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Among the various consequence arising from lung injury, hepatic fibrosis is the most severe. Decreasing the effects of hepatic fibrosis remains one of the primary therapeutic challenges in hepatology. Dysfunction of hepatic sinusoidal endothelial cells is considered to be one of the initial events that occur in liver injury. Vascular endothelial growth factor signaling is involved in the progression of genotype changes. The aim of the present study was to determine the effect of the tyrosine kinase inhibitor, vatalanib, on hepatic fibrosis and hepatic sinusoidal capillarization in a carbon tetrachloride (CCl4)-induced mouse model of liver fibrosis. Liver fibrosis was induced in BALB/c mice using CCl4 by intraperitoneal injection for 6 weeks. The four experimental groups included a control, and three experimental groups involving administration of CCl4, vatalanib and a combination of the two. Histopathological staining and measuring live hydroxyproline content evaluated the extent of liver fibrosis. The expression of α-smooth muscle actin (SMA) and cluster of differentiation (CD) 34 was detected by immunohistochemistry. Collagen type I, α-SMA, transforming growth factor (TGF)-β1 and vascular endothelial growth factor receptor (VEGFR) expression levels were measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The average number of fenestrae per hepatic sinusoid was determined using transmission electron microscopy. Liver fibrosis scores and hydroxyproline content were decreased in both vatalanib groups. In addition, both doses of vatalanib decreased mRNA expression levels of hepatic α-SMA, TGF-β1, collagen-1, VEGFR1, and VEGFR2. Levels of α-SMA and CD34 protein were decreased in the vatalanib group compared with the CCl4 group. There were significant differences in the number of fenestrae per sinusoid between the groups. The present study identified that administration of vatalanib was associated with decreased liver fibrosis and hepatic sinusoidal capillarization in CCl4-induced mouse models, and is a potential compound for counteracting liver fibrosis. [ABSTRACT FROM AUTHOR]

Background: Searching for two-dimensional (2D) structural similarities is a useful tool to identify new active compounds in drug-discovery programs. However, as 2D similarity measures neglect important structural and functional features, similarity by 2D might be underestimated. In the present study, we used combined 2D and three-dimensional (3D) similarity comparisons to reveal possible new functions and/or side-effects of known bioactive compounds. Results: We utilised more than 10,000 compounds from the SuperTarget database with known inhibition values for twelve different anti-cancer targets. We performed all-against-all comparisons resulting in 2D similarity landscapes. Among the regions with low 2D similarity scores are inhibitors of vascular endothelial growth factor receptor (VEGFR) and inhibitors of poly ADP-ribose polymerase (PARP). To demonstrate that 3D landscape comparison can identify similarities, which are untraceable in 2D similarity comparisons, we analysed this region in more detail. This 3D analysis showed the unexpected structural similarity between inhibitors of VEGFR and inhibitors of PARP. Among the VEGFR inhibitors that show similarities to PARP inhibitors was Vatalanib, an oral "multi-targeted" small molecule protein kinase inhibitor being studied in phase-III clinical trials in cancer therapy. An in silico docking simulation and an in vitro HT universal colorimetric PARP assay confirmed that the VEGFR inhibitor Vatalanib exhibits off-target activity as a PARP inhibitor, broadening its mode of action. Conclusion: In contrast to the 2D-similarity search, the 3D-similarity landscape comparison identifies new functions and side effects of the known VEGFR inhibitor Vatalanib. [ABSTRACT FROM AUTHOR]

