Additive interaction of gefitinib ('Iressa', ZD1839) and ionising radiation in human tumour cells in vitro

Cultures of human carcinoma A-431, A-549 and HeLa cells were challenged with gamma-rays without or with concomitant exposure to gefitinib, a potent inhibitor of the tyrosine kinase activity of epidermal growth factor receptor (EGFR). The outcome of treatment was determined from cell and colony count, cell cycle progression and DNA double-strand break formation and rejoining. Apoptosis was measured in parallel from hypodiploid DNA and using an annexin V assay. Gefitinib developed a cytostatic effect in all cell lines, with drug sensitivity correlating the level of EGFR expression. A weak cytotoxicity of gefitinib was observed in HeLa cells only, although the drug was unable to induce significant cell cycle redistribution in this cell line. In contrast, substantial G1 block and S-phase depletion was observed in A-431 and A-549 cells exposed to gefitinib. The drug brought about additive to subadditive interaction with radiation with regard to growth inhibition, clonogenic death and induction of apoptosis. Consistently, gefitinib did not hinder the rejoining of radiation-induced DNA double-strand breaks in any cell line. The results demonstrate that gefitinib may elicit cytotoxicity at high concentration, but does not act as a radiosensitiser in vitro in concomitant association with radiation.     

Effect of re-treatment with gefitinib ('Iressa', ZD1839) after acquisition of resistance.

A 70-year-old man with adenocarcinoma of the lung developedpulmonary metastases 7 months after middle and lower lobectomyof the right lung in October 1998. He received four coursesof first-line chemotherapy with docetaxel/irinotecan from Juneto September 1999. The best response was stable disease and,after 6 months of treatment, there was evidence of progressivedisease with     

Gefitinib ('Iressa', ZD1839) and new epidermal growth factor receptor inhibitors

The epidermal growth factor receptor (EGFR) is a promising target for cancer therapy and a number of EGFR-targeted agents have been developed. Those most advanced in development are the EGFR tyrosine kinase inhibitors gefitinib ('Iressa', ZD1839) and erlotinib ('Tarceva', OSI-774), and the monoclonal antibody cetuximab ('Erbitux', IMC-C225). This review provides a clinical overview of these agents, highlighting their antitumour activities in different tumour types. Epidermal growth factor receptor-targeted agents are generally well tolerated and are not typically associated with the severe adverse events often seen with cytotoxic chemotherapy. Gefitinib is the agent with the most extensive clinical experience, particularly in non-small-cell lung cancer (NSCLC). Recently, gefitinib became the first-approved EGFR-targeted agent, for use in patients with previously treated advanced NSCLC in Japan, the USA and other countries. Further studies are required to explore the full potential of these novel agents either as monotherapy or combination therapy.     

Analysis of epidermal growth factor receptor expression as a predictive factor for response to gefitinib ('Iressa', ZD1839) in non-small-cell lung cancer

Gefitinib ('Iressa', ZD1839) is an orally active epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated antitumour activity and favourable tolerability in Phase II studies. We investigated whether EGFR expression levels could predict for response to gefitinib in patients with advanced non-small-cell lung cancer (NSCLC), who received gefitinib (250 mg day(-1)) as part of a worldwide compassionate-use programme. Tissue samples were analysed by immunohistochemistry to assess membrane EGFR immunoreactivity. Of 147 patients enrolled in our institution, 50 patients were evaluable for assessment of both clinical response and EGFR expression. The objective tumour response rate was 10% and disease control was achieved in 50% of patients. Although high EGFR expression was more common in squamous-cell carcinomas than adenocarcinomas, all objective responses were observed in patients with adenocarcinoma. Response and disease control with gefitinib were not associated with high EGFR expression. Overall, median survival was 4 months, and the 1-year survival rate was 18%. Strong EGFR staining correlated with shorter survival time for all patients. Gefitinib demonstrated promising clinical activity in this group of patients with NSCLC. These results have also shown that EGFR expression is not a significant predictive factor for response to gefitinib.     

