%), and patient enrichment (14%) were cited as objectives. Among expansion cohorts with safety objectives, the recommended phase II dose was modified in 13% and new toxicities were described in 54% of trials. Among trials aimed at assessing efficacy, only 11% demonstrated antitumor activity assessed by response criteria that was not previously observed during dose escalation.

CONCLUSION

The utilization of expansion cohorts has increased with time. Safety and efficacy are common objectives, but 26% fail to report explicit aims. Expansion cohorts may provide useful supplementary data for phase I trials, particularly with regard to toxicity and definition of recommended dose for phase II studies.

The VEGF pathway in cancer and disease: responses, resistance, and the path forward

Antiangiogenesis was proposed as a novel target for the treatment of cancer 40 years ago. Since the original hypothesis put forward by Judah Folkman in 1971, factors that mediate angiogenesis, their cellular targets, many of the pathways they signal, and inhibitors of the cytokines and receptors have been identified. Vascular endothelial growth factor (VEGF) is the most prominent among the angiogenic cytokines and is believed to play a central role in the process of neovascularization, both in cancer as well as other inflammatory diseases. This article reviews the biology of VEGF and its receptors, the use of anti-VEGF approaches in clinical disease, the toxicity of these therapies, and the resistance mechanisms that have limited the activity of these agents when used as monotherapy.

Vascular endothelial growth factor (VEGF) receptors: drugs and new inhibitors

The recent launch onto the market of five VEGFR inhibitors indicates the therapeutic value of these agents and the importance of the research in the field of angiogenesis inhibitors for future oncologic therapy. In this Perspective we briefly report the inhibitors that are in clinical use, while we dedicate two wider sections to the compounds that are in clinical trials and to the new derivatives appearing in the literature. We especially consider the medicinal chemistry aspect of the topic and report the structure-activity relationship studies and the binding mode of some inhibitors as well as the biological data of the compounds discovered in the past 5 years.

Imaging vascular function for early stage clinical trials using dynamic contrast-enhanced magnetic resonance imaging

Many therapeutic approaches to cancer affect the tumour vasculature, either indirectly or as a direct target. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has become an important means of investigating this action, both pre-clinically and in early stage clinical trials. For such trials, it is essential that the measurement process (i.e. image acquisition and analysis) can be performed effectively and with consistency among contributing centres. As the technique continues to develop in order to provide potential improvements in sensitivity and physiological relevance, there is considerable scope for between-centre variation in techniques. A workshop was convened by the Imaging Committee of the Experimental Cancer Medicine Centres (ECMC) to review the current status of DCE-MRI and to provide recommendations on how the technique can best be used for early stage trials. This review and the consequent recommendations are summarised here. Key Points • Tumour vascular function is key to tumour development and treatment • Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can assess tumour vascular function • Thus DCE-MRI with pharmacokinetic models can assess novel treatments • Many recent developments are advancing the accuracy of and information from DCE-MRI • Establishing common methodology across multiple centres is challenging and requires accepted guidelines.

Novel targets for VEGF-independent anti-angiogenic drugs

INTRODUCTION

In the last decades, the active research in the field of tumor angiogenesis led to the development of a class of agents providing an effective inhibition of neovessels formation through the blockade of VEGF-related pathways. More recently, the identification of several non-VEGF factors such as PDGF, FGF, HGF, angiopoietins, ALK1/endoglin, endothelis and ephrins involved in tumor angiogenesis have emphasized the need to develop agents targeting multiple pro-angiogenic pathways.

AREAS COVERED

This review aimed at summarizing the role of non-VEGF molecular pathways in targeting tumor angiogenesis. Preclinical and clinical data for investigational agents against non-VEGF targets have been reviewed emphasizing the role of combined inhibition strategies.

EXPERT OPINION

Besides the successful development of drugs providing a specific VEGF blockade, novel agents targeting alternative angiogenesis-related pathways are being tested. Although it seems that the potential clinical usefulness of these novel compounds have been not yet fully investigated, sunitinib, sorafenib, pazopanib and other multikinase inhibitors have certainly displayed encouraging results. A more in-depth clarification of anti-angiogenic agents is still needed, in order to design the best clinical setting and schedule for target-based agents and possibly anticipate potential tools to overcome the emerging issue of anti-angiogenic drug resistance.