Cancer microenvironment is characterized by significantly lower oxygen concentration. This hypoxic condition is known to reduce drug responsiveness to cancer chemotherapy via multiple mechanisms, among which the upregulation of the ATP-binding cassette (ABC) efflux transporters confers resistance to a wide variety of structurally unrelated anticancer drugs. Vatalanib (PTK787/ZK22584) is a multitargeted tyrosine kinase inhibitor for all isoforms of VEGFR, PDGFR and c-Kit, which exhibit potent anticancer activity in vitro and in vivo. We investigated the potentiation effect of vatalanib on the anticancer activity of conventional cytotoxic drugs in colon cancer cell lines under both normoxic and hypoxic conditions. Mechanistically, vatalanib was found to inhibit ABCG2 and ABCB1 efflux activity, presumably by acting as a competitive inhibitor and interfering with their ATPase activity. Under hypoxic growth condition, ABCG2 and ABCB1-overexpressing cells sorted out by FACS technique as side population (SP) were found to be significantly more responsive to SN-38 (ABCG2 and ABCB1 substrate anticancer drug) in the presence of vatalanib. The anchorage independent soft agar colony formation capacity of the SP cells was remarkably reduced upon treatment with a combination of SN-38 and vatalanib, compared to SN-38 alone. However, vatalanib, at concentrations that produced the circumvention of the transporters-mediated resistance, did not appreciably alter ABCG2/ABCB1 mRNA or protein expression levels or the phosphorylation of Akt and extracellular signal-regulated kinase (ERK1/2). Our study thus advocates the further investigation of vatalanib for use in combination chemotherapy to eradicate drug-resistant cancer cells under hypoxia. [ABSTRACT FROM AUTHOR]

AIMS Vatalanib is an oral anti-angiogenesis agent that inhibits vascular endothelial growth factor receptor tyrosine kinases, which in patients showed auto induction of metabolism and variability in pharmacokinetic (PK) disposition. The objective was to characterize the population PK and time-dependent change in vatalanib clearance and assess exposure-toxicity relationship in patients with myelodysplastic syndrome (MDS). METHODS This was an open-label phase II study of vatalanib in MDS patients receiving 750-1250 mg once daily in 28-day cycles. Serial blood samples were obtained and plasma vatalanib concentrations measured by HPLC. Population PK analysis was performed using NONMEM 7.2 with FO estimation since FOCE failed. The final model was evaluated using goodness-of-fit plots, bootstrap analysis, and visual predictive check. METHODS This was an open-label phase II study of vatalanib in MDS patients receiving 750-1250 mg once daily in 28-day cycles. Serial blood samples were obtained and plasma vatalanib concentrations measured by HPLC. Population PK analysis was performed using NONMEM 7.2 with FO estimation since FOCE failed. The final model was evaluated using goodness-of-fit plots, bootstrap analysis, and visual predictive check. RESULTS Pharmacokinetic data were complete for 137 patients (86 M, 51 F), of median age 70 years (range 20-91). A one-compartment model with lagged first-order absorption and time-dependent change in oral clearance was fitted to the vatalanib plasma concentration versus time data. The population means for pre-induction and post-induction oral clearance were 24.1 l h-1 (range: 9.6-45.5) and 54.9 l h-1 (range: 39.8-75.6), respectively. The apparent oral clearance increased 2.3-fold, (range: 1.7-4.1-fold) from first dose to steady state. Our data did not identify a significant relationship of the predefined covariates with vatalanib pharmacokinetics, although power to detect such a relationship was limited. CONCLUSIONS Vatalanib pharmacokinetics were highly variable and the extent of auto induction was not determined to correlate with any of the pre-defined covariates. [ABSTRACT FROM AUTHOR]

PTK787/ZK222584 (vatalanib), an orally active inhibitor of vascular endothelial growth factor receptors (VEGFRs), was evaluated in this phase II study of 20 patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL). Patients received once-daily PTK787/ZK222584 at a target dose of 1250 mg. Eighteen patients were evaluable for response: one patient had a complete response (CR), six patients had stable disease but subsequently progressed, 10 patients had progressive disease by three cycles and one subject withdrew before response evaluation. The patient who attained a CR underwent autologous stem cell transplant and remains disease-free 76 months after study completion. There were no grade 4 toxicities. Grade 3 thrombocytopenia occurred in 20% and grade 3 hypertension occurred in 10%. There were no episodes of grade 3 proteinuria. In conclusion, PTK787/ZK222584 was well tolerated in a heavily pretreated population of patients with DLBCL, although its therapeutic potential as a single agent in DLBCL appears limited. [ABSTRACT FROM AUTHOR]

