UMLS:C0027651 - FACTA Search

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Query: UMLS:C0027651 (tumor)
685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As a single agent the ERBB1 inhibitor, gefitinib (Iressa; ZD1839) showed minimal activity against a panel of 10 pediatric tumor xenografts that do not express the ERBB1 receptor. However, combined with irinotecan (CPT-11), significantly greater than additive activity was observed in four of eight models (P < 0.05), and the combination showed enhanced activity against three additional tumor lines. Breast cancer resistance protein (ABCG2), a transporter that confers resistance to SN-38 (the active metabolite of irinotecan), was readily detected in six of nine xenograft models examined by immunohistochemistry. In vitro gefitinib potently reversed resistance to SN-38 only in a cell line that overexpressed functional ABCG2. However, overexpression of ABCG2 did not decrease accumulation nor increase the rate of efflux of [(14)C]gefitinib. On the basis of these results and the distribution of Abcg2 in mouse tissues, we assessed the ability of gefitinib to modulate irinotecan pharmacokinetics. Oral gefitinib coadministration resulted in no change in clearance of intravenously administered irinotecan. However, gefitinib treatment dramatically increased the oral bioavailability of irinotecan after simultaneous oral administration. It is concluded that gefitinib may modulate SN-38 activity at the cellular level to reverse tumor resistance mediated by ABCG2 through inhibiting drug efflux and may be used potentially in humans to modulate the oral bioavailability of a poorly absorbed camptothecin such as irinotecan.
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PMID:Gefitinib enhances the antitumor activity and oral bioavailability of irinotecan in mice. 1549 75

Gefitinib (Iressa, ZD1839), an inhibitor of epidermal growth factor receptor-tyrosine kinase, has shown potent anti-tumor effects and improved symptoms and quality-of-life of a subset of patients with advanced non-small cell lung cancer (NSCLC). However, a large portion of the patients showed no effect to this agent. To establish a method to predict the response of NSCLC patients to gefitinib, we used a genome-wide cDNA microarray to analyze 33 biopsy samples of advanced NSCLC from patients who had been treated with an identical protocol of second to seventh line gefitinib monotherapy. We identified 51 genes whose expression differed significantly between seven responders and 10 non-responders to the drug. We selected the 12 genes that showed the most significant differences to establish a numerical scoring system (GRS, gefitinib response score), for predicting response to gefitinib treatment. The GRS system clearly separated the two groups without any overlap, and accurately predicted responses to the drug in 16 additional NSCLC cases. The system was further validated by the semi-quantitative RT-PCR, immunohistochemistry and ELISA for serological test. Moreover, we proved that the anti-apoptotic activity of amphiregulin, a protein that was significantly over-expressed in non-responders but undetectable in responders, leads to resistance of NSCLC cells to gefitinib in vitro. Our results suggested that sensitivity of a given NSCLC to gefitinib can be predicted according to expression levels of a defined set of genes that may biologically affect drug sensitivity and survival of lung cancer cells. Our scoring system might eventually lead to achievement of personalized therapy for NSCLC patients.
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PMID:Prediction of sensitivity of advanced non-small cell lung cancers to gefitinib (Iressa, ZD1839). 1549 27

Recent reports revealed a strong correlation between the presence of somatic activating mutations in the kinase domain of the EGF receptor in some human lung cancers and a striking clinical response to the selective EGF receptor inhibitor, Gefitinib. These oncogenic receptors exhibit altered signaling properties such that they selectively activate downstream survival pathways on which tumor cells have become dependent. Thus, tumor cells are effectively killed by Gefitinib treatment. In addition, the catalytic function of the mutant receptors exhibits increased sensitivity to Gefitinib, raising the possibility that two distinct consequences of Gefitinib action account for its clinical efficacy.
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PMID:Inhibition of mutant EGF receptors by gefitinib: targeting an Achilles' heel of lung cancer. 1553 55