Clinically meaningful response to the EGFR tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839) in non small cell lung cancer

Preclinical research and ongoing clinical trials are validating epidermal growth factor receptor (EGFR) as a suitable molecular target in cancer therapy. Here we report the case of a 39-year-old non-smoking man with heavily pretreated stage IV bronchioloalveolar NSCLC who was treated with gefitinib ('Iressa', ZD1839) at the dose of 250 mg/day, orally. Symptomatic relief was already detectable after 2 weeks of gefitinib therapy, pulmonary function tests readily improved, performance status went from 2 to 0 within 8 weeks, CT scan performed after 10 weeks of treatment showed nearly complete resolution of the clinical picture, and clinical remission was maintained up to 32 weeks. This case-report illustrates the potential of EGFR tyrosine kinase inhibition to induce clinically meaningful responses in heavily pretreated, advanced NSCLC patients and suggests that participation of such patients into clinical trials of signal transduction inhibitors should be encouraged.     

Phase I pharmacokinetic trial of the selective oral epidermal growth factor receptor tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839) in Japanese patients with solid malignant tumors.

BACKGROUND: This phase I dose-escalating study investigated the tolerability and toxicity of the selective epidermal growth factor receptor tyrosine kinase inhibitor gefitinib ('Iressa', ZD1839) in Japanese patients with solid tumors. Thirty-one patients were included. PATIENTS AND METHODS: Patients initially received a single oral dose of gefitinib followed by 10-14 days of observation. Oral gefitinib was subsequently administered on 14 consecutive days, every 28 days. Dose escalation was from 50 mg/day to a maximum of 925 mg/day or dose-limiting toxicity (DLT). RESULTS: Most adverse events were mild (grade 1/2); the most frequent were an acne-like rash and gastrointestinal effects. Two of six patients at 700 mg/day had DLT; no further dose escalation occurred. C(max) was reached within 3-7 h and exposure to gefitinib increased with dose. Mean terminal half-life following multiple dosing was 50.1 h (range 27.8-79.7 h). A partial response (duration 35-361 days) was observed in five of the 23 patients with non-small-cell lung cancer over a range of doses (225-700 mg/day), and seven patients with a range of tumors had disease stabilization (duration 40-127 days). CONCLUSIONS: In conclusion, gefitinib showed a favorable tolerability profile in Japanese patients. The safety profile, pharmacokinetic parameters and antitumor activity observed in our study are comparable to those observed in patients from the USA and Europe.     

Alveolar hemorrhage as a possible adverse drug reaction by gefitinib (ZD1839, Iressa)

We experienced a case in which severe alveolar hemorrhage occurred in the course of gefitinib therapy. A 56-year-old man with non-small cell lung cancer had been treated with CDDP + CPT-11, CDDP + GEM + VNR, CDDP + TXT. After the chemotherapy with these regimens was found to be ineffective, daily oral gefitinib was started. Four weeks later, the patient complained of cough, bloody sputum and dyspnea. Chest X-ray and CT showed bilateral infiltrations with air bronchogram. Fiberoptic bronchoscopy revealed alveolar hemorrhage with an increase of lymphocytes in the BALF. After the cessation of gefitinib therapy and the administration of steroid, he gradually recovered.     