Abstract: Hemangioblastomas (HBs) are rare indolent vascular tumors that may occur sporadically or in association with von Hippel–Lindau (VHL) disease. Total neurosurgical resection is the standard upfront approach providing long-term tumor control. At time of tumor recurrence, second surgery, radiosurgery or radiotherapy are the main therapeutic strategies. Limited information is available on the role of pharmacological strategies. Anti-angiogenic agents, particularly multitarget tyrosine kinase inhibitors (semaxanib, sunitinib, vatalanib), thalidomide and interferon alfa-2a are currently the most widely studied strategies to prolonge disease stability. Salvage therapy with anti-angiogenetic drugs may be of benefit in some patients who are not suitable for surgery, radiosurgery or radiotherapy, with progressive or recurrent hemangioblastoma especially those located in retina, since anti-angiogenetic therapy may delay tumor progression. This strategy warrants prospective evaluation in a clinical trial. [Copyright &y& Elsevier]

Abstract: Introduction: The Cancer and Leukemia Group B (CALGB) conducted a multi-center phase II trial to evaluate the efficacy and safety of vatalanib in previously untreated patients with malignant mesothelioma and to evaluate potential biomarkers of disease response (CALGB 30107). Methods: Treatment consisted of vatalanib 1250mg given orally once daily. CT scans were obtained at baseline and every 6 weeks thereafter. Baseline serum levels of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), thrombospondin-1 (TSP-1), and mesothelin were obtained. The primary endpoint was 3-month progression-free survival (PFS). Results: Forty-seven patients enrolled at 19 centers. The median age was 75 years, and the majority of patients (79%) had an ECOG performance status of 1. Tumors were classified as epithelial (77%), sarcomatoid (10%), or mixed (9%) histology. Toxicity was mild; the most common grade 3/4 adverse events were neutropenia (2%), nausea (15%), elevated alanine aminotransferase (11%), hypertension (2%), and gastrointestinal bleeding (2%). Partial responses were observed in 6% of patients and stable disease in 72% of patients. The 3-month PFS rate was 55% (95% CI: 40%, 68%). The median PFS was 4.1 months. Median overall survival was 10.0 months. There was no correlation between serum levels of VEGF, PDGF, TSP-1, or mesothelin and treatment response, PFS, or survival. Conclusions: Vatalanib as a single agent with this dose and schedule does not warrant further study in this disease. [Copyright &y& Elsevier]

Abstract: We here describe an HPLC–DAD method to analyse different protein kinase inhibitors. Potential applications of this method are pharmacokinetic studies and therapeutic drug monitoring. Optimised chromatography conditions resulted in a very good separation of seven inhibitors (vatalanib, bosutinib, canertinib, tandutinib, pazopanib, dasatinib – internal standard and erlotinib). The good sensitivity makes this method competitive with LC/MS/MS. The separation was performed with a Lichrospher 100-5 RP8, 250mm×4mm column maintained at 30±1°C, and with a mobile phase of 0.05M H3PO4/KH2PO4 (pH=2.3)–acetonitrile (7:3, v/v) at a flow rate of 0.7mL/min. A simple and fast sample preparation sequence with liquid–liquid extraction led to good recoveries (73–90%) of all analytes. The recovery hardly reached 50% only for pazopanib. This method can also be used for targeted protein kinase inhibitor quantification. A perfect linearity in the validated range (20–10,000ng/mL) and an LOQ of 20ng/mL were achieved. The relative standard deviations and accuracies of all examined drug concentrations gave values much lower than 15% both for between- and within-batch calculations. All analysed PKIs were stable for 6 months in a 1mg/mL dimethyl sulfoxide stock solution. Vatalanib, bosutinib and erlotinib were also stable in human serum in the whole examined concentration range. [Copyright &y& Elsevier]