Recent advances in cancer therapy have resulted in the development of drugs that target mechanisms involved in neoplastic change and angiogenesis. One example is gefitinib ('Iressa', ZD1839), an orally-active epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that blocks EGFR signaling in vitro, thereby inhibiting the growth, proliferation and survival of many solid tumors. Clinical trial data show that gefitinib monotherapy is generally well tolerated in patients with a wide range of tumor types (including lung, head and neck, colon, breast, and prostate cancers). The most common adverse events (AEs) were mild and reversible skin and gastrointestinal disorders (National Cancer Institute common toxicity criteria grade 1/2). Few drug-related grade 3/4 skin and gastrointestinal disorders were observed, and drug-related hematologic AEs were uncommon. The clinical benefit of gefitinib in non-small-cell lung cancer (NSCLC), head and neck, colon, breast, and prostate cancer is being investigated, as antitumor activity has been observed in a range of solid tumors, including NSCLC. In two large phase II NSCLC trials (IDEAL ['Iressa' Dose Evaluation in Advanced Lung Cancer] 1 and 2) objective tumor responses of 18.4% and 11.8%, and disease control rates (complete and partial responses plus stable disease) of 54.4% and 42.2%, respectively, were seen in patients given 250 mg/day gefitinib. Additionally, disease-related symptoms improved in 40.3% and 43.1% of patients, and improved quality of life was experienced by 23.9% and 34.3% patients in IDEAL 1 and 2, respectively. Furthermore, the majority of patients who had an objective response also experienced symptom improvement. Gefitinib has been approved for the treatment of advanced NSCLC in Japan, the USA, and other countries. This review discusses the potential of gefitinib in a wide range of solid tumors. 'Iressa' is a trademark of the AstraZeneca group of companies.
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PMID:Gefitinib (Iressa, ZD1839): a novel targeted approach for the treatment of solid tumors. 1558 98

ZD6474 is a novel, orally available inhibitor of vascular endothelial growth factor (VEGF) receptor-2 (KDR) tyrosine kinase, with additional activity against epidermal growth factor receptor (EGFR) tyrosine kinase. ZD6474 has been shown to inhibit angiogenesis and tumor growth in a range of tumor models. Gefitinib ("Iressa") is an selective EGFR tyrosine kinase inhibitor (TKI) that blocks signal transduction pathways. We examined the antitumor activity of ZD6474 in the gefitinib-sensitive lung adenocarcinoma cell line, PC-9, and a gefitinib-resistant variant (PC-9/ZD). PC-9/ZD cells showed cross-resistance to ZD6474 in an in vitro dye formation assay. In addition, ZD6474 showed dose-dependent inhibition of EGFR phosphorylation in PC-9 cells, but inhibition was only partial in PC-9/ZD cells. ZD6474-mediated inhibition of tyrosine residue phosphorylation (Tyr992 and Tyr1045) on EGFR was greater in PC-9 cells than in PC-9/ZD cells. These findings suggest that the inhibition of EGFR phosphorylation by ZD6474 can contribute a significant, direct growth-inhibitory effect in tumor cell lines dependent on EGFR signaling for growth and/or survival. The effect of ZD6474 (12.5-50 mg/kg/day p.o. for 21 days) on the growth of PC-9 and PC-9/ZD tumor xenografts in athymic mice was also investigated. The greatest effect was seen in gefitinib-sensitive PC-9 tumors, where ZD6474 treatment (>12.5 mg/kg/day) resulted in tumor regression. Dose-dependent growth inhibition, but not tumor regression, was seen in ZD6474-treated PC-9/ZD tumors. These studies demonstrate that the additional EGFR TKI activity may contribute significantly to the antitumor efficacy of ZD6474, in particular in those tumors that are dependent on continued EGFR-signaling for proliferation or survival. In addition, these results provide a preclinical rationale for further investigation of ZD6474 as a potential treatment option for both EGFR-TKI-sensitive and EGFR-TKI-resistant tumors.
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PMID:Anticancer effects of ZD6474, a VEGF receptor tyrosine kinase inhibitor, in gefitinib ("Iressa")-sensitive and resistant xenograft models. 1559 48

Gefitinib is active and well tolerated in patients with advanced non-small cell lung cancer (NSCLC); however, its role in patients with brain metastases has not been clearly defined. We had conducted a prospective study to give gefitinib to NSCLC patients irrespective of their performance status (PS), number of prior treatment regimens and the presence of brain metastases. A total of 76 patients were enrolled. Fifty-seven patients had measurable lesions and the objective response rate was 33.3% (95% confidence interval [95% CI], 20.7-46.0%). For all enrolled patients, the disease control rate was 63.2% (95% CI, 52.1-74.3%) with a median progression-free survival of 5.0 months (95% CI, 3.6-6.5 months) and median overall survival 9.9 months (95% CI, 4.9-14.8 months). Twenty-one patients had simultaneously assessable intracranial lesions (ICLs) and extracranial lesions (ECLs), 17 of them (81.0%) showed comparable tumor response. There was no survival difference between the patients with and without metastatic brain disease. Most drug-related adverse events were mild. Intolerable toxicities happened in five patients, four of them were interstitial pneumonia (5.8%). Severity of skin toxicity was tightly associated with tumor response and patient survival (P = 0.007 and <0.001) and the association was consistent in the analysis using early toxicity profile (P = 0.033 and 0.001). In conclusion, gefitinib is active in patients with brain metastasis from NSCLC and tumor response is related to skin toxicity. It is feasible to conduct randomized trials to identify the role of gefitinib alone or in combination with other modality for treatment of NSCLC patients who have metastatic brain lesion(s).
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PMID:Gefitinib is active in patients with brain metastases from non-small cell lung cancer and response is related to skin toxicity. 1560 63

