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PubMed2006

Clinical factors affecting acquired resistance to gefitinib in previously treated Japanese patients with advanced nonsmall cell lung cancer.

BACKGROUND: The risk factors for the development of acquired resistance in nonsmall cell lung cancer (NSCLC) patients responding to gefitinib are unclear. The current study assessed clinicopathologic factors affecting acquired resistance to gefitinib in previously treated patients with advanced NSCLC. METHODS: Between 2000 and 2004, 197 consecutive Japanese patients with advanced NSCLC underwent treatment with gefitinib. Of these patients, 56 who had continued gefitinib treatment without disease progression for at least 6 months were included in the study. RESULTS: At a median follow-up time of 21.6 months (range, 7.7-59.7 months), the median time to disease progression was 19.5 months, with progression-free survival rates of 68.5% at 1 year, 33.6% at 2 years, and 21.2% at 3 years. In a multivariate analysis using a Cox regression model, baseline brain metastasis was the strongest prognostic factor affecting acquired resistance to gefitinib (hazards ratio, 2.14; 95% confidence interval, 1.10- 4.17 [P = .025]). In addition, a decreased baseline hemoglobin level (P = .074) and the administration of >1 chemotherapy regimen before gefitinib treatment (P = .069) tended to be significant negative prognostic factors. CONCLUSIONS: In patients undergoing treatment with gefitinib, the presence of brain metastasis was strongly associated with the emergence of acquired resistance in the current series of NSCLC patients. The finding requires confirmation in a large cohort of patients with advanced NSCLC, including a non-Japanese/Asian population.

Adult↗
PubMed2007

Tumor inhibitory effect of gefitinib (ZD1839, Iressa) and taxane combination therapy in EGFR-overexpressing breast cancer cell lines (MCF7/ADR, MDA-MB-231).

Some kinds of breast cancer cell lines, similar to several types of solid tumors, express epidermal growth factor receptor (EGFR). However, gefitinib, an EGFR tyrosine kinase inhibitor, is not effective for all these cell lines. Similarly, taxane is effective for many of the cell lines, although some, such as the multidrug-resistant MCF7/ADR cell line, show taxane-resistance. Here, we examined the growth inhibitory effect of combination treatment with gefitinib and taxane on the breast cancer cell lines MDA-MB-231 (EGFR-positive) and MCF7/ADR (EGFR- and HER2-positive). To estimate the combined effect, a Combination Index was calculated for each cell line. The combination of gefitinib and taxane showed a strong synergistic effect on MCF7/ADR cells, but an invitro additive-antagonistic effect on MDA-MB-231 cells. Similarly, the combination treatment showed a significantly increased tumor inhibitory effect on MCF7/ADR xenografts, but not on MDA-MB-231 xenografts. Regarding the mechanism of the synergistic effect, Western blotting analysis revealed that taxane activated the EGFR-Akt pathway in MCF7/ADR cells but not in MDA-MB-231. To determine the optimal sequential administration of gefitinib and taxane for MCF7/ADR cells, we used flow cytometry to analyze the cell cycle and apoptosis; finding that taxane treatment followed by gefitinib produced a higher rate of G2 arrest and apoptosis than gefitinib treatment followed by taxane. These results suggest gefitinib overcomes the drug-resistance of these cells, thereby increasing the effects of taxane on MCF7/ADR cells. Further, activation of the EGFR-Akt pathway by taxane is related to this synergistic effect.

Animals↗
PubMed2006

The MEK/MAPK pathway is involved in the resistance of breast cancer cells to the EGFR tyrosine kinase inhibitor gefitinib.