Biologic and clinical activity of tivozanib (AV-951, KRN-951), a selective inhibitor of VEGF receptor-1, -2, and -3 tyrosine kinases, in a 4-week-on, 2-week-off schedule in patients with advanced solid tumors

PURPOSE

To assess the maximum tolerated dose (MTD)/dose-limiting toxicities (DLT), safety, pharmacokinetics, and pharmacodynamics of tivozanib, a potent and selective oral VEGF receptor (VEGFR) tyrosine kinase inhibitor.

EXPERIMENTAL DESIGN

Dose levels of 1.0, 1.5, and 2.0 mg/d tivozanib for 28 days followed by 14 days of medication were explored in patients with advanced solid tumors.

RESULTS

Forty-one patients were enrolled. Animal data incorrectly predicted toxicity, resulting in DLTs at the starting dose (2.0 mg) consisting of grade 3 proteinuria and hypertension and grade 3 ataxia. At 1.0 mg, no DLT was observed. At an intermediate dose (1.5 mg), 1 patient experienced DLT consisting of grade 3 hypertension. This dose was determined as the MTD. Of 10 additional patients treated at 1.5 mg, 1 patient each experienced grade 3 hypertension and grade 3 fatigue, and 2 patients experienced grade 3 and 4 transaminase elevation. In 12 additional patients treated at 1.0 mg, no DLT was observed. Pharmacokinetics displayed long absorption time, dose proportional exposure, and a half-life of 4.7 days. Plasma levels of VEGF-A and soluble VEGFR-2 showed dose-dependent increases and decreases, respectively. Dynamic contrast-enhanced MRI indicated reduction in tumor perfusion. Clinical activity was observed in renal cell cancer, colorectal cancer, and other tumors.

CONCLUSION

Tivozanib was well tolerated with manageable side effects. The pharmacokinetics profile revealed that tivozanib was suitable for once-daily dosing. Encouraging and durable clinical activity was observed. The recommended daily dose of tivozanib in a 4-week-on and 2-week-off dosing regimen is 1.5 mg.

Phase I evaluation of telatinib, a VEGF receptor tyrosine kinase inhibitor, in combination with bevacizumab in subjects with advanced solid tumors

BACKGROUND

Blocking both receptor and ligand of the vascular endothelial growth factor (receptor) VEGF(R) pathway might be feasible and increase antitumor activity. This phase I study investigated telatinib, an oral tyrosine kinase inhibitor targeting VEGFR-2, combined with bevacizumab, in adults with solid tumors.

PATIENTS AND METHODS

Twenty-six patients were treated in successive cohorts with telatinib (twice-daily continuously, 450-900 mg) or bevacizumab (bi-weekly, starting dose 5 mg/kg). Safety, pharmacokinetics, endothelial (progenitor) cell (E(P)C)/growth factor kinetics and efficacy were assessed.

RESULTS

Most frequent adverse events were pain, nausea, voice changes and fatigue. Five dose-limiting toxicities (DLTs) occurred: hypertension (cohort I and II), bowel perforation, lipase increase and atrial flutter (cohort III). Cumulative toxicity resulted in a bevacizumab dose reduction to 1 mg/kg (cohort III). Due to three DLTs (n = 14), this cohort represented the best-tolerated dose level. Bevacizumab effectively neutralized plasma VEGF even at 1 mg/kg. Twelve patients had stable disease (clinical benefit 46%). EPC and SDF-1α levels increased during monotherapy telatinib.

CONCLUSIONS

Telatinib (450 mg b.i.d.) combined with bevacizumab (1 mg/kg bi-weekly) shows antitumor activity, but accumulating constitutional toxicity impedes long-term treatment of patients. Therefore, this combination will not be pursued in a phase II setting.