ZD6474 is an inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2/KDR) tyrosine kinase, with additional activity against epidermal growth factor receptor (EGFR) tyrosine kinase. ZD6474 inhibits angiogenesis and growth of a wide range of tumor models in vivo. Gefitinib ("Iressa") is a selective EGFR tyrosine kinase inhibitor that blocks signal transduction pathways implicated in cancer cell proliferation. Here, the ability of gefitinib and ZD6474 to inhibit tumor cell proliferation was examined directly in eight cancer cell lines in vitro, and a strong correlation was noted between the IC(50) values of gefitinib and ZD6474 (r = 0.79). No correlation was observed between the sensitivity to ZD6474 and the level of EGFR or VEGFR expression. The NSCLC cell line PC-9 was seen to be hypersensitive to gefitinib and ZD6474, and a small (15-bp) in-frame deletion of an ATP-binding site (exon 19) in the EGFR was detected (delE746-A750-type deletion). To clarify the involvement of the deletional mutation of EGFR in the cellular sensitivity to ZD6474, we examined the effect of this agent on HEK293 stable transfectants expressing deletional EGFR that designed as the same deletion site observed in PC-9 cells (293-pDelta15). These cells exhibited a 60-fold higher sensitivity to ZD6474 compared with transfectants expressing wild-type EGFR. ZD6474 inhibited the phosphorylation of the mutant EGFR by 10-fold compared with cells with wild-type EGFR. In conclusion, the findings suggested that a small in-frame deletion in the EGFR increased the cellular sensitivity to ZD6474.
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PMID:Small in-frame deletion in the epidermal growth factor receptor as a target for ZD6474. 1560 79

Gefitinib (Iressa) is a novel drug approved in 28 countries (as of June 2004), including Japan, the US, Canada and Australia as second- and third-line monotherapy for the treatment of locally advanced or metastatic non-small cell lung cancer refractory to prior chemotherapy. Gefitinib is an orally active, epidermal growth factor receptor (EGFR)-tyrosine kinase (EGFR-TK) reversible inhibitor which blocks EGFR phosphorylation and subsequent signal transduction pathways involved in proliferation, metastasis, angiogenesis and apoptosis inhibition. Recently, mutations in the TK domain of the EGFR have been identified in those patients with refractory non-small cell lung cancer who achieved dramatic tumor responses to gefitinib. Although the role of EGFR-TK mutation status in predicting other clinical benefits with gefitinib, i.e. disease stabilization and symptom improvement, is unclear, these findings, along with increasing knowledge of other potential biomarkers of response, are significant developments towards further optimizing the use of gefitinib. Gefitinib has favorable pharmacokinetic and pharmacodynamic properties and low toxicity. No dosage adjustment is required for patient age, body weight, gender, ethnicity or moderate to severe hepatic impairment due to liver metastases. Several clinical studies on gefitinib as monotherapy have demonstrated clinically significant symptom relief, tumor response and good tolerability after failure of chemotherapy-based treatment in non-small cell lung cancer. These studies led to gefitinib approval in many countries as a new therapeutic option for patients with advanced non-small cell lung cancer that failed prior chemotherapy. In contrast to the clinical benefit imparted by gefitinib as monotherapy in patients previously treated with chemotherapy, gefitinib in combination with standard platinum-based chemotherapy in chemonaive patients did not improve either survival or other clinical endpoints in non-small cell lung cancer. This review provides currently available data from clinical studies on gefitinib as monotherapy or in combination with platinum-containing chemotherapy.
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PMID:Gefitinib: current status in the treatment of non-small cell lung cancer. 1560 16

