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PubMed2004

The in vitro effect of gefitinib ('Iressa') alone and in combination with cytotoxic chemotherapy on human solid tumours.

BACKGROUND: Activation of the epidermal growth factor receptor (EGFR) triggers downstream signaling pathways that regulate many cellular processes involved in tumour survival and growth. Gefitinib ('Iressa') is an orally active tyrosine kinase inhibitor (TKI) targeted to the ATP-binding domain of EGFR (HER1; erbB1). METHODS: In this study we have used a standardised ATP-based tumour chemosensitivity assay (ATP-TCA) to measure the activity of gefitinib alone or in combination with different cytotoxic drugs (cisplatin, gemcitabine, oxaliplatin and treosulfan) against a variety of solid tumours (n = 86), including breast, colorectal, oesophageal and ovarian cancer, carcinoma of unknown primary site, cutaneous and uveal melanoma, non-small cell lung cancer (NSCLC) and sarcoma. The IC50 and IC90 were calculated for each single agent or combination. To allow comparison between samples the IndexSUM was calculated based on the percentage tumour growth inhibition (TGI) at each test drug concentration (TDC). Gefitinib was tested at concentrations ranging from 0.0625-2 microM (TDC = 0.446 microg/ml). This study represents the first use of a TKI in the assay. RESULTS: There was heterogeneity in the degree of TGI observed when tumours were tested against single agent gefitinib. 7% (6/86) of tumours exhibited considerable inhibition, but most showed a more modest response resulting in a low TGI. The median IC50 value for single agent gefitinib in all tumours tested was 3.98 microM. Interestingly, gefitinib had both positive and negative effects when used in combination with different cytotoxics. In 59% (45/76) of tumours tested, the addition of gefitinib appeared to potentiate the effect of the cytotoxic agent or combination (of these, 11% (5/45) had a >50% decrease in their IndexSUM). In 38% of tumours (29/76), the TGI was decreased when the combination of gefitinib + cytotoxic was used in comparison to the cytotoxic alone. In the remaining 3% (2/76) there was no change observed. CONCLUSION: The in vitro model suggests that gefitinib may have differential effects in response to concomitant cytotoxic chemotherapy with the agents tested during this study. The mechanism involved may relate to the effect of TKIs on growth rate versus their effect on the ability of the cell to survive the stimulus to apoptosis produced by chemotherapy.

Adenocarcinoma↗
PubMed2005

Interstitial lung disease following erlotinib (Tarceva) in a patient who previously tolerated gefitinib (Iressa).

OBJECTIVE: To report a case of who a patient developed clinical and radiographical evidence of interstitial lung disease (ILD) on erlotinib after having tolerated gefitinib therapy. CASE SUMMARY: A 58-year-old man with stage IV non-small-cell lung cancer (NSCLC) failed first and second line chemotherapy. He then received gefitinib, a small molecule epidermal growth factor receptor (EGFR) inhibitor, a therapy which was well tolerated, but did cause a grade 1 rash. On gefitinib, the patient's disease remained stable for seven months. Subsequent disease progression was treated with the newer EGFR inhibitor, erlotinib. After 5 days of erlotinib therapy, the patient presented with a sore throat and dyspnea, followed by a grade 2 rash and significant hemoptysis. Erlotinib was discontinued for three days, during which time his symptoms abated. Erlotinib was restarted and the patient again developed sore throat, dyspnea and severe hemotpysis, with progression of the rash to grade 3. Erlotinib therapy was discontinued and the patient recevied prednisone and supplemental oxygen. A CT scan of the chest demonstrated new areas of patchy ground glass opacity bilaterally and increased interstitial markings consistent with ILD. DISCUSSION: The case demonstrates that clinical ILD can occur following erlotinib therapy, even in patients who previously tolerated gefitinib. ILD has not been reported to occur more frequently with erlotinib than with gefitinib. However, the dose of erlotinib employed clinically is the maximum tolerated dose identified in phase 1 trials, and is associated with an increased incidence of grade 3-4 rash and diarrhea, as compared to gefitinib. Thus, the observation of clinical ILD following erlotinib, but not gefitinib, may be the consequence of increased potency of erlotinib 150 mg/day compared to gefitinib 250 mg/day. CONCLUSION: Clinical ILD can occur following erlotinib even in patients who previously tolerated gefitinib. IT is important to carefully monitor pulmonary symptoms in all patients who are receiving erlotinib, as early diagnosis and timely intervention are critical in managing drug-induced ILD.