FDA drug approval summary: gefitinib (ZD1839) (Iressa) tablets

On May 5, 2003, gefitinib (Iressa), ZD1839) 250-mg tablets received accelerated approval by the U.S. Food and Drug Administration as monotherapy treatment for patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) after failure of both platinum-based and docetaxel chemotherapies. Information provided in this summary includes efficacy and safety results of relevant clinical trials. Effectiveness was demonstrated in a randomized, double-blind, phase II, multicenter trial comparing two oral doses of gefitinib (250 mg/day versus 500 mg/day). Two hundred sixteen patients were enrolled. The 142 patients who were refractory to or intolerant of a platinum and docetaxel comprised the evaluable population for the efficacy analysis. A partial tumor response occurred in 14% (9 of 66) of patients receiving gefitinib 250 mg/day and in 8% (6 of 76) of patients receiving gefitinib 500 mg/day. The overall objective response rate for both doses combined was 10.6% (15 of 142 patients) (95% confidence interval 6.0%-16.8%). Responses were more frequent in females and in nonsmokers. The median duration of response was 7.0 months (range 4.6-18.6+ months). Other submitted data included the results of two large trials conducted in chemotherapy-naive, stage III and IV NSCLC patients. Patients were randomized to receive gefitinib (250 mg or 500 mg daily) or placebo, in combination with either gemcitabine plus cisplatin (n = 1,093) or carboplatin plus paclitaxel (n = 1,037). Results from those studies showed no benefit (response rate, time to progression, or survival) from adding gefitinib to chemotherapy. Consequently, gefinitib is only recommended for use as monotherapy. Common adverse events associated with gefitinib treatment included diarrhea, rash, acne, dry skin, nausea, and vomiting. Most toxicities were Common Toxicity Criteria grade 1 or 2. Interstitial lung disease (ILD) has been observed in patients receiving gefitinib. Worldwide, the incidence of ILD is about 1% (2% in the Japanese postmarketing experience and about 0.3% in a U.S. expanded access program). Approximately one-third of the cases were fatal. Physicians should promptly evaluate new or worsening pulmonary symptoms. If ILD is confirmed, appropriate management includes discontinuation of gefitinib. Gefitinib was approved under accelerated approval regulations on the basis of a surrogate end point response rate. No controlled gefitinib trials, to date, demonstrate a clinical benefit, such as improvement in disease-related symptoms or greater survival. Accelerated approval regulations require the sponsor to conduct further studies to verify that gefitinib therapy produces such a benefit.     

Molecular mechanisms underlying the interaction between ZD1839 ('Iressa') and cisplatin/5-fluorouracil

ZD1839 ('Iressa'), an orally active, selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is currently being investigated in clinical trials as a treatment for cancer. 'Iressa' is a trademark of the AstraZeneca group of companies. We have previously demonstrated a synergistic interaction between ZD1839 and cisplatin/5-fluorouracil (5FU) in CAL33, a human head and neck cancer cell line that markedly expresses EGFR. This study examined the effects of this drug combination on the cell cycle, cell cycle regulators, apoptosis-related factors, EGFR-related signalling and DNA repair in CAL33 cells. The cells were incubated with ZD1839 alone for 48 h, then cisplatin and 5FU were added. Exposure to the drug combination continued for a further 48 h. ZD1839 alone induced accumulation of cells in the G0/G1 phase of the cell cycle at 24 h accompanied by a concomitant increase in p21, p27 and Bax, a significant decrease in Bcl2 and a decrease in Akt phosphorylation. A decrease in DNA-PK was observed at 48 h. ZD1839 alone had no effect on caspase-3 activity, but addition of ZD1839 to cisplatin-5FU led to a significant increase in caspase-3 activity at 96 h. Thus, ZD1839 affects key cellular pathways controlling cell proliferation, apoptosis and DNA repair. These data provide a rationale to support clinical trials combining ZD1839 and cisplatin-5FU and other protocols that combine EGFR-targeting agents with chemotherapy or radiotherapy.     

Sequence-dependent effects of ZD1839 ('Iressa') in combination with cytotoxic treatment in human head and neck cancer

Elevated levels of epidermal growth factor receptor in head and neck cancer have been extensively reported, and are correlated with poor prognosis. The combination of cisplatin and 5-fluorouracil is a standard treatment regimen for head and neck cancer, with radiation representing another therapeutic option. Six head and neck cancer cell lines were used to study the cytotoxic effects of combining ZD1839 ('Iressa'), a new selective epidermal growth factor receptor tyrosine kinase inhibitor, and radiation. Two of the cell lines were also used to study the combination of ZD1839 and cisplatin/5-fluorouracil. Cytotoxic effects were assessed by the MTT test. The results indicated that ZD1839 applied before radiation gave the best effects (P=0.002); an effect that was strongest in those p53-mutated cell lines that express the highest epidermal growth factor receptor levels. The effects of ZD1839 with cisplatin and/or 5-fluorouracil were sequence dependent (P<0.003), with the best results achieved when ZD1839 was applied first. For the triple combinations, ZD1839 applied before cisplatin and 5-fluorouracil resulted in a slight synergistic effect (P=0.03), although the effect was greater when ZD1839 was applied both before and during cytotoxic drug exposure. In conclusion, ZD1839 applied before radiation and before and/or during cisplatin/5-fluorouracil may improve the efficacy of treatment for head and neck cancer.     

Long-term effect of gefitinib (ZD1839) on squamous cell carcinoma of the lung

This case report describes the effects of long-term treatment with the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) gefitinib ('Iressa', ZD1839) on a patient with squamous cell carcinoma of the lung. Gefitinib is an orally active agent that blocks signal transduction pathways implicated in the proliferation and survival of cancer cells and host-dependent processes that promote tumor growth. A 62-year-old Japanese man with a history of heavy smoking was diagnosed with squamous cell carcinoma of the lung, clinical stage IIIB (T4N3M0), in August 2000. He received two cycles of cisplatin-based chemotherapy and subsequently underwent left upper lobectomy followed by thoracic radiotherapy. After these treatments, he underwent partial lobectomy and pneumonectomy because of disease recurrence. In June 2002, he started treatment with gefitinib 250 mg/day orally because of mediastinal lymph node recurrence and an elevated serum cytokeratin 19 fragment (CYFRA) level. As a result, the mediastinal lymph node markedly regressed and the serum CYFRA level became normalized. Although he experienced recurrence three times during the 18 months prior to treatment with gefitinib, recurrence has not been experienced in the 13 months since the start of gefitinib treatment, while tolerability has been acceptable.     

Cell growth after withdrawal of gefitinib ("Iressa", ZD1839) in human lung cancer cells

Gefitinib ("Iressa", ZD1839) is a selective epidermal growth factor receptor-tyrosine kinase inhibitor, which blocks signal transduction pathways implicated in proliferation and survival of cancer cells. However, in vitro and in vivo studies concerning cell growth after withdrawal of gefitinib are limited. To determine whether cancer cells would resume proliferation upon removal of gefitinib, an in vitro study was undertaken using 4 human non-small cell lung cancer cell lines. With immunocytochemical staining and Western blot analysis, we confirmed positive expression of EGFR in these cell lines. We next evaluated growth inhibition before and after withdrawal of gefitinib. After incubation with 0-100 microM gefitinib for 24 h, medium containing gefitinib was removed, followed by addition of fresh growth medium to cell cultures. MTT assays were performed daily over a 6-day time course. Even at very low levels of gefitinib (<1 microM), these 4 TKB cells had 1-10% growth inhibition, respectively. With these levels of gefitinib, continued inhibitory effects after withdrawal of getitinib were observed in 3 of the 4 cell lines. Furthermore, none of the 4 cell lines, including the cell line which had abolished growth inhibition, showed accelerated re-growth rate after the withdrawal of gefitinib even in these exposure conditions. Based on our in vitro experiments, additional in vivo studies, which can compare the pre- and post-treatment growth rate, will be necessary to help better understand the mechanisms behind cell growth recovery after temporary gefitinib treatment.     

A novel approach in the treatment of neuroendocrine gastrointestinal tumours. Targeting the epidermal growth factor receptor by gefitinib (ZD1839)

Therapeutic options to inhibit the growth and spread of neuroendocrine (NE) gastrointestinal tumours are still limited. Since gefitinib (4-(3-chloro-4-fluoroanilino)-7-methoxy-6-(3-morpholinopropoxy)quinazoline), an inhibitor of epidermal growth factor receptor-sensitive tyrosine kinase (EGFR-TK), had been shown to suppress potently the growth of various non-NE tumour entities, we studied the antineoplastic potency of gefitinib in NE gastrointestinal tumour cells. In human insulinoma (CM) cells, in human pancreatic carcinoid (BON) cells and in NE tumour cells of the gut (STC-1), gefitinib induced a time- and dose-dependent growth inhibition by almost 100%. The antiproliferative potency of gefitinib correlated with the proliferation rate of the tumour cells. So the IC(50) value of gefitinib was 4.7+/-0.6 microM in the fast-growing CM cells, still 16.8+/-0.4 microM in the moderate-growing BON cells, and up to 31.5+/-2.5 microM in the slow-growing STC-1 cells. Similarly, the induction of apoptosis and cell-cycle arrest by gefitinib differed according to growth characteristics: fast-growing CM cells displayed a strong G0/G1 arrest in response to gefitinib, while no significant cell-cycle alterations were seen in the slow-growing STC-1. Vice versa, the proapoptotic effects of gefitinib, as determined by caspase-3 activation and DNA fragmentation, were most pronounced in the slow-growing STC-1 cells. Using cDNA microarrays, we found extensive changes in the expression of genes involved in the regulation of apoptosis and cell cycle after incubation with gefitinib. Among them, an upregulation of the growth arrest and DNA damage-inducible gene GADD153 was observed. Phosphorylation of ERK1/2, which inhibits GADD153 expression, was reduced in a time-dependent manner. However, no gefitinib-induced activation of the GADD153-inducing p38 mitogen-activated protein kinase was detected. Our data demonstrate that the inhibition of EGFR-TK by gefitinib induces growth inhibition, apoptosis and cell-cycle arrest in NE gastrointestinal tumour cells. Thus, EGFR-TK inhibition appears to be a promising novel approach for the treatment of NE tumour disease.     

Modulation of radiation response and tumor-induced angiogenesis after epidermal growth factor receptor inhibition by ZD1839 (Iressa)

ZD1839 ("Iressa") is an orally-active, selective epidermal growth factor receptor-tyrosinekinase inhibitor. We evaluated the antitumor activity of ZD1839 in combination with radiation in human squamous cell carcinomas (SCCs) of the head and neck. ZD1839 produced a dose-dependent inhibition of cellular proliferation in human SCCs grown in culture. Flow cytometry analysis of cell cycle progression confirmed the accumulation of cells in G(1) phase after exposure to ZD1839. Clonogenic analysis demonstrated that treatment of SCCs with ZD1839 reduced cell survival after radiation exposure. Flow cytometric analysis further demonstrated that treatment of SCCs with ZD1839 amplified radiation-induced apoptosis. Tumor xenograft studies confirmed that oral administration of ZD1839, or focal radiation, resulted in partial and transient tumor regression in both SCC-1 and SCC-6 xenografts. In contrast, profound tumor regression and regrowth delay was observed in mice treated with the combination of ZD1839 and radiation. To examine antiangiogenic effects, we studied the impact of ZD1839 on human umbilical vascular endothelial cells (HUVECs). In the presence of reconstituted Matrigel matrix, HUVECs established a capillary-like network structure (tube formation). Treatment with ZD1839 reduced the cell-to-cell interaction of HUVECs, resulting in disruption of tube formation. The effect of ZD1839 was further examined using an in vivo tumor xenograft model of angiogenesis (Matrigel plug) in athymic mice. Systemic treatment with ZD1839 significantly inhibited tumor-induced neovascularization across the Matrigel plug. Taken together, these results suggest that the antitumor activity of ZD1839 in combination with radiation appears to derive from not only proliferative growth inhibition (with associated cell cycle arrest and enhancement of radiation-induced apoptosis) but also from inhibition of tumor angiogenesis.     

Dramatic effect of ZD1839 ('Iressa') in a patient with advanced non-small-cell lung cancer and poor performance status

We describe the case of a 52-year-old Japanese woman with advanced adenocarcinoma of the lung, in whom once-daily treatment with 250 mg ZD1839 ('Iressa') demonstrated a marked antitumour effect. She had initially achieved a partial response with cisplatin-based combination chemotherapy, but had subsequently progressed and had failed to respond to salvage chemotherapy. She had also received whole-brain irradiation for brain metastases. On admission, the patient was confined to bed due to dyspnoea and had rapidly progressing hypoxia secondary to lymphangitis carcinomatosa and a massive right pleural effusion. She was treated with oxygen supplementation and oral ZD1839, which, within a week, led to marked tumour regression and gradually improving dyspnoea. The main adverse event observed was a grade 2 rash. A month after starting ZD1839 treatment, the patient was discharged without the need for oxygen supplementation and had since returned to full-time work. This is a demonstration of ZD1839 producing a dramatic clinical response when administered to a patient with poor performance status who had received extensive prior treatment with cytotoxic agents.'Iressa' is a trademark of the AstraZeneca group of companies.     

ZD1839 (Iressa) induces antiangiogenic effects through inhibition of epidermal growth factor receptor tyrosine kinase

Epidermal growth factor receptor (EGFR) tyrosine kinase is a potential target for anticancer therapy. ZD1839 (Iressa) is a selective inhibitor of EGFR tyrosine kinase. In this study, we investigated the question as to whether the antitumor effect of ZD1839 is partly attributable to antiangiogenic activity and the potential mechanisms involved. Both ZD1839 and SU5416 [a vascular endothelial growth factor (VEGF)-receptor tyrosine kinase inhibitor] inhibited the migration of human umbilical vein endothelial cell cocultivated with EGF-stimulated cancer cells. ZD1839 also inhibited EGF-induced migration and the formation of tube-like structures by human microvascular endothelial cells. Moreover, ZD1839 almost completely blocked EGF-induced neovascularization of mice cornea, and SU5416 partially blocked neovascularization. In contrast, ZD1839 did not inhibit VEGF-induced angiogenesis. However, EGF-induced up-regulation of the angiogenic factors, VEGF and IL-8, was almost completely blocked by ZD1839. The antitumor effects of ZD1839 could, therefore, be mediated in part by the inhibition of tumor angiogenesis through direct effects on microvascular endothelial cells that express EGFR and also through reduced production of proangiogenic factors by tumor cells.     

Epidermal growth factor receptor (EGFR) downstream molecules as response predictive markers for gefitinib (Iressa, ZD1839) in chemotherapy-resistant non-small cell lung cancer

Gefitinib has shown meaningful antitumor activity with tolerable toxicity in chemotherapy-refractory NSCLC in previous studies. Moreover, EGFR expression failed to show a correlation with response. In an attempt to identify predictive markers of response, we have investigated the tumoral expression of key signaling molecules of EGFR (EGFR, p-EGFR, p-Akt, p-Erk, p-STAT3) by immunohistochemistry and analyzed their correlations with response. Of 65 patients who received gefitinib (250 mg/day) for chemotherapy-refractory NSCLC, there were 14 partial responses (21.5%), 21 stable diseases (32.3%) and 21 progressive diseases (32.3%). Median durations of overall survival and time to progression were 6.7 months and 2.8 months, respectively. Immunohistochemistry was performed in 34 patients with evaluable tissue specimens. EGFR was overexpressed (2+ or 3+) in 32.4% and p-EGFR was positive in 26.5%. The expressions of p-Akt, p-Erk and p-STAT3 were positive (1+ or 2+) in 50%, 38.2% and 79.4%, respectively. The EGFR expression was not correlated with p-EGFR or the downstream molecules. EGFR or p-EGFR status did not correlate with response. Positive expression of p-Erk was significantly associated with poor response (38.1% in -, 14.3% in 1+, 0% in 2+; p = 0.046). Furthermore, tumors with positive p-Akt and negative p-Erk nuclear expression exhibited the best response (60%), whereas there was no response in the opposite [p-Akt (-), p-Erk (+)] cases. Intense nuclear staining of p-Akt (2+) was associated with prolonged TTP (HR 0.25, 95% confidence interval [CI] 0.08-0.79, p = 0.018) and OS (HR 0.16, 95% CI 0.04-0.62, p = 0.008). These results support the assumption that gefitinib responsiveness might be predicted by activated EGFR downstream molecules such as p-Akt and p-Erk.