Tyrosine Kinase Inhibitor ZD1839 Research Articles

Micellear Gold Nanoparticles as Delivery Vehicles for Dual Tyrosine Kinase Inhibitor ZD6474 for Metastatic Breast Cancer Treatment.

The therapeutic index of poorly water-soluble drugs is often hampered due to poor pharmacokinetics, reduced blood retention, and lack of effective drug concentrations in the tumor region. In order to overcome these issues, drugs are often delivered by use of delivery vehicles to provide an enhanced therapeutic index. Gold nanoparticles synthesized in micellar networks of amphiphilic block copolymer (AuNM) provide an efficient nanocarrier for tissue- and site-specific drug delivery owing to their low cytotoxicity and immunogenicity. AuNM is formed by exploiting the properties of both inorganic Au material and an amphiphilic polymer of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG). We further functionalized AuNM with the FDA-approved dual tyrosine kinase inhibitor ZD6474 and studied the physicochemical properties of the conjugate ZD6474-AuNM. Both AuNM and ZD6474-AuNM, with a diameter of ∼70 nm, were very stable at physiological pH. Conversely, at an acidic pH of 5.2, a slow sustained-release profile of ZD6474 was evident from AuNM, which could provide a method of facilitating release of the drug in an acidic tumor environment. In vitro, in triple-negative breast cancer cells, ZD6474-AuNM inhibited tumor cell proliferation, migration, and invasion and induced apoptosis. There was no detectable lysis of red blood cells observed when they were treated with AuNM and ZD6474-AuNM, confirming hemocompatibility. To reinforce the possibility of AuNM serving as a delivery vehicle, AuNM was conjugated with the IR680 dye for tracking, and this conjugate was systemically delivered in female nude mice bearing MDA-MB-231 human breast cancer xenografts. Fluorescence signal was retained in the tumor region in a temporal manner as compared to other organs, indicating passive retention of AuNM in the tumor locale. Moreover, delivery of ZD6474-AuNM in nude mice bearing MDA-MB-231 xenografts led to decreased tumor size as compared to the control group. The promising safety, targeting, and therapeutic results of systemic delivery of ZD6474 by AuNM provide an attractive alternative method for treating patients with metastatic breast cancer.

Nonmuscle Myosin II Is Required for Internalization of the Epidermal Growth Factor Receptor and Modulation of Downstream Signaling

Ligand-induced internalization of the epidermal growth factor receptor (EGFR) is an important process for regulating signal transduction, cellular dynamics, and cell-cell communication. Here, we demonstrate that nonmuscle myosin II (NM II) is required for the internalization of the EGFR and to trigger the EGFR-dependent activation of ERK and AKT. The EGFR was identified as a protein that interacts with NM II by co-immunoprecipitation and mass spectrometry analysis. This interaction requires both the regulatory light chain 20 (RLC20) of NM II and the kinase domain of the EGFR. Two paralogs of NM II, NM II-A, and NM II-B can act to internalize the EGFR, depending on the cell type and paralog content of the cell line. Loss (siRNA) or inhibition (25 μm blebbistatin) of NM II attenuates the internalization of the EGFR and impairs EGFR-dependent activation of ERK and AKT. Both internalization of the EGFR and downstream signaling to ERK and AKT can be partially restored in siRNA-treated cells by introduction of wild type (WT) GFP-NM II, but cannot be restored by motor mutant NM II. Taken together, these results suggest that NM II plays a role in the internalization of the EGFR and EGFR-mediated signaling pathways.

Abstract C161: Modulation of thymidine phosphorylase (TP) expression in breast cancer cell lines exposed to the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor ZD1839