Added value of molecular targeted agents in oncology

The treatment of certain cancers has been revolutionised in recent years by the introduction of novel drugs designed to target specific molecular factors implicated in tumour growth. Notable examples include trastuzumab, a humanized monoclonal antibody (mAb) against human epidermal growth factor receptor (HER)-2 in women with HER2-positive breast cancer; rituximab, an anti-CD20 mAb in patients with non-Hodgkin's lymphoma; imatinib, a tyrosine kinase inhibitor in KIT-positive gastrointestinal stromal tumours and sunitinib, another tyrosine kinase inhibitor, in metastatic renal cell carcinoma. For regulatory reasons, new molecular targeted agents are first evaluated in advanced and metastatic disease, wherein they prolong survival. However, their most profound impact has been observed in the adjuvant setting, where they may contribute to curative therapy rather than mere palliation. Expansion in the use of molecular targeted therapies will have important cost implications for health care systems. Although expensive, on a monthly basis, molecular targeted therapies may not be more costly than treatments for other major chronic diseases, especially considering the contribution of cancer to the global disease burden, the associated socioeconomic costs and the long-term benefits of therapy. Nevertheless, the use of these agents must be optimised, in part using molecular biomarkers associated with drug response.

Phase I evaluation of telatinib, a vascular endothelial growth factor receptor tyrosine kinase inhibitor, in combination with irinotecan and capecitabine in patients with advanced solid tumors

PURPOSE

We studied the safety and tolerability of telatinib, an orally available, small-molecule tyrosine kinase inhibitor of the vascular endothelial growth factor receptor (VEGFR-2/VEGFR-3), platelet-derived growth factor receptor beta, and c-Kit in combination with capecitabine and irinotecan.

EXPERIMENTAL DESIGN

Telatinib twice daily continuously, irinotecan once every 3 weeks, and capecitabine oral twice daily on day 1 to 14 were administered in cycles of 21 days in escalating doses in successive cohorts. Toxicity was evaluated to conform to the Common Terminology Criteria for Adverse Events version 3.0. Pharmacokinetic and (circulating) endothelial (progenitor) cell measurements were done. Tumor efficacy was evaluated using the Response Evaluation Criteria in Solid Tumors.

RESULTS

Twenty-three patients were included in this phase I trial. Most frequently (>25%) reported adverse events of any grade were vomiting, nausea, fatigue, diarrhea, alopecia, and hand-foot syndrome. A silent myocardial infarction and two cases of decreased left ventricular ejection fraction were reported; both were reversible. Cardiac monitoring of the subsequent patients did not reveal other abnormalities. The study was terminated when the recommended single agent phase II doses of telatinib (900 mg twice daily) and capecitabine/irinotecan was reached. Pharmacokinetic profiles showed no clinically relevant changes upon coadministration of the three drugs. (Circulating) endothelial (progenitor) cell levels stabilized during treatment. Five of 23 patients had partial remission and 9 of 23 patients showed stable disease.

CONCLUSIONS

Continuous administration of 900 mg telatinib twice daily can be safely combined with irinotecan (180 mg/m(2)) and capecitabine (1,000 mg/m(2) twice daily, day 1-14) and is the recommended schedule for further phase II studies. Tumor shrinkage and disease stabilization was observed. Cardiac toxicity needs further investigation in following studies.

Pharmacogenetics of telatinib, a VEGFR-2 and VEGFR-3 tyrosine kinase inhibitor, used in patients with solid tumors

PURPOSE

Telatinib is an orally active small-molecule tyrosine kinase inhibitor of kinase insert domain receptor (KDR; VEGFR-2) and fms-related tyrosine kinase 4 (FLT4; VEGFR-3). This study aims at the identification of relationships between single nucleotide polymorphisms (SNPs) in genes encoding for transporter proteins and pharmacokinetic parameters in order to clarify the significant interpatient variability in drug exposure. In addition, the potential relationship between target receptor polymorphisms and toxicity of telatinib is explored.

METHODS

Blood samples from 33 patients enrolled in a phase I dose-escalation study of telatinib were analyzed. For correlation with dose normalized AUC(0-12), ATP-binding cassette (ABC) B1 (ABCB1), ABCC1, and ABCG2 were the genes selected. For correlation with telatinib toxicity, selected genes were the drug target genes KDR and FLT4.

RESULTS

No association between dose normalized AUC(0-12) and drug transporter protein polymorphisms was observed. In addition, no association between toxicity and KDR or FLT4 genotype or haplotype was seen.

CONCLUSIONS

Our pharmacogenetic analysis could not reveal a correlation between relevant gene polymorphisms and clinical and pharmacokinetic observations of telatinib.