Carcinoma, Non-Small-Cell Lung↗
PubMed2004

Gefitinib in combination with gemcitabine and cisplatin in advanced non-small-cell lung cancer: a phase III trial--INTACT 1.

PURPOSE: The purpose of this study was to determine whether the addition of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib (Iressa, ZD1839; AstraZeneca, Wilmington, DE) to standard first-line gemcitabine and cisplatin provides clinical benefit over gemcitabine and cisplatin alone in patients with advanced or metastatic non-small-cell lung cancer (NSCLC). Gefitinib has demonstrated encouraging efficacy in advanced NSCLC in phase II trials in pretreated patients, and a phase I trial of gefitinib in combination with gemcitabine and cisplatin showed favorable tolerability. PATIENTS AND METHODS: This was a phase III randomized, double-blind, placebo-controlled, multicenter trial in chemotherapy-naive patients with unresectable stage III or IV NSCLC. All patients received up to six cycles of chemotherapy (cisplatin 80 mg/m(2) on day 1 and gemcitabine 1,250 mg/m(2) on days 1 and 8 of the 3-week cycle) plus either gefitinib 500 mg/d, gefitinib 250 mg/d, or placebo. Daily gefitinib or placebo was continued until disease progression. End points included overall survival (primary), time to progression, response rates, and safety evaluation. RESULTS: A total of 1,093 patients were enrolled. There was no difference in efficacy end points between the treatment groups: for the gefitinib 500 mg/d, gefitinib 250 mg/d, and placebo groups, respectively, median survival times were 9.9, 9.9, and 10.9 months (global ordered log-rank [GOLrank] P =.4560), median times to progression were 5.5, 5.8, and 6.0 months (GOLrank; P =.7633), and response rates were 49.7%, 50.3%, and 44.8%. No significant unexpected adverse events were seen. CONCLUSION: Gefitinib in combination with gemcitabine and cisplatin in chemotherapy-naive patients with advanced NSCLC did not have improved efficacy over gemcitabine and cisplatin alone. The reasons for this remain obscure and require further preclinical testing.

Adult↗
PubMed2006

EGFR mutations in patients with brain metastases from lung cancer: association with the efficacy of gefitinib.

Gefitinib--a specific inhibitor of epidermal growth factor receptor (EGFR)-associated tyrosine kinase--has demonstrated efficacy in a subgroup of patients with non-small-cell lung carcinoma (NSCLC) who fail conventional chemotherapy. It is also reported to have an antitumor effect in brain metastases from NSCLC. Additionally, EGFR mutations have shown a strong association with gefitinib sensitivity for NSCLC. Here, we assessed the efficacy of gefitinib in brain metastases from NSCLC and evaluated the association of this efficacy with EGFR mutations. We retrospectively reviewed eight cases in which patients were suffering from brain metastases before the initiation of gefitinib treatment. Brain tumor response could be evaluated by MRI in these patients; EGFR gene analyses were also available. We evaluated whether objective tumor response was observed after gefitinib treatment and assessed the efficacy of gefitinib as effective, noneffective, or not assessable in consideration of the influence of previous radiotherapy. Of the eight patients, the efficacy of gefitinib was assessed as effective in three and as noneffective in three. All three patients demonstrating effective efficacy had EGFR mutations in the tyrosine kinase domain (deletion mutation in two patients and point mutation in one patients), whereas none of the three patients demonstrating noneffective efficacy had EGFR mutations. Gefitinib appears to be effective in treating brain metastases in a subgroup of patients. Our data suggested a possible association between the efficacy of gefitinib in the treatment of brain metastases and EGFR mutations.

Adult↗
PubMed2005

A pilot trial of gefitinib in combination with docetaxel in patients with locally advanced or metastatic non-small-cell lung cancer.