Abstract Capecitabine is a potent antitumor drug used in the treatment of many types of cancer such as bowel, breast and stomach cancer. It is administered orally and is first metabolized in the liver by carboxylesterase to generate 5′-deoxy-5-flurocytidine ribose (5′-DFCR) that is subsequently converted to 5′-deoxy-5-fluorouridine ribose (5′-DFUR) by cytidine deaminase. While 5′-DFCR can be further converted to 5′-DFUR in tumor or normal tissues, the conversion of 5′-DFUR to the cytotoxic inhibitor of DNA synthesis 5-FU, is catalyzed by thymidine phosphorylase (TP), which is highly expressed in tumors. Factors modulating the TP levels in tumors are not well understood, however, recent reports suggest that drugs such as taxol and epidermal growth factor receptor (EGFR) inhibitors could induce an increase in TP levels in tumor cells. Here, we sought to determine whether inhibition of EGFR could modulate the levels of TP in a panel of six breast cancer cell lines with varied levels of sensitivity to ZD1839, an EGFR tyrosine kinase inhibitor. Three of the cell lines used in the study (SUM 149, BT474, SKBR3) are commonly classified as sensitive to ZD1839 and the others are known to be moderately sensitive or resistant (MDA-MB 468, BT20, BT549). All cell lines were studied according to two different treatment conditions: either they were provided with DMEM medium supplemented with FBS or starved and subsequently stimulated with 8 nM EGF for 1h. Furthermore, we investigated the in vitro growth inhibitory potency of 5′-DFUR (a Capecitabine metabolite) and ZD1839 in the panel of cell lines. The results showed that: (1) following exposure to 10 µM of ZD1839 for 24h, cells pre-incubated with serum-containing medium did not exhibit a significant change in TP levels. (2) in contrast, all cells starved for 24h and subsequently given 10 µM of ZD1839 for 24h showed varied levels of increase in TP (1.2- to 4.7-fold) except SUM149 in which TP levels remained high, before and after EGF stimulation. BT549, the most ZD1839 resistant cell line showed a low TP expression with no increase after treatment. (3) IC50 values were in agreement with the known levels of sensitivity of all the cell lines ZD1839 and TP expression correlated with cell line sensitivity to 5′DFUR but not to ZD1839. The results in toto suggest that basal and stimulated levels of TP vary among breast cancer cell lines and that EGFR inhibition induces an increase in TP expression in the latter cells. TP induction was mostly seen in cells that were starved, treated with ZD1839 and stimulated with EGF. This suggests that starved cells perhaps synchronized in G0–G1 phase, upon EGF-stimulation may have entered S phase, a cell cycle phase where TP expression is known to reach its maximum. Further studies are ongoing to investigate the sensitivity of the cell panel to ZD1839, 5′DFUR and their corresponding combination. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C161.

Sequence dependence of cell growth inhibition by EGFR–tyrosine kinase inhibitor ZD1839, docetaxel, and cisplatin in head and neck cancer

This study was to explore whether the efficacy of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor ZD1839 (Z, Iressa, gefitinib) plus chemotherapeutic agents docetaxel (D) and cisplatin (P) may benefit from sequencing of the combination. Three head and neck cancer cell lines were used to study the effect of various combinations of and relative sequencing of D, P, and Z in cell growth inhibition. A population pharmacokinetic stimulation study was conducted on Z in silico and used together with the growth inhibition data to derive principles for future in vivo use of this drug combination. The inhibitory effects of Z on combinations of D and P were sequence dependent. Treatment simultaneously with DPZ or with DP followed by Z (DP-->Z) showed synergistic effects in all 3 cell lines. However, sequencing with Z followed by DP (Z-->DP), gave an antagonistic effect, suggesting that D and P should be administered when the effect of Z is low. The induction of apoptosis was also sequence dependent. The in silico pharmacokinetic study suggested the feasibility of deriving a 5-day-on/2-day-off regimen for Z, in which D and P administration commences when levels of Z are low, allowing levels of Z to accumulate sufficiently during the remainder of the cycle. These data suggests that it is feasible to design clinical trials with these settings to maximize the efficacy of this combined drug regimen.

A transplantable human medullary thyroid carcinoma as a model for RET tyrosine kinase-driven tumorigenesis