Background: The objective of this multicenter, prospective uncontrolled phase II trial was to determine efficacy, safety and tolerability of vatalanib, an oral angiogenesis inhibitor targeting all known vascular endothelial growth factor receptors, in the second-line treatment of non-small-cell lung cancer (NSCLC). Patients and methods: Patients with stage IIIB/IV NSCLC-proven tumor progression during or after one platinum-based chemotherapy regimen received a fixed dose of 1250 mg vatalanib either once-daily dosing (QD) or two divided daily dosing (TDD: 500 mg a.m. + 750 mg p.m.) until disease progression or unacceptable toxicity. Primary end point was the disease control rate (DCR) at 12 weeks. Results: Fifty-four and 58 patients were enrolled to the QD and TDD arms. DCR at 12 weeks was 35% in the QD and 37% in the TDD arm. The best overall response included one (2%) patient with confirmed partial response with QD and three (5%) with TDD. Median progression-free survival and overall survival were 2.1/7.3 months in the QD arm and 2.8/9.0 months with TDD arm. This therapy showed a moderate toxicity profile for the majority of patients. Conclusions: In the chosen patient population, vatalanib QD and TDD dosing demonstrated potential benefits in tumor size reduction, DCR, and survival. [ABSTRACT FROM PUBLISHER]

Abstract: Background: Fibroblast growth factor receptor 3 (FGFR3) is up-regulated as a result of the t(4;14)(p16;q32) translocation that occurs in up to 20% of multiple myeloma (MM) patients. Recent studies have demonstrated that up-regulation of FGFR3 promotes cell survival, growth and drug resistance in malignant plasma cells, both in vitro and in vivo. Therefore, inhibition of FGFR3 signalling is potential target for the chemotherapeutic intervention in t(4;14) MM. Methods: Small molecule receptor tyrosine kinase inhibitors (PD173074, sunitinib (SU-11248), vandetanib (ZD6474) and vatalanib (PTK-787)) with varying degrees of inhibitory activity and selectivity against FGFR, were assessed in Ba/f3 cells expressing ZNF198-FGFR1 and MM cell lines. Cell viability, FGFR3 and ZNF198-FGFR1 phosphorylation and apoptosis were evaluated by growth inhibition assays, immunoblotting and fluorescence-activated cell sorting analysis, respectively. An in vivo study was performed with sunitinib in t(4;14)-positive and t(4;14)-negative human MM tumour xenograft models. Results: PD173074 and sunitinib differentially inhibited the growth of Ba/f3 cells expressing ZNF198-FGFR1 (GI50 =10nM and 730nM, versus GI50 >1μM and 2.7μM for parental cells; p <0.0001) and t(4;14) positive MM cell lines (GI50 =4–10μM and 1–3μM, versus GI50 =14–15μM and 4–5μM for t(4;14) negative MM cells; p ≤0.002). In addition, both PD173074 and sunitinib inhibited the activation of FGFR3 in t(4;14)-positive MM cells. PD173074 and sunitinib induced an apoptotic response in a concentration and time-dependent manner in a t(4;14)-positive (PD174073 and sunitinib) but not a t(4;14)-negative MM cell line (sunitinib only); however, in in vivo tumours derived from the same cell lines, sunitinib was only active in the t(4;14)-negative model. Conclusions: These data demonstrate that PD173074 and sunitinib are inhibitors of FGFR3 in MM cell lines, and that sunitinib has in vivo activity in a human MM tumour xenograft model. However, caution should be exercised in using the t(4;14) translocation as a predictive biomarker for patient selection in clinical trials with sunitinib. [Copyright &y& Elsevier]