Despite improvements in conventional treatment, patients with advanced non-small-cell lung cancer (NSCLC) have a poor prognosis, leaving a significant unmet need for novel treatments. One such novel, biologically targeted agent is the orally active epidermal growth factor receptor tyrosine kinase inhibitor gefitinib. This open-label pilot trial investigated the safety, pharmacokinetics, and efficacy of 2 doses of gefitinib (250 and 500 mg per day) combined with docetaxel (75 mg/m2) in patients with locally advanced or metastatic NSCLC as first- and second-line chemotherapy. Eighteen patients were recruited: 6 received gefitinib 250 mg per day plus docetaxel; 12 received gefitinib 500 mg per day plus docetaxel. Combination therapy was feasible with no overlapping toxicities. No patients experienced dose-limiting toxicities (DLTs) at 250 mg per day; 1 patient had 2 DLT events at 500 mg per day (grade 3 rash and diarrhea for >4 days). Adverse events were mild to moderate, including fatigue, mucositis, nausea, anorexia, rash, diarrhea, and fever. Docetaxel did not appear to alter steady-state exposure to gefitinib. The effect of gefitinib on exposure to docetaxel was equivocal; with the exception of 2 patients in the gefitinib 250 mg per day dose group, there appeared to be no trend toward a higher or lower exposure to docetaxel when given in the presence of gefitinib compared with that when given alone. Combination therapy was associated with antitumor activity and responses were seen with gefitinib in 2 of 6 patients at 250 mg per day and 4 of 12 patients at 500 mg per day. This combination is feasible and has an acceptable and predictable safety profile, as well as associated antitumor activity.

Administration, Oral↗
PubMed2005

[A case of lung adenocarcinoma of the lung with disappearance of brain metastasis by re-treatment with gefitinib].

BACKGROUND: Tumor response rate to gefitinib by previously treated patients with advanced non-small-cell lung cancer was approximately 20%. However, there are few reports about effect of re-treatment with gefitinib. CASE: A 40-year-old man was given a diagnosis of adenocarcinoma of lung (c-T2N3M1). Response was not obtained with chemotherapy (paclitaxel + carboplatin, vinorelbine + gencitabin). He developed brain metastasis and received whole brain radiation therapy. He was then given gefitinib. Reduction of the primary tumor, brain metastasis, pulmonary metastasis and liver metastasis was seen. Recurrence of pulmonary metastasis and liver metastasis was discovered 8 months after treatment with gefitinib. Therefore, treatment by gefitinib was stopped. Response was not achieved with chemotherapy (docetaxel and amrubicin). At the request of the patient, retreatment with gefitinib was resumed. Disappearance of brain metastasis was achieved. However, primary tumor, pulmonary metastasis and liver metastasis progressed. CONCLUSION: We reported a case whose brain metastases disappeared with re-treatment with gefitinib. This report is thought to be useful in terms of information about the acquired resistance of gefitinib. Further investigations are needed to determine the indication of re-treatment with gefitinib.

Adenocarcinoma↗
PubMed2007

Gefitinib induces premature senescence in non-small cell lung cancer cells with or without EGFR gene mutation.

Despite its tremendous antitumor effect in a subset of patients with non-small cell lung cancer (NSCLC), the exact mechanism of gefitinib-induced cell death has not been fully determined. In this study, forms of cell death in various NSCLC cell lines after gefitinib exposure was analyzed to elucidate the cell death mechanism of gefitinib. Though higher concentration of gefitinib (10 microM) induced extensive apoptosis in two cell lines (EGFR-mutated PC-9 cells and EGFR wild- type EBC-2/R cells), clinically relevant concentrations of gefitinib (1 microM) induced prominent premature senescence instead of apoptosis in these cells. This induction of senescence was preceded by immediate increase of p16INK4A, p21WAF1/Cip1 and p27Kip1 levels and subsequent G1 cell cycle arrest. These phenomena were not observed in gefitinib-resistant (RERF-LC-MS) cells. Additionally, ex vivo exposure to gefitinib induced senescence in short-term cultured tumor cells that were obtained from malignant pleural effusion of a patient with NSCLC, whose tumor was later revealed to be clinically sensitive to gefitinib. Our results indicate that senescence might be a major anti-tumor mechanism of gefitinib in these NSCLC cells regardless of the EGFR gene mutation status.