Hereditary medullary thyroid carcinoma (MTC) is caused by germline mutations in the RET proto-oncogene, resulting in constitutive activation of the RET tyrosine kinase. A substantial proportion of sporadic MTCs also have RET mutations, making the RET tyrosine kinase a potential therapeutic target in MTC. We have established a transplantable MTC in nude mice from a sporadic human MTC carrying a RET C634R mutation. Transplanted tumors had an exponential growth rate with an approximate doubling time of about 3 weeks, and expressed a neuroendocrine phenotype characteristic of MTC, e.g., expression of calcitonin, chromogranin A (CgA), synaptophysin, synaptic vesicle protein 2 (SV2), vesicular monoamine transporter-1 and -2, carcinoembryonic antigen, cytokeratin 8/18, epithelial cadherin, and neural cell adhesion molecule. Plasma calcitonin and CgA levels were elevated in tumor-bearing mice and correlated with tumor size. Cytogenetic analysis, including spectral karyotyping, confirmed the human origin of the xenografted tumors and demonstrated an abnormal, near triploid karyotype. Treatment of tumor-bearing nude mice with the tyrosine kinase inhibitor ZD6474, which specifically inhibits RET, epidermal growth factor receptor (EGFR), and vascular endothelium growth factor receptor (VEGFR) tyrosine kinases, resulted in a dose-dependent inhibition of tumor growth. Oral ZD6474 given once daily (250 mg/kg, 5 days/week) reduced tumor volume to 11% when compared with controls after 4 weeks. Our results show that this transplantable MTC, designated GOT2, represents a novel and useful model for studies of MTC and RET tyrosine kinase-dependent tumor growth.

Antiangiogenic and antitumor activity of a novel vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor ZD6474 in a metastatic human pancreatic tumor model

ZD6474 is a novel, orally available inhibitor of vascular endothelial growth factor receptor kinase insert domain receptor/flk-1 tyrosine kinase activity with additional activity against the epidermal growth factor receptor-1 tyrosine kinase. The aim of this study was to evaluate ZD6474, alone and in combination with gemcitabine, in an orthotopic model of metastatic pancreatic cancer. Nude mice (nine to 10/group) were injected orthotopically with 1x10(6) L3.6pl human pancreatic cancer cells. Eight days later, treatment was initiated with vehicle only, gemcitabine (100 mg/kg intraperitoneal twice weekly), ZD6474 (50 mg/kg oral once daily) or a combination of the two treatments. Animals were killed on day 24 posttreatment initiation. The phosphorylation status level of vascular endothelial growth factor receptor-2 and epidermal growth factor receptor as well as the phosphorylation level of AKT and extracellular signal-regulated kinase-1/2 in different human pancreatic carcinoma cells and in human umbilical vein endothelial cells was analyzed by Western blotting. Compared with controls (1231 mg), the mean weight of treated tumors was reduced to 836, 541 and 308 mg in the gemcitabine, ZD6474 and combination groups, respectively. Lymph node metastasis was significantly reduced in both the ZD6474 alone and combined treatment groups, with 3/10 and 1/5 animals developing metastases, compared with 10/10 and 9/9 in the control and gemcitabine groups (P<0.003 and <0.0003, respectively). Microvessel density and cell proliferation were significantly reduced in the ZD6474 and combined treatment groups (P<0.02). Immunohistochemistry of tumor samples following treatment with ZD6474 resulted in a reduction of the activated and phosphorylated epidermal growth factor receptor, whereas total epidermal growth factor receptor levels were comparable with control tumors. On the basis of Western blot analysis, ZD6474 provides inhibition of tumor angiogenesis through an anti-vascular endothelial growth factor receptor-2 mechanism and inhibition of cancer cell growth through an anti-epidermal growth factor receptor mechanism. ZD6474 decreased primary pancreatic tumor growth and reduced lymph node and liver metastases compared with controls or gemcitabine alone. Tumor growth was inhibited further in animals receiving ZD6474 and gemcitabine in combination.

91 POSTER Impact of tumor VEGF expression level on the in situ efficacy of the VEGFR2 associated tyrosine kinase inhibitor ZD6474

91 POSTER Impact of tumor VEGF expression level on the in situ efficacy of the VEGFR2 associated tyrosine kinase inhibitor ZD6474

225 Tyrosine kinase inhibitor ZD6474 (Zactima) and its effects on malignant mesothelioma cell lines

225 Tyrosine kinase inhibitor ZD6474 (Zactima) and its effects on malignant mesothelioma cell lines

Tissue Distribution and Metabolism of the Tyrosine Kinase Inhibitor ZD6474 (Zactima) in Tumor-Bearing Nude Mice following Oral Dosing