Gefitinib is a small molecule that specifically inhibits the tyrosine kinase activity of the epidermal growth factor receptor (EGFR) type 1 by interfering with the adenosine triphosphate (ATP) binding site. At doses that maximally inhibit EGFR tyrosine kinase activity chosen for phase II trials, the most common side effects of gefitinib are low-grade rash or diarrhea. An infrequent but serious side effect of gefitinib is interstitial lung disease (ILD). The Iressa dose evaluation for advanced lung cancer phase II trials (IDEAL 1 and IDEAL 2) of single agent gefitinib, 250 or 500 mg orally per day in pretreated patients with non-small cell lung cancer (NSCLC), found about 20% of patients on IDEAL-1 and 10% of patients on IDEAL-2 had major objective responses and improvement of symptoms. The data from the IDEAL trials and the extensive experience from the 21,000 patients treated on the expanded access program, suggests that the patients who have a major objective response probably have a significant survival benefit in addition to palliative benefit. In addition, approximately 40% of patients on the IDEAL trials experienced improvement in symptoms. Gefitinib was approved for third line treatment of NSCLC. Gefitinib is effective, safe, and well-tolerated single-agent therapy in previously treated NSCLC. Although there have been no direct comparisons, the small molecule inhibitors of EGFR gefitinib and erlotinib appear to have similar efficacy. Erlotinib has been shown to produce a survival advantage compared to best supportive care in an unselected group of previously treated patients with NSCLC. Until similar trials are completed comparing gefitinib to best supportive care, there is a similar survival advantage for gefitinib. Nonsmokers, women, and patients with adenocarcinoma, are more likely to have major objective responses than other patients. Bronchioalveolar lung cancer is a subtype of NSCLC that is more likely to respond to gefitinib. Several groups have now reported that most, but not all, tumors experiencing a major objective response to gefitinib have mutations associated with the ATP-binding site of EGFR. It is reasonable to move gefitinib in to second-line therapy for patients who are known to have a tumor that is more likely to respond to gefitinib. Also, I would treat such patients with gefitinib as first-line therapy on an appropriate clinical trial approved by the Institutional Review Board (IRB). Outside of a clinical trial, patients with advanced disease should initially be treated with a combination of doublet chemotherapy. There is strong evidence that there is no benefit to concurrent chemotherapy and gefitinib. Gefitinib should not be given concurrently with cytotoxic chemotherapy as initial treatment for NSCLC. Sequential therapy combining chemotherapy and gefitinib in advanced disease or as adjuvant therapy should only be done in the context of a clinical trial approved by the IRB. There is preclinical evidence suggesting that gefitinib is a radiosensitizer. Early results from trials combining radiation, or chemoradiotherapy with gefitinib have shown that these combinations are without excessive additive toxicity. There is no proven clinical benefit for concurrent Gefitinib and radiation. Gefitinib should only be given with radiation as part of an appropriate clinical trial approved by the IRB.
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PMID:Gefitinib therapy for non-small cell lung cancer. 1561 Jul 17

Molecular targeting strategies for cancer therapy are distinct from conventional chemotherapy and radiotherapy in their potential to provide increased tumor specificity. One particular molecular target of high promise in oncology is the epidermal growth factor receptor (EGFR). The EGFR is overexpressed, dysregulated or mutated in many epithelial malignancies, and EGFR activation appears important in tumor growth and progression. Advances in signal transduction biology continue to sharpen our understanding regarding specific contributions of EGFR signaling networks to cancer behavior. Two predominant classes of EGFR inhibitors have been developed including monoclonal antibodies (mAbs) that target the extracellular domain of EGFR, such as cetuximab (Erbitux), and small molecule tyrosine kinase inhibitors (TKIs) that target the receptor catalytic domain of EGFR, such as gefitinib (Iressa) and erlotinib (Tarceva). Mechanisms of action for EGFR inhibitors have been investigated in preclinical model systems. Safety, activity, pharmacokinetics and pharmacodynamics have been assessed in clinical trials. The anti-EGFR mAbs and TKIs have partially overlapping toxicity profiles, but distinct routes of administration, serum half-lives and therefore dosing schedules. Both classes of agents show clear antitumor activity, and cetuximab and gefitinib have been recently FDA approved for colorectal and lung cancer indications respectively. However, the absence of survival benefit for EGFR TKIs in combination with chemotherapy in large-scale phase III lung cancer trials in 2003 underscores a major challenge in anti-EGFR oncology therapeutics; namely to identify those tumors and patients that will respond predictably to EGFR inhibitor approaches. Newly identified mutations in the EGFR catalytic domain that appear to confer sensitivity to EGFR TKIs promise to open new doors of investigation regarding response prediction. Advances will also require enhanced molecular understanding of the overall EGFR signaling network, and improved methods to gauge the dependence of individual tumors on EGFR signaling pathways for growth advantage. Results from newly reported phase III trials in 2004 now confirm a survival advantage for the use of EGFR inhibitors in combination with high-dose radiation in head and neck cancer, and in refractory lung cancer respectively. It appears likely that EGFR inhibitors (and other rationally designed molecular growth inhibitors) will play a meaningful role in cancer therapy in the years to come.
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PMID:Epidermal growth factor receptor inhibition strategies in oncology. 1561 46

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