Background: Vatalanib (PTK787/ZK 222584) inhibits a few tyrosine kinases including KIT, platelet-derived growth factor receptors (PDGFRs) and vascular endothelial growth factor receptors (VEGFRs). We report efficacy and safety results of vatalanib in advanced gastrointestinal stromal tumour (GIST) resistant to imatinib or both imatinib and sunitinib.Patients and Methods: Forty-five patients whose metastatic GIST had progressed on imatinib were enrolled. Nineteen (42.2%) patients had received also prior sunitinib. Vatalanib 1250 mg was administered orally daily.Results: Eighteen patients (40.0%; 95% confidence interval (CI), 25.7-54.3%) had clinical benefit including 2 (4.4%) confirmed partial remissions (PR; duration, 9.6 and 39.4 months) and 16 (35.6%) stabilised diseases (SDs; median duration, 12.5 months; range, 6.0-35.6+ months). Twelve (46.2%) out of the 26 patients who had received prior imatinib only achieved either PR or SD compared with 6 (31.6%, all SDs) out of the 19 patients who had received prior imatinib and sunitinib (P=0.324). The median time to progression was 5.8 months (95% CI, 2.9-9.5 months) in the subset without prior sunitinib and 3.2 (95% CI, 2.1-6.0) months among those with prior imatinib and sunitinib (P=0.992). Vatalanib was generally well tolerated.Conclusion: Vatalanib is active despite its narrow kinome interaction spectrum in patients diagnosed with imatinib-resistant GIST or with imatinib and sunitinib-resistant GIST. [ABSTRACT FROM AUTHOR]

Abstract: A sensitive and accurate method for the determination of vatalanib in human EDTA plasma was developed using high-performance liquid chromatography and detection with tandem mass spectrometry. Stable isotopically labeled imatinib was used as internal standard. Plasma proteins were precipitated and an aliquot of the supernatant was directly injected onto a Phenomenex Gemini C18 analytical column (50mm×2.0mm ID, 5.0μm particle size) and then compounds were eluted with a linear gradient. The outlet of the column was connected to a Sciex API 365 triple quadrupole mass spectrometer and ions were detected in positive multiple reaction monitoring mode. The lower limit of quantification was 10ng/mL (S/N≈10, CV≤8.4%). This method was validated over a linear range from 10 to 2500ng/mL, and results from the validation study demonstrated a good intra- and inter-assay accuracy (inaccuracy ≤9.57%) and precision (CV≤8.81%). This method has been used to determine plasma vatalanib concentrations in patients with advanced solid tumor, enrolled in a phase I pharmacokinetic trial with the drug. [Copyright &y& Elsevier]

As targeted therapies for cancer become increasingly integrated into standard practice, appropriate selection of the patients most likely to benefit from these therapies is now receiving critical scrutiny. Early experience with therapies directed at targets that are definitively overactive (e.g. the bcr-abl tyrosine kinase targeted by imatinib) or over-expressed [e.g. the human epidermal growth factor receptor 2 (HER2) targeted by trastuzumab] has generated the perception that pre-treatment target assessment is a pre-requisite for therapy with all targeted agents. However, emerging evidence suggests that this is not presently feasible for anti-angiogenic agents. Despite considerable evidence for the association of intratumoral and/or plasma vascular endothelial growth factor (VEGF) levels with tumor progression and/or poor prognosis, pre-treatment VEGF levels do not appear to be predictive of response to anti-angiogenic therapy. This may possibly be due to the complexity of the angiogenic pathways and the limitations associated with current methods of VEGF detection and quantification; e.g. low assay sensitivity and lack of standardized methods could prevent detection of very small increases in VEGF, which may be clinically important in patients with tumors that are highly dependent on this growth factor. In addition to a general lack of agreement as to the relative clinical relevance of circulating versus tumor VEGF levels, the absence of a ‘gold standard’ VEGF detection assay and the lack of a predefined, clinically relevant cut-off pose a significant hindrance to the clinical utility of VEGF measurements for therapy selection. Given the fundamental importance of angiogenesis for tumor growth and progression, and the key role of VEGF in these processes, presently it seems appropriate to view anti-VEGF agents such as bevacizumab (Avastin®) as having potential utility, independently of pre-treatment screening. Further research is needed to define the relationship between potential surrogate markers of VEGF pathway activity and clinical outcomes. [ABSTRACT FROM AUTHOR]

Reports on the outcome of the 2005 annual meeting of the American Society of Clinical Oncology. Theme of the meeting; Sessions conducted during the meeting; Trastuzumab for HER2-Positive Breast Cancer.