We investigated the role of the MEK/MAPK pathway in the sensitivity/resistance of breast carcinoma cells to the EGFR tyrosine kinase inhibitor gefitinib (IRESSA). We assessed the effects of gefitinib on the growth of three breast cancer cell lines that showed high (SK-Br-3; IC50 4 microM), intermediate (MDA-MB-361; IC50 5.3 microM), and low (MDA-MB-468; IC50 6.8 microM) sensitivity to the drug. Although treatment with gefitinib inhibited EGFR activation in the three cell lines in a similar fashion, significant reduction of both p42/p44-MAPK and AKT phosphorylation was observed in SK-Br-3 and MDA-MB-361, but not in MDA-MB-468 cells. The growth of MDA-MB-468 cells was significantly inhibited by treatment with either the PI3K-inhibitor LY294002 or the MEK-inhibitor PD98059. In agreement with these findings, treatment of MDA-MB-468 cells with a combination of PD98059 and gefitinib produced a synergistic anti-tumor effect, whereas this combination was only additive in SK-Br-3 and MDA-MB-361 cells. The combination of gefitinib and PD98059 also produced a significant increase in the levels of apoptosis in MDA-MB-468 cells as compared with treatment with a single agent. This phenomenon was associated with a profound decrease in MAPK activation, reduction of BAD (ser112) phosphorylation and a paradoxical increase in the levels of AKT activation. Finally, overexpression of a constitutively activated form of p42-MAPK in MCF-10A non-transformed human mammary epithelial cells resulted in a two- to three-fold increase in the IC50 to gefitinib. Taken together, these data strongly support the role of the MEK/MAPK pathway in the resistance to gefitinib, and provide the rationale for novel therapeutic approaches based on combinations of signal transduction inhibitors.

Antineoplastic Agents↗
PubMed2006

A phase I trial of intermittent high-dose gefitinib and fixed-dose docetaxel in patients with advanced solid tumors.

PURPOSE: Based on our mouse xenograft model demonstrating that intermittent high-dose gefitinib sensitizes tumors to subsequent treatment with taxanes, we initiated this phase I trial to explore docetaxel in combination with escalating doses of intermittent gefitinib (Iressa) given prior to docetaxel. METHODS: This was a phase I study where patients with advanced cancer were treated with escalating doses of gefitinib (1,000, 1,500, 2,250, 3,000 mg) on days 1 and 2 followed by docetaxel (75 mg/m2) on day 3 of a 21 day cycle. Gefitinib pharmacokinetic data were obtained on days 1, 2, and 3 of cycles 1 and 2 at each dose level. RESULTS: 18 patients were enrolled in this study with the most frequent tumor types being non-small cell lung cancer and head and neck squamous cell cancer. The dose-limiting toxicity was neutropenia (n=1 at dose level 2, n=2 at dose level 4). Rash, diarrhea, and fatigue were the most common grade 1-2 toxicities. Pharmacokinetic data indicated no accumulation of gefitinib between cycles 1 and 2 and no clear correlation between gefitinib plasma levels and toxicity. Partial responses were observed in one patient with head and neck squamous cell carcinoma and one patient with anaplastic thyroid cancer. CONCLUSION: The recommended dose for phase II studies is gefitinib 2,250 mg on days 1 and 2, followed by docetaxel 75 mg/m2 on day 3.

Adult↗
PubMed2004

Targeting the epidermal growth factor receptor by gefitinib for treatment of hepatocellular carcinoma.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) is one of the most common cancer-related causes of death worldwide. Due to very poor 5-year-survival new therapeutic approaches are mandatory. Gefitinib, an inhibitor of epidermal growth factor receptor tyrosine kinase (EGFR-TK), potently suppresses the growth of various tumors, but its effect on HCC remains unexplored. We therefore studied the antineoplastic potency of gefitinib in human HCC cells. RESULTS: Gefitinib induced a time- and dose-dependent growth inhibition of the human HCC cell lines Huh-7 and HepG2. Gefitinib-treatment induced both mitochondria-dependent and -independent apoptosis. Changes in mitochondrial membrane potential and caspase-8 activation, followed by caspase-3 activation and nuclear degradation, were detected. Moreover, gefitinib induced cell cycle arrest at the G1/S checkpoint and decreased the phosphorylation of mitogen-activated protein kinase ERK1/2. Finally, gefitinib suppressed the expression of antiapoptotic Bcl-2 and Bcl-X(L), further rendering HCC cells prone to apoptosis. CONCLUSIONS: Our data demonstrate that the inhibition of EGFR-TK by gefitinib induced growth inhibition, apoptosis and cell cycle arrest in human HCC cells. Thus, EGFR-TK inhibition appears to be a promising novel approach for future treatment strategies of HCC.