ZD6474 [N-(4-bromo-2-fluorophenyl)-6-methoxy-7-[(1-methylpiperidin-4-yl)methoxy]-quinazolin-4-amine; Zactima] is a tyrosine kinase inhibitor with antiangiogenic and antitumor activity currently undergoing human trials for cancer treatment. Pharmacokinetic studies in animal models are an important component in the clinical development of this agent to relate preclinical studies to patient treatment. In the studies presented here, the pharmacokinetics of ZD6474 was determined in plasma and tissues of MCF-7 tumor-bearing nude mice following single p.o. doses at 10, 25, and 50 mg/kg. Plasma area under the curve and Cmax were linear, increasing proportionally with dose. Tissue analysis showed that ZD6474 is extensively distributed to tissues, with liver and lung accumulating concentrations of 212 microg/g (approximately 450 microM) and 161 microg/g (approximately 340 microM), respectively. Tumor levels ranged from 27 to 71 microg/g at Cmax levels across the three dose ranges, and ZD6474 was distributed to all of the tissues in a dose-dependent manner. Analysis of putative ZD6474 metabolites in feces found four, with the N-demethyl-piperidinyl-ZD6474 metabolite being the most prominent but still accounting for less than 2% of the total amount of ZD6474 present. The lack of significant metabolism of ZD6474 is consistent with the relatively long half-life in mice (approximately 30 h), as well as that seen in humans (approximately 120 h), and the primary method of drug elimination appears to be unchanged in the feces (approximately 25%). The incorporation of an empirical approach to dosing in mouse models of cancer in preclinical studies may allow for better prediction of clinical efficacy for ZD6474 alone and in combination with other therapeutic modalities based on equivalent drug exposure.

487 ORAL The VEGF-R tyrosine kinase inhibitor ZD6474 enhanced the anti-tumoural effects of temozolomide in the intracerebral BT4C rat glioma model

Incidence, outcome and prognostic factors of metastatic spinal cord compression (MSCC) patients reirradiated for in-field recurrence were analyzed. Radiation therapists’ attitude in reirradiate spinal cord relapses, doses adopted and incidence of myelopathy were also examined.Data deriving from 579 evaluable patients entered two randomized trials on radiotherapy (RT) for MSCC were revised.Twenty-four (4.15%) patients had an in-field recurrence and 12 (50%) were reirradiated. At the time of analysis all reirradiated patients had died. Median time from first and second RT was 5 months (range, 2–31). Six patients received an 8 Gy single-dose, 2 patients 5 × 3 Gy and remaining four patients 2 × 8, 5 × 4, or a single dose of 7 and 4 Gy, respectively. The median cumulative Biologically Effective Dose (BED) calculated was 114.5 Gy2 (range, 80–120 Gy2). Six of seven (85.7%) ambulant patients maintained walking ability, whereas none of five not ambulant patients recovered the function. Median duration of response was 4.5 months (range, 1–24). The effect of reirradiation on motor function was significantly associated with walking capacity before reirradiation. Myelopathy was never recorded.In MSCC reirradiation was safe and effective. Patient walking capacity before reirradiation was the strongest prognostic factor for functional outcome. Reirradiation was given in about one-half of patients with in-field recurrence and different doses and fractionations were used, even though cumulative BED was in all cases ⩽120 Gy2.

Elevated ERK1/ERK2/estrogen receptor cross-talk enhances estrogen-mediated signaling during long-term estrogen deprivation