Antineoplastic Agents↗
PubMed2003

Gefitinib in the treatment of advanced, refractory non-small-cell lung cancer: results in 124 patients.

To evaluate the feasibility, toxicity, and efficacy of oral gefitinib (ZD1839, Iressa) in patients with refractory non-small-cell lung cancer (NSCLC) treated in a community-based setting. One hundred twenty-four patients with advanced, refractory NSCLC received treatment with gefitinib 250 mg orally each day. Ninety-six percent of patients had received >or= 1 previous chemotherapy regimens and 79% had received previous platinum and taxane therapy. Patients were evaluated for response after 6-12 weeks of daily gefitinib therapy; patients with objective response or stable disease continued gefitinib until disease progression occurred. Gefitinib was well-tolerated in these patients with advanced, refractory NSCLC. There were no grade 4 toxicities, and grade 3 skin toxicity and diarrhea were observed in only 4% and 2% of patients, respectively. Nine of 120 evaluable patients (8%) had partial responses to treatment; however, 54 patients (45%) had no evidence of progression at first reevaluation, and a total of 35 patients (29%) reported improvement in lung cancer-related symptoms while receiving gefitinib. Median survival for the entire group was 6.5 months, with a 1-year survival rate of 35%. Gefitinib is active and very well-tolerated in patients with advanced, refractory NSCLC. Although the major response rate was low, nearly 50% of patients derived substantial palliative benefit from gefitinib therapy. The median survival of 6.5 months achieved in this large group of relatively unselected patients is unprecedented in the third-line treatment setting, and compares favorably to other available second-line treatment including docetaxel. A therapeutic trial of gefitinib should be considered in all patients with refractory NSCLC.

Journal Article↗
PubMed2005

A phase I study to determine the effect of tamoxifen on the pharmacokinetics of a single 250 mg oral dose of gefitinib (IRESSA) in healthy male volunteers.

OBJECTIVES: To determine the effect of tamoxifen on the pharmacokinetics of a single 250 mg oral dose of gefitinib (IRESSA) in healthy volunteers. METHODS: An open-label, single-center, phase I study in healthy male volunteers. Each volunteer received a single 250 mg oral dose of gefitinib on day 1. On days 11-14, oral loading doses of 60 mg tamoxifen were administered, followed by 20 mg tamoxifen for a further 16 days to maintain steady-state exposure. On day 24, volunteers received a second single 250 mg oral dose of gefitinib. The last dose of tamoxifen was given on day 30. Pharmacokinetic and safety assessments were conducted throughout the trial. RESULTS: A total of 18 volunteers were recruited. The presence of tamoxifen did not have a clinically significant effect on the primary variables AUC and Cmax of gefitinib, nor on the secondary variables AUC(0-t), tmax, t1/2, and lambdaz. The geometric least square mean values for AUC were 3,407.6 versus 3,397.9 ng.h/ml in the absence and presence of tamoxifen, respectively (90% CL 0.894, 1.112) and for Cmax were 110.8 versus 103.6 ng/ml, respectively (90% CL 0.786, 1.111). The combination of gefitinib with tamoxifen was generally well tolerated by the volunteers. There were no serious adverse events and no volunteer discontinued the study due to an adverse event. NCI-CTC grade 1/2 drug-related adverse events were observed in seven volunteers, including loose stools and skin events associated with gefitinib, and lethargy and headache, flushing, and dizziness associated with tamoxifen. CONCLUSIONS: This study suggests that tamoxifen has no significant effect on the pharmacokinetics, tolerability, or safety of a single 250 mg oral dose of gefitinib. Therefore, in clinical investigations of this combination, no dose adjustment of gefitinib is indicated.

Adult↗
PubMed2007

Phase I study of gefitinib, irinotecan, 5-fluorouracil and leucovorin in patients with metastatic colorectal cancer.

PURPOSE: To determine the maximum tolerated doses (MTD), toxicities, efficacy, and pharmacokinetics (PK) of gefitinib combined with irinotecan, 5-fluorouracil (5-FU) and leucovorin (IFL) in patients with previously untreated advanced colorectal cancer. EXPERIMENTAL DESIGN: Starting doses were gefitinib 250 mg/day orally without interruption, irinotecan 100 mg/m(2) as a 90 min intravenous (i.v.) infusion, 5-FU 400 mg/m(2) bolus i.v. and leucovorin 20 mg/m(2) i.v. on days 1 and 8 of a 21-day cycle. Dose escalations involved increasing gefitinib to 500 mg then increasing irinotecan to 125 mg/m(2) and 5-FU to 500 mg/m(2). RESULTS: Twenty-four patients received therapy. The starting doses proved to be the MTD, as attempts to increase the dose of either gefitinib or the chemotherapeutic agents resulted in dose-limiting toxicities. Gastrointestinal effects and bone marrow suppression were the principal toxicities; however, only 1/17 (6%) patients treated with the MTD had severe (grades 3-4) diarrhea and severe neutropenia occurred in only two (12%) patients. Partial responses occurred in 10/17 patients receiving the MTD and another five had stable disease. Median progression-free and overall survivals were 12.2 and 26.6 months, respectively. In ten patients treated with the MTD, the steady-state PK of gefitinib was not affected by IFL nor did gefitinib appear to influence the PK of either irinotecan or 5-FU. CONCLUSIONS: Gefitinib can be safely combined with an intermittent weekly schedule of IFL. Evidence of promising activity should encourage further clinical evaluation of epidermal growth factor receptor tyrosine kinase inhibitors, such as gefitinib, combined with multiagent chemotherapy for metastatic colorectal cancer.

Adult↗
PubMed2004

Relative bioavailability and safety profile of gefitinib administered as a tablet or as a dispersion preparation via drink or nasogastric tube: results of a randomized, open-label, three-period crossover study in healthy volunteers.

BACKGROUND: Many patients with head and neck cancer have difficulty swallowing tablet formulations of medications, and use of dispersion preparations may be advantageous. OBJECTIVE: The aim of the present study was to determine the relative bioavailability and safety profile of a single dose of gefitinib, an orally active inhibitor of epidermal growth factor receptor tyrosine kinase, when administered as a whole 250-mg tablet or as a dispersion preparation via drink or nasogastric tube in healthy male volunteers. METHODS: This was a Phase 1, randomized, open-label, 3-period crossover study. Plasma samples obtained before dosing to 240 hours after dosing were analyzed for gefitinib using reverse-phase high-performance liquid chromatography with tandem mass-spectrometric detection. The pharmacokinetic parameters of interest included AUC, C(max), and the relative bioavailability of the dispersion via drink or nasogastric tube compared with the standard tablet. RESULTS: Eighteen healthy white male volunteers were enrolled. They had a mean age of 43 years (range, 21-59 years), mean body weight of 85.1 kg (range, 60-101 kg), and mean height of 180.3 cm (range, 171-187 cm). The geometric mean AUC was 2219 ng.h/mL for a single 250-mg dose of gefitinib administered as a whole tablet, 2233 ng.h/mL for the dispersion preparation administered by drink, and 2007 ng.h/mL for the dispersion preparation administered by nasogastric tube. The corresponding values for the geometric mean C(max) were 95.2, 96.3, and 89.9 ng/mL. The gefitinib dispersion preparation administered by drink had a mean bioavailability of 103.8% relative to the whole tablet; the dispersion preparation administered by nasogastric tube had a mean bioavailability of 99.1% relative to the whole tablet. For the drink-tablet and nasogastric tube-tablet comparisons, the estimate-of-treatment ratios for the AUC were a respective 1.006 and 0.928; for the C(max), they were 1.012 and 0.964. There appeared to be no clinically significant differences in absorption or elimination between the preparations. Three volunteers experienced adverse events (AEs) that were considered possibly related to gefitinib (pruritus and dry skin), and 6 volunteers experienced procedure-related AEs (cannula-site reaction and rhinorrhea); these AEs were mild or moderate. No serious AEs were recorded, and no AEs led to withdrawal of any volunteer. CONCLUSIONS: Administration of a 250-mg dose of gefitinib as a dispersion preparation by drink or nasogastric tube achieved a systemic exposure to gefitinib that was consistent with that achieved when gefitinib was administered as a whole tablet. There was no evidence of tolerability problems associated with the routes of administration studied in these healthy volunteers.

Administration, Oral↗
PubMed2004

Effect of gefitinib ('Iressa', ZD1839) on brain metastases in patients with advanced non-small-cell lung cancer.

BACKGROUND: Gefitinib ('Iressa', ZD1839), an orally active epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (EGFR-TKI), has shown antitumor activity in refractory patients with non-small-cell lung cancer (NSCLC) in clinical trials. We have retrospectively analyzed the efficacy and tolerability of gefitinib in patients with advanced NSCLC treated at Okayama University Hospital. METHODS: We reviewed the clinical records of 57 patients with advanced NSCLC who had received 250 mg/day gefitinib at our hospital between November 2000 and May 2003. Correlations between the sensitivity of brain metastases and extracranial disease following treatment with gefitinib were also investigated. RESULTS: Extracranial objective responses were observed in 15 (27%; 95% confidence interval 15.8-40.3%) patients. Fourteen out of 57 patients had brain metastases; six experienced objective responses (one complete response, CR and five partial responses, PR) and eight had stable disease (SD) in the brain. Seven out of 14 patients with brain metastases experienced objective responses in their extracranial tumors and, interestingly, objective responses in the brain were observed in six (86%) of these patients. Multivariate analysis found that advanced age (> or = 70 years) and the presence of brain metastases were associated with clinical response to gefitinib (P = 0.01 and 0.05, respectively), and that female patients were more likely to respond. Median survival and median duration of response were 9.1 and 7.7 months, respectively. The majority of adverse events (AEs) were mild and reversible skin and gastrointestinal disorders, with grade 3 adverse events observed in six (11%) patients. CONCLUSIONS: This retrospective analysis has found that gefitinib is effective and well tolerated in patients with refractory NSCLC, confirming previous phase II trial data. Interestingly, gefitinib appeared to be effective for brain metastases as well as extracranial tumors. Further prospective trials are warranted to evaluate the efficacy of gefitinib in elderly patients and in patients with brain metastases.

Adult↗
PubMed2006

Imaging of gefitinib-related interstitial lung disease: multi-institutional analysis by the West Japan Thoracic Oncology Group.

Gefitinib (Iressatrade mark) is an epidermal growth factor receptor tyrosine kinase inhibitor that has been approved for the treatment of lung cancer in Japan, however, after marketing several cases of severe pulmonary toxicity were reported. The West Japan Thoracic Oncology Group conducted an independent survey of acute pulmonary toxicity and interstitial lung disease (ILD) caused by gefitinib in its member's institutions. The purpose of this study was to clarify the image characteristics of ILD caused by the molecular-targeting drug gefitinib. A total of 1976 patients had been treated with gefitinib between August and December 2002, and 102 of them were suspected of having acute pulmonary toxicity and ILD. A final definite diagnosis of gefitinib-induced ILD was made by at least three radiologists based on a review and analysis of the chest radiography and CT findings plus the clinical data in the medical records. The imaging findings were classified into four patterns: (A) a nonspecific area with ground-glass attenuation, (B) a multifocal area of airspace consolidations, (C) patchy distribution of ground-glass attenuation accompanied by interlobar septal thickening, and (D) extensive bilateral ground-glass attenuation or airspace consolidations with traction bronchiectasis. CT as well as chest radiography had been performed in 65 of the 102 patients at the onset of ILD, and chest radiography alone had been performed in 26. After excluding 11 cases with insufficient data and 21 cases concluded to be other pulmonary diseases, 70 patients were diagnosed with gefitinib-induced ILD. Finally, the diagnostic image findings were classified as pattern A in 29 cases, pattern B in 7 cases, pattern C in 3 cases, pattern D in 20 cases and others in 11 cases. The CT images were classified as pattern A, B, C, and D in 24, 7, 1, and 12 cases, respectively. The mortality rate was significantly higher in the patients with pattern D than the other patterns. Pattern D were thought to represent the features of diffuse alveolar damage. In conclusion, the molecular-targeting drug gefitinib induces pulmonary toxicity at a certain rate and the imaging findings of ILD induced by gefitinib are similar to those of pulmonary toxicity induced by conventional antineoplastic agents.

Adult↗
PubMed2004

Gefitinib ('Iressa', ZD1839) inhibits the growth response of bladder tumour cell lines to epidermal growth factor and induces TIMP2.

The effect of EGF stimulation and its inhibition with gefitinib ('Iressa', ZD1839), an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has been investigated in two EGFR-positive human bladder tumour cell lines, RT112 and RT4. The growth of RT112 cells in a medium containing 10% foetal bovine serum was inhibited by 50% with 10 microM gefitinib, whereas this dose completely inhibited RT4 cell growth. Cells were more sensitive to growth inhibition in the serum-free medium. Increased growth of cells in the serum-free medium was observed with 10 or 50 ng x ml(-1) EGF and the proliferative effect of EGF stimulation in both cell lines was inhibited in the presence of 1 microM, but not 0.1 microM gefitinib. Zymography of the conditioned medium from RT112 cells treated with EGF and gefitinib showed a decrease in matrix metalloproteinase 2 (MMP2) concentrations. Western blot analysis showed that tissue inhibitor of metalloproteinase 1(TIMP1) increased in the conditioned medium from RT112 cells treated with EGF, and this was partially inhibited with both 1 and 5 microM gefitinib. Conversely, TIMP2 decreased with EGF stimulation and this was reversed with gefitinib. Tissue inhibitor of metalloproteinase 1 had no effect on the growth of either cell line. These studies show alterations in the balance of MMPs and their inhibitors in EGF-stimulated bladder tumour cells, which are reversed by gefitinib, suggesting gefitinib should be investigated for its effect on human bladder tumours.

Antineoplastic Agents↗
PubMed2004

Laminin-5 offsets the efficacy of gefitinib ('Iressa') in hepatocellular carcinoma cells.

Prognosis and survival of patients with hepatocellular carcinoma (HCC) is still very poor, and no therapies are currently available to inhibit tumour growth and metastases. Recently, we reported that the expression of an extracellular matrix component (ECM), namely Laminin-5 (Ln-5), is directly related to poor prognosis in HCC patients. The aim of our study is to investigate the preclinical effect of gefitinib in an in vitro HCC model. We found that the IC(50) of gefitinib in HCC cells ranged from 0.7 to 10.0 muM, whereas Ln-5 inhibited the activity of gefitinib in a dose-dependent manner. Complete inhibition of phosphorylated (p)-EGFR (epidermal growth factor receptor) was obtained within 6 h exposure to gefitinib and complete restoration of the receptor status was obtained after 24 h. A downstream effect yields a decrease in p-Akt and p-Erk 1/2. The addition of exogenous Ln-5 has no effect on p-EGFR, whereas it restores p-Erk 1/2 and p-Akt. Consistently, Ln-5 induces recovery of HCC cells from Gefitinib-induced apoptosis. In conclusion, gefitinib inhibits HCC cell growth and we report for the first time that Ln-5, but not other ECM molecules, reduces the ability of gefitinib to inhibit cell growth via Akt. As patients with HCC have different Ln-5 expression levels, these results may help to better understand which patients might benefit from gefitinib treatment.

Antineoplastic Agents↗
PubMed2005

Reduction of PTEN protein and loss of epidermal growth factor receptor gene mutation in lung cancer with natural resistance to gefitinib (IRESSA).