Abstract: The family of VEGF receptors are important mediators of angiogenesis, which is essential for tumour growth and metastasis. PTK/ZK is a multiple VEGF receptor inhibitor that blocks the activity of all known VEGF receptor tyrosine kinases. This phase I/II trial evaluated the safety, pharmacokinetics and efficacy of PTK/ZK in patients with liver metastases from solid tumours. Patients were administered oral PTK/ZK monotherapy once daily at doses of 300–1200mg/day in 28-day cycles until unacceptable toxicity or tumour progression occurred. Twenty-seven patients were enrolled and treatment with PTK/ZK was generally well tolerated. The most frequently reported adverse events were fatigue, nausea, dizziness, and vomiting (mostly National Cancer Institute Common Toxicity Criteria grade 1 or 2). The area under the concentration–time curve (AUC) of PTK/ZK increased between 300 and 1000mg/day with no further increase from 1000 to 1200mg/day; the AUC decreased by 50% between day 1 and day 15. The DCE-MRI showed a statistically significant early reduction of tumour blood supply (measured as Ki) at day 2 at doses ⩾750mg/day. Disease progression was significantly correlated with percent change from baseline Ki. Thirteen patients had stable disease for at least two cycles (56 days). Median overall survival was 11.8 months (95% CI=6.6, 17.1 months). Long-term therapy with PTK/ZK demonstrated predictable pharmacokinetics, was safe and feasible in patients with metastatic disease, and showed promising clinical activity. The minimum biologically active dose was established at 750mg/day whereas the recommended dose for phase III studies is 1200mg/day. [Copyright &y& Elsevier]

Angiogenesis is a fundamental developmental process and a hallmark of cancer progression. Receptor tyrosine kinases (RTK) are targets for cancer therapy which may include their action as anti-angiogenic agents. Derazantinib (DZB) is an inhibitor of the fibroblast growth factor receptors (FGFRs) 1–3 as well as other kinase targets including vascular endothelial growth factor receptor 2 (VEGFR2), colony stimulating factor-1 receptor (CSF1R) and platelet-derived growth factor beta receptor (PDGFRbeta). This study aimed to investigate the effect of DZB on blood vessel morphogenesis and to compare its activity to known specific FGFR and VEGFR inhibitors. For this purpose, we used the developing vasculature in the zebrafish embryo as a model system for angiogenesis in vivo. We show that DZB interferes with multiple angiogenic processes that are linked to FGF and VEGF signalling, revealing a potential dual role for DZB as a potent anti-angiogenic treatment. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a highly prevalent neurodegenerative disease characterized by Aβ accumulation and tau hyperphosphorylation. Epidemiological evidence for a negative correlation between cancer and AD has led to the proposed use of tyrosine kinase inhibitors (TKIs) such as dasatinib and masitinib for AD, with reported beneficial effects in the AD brain. The TKI vatalanib inhibits angiogenesis by inhibiting vascular endothelial growth factor receptor (VEGFR). Although changes in VEGF and VEGFR have been documented in AD, the effect of vatalanib on AD pathology has not been investigated. In this study, the effects of vatalanib on tau phosphorylation and Aβ accumulation in 5xFAD mice, a model of AD, were evaluated by immunohistochemistry. Vatalanib administration significantly reduced tau phosphorylation at AT8 and AT100 by increasing p-GSK-3β (Ser9) in 5xFAD mice. In addition, vatalanib reduced the number and area of Aβ plaques in the cortex in 5xFAD mice. Our results suggest that vatalanib has potential as a regulator of AD pathology. [ABSTRACT FROM AUTHOR]