The knowledge that steroids play a pivotal role in the development of breast cancer has been exploited clinically by the development of endocrine treatments. These have sought to perturb the steroid hormone environment of the tumour cells, predominately by withdrawal or antagonism of oestrogen. Unfortunately, the beneficial actions of existing endocrine treatments are attenuated by the ability of tumours to circumvent the need for steroid hormones, whilst in most cases, retaining the nuclear steroid receptors. The mechanisms involved in resistance to estrogen deprivation are of major clinical relevance for optimal treatment of breast cancer patients and the development of new therapeutic regimes. We have shown that long-term culture of MCF7 cells in medium depleted of oestrogen (LTED) results in hypersensitivity to oestradiol (E2) coinciding with elevated levels of both ERalpha phosphorylated on Ser(118) and ERK1/ERK2. Our data suggest elevated ERK1/ERK2 activity results wholly or in part from enhanced ERBB2 expression in the LTED cells. These cells showed greater sensitivity to the tyrosine kinase inhibitor ZD1839 in both ERalpha-mediated transcription and growth assays compared with the wt-MCF7. Similarly the MEK inhibitor U0126 decreased basal ERalpha-mediated transcription and proliferation in the LTED cells by 50% and reduced their sensitivity to the proliferative effects of E2 10-fold, whilst having no effect on the wild type (wt). However, complete suppression of ERK1/ERK2 activity in the LTED cells did not inhibit ERalpha Ser(118) phosphorylation suggesting that the cells remained ligand-dependent. This was further confirmed by the increased sensitivity of the LTED cells to the growth suppressive effects of ICI 182,780 and suggested that the LTED cells remained wholly or partially dependent on oestrogen receptor (ER)/oestrogen responsive elements directed growth. These findings suggest that treatments targeted at growth factor signalling pathways may be useful in patients acquiring resistance to oestrogen deprivation with aromatase inhibitors and that the pure anti-oestrogen ICI 182,780 may also be effective by blocking or destabilizing ER and hence disrupting cross-talk.

Rapid and sensitive LC/MS/MS analysis of the novel tyrosine kinase inhibitor ZD6474 in mouse plasma and tissues

ZD6474 ( N-(4-Bromo-2-fluorophenyl)-6-methoxy-7-[(1-methylpiperidin-4-yl)methoxy] quinazolin-4-amine) is a tyrosine kinase inhibitor with anti-angiogenic and anti-tumor activity that is currently undergoing human trials for cancer treatment. Pharmacokinetic studies in animal models are an important component in clinical development of this agent to relate pre-clinical models to patient treatment. A liquid chromatography tandem mass spectrometry method was developed for the determination of ZD6474 levels in mouse plasma and tissues. Plasma (0.05 mL) and tissue homogenates (0.1 mL of 10 mg/mL) were extracted under alkaline conditions with ethyl acetate:pentane (1:1, v/v) after addition of the internal standard (trazodone, 2-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-1,2,4-triazolo[4,3-a]pyridine-3(2H)-one). Separation was achieved on a C18, 50 mm × 2 mm column with quantitation by internal standard reference and multiple reaction monitoring of the ion transitions m/ z 475 → 112 (ZD6474) and m/ z 372 → 176 (trazodone). The calibration curve was linear from a range spanning 20–20,000 ng/mL in plasma and 10–320 ng/mg in tissue homogenates. Mean recoveries from plasma and tissue homogenates were 88 and 90%, respectively. The accuracy in plasma was 88% at the lower limit of quantitation (20 ng/mL with a 50 μL plasma sample) with high precision (R.S.D.% < 10%). Assay performance in liver and other tissue homogenates is also reported. The assay was applied to a pharmacokinetic study in mice to determine dosing schedules that would approximate therapeutic ZD6474 levels determined in humans.

ZD6474 Suppresses Oncogenic RET Isoforms in a Drosophila Model for Type 2 Multiple Endocrine Neoplasia Syndromes and Papillary Thyroid Carcinoma

Patients with hereditary medullary thyroid carcinoma (MTC) associated with multiple endocrine neoplasia (MEN) types 2A and 2B and familial MTC (FMTC) have mutations in the RET proto-oncogene. Approximately 40 percent of patients with papillary thyroid carcinoma (PTC) typically have either intrachromosomal or extrachromosomal rearrangements that join the promoter and NH(2)-terminal domains of unrelated genes to the COOH-terminal fragment of RET. The RET point mutations associated with MEN2A, MEN2B, or FMTC, or the chromosomal breakpoints and translocations associated with PTC, typically activate the RET receptor tyrosine kinase (RTK). RET kinase inhibitors are likely to be beneficial for patients with hereditary MTC, where currently there is no effective chemotherapy or radiation therapy. Recently, the low molecular weight tyrosine kinase inhibitor ZD6474 was found to block the enzymatic activity of RET-derived oncoproteins in cultured cell lines. We have developed a Drosophila model for MEN2A and MEN2B diseases by targeting oncogenic forms of RET to the developing Drosophila eye. Here we show that, when fed orally, ZD6474 suppressed RET-mediated phenotypes within the context of this in vivo model. Importantly, ZD6474 showed high efficacy and very low toxicity. This compound failed to significantly suppress an activated form of another RTK, the Drosophila epidermal growth factor receptor, nor did it suppress the activity of downstream components of the RET/Ras pathway. Our results support the view that targeting chemical kinase inhibitors such as ZD6474 to tissues with oncogenic forms of RET is a useful treatment strategy for RET-dependent carcinomas.