Gefitinib (IRESSA), an epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitor, has antitumour activity in the advanced non-small-cell lung cancer (NSCLC) setting. However, in chemotherapy-naïve patients with advanced NSCLC, the addition of gefitinib to standard chemotherapy regimens failed to increase survival. These results suggest the need for improved patient selection and combination rationales for targeted therapies. We have identified subpopulations of an adenocarcinoma cell line that are naturally resistant to gefitinib, and have analysed the cDNA expression profiles, genomic status of EGFR gene and the effect of gefitinib on signalling pathways in these cell lines in order to identify key mechanisms for naturally acquired resistance to gefitinib. Gefitinib-resistant subpopulations demonstrated increased Akt phosphorylation (not inhibited by gefitinib), reduced PTEN protein expression and loss of the EGFR gene mutation when compared with parental cell lines. These differences in Akt and PTEN protein expression were not evident from the cDNA array profiles. These data suggests that (1) the EGFR gene mutation may be possibly lost in some cancer cells with other additional mechanisms for activating Akt, (2) reintroduction of PTEN or pharmacological downregulation of the constitutive PI3K-Akt-pathway activity may be an attractive therapeutic strategy in cancers with gefitinib resistance.

Adenocarcinoma↗
PubMed2004

Pharmacokinetics of gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, in rat and dog.

The pharmacokinetics of gefitinib and its metabolites in rat and dog were investigated in preclinical studies conducted to support the safety evaluation and clinical development of gefitinib, the first EGFR tyrosine kinase inhibitor approved for the treatment of non-small-cell lung cancer. Following intravenous dosing (5 mg kg(-1), gefitinib plasma half-life was 3-6h in rats and dogs, although studies using a more sensitive HPLC-MS assay produced longer estimates of half-life (7-14h). In these studies, plasma clearance was high (male rat: 25 ml min(-1) kg(-1); female rat: 16 ml min(-1) kg(-1); male dog: 16 ml min(-1) kg(-1)), as was the volume of distribution (8.0-10.41 kg(-1) in rat; 6.31 kg(-1) in dog), and exposure in female rats was double that in males. Following administration of [14C]-gefitinib, concentrations of radioactivity in plasma exceeded gefitinib throughout the profile, indicating the presence of circulating metabolites in both rat and dog. An HPLC-MS assay was developed to measure concentrations of gefitinib and five potential metabolites in plasma. All five metabolites were detected in the rat, but at levels much lower than gefitinib. In the dog, exposure to gefitinib and M523595 was similar, with much lower concentrations of M537194 and only trace levels of the other metabolites. This profile of metabolites is similar to that observed in man.

Administration, Oral↗
PubMed2004

Combination therapy with gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, gemcitabine and cisplatin in patients with advanced solid tumors.

BACKGROUND: The aim of this study was to investigate the tolerability, pharmacokinetic interaction and antitumor activity of gefitinib ("Iressa", ZD1839), an orally active, selective epidermal growth factor receptor tyrosine kinase inhibitor, combined with gemcitabine and cisplatin in chemotherapy-naïve patients with advanced solid tumors. PATIENTS AND METHODS: This was an open-label feasibility trial evaluating two doses of gefitinib (250 and 500 mg/day) in combination with gemcitabine and cisplatin. Gefitinib was administered daily from day 2 onwards. Gemcitabine 1250 mg/m(2) was given on days 1 and 8 and cisplatin 80 mg/m(2) on day 1 for up to six 3-week cycles. Patients could then continue to receive gefitinib monotherapy. RESULTS: Eighteen patients were entered, nine at each gefitinib dose level. Two patients developed dose-limiting toxicity: one grade 3 convulsion (250 mg/day dose group) and one grade 3 rash (500 mg/day dose group). The most frequently occurring adverse events in the combination phase were vomiting (17 patients), asthenia (16), nausea (14), diarrhea (14) and skin rash (13). The most common grade 3/4 adverse events were vomiting (seven patients), asthenia (six), thrombocytopenia (six), diarrhea (five) and anorexia (five). Pharmacokinetic analyses showed no apparent pharmacokinetic interaction between gefitinib and cisplatin or gemcitabine, with the exception of a possible small increase in the geometric mean exposure to gemcitabine seen on day 8 of therapy when given alone with the higher dose of gefitinib. Of 17 evaluable patients, nine had confirmed partial responses, seven had stable disease and one had progressive disease. CONCLUSIONS: Combination therapy of gefitinib with cisplatin and gemcitabine had a manageable and predictable safety profile, no major effect on exposure to any of the three drugs and antitumor activity.

Adult↗