Antineoplastic Agents↗
PubMed2005

Gefitinib, an EGFR tyrosine kinase inhibitor, directly inhibits the function of P-glycoprotein in multidrug resistant cancer cells.

Gefitinib (Iressa) is a selective epidermal growth factor receptor tyrosine kinase inhibitor and is used for the treatment of lung cancer. Recently, we discovered that it inhibits the breast cancer resistance protein, which is an ATP-binding cassette transporter. P-glycoprotein (Pgp) also pumps multiple types of drugs out of the cell using energy generated from ATP, and confers multidrug resistance on cancer cells. This study was designed to examine whether gefitinib inhibits the function of Pgp. We used multidrug resistant PC-6/PTX lung cancer and MCF-7/Adr breast cancer cells which overexpress Pgp and measured their drug sensitivity and drug-efflux function by tetrazolium assay and flowcytometry, respectively. In addition, the drug-stimulated ATPase activity of Pgp was measured using insect membranes that express human Pgp. Epidermal growth factor receptor was expressed in MCF-7/Adr, but not in PC-6/PTX cells, and the overexpression of Pgp did not confer resistance to gefitinib to both cell types. However, clinically achievable levels of gefitinib moderately reversed the Pgp-mediated resistance to paclitaxel and docetaxel in Pgp overexpressing cells. In addition, gefitinib increased the intracellular accumulation of the Pgp substrate rhodamine-123 in resistant cells, and activated ATPase in a preparation of pure Pgp-expressing membrane. These findings suggest that gefitinib directly interacts with Pgp and inhibits its function. Gefitinib may clinically inhibit the excretion of Pgp substrate drugs including anticancer agents, and its drug-interaction should therefore be considered.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2005

Gefitinib inhibits MUC5AC synthesis in mucin-secreting non-small cell lung cancer cells.

Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is an active agent in non-small cell lung cancer, and rapidly relieves bronchorrhea in patients with bronchioloalveolar carcinoma before the improvement of radiological findings. In addition, epidermal growth factor regulates mucin secretion in normal airway goblet cells. The present study was designed to clarify whether gefitinib modifies mucin production in lung cancer cell lines apart from its anti-proliferative effects, using A549 adenocarcinoma and NCI-H292 mucoepidermoid carcinoma cells expressing EGFR and MUC5AC mRNA. Mucin synthesis was measured by RT-PCR and ELISA, and MAPK and Akt, the downstream targets of EGFR, were examined by Western blotting assay. The clinically-achievable concentration of 1muM gefitinib inhibited the growth of both cells by only 10%, but gefitinib suppressed MUC5AC mRNA levels subsequent to a decrease in intracellular and secreted MUC5AC protein. Gefitinib also inhibited the phosphorylation of MAPK and Akt, and the selective inhibitors PD98059 and LY294002 also suppressed MUC5AC protein synthesis. These findings suggest that gefitinib may inhibits MUC5AC synthesis, at least in part, through MAPK and Akt signaling pathways. Thus, gefitinib inhibits mucin production, which is encouraging for trials involving its use against bronchorrhea in patients with lung cancer.

Adenocarcinoma↗
PubMed2005

Skin rash and bronchoalveolar histology correlates with clinical benefit in patients treated with gefitinib as a therapy for previously treated advanced or metastatic non-small cell lung cancer.