Radiosensitivity of Tumor Cell Lines after Pretreatment with the EGFR Tyrosine Kinase Inhibitor ZD1839 (Iressa®)

The epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor ZD1839 (Iressa) reduces survival and augments radiation response of certain tumor cells. The aim of this study was to identify cellular events that are associated with the modulation of radiosensitivity by ZD1839. Three tumor cell lines (A549, H596, FaDu) were exposed to ionizing radiation, treatment with ZD1839, and combined treatment. Clonogenic cell survival was determined by colony assays, EGFR and transforming growth factor-(TGF-)alpha expression by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR), cell cycle distribution and apoptosis by flow cytometry. In A549 and H596 cells ZD1839 had little effect on clonogenic growth, but survival curves revealed a radiosensitizing effect of 5 microM ZD1839 on A549 cells. Both cell lines expressed moderate amounts of EGFR mRNA and very low levels of TGF-alpha mRNA. FaDu cells expressed relatively high amounts of EGFR and TGF-alpha transcripts and showed marked inhibition of clonogenic growth, reduction of S-phase cells, and induction of apoptosis after treatment with 1 microM ZD1839 and combined treatment. Surprisingly, the subpopulation of FaDu cells surviving ZD1839 pretreatment was more radioresistant. Exposure to ZD1839 caused a decrease in EGFR mRNA expression in A549 cells, no change in H596, and even an increase in FaDu cells. The sensitivity to ZD1839 correlated with the EGFR expression level, an inhibition of cell proliferation, and induction of apoptosis in the cell lines analyzed. A radiosensitizing effect of ZD1839 was associated with downregulation of EGFR mRNA expression.

Tyrosine kinase inhibitors in endometrial cancer

Tyrosine kinase inhibitors in endometrial cancer

A phase I study of oral ZD 1839 given daily in patients with solid tumors: IND.122, a study of the Investigational New Drug Program of the National Cancer Institute of Canada Clinical Trials Group

To define the maximum tolerated dose (MTD), the dose limiting toxicity (DLT), the biological active (BA) dose and the pharmacokinetics (PK) of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor ZD1839 (Iressa) when administered continuously as a once daily dose in patients with advanced, incurable solid tumours. Twenty-eight patients were enrolled in cohorts of three from three National Cancer Institute of Canada Clinical Trials Group (NCIC CTG) centers. ZD1839 was given at doses from 150 to 800 mg daily orally and patients underwent a pretreatment and a 28 day post treatment tumor biopsy, while PK sampling was performed on days 8, 15, 22, 29, and a toxicity assessment every 28 days. All twenty-eight patients were evaluable for non-hematological and hematological toxicity. Twenty-seven were evaluable for response. The MTD was not reached but DLT included reversible rash and diarrhea. One patient with urachal cancer had a transient 55% decrease in tumor size and two other patients (breast and non-small cell lung cancer) had minor responses; three additional patients had pharmacodynamic evidence of target effect. PK demonstrated steady state within the first 2 weeks of dosing and dose dependent exposure. It appears that ZD 1839 at a dose of 800 m/day was tolerable, although some patients required dose modification for diarrhea. Doses above 250 m/day demonstrate biologic activity and could be consider for future study in a variety of EGFR positive tumor types.

Integrating basic science and clinical research in bladder cancer: update from the first bladder Specialized Program of Research Excellence (SPORE).

To review the progress of the genitourinary SPORE (Specialized Program of Research Excellence) in bladder cancer. The optimal management of bladder cancer depends on the accurate assessment of the biological potential of the disease. Methotrexate, vincristine, adriamycin and cisplatin (M-VAC) chemotherapy has been the standard of therapy for over a decade. However, there has been no improvement in patient survival. Encouraging preclinical data have resulted in the rapid translation of epidermal growth factor receptor antagonists into the clinic. However, phase I and II single-agent clinical trials in head and neck, lung, and colon cancer failed to match the hope generated by laboratory investigations since only a minority of patients seemed to benefit from this approach. Nonetheless, recent data revealed that non-small-cell lung cancer tumors that responded to single-agent Iressa possessed activating epidermal growth factor receptor mutations. These findings have generated refound interest for epidermal growth factor receptor-dependent tumors that are identified by molecular and pharmacodynamic approaches prior to or early in the course of therapy. Targeted therapy against epidermal growth factor receptor has become one of the primary focuses of the genitourinary SPORE in bladder cancer. The SPORE grant scheme is designed to encourage rapid development of new and innovative cancer research in areas of high priority, in this case bladder cancer. The SPORE has facilitated the advancement of novel epidermal growth factor receptor-targeted therapy, such as the monoclonal antibody IMC-225 and the tyrosine kinase inhibitor ZD1839 (Iressa), from the laboratory to clinical trials. The integration of these new biological agents in combination with chemotherapy, in order to abrogate the progression of advanced bladder cancer, is the prime directive of our current phase II Iressa/docetaxel trial.

160 Antitumor therapy with VEGF receptor tyrosine kinase inhibitor ZD6474 in a mouse model of intestinal cancer

160 Antitumor therapy with VEGF receptor tyrosine kinase inhibitor ZD6474 in a mouse model of intestinal cancer

ZD1839 (Iressa) in the treatment of non-small cell lung cancer patients

To investigate the antitumor effects and toxicity of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor ZD1839 (Iressa) in patients with advanced non-small cell lung cancer (NSCLC). From December 2002 to August 2003, 39 patients with unresectable NSCLC were enrolled for 250 mg once-daily oral treatment with ZD1839. Clinical data was analysed using chi-square test, t test and Kaplan-Meier survival analysis. Quality of Life (QoL) was analyzed using Chinese Version of European Organization for Research and Treatment of Cancer (EORTC) core questionnaire QLQ-C30 and lung cancer related questionnaire QLQ-LC13. Tumor response rate (complete response and partial response) was 28.2% . Disease control rate, which included both tumor responses and stable disease, was 59.0%. Objective tumor response was correlated with gender and pathological type. Time to progress was (6.6±1.6) months (95% CI, 3.4-9.7), and 1 year survival rate was 54.3%. Response rate of global, functional and lung cancer-related symptom scales were 34.8%, 65.2% and 73.9% respectively. The ZD1839 of 250 mg/d was well tolerated by patients. The majority of adverse events were grade I or grade II skin rash and diarrhea, which were manageable and reversible. ZD1839 offers a new treatment option providing meaningful tumor control and symptom relief for many patients with advanced NSCLC.

The tyrosine kinase inhibitor ZD6474 inhibits tumour growth in an intracerebral rat glioma model.

Malignant glioma is characterised by extensive neovascularisation, principally influenced by vascular endothelial growth factor (VEGF). ZD6474 is a potent inhibitor of VEGF-R2 tyrosine kinase activity, but with additional inhibitory effects on other growth factors. In this study, we have investigated the effects of ZD6474 with regard to tumour growth, neovascularisation, proliferation and apoptosis in the intracerebral rat glioma model, BT4C. ZD6474 (50 and 100 mg kg−1) was given as a daily oral gavage. Animals were killed on day 19 and tumour volume was measured. Sections were stained for factor VIII, Ki-67 and for apoptosis. The ability of ZD6474 to inhibit cell growth directly was examined in vitro, using the glioma cell line BT4C and the transformed rat brain endothelial cell line RBE4. Cell growth was analysed with fluorometric microculture cytotoxicity assay to quantify the cytotoxic effects. ZD6474 significantly decreased tumour volume compared to controls. Microvascular density increased after treatment with ZD6474, and tumour cell proliferation index was reduced. There was also an increase in tumour cell apoptosis. In vitro, the growth of both cell lines was significantly reduced. The results reported justify further experimental investigations concerning the effects of ZD6474 in malignant glioma alone or in combination with other modalities.