BACKGROUND: Only 15% of patients with non-small cell lung cancer (NSCLC) treated with oral epidermal growth factor tyrosine kinase inhibitor gefitinib, as a second-line therapy have objective responses. Fifty percent will have improvement of lung cancer related symptoms. It will be critical to identify patients who will benefit clinically from this therapy even when there is no objective response seen on imaging studies. We have performed a retrospective analysis of 76 patients who received gefitinib as a therapy for previously treated metastatic NSCLC at the University of Minnesota Comprehensive Cancer Center in order to describe characteristics of patients who will likely derive benefits from gefitinib therapy. METHODS: All patients treated with gefitinib therapy at the University of Minnesota from September 2001 to January 2004 were entered into the study. The Log-rank Test and Cox proportional hazards regression were used to assess the effect of the number of previous therapy lines, histology subtype, performance status, gender, stage of disease at initial diagnosis, and presence of skin rash on time to disease progression and overall survival (OS). Fisher's Exact Test and multiple logistic regressions were used to assess the effect of these covariates on disease response. RESULTS: Seventy-six patients entered the study, with a median age of 60 years (range 37-82). There were 37 female and 39 male patients; 47 patients had adenocarcinoma, 22 had squamous and 7 had other NSCLC histologies. Six patients had no prior therapy, 23 had one, 32 had two, 8 had three, and 7 had four prior therapies for lung cancer. Fifty-six were current smokers. Median time to disease progression was 3 months (95% CI: 3.0, 6.0). There was no difference in time to disease progression whether patients had one or more prior therapies. Patients with brain metastases (26 patients) benefited from gefitinib therapy at least equally well as those without brain metastatic disease. Patients with adenocarcinoma histology with bronchoalveolar features had superior median time to progression versus other lung cancer histology (14 months versus 3 months, p=0.076), which translated into survival advantage in this group >24 months (95% CI: 0.76, 24+) versus 6.6 months (p=0.0096). Patients with EGFR positive tumors had median survival of 10.2 months (95% CI: 1.45, 16.94) versus 3.7 months (95% CI: 2.66, 4.74) with EGFR negative tumors. Patients who developed any degree of skin rash had prolonged time to disease progression with median of 6 months (95% CI: 2.56, 15.5) versus patients without skin rash median 3 months (95% CI: 1.43, 2.83) (p=0.023). This last factor was the best predictor of improved time to disease progression in multiple regression analysis (p=0.0405). CONCLUSION: A subgroup of patients with NSCLC will benefit from gefitinib therapy. Objective responses will likely be seen in half the patients with mutation of internal domain of EGFR; however, a larger group of patients will also enjoy prolonged disease stabilization and clinical benefit. We suggest that adenocarcinoma with bronchoalveolar features and the presence of skin rash may be used as predictors of gefitinib benefit.

Adult↗
PubMed2006

Clinical predictors versus epidermal growth factor receptor mutation in gefitinib-treated non-small-cell lung cancer patients.

BACKGROUND: Clinical predictors including Asian, female, adenocarcinoma and never-smoker and epidermal growth factor mutation are associated with gefitinib responsiveness in non-small-cell lung cancer. Direct comparison between clinical predictors and EGFR mutation for their predictive power has not been reported. PATIENTS AND METHODS: For 120 Korean NSCLC patients treated with gefitinib, we have analyzed EGFR mutational status in exons 18, 19 and 21. Patients were grouped according to the number of clinical predictors (female, adenocarcinoma and never-smoker). Response rate (RR), time-to-progression (TTP) and overall survival (OS) were analyzed. Multivariate analysis was performed to investigate which approach yielded better prediction. RESULTS: RRs according to number of clinical predictors were 0: 3.4%, 1: 17.1%, 2: 29.4% and 3: 33.3% (p=0.002). Patients with gefitinib-sensitive EGFR mutation showed 61.9% RR compared with 12.1% in the remaining patients (p<0.001). RRs were higher in patients with the EGFR mutations regardless of the number of clinical predictors. In multivariate analysis, gefitinib-sensitive EGFR mutation showed higher odds ratio of response (9.6, 95% confidence interval [CI] 3.2-28.7) compared with number of clinical predictors (1.7, 95% CI 1.1-2.7). Hazard ratio (HR) of TTP was also better in gefitinib-sensitive EGFR mutation (0.24, 95% CI 0.12-0.47) than number of clinical predictors (0.83, 95% CI 0.69-0.99). Only gefitinib-sensitive EGFR mutation was associated with improved OS (HR 0.25, 95% CI 0.12-0.52). CONCLUSION: EGFR mutation should be analyzed whenever possible for effective prediction of objective benefit from gefitinib in NSCLC patients with one or more clinical predictors.

Adenocarcinoma↗
PubMedDate not supplied

Gefitinib plus best supportive care in previously treated patients with refractory advanced non-small-cell lung cancer: results from a randomised, placebo-controlled, multicentre study (Iressa Survival Evaluation in Lung Cancer).

BACKGROUND: This placebo-controlled phase III study investigated the effect on survival of gefitinib as second-line or third-line treatment for patients with locally advanced or metastatic non-small-cell lung cancer. METHODS: 1692 patients who were refractory to or intolerant of their latest chemotherapy regimen were randomly assigned in a ratio of two to one either gefitinib (250 mg/day) or placebo, plus best supportive care. The primary endpoint was survival in the overall population of patients and those with adenocarcinoma. The primary analysis of the population for survival was by intention to treat. This study has been submitted for registration with ClinicalTrials.gov, number 1839IL/709. FINDINGS: 1129 patients were assigned gefitinib and 563 placebo. At median follow-up of 7.2 months, median survival did not differ significantly between the groups in the overall population (5.6 months for gefitinib and 5.1 months for placebo; hazard ratio 0.89 [95% CI 0.77-1.02], p=0.087) or among the 812 patients with adenocarcinoma (6.3 months vs 5.4 months; 0.84 [0.68-1.03], p=0.089). Preplanned subgroup analyses showed significantly longer survival in the gefitinib group than the placebo group for never-smokers (n=375; 0.67 [0.49-0.92], p=0.012; median survival 8.9 vs 6.1 months) and patients of Asian origin (n=342; 0.66 [0.48-0.91], p=0.01; median survival 9.5 vs 5.5 months). Gefitinib was well tolerated, as in previous studies. INTERPRETATION: Treatment with gefitinib was not associated with significant improvement in survival in either coprimary population. There was pronounced heterogeneity in survival outcomes between groups of patients, with some evidence of benefit among never-smokers and patients of Asian origin.

Adult↗
PubMed2005

Interstitial pneumonia during gefitinib treatment of non-small-cell lung cancer.

Gefitinib, an orally active, selective inhibitor of epidermal growth factor-receptor tyrosine kinase, is an effective treatment for patients with advanced non-small-cell lung cancer (NSCLC). Most drug-related adverse events are mild to moderate; however, some patients may develop acute interstitial pneumonia that is sometimes fatal. In a prospective study of gefitinib in 76 patients with advanced NSCLC, 69 patients were evaluable for toxicity, and 4 cases (5.8%) of gefitinib-related interstitial pneumonia were diagnosed: 1 occurred in the second week; 2 in the second month; and 1 during the fourth month of treatment. When interstitial pneumonia occurred, the patients had stable disease (n = 2), a partial response (n = 1), or progressive disease (n = 1). All 4 patients recovered when gefitinib treatment was stopped and glucocorticosteroid therapy was started; no deaths related to gefitinib therapy were noted in this series. While treating NSCLC patients with gefitinib, it is important to carefully evaluate any new-onset respiratory symptoms and promptly arrange radiographic examinations, and to stop gefitinib treatment and begin glucocorticosteroid therapy whenever pulmonary toxicity is highly suspected.

Aged↗
PubMed2006

Inhibition of insulin receptor isoform-A signalling restores sensitivity to gefitinib in previously de novo resistant colon cancer cells.

Resistance to antiepidermal growth factor (EGFR) strategies is an emerging clinical problem. Using human colorectal cancer (CRC) cells, we evaluated the involvement of the insulin receptor isoform-A (InsR-A) in de novo resistance to gefitinib, an EGFR tyrosine kinase inhibitor. Challenging the EGFR positive LoVo cells with gefitinib (1 microM) resulted in a small ( approximately 18%) inhibition of cell growth and although a modest reduction in phospho (p)EGFR Tyr845 was seen, pEGFR at residues -Tyr1068 and -Tyr1173 were unchanged. LoVo cells produced unprocessed pro-IGF-1R protein, substantial levels of IGF-II mRNA and mature InsR protein, consisting mainly of the InsR-A isoform. Insulin and IGF-II promoted cell growth and pEGFR Tyr845, Tyr1068 and Tyr1173 activity and conversely, the insulin-like growth factor-1 receptor (IGF-1R)/InsR inhibitor ABDP (1 muM) inhibited growth and reduced pEGFR activity at all three tyrosine residues. pInsR and pAkt levels were increased after gefitinib treatment. Blocking of pInsR with ABDP enabled gefitinib to markedly reduce pEGFR Tyr845, Tyr1068 and Tyr1173. Short-term gefitinib/ABDP dual treatment was more effective than either agent alone and chronic exposure to this combination resulted in total cell loss after 9 weeks, preventing acquisition of resistance to ABDP. LoVo cells with acquired resistance to ABDP were acutely sensitive to gefitinib. We concluded that InsR-A reduces sensitivity to gefitinib in LoVo CRC cells, thus its co-targeting alongside EGFR can improve the anti-tumour effect of gefitinib.

Cell Line, Tumor↗
PubMed2006

Molecular basis for sensitivity and acquired resistance to gefitinib in HER2-overexpressing human gastric cancer cell lines derived from liver metastasis.

Gastric cancer metastasised to the liver was found to overexpress HER2 at a significantly higher incidence than primary gastric cancers. The purpose of the present study was to investigate the possibility of molecular therapy targeting HER2 overexpression in gastric cancer liver metastasis. We developed three new HER2-overexpressing gastric cancer cell lines (GLM-1, GLM-2, GLM-4) without epidermal growth factor receptor (EGFR) mutations derived from such liver metastasis, two of which had HER2 gene amplifications. All these GLM series of cell lines were highly sensitive to gefitinib in vitro, a specific inhibitor of EGFR tyrosine kinase (Iressa) rather than anti-HER2 antibody trastuzumab (Herceptin), whereas most of the HER2 low-expressing counterparts were not. In these HER2-overexpressing GLM series, protein kinase B (Akt), but not extracellular signal-regulated kinase 1/2 (ERK1/2), was constitutively phosphorylated, and gefitinib efficiently inhibited this Akt phosphorylation, induced strong apoptosis in vitro and exhibited antitumour activity in tumour xenografts in nude mice. This gefitinib-mediated antitumour effect in xenograft was significantly potentiated by trastuzumab treatment. On the other hand, gefitinib-resistant cells (GLM-1R) exhibited increased EGFR expression, followed by constitutive activation of mitogen-activated protein kinase (MAPK) pathway. These results suggest that the antitumour effect of gefitinib is due to the effective inhibition of HER2-driven constitutive activation of phosphatidylinositol-3-kinase (PI3K)/Akt pathway, and that the acquired resistance to gefitinib is due to the constitutive activation of Ras/MAPK pathway in compensation for PI3K/Akt pathway. Gastric cancer liver metastasis with HER2 overexpression would be a potential molecular target for gefitinib and trastuzumab.

Animals↗
PubMed2005

Cytochrome P450-dependent metabolism of gefitinib.

The in vitro metabolism of [(14)C]-gefitinib (1-3 microM) was investigated using human liver microsomes and a range of expressed human cytochrome P450 enzymes, with particular focus on the formation of O-desmethyl-gefitinib (M523595), the major metabolite observed in human plasma. High-performance liquid chromatography with ultraviolet light, radiochemical and mass spectral analysis, together with the availability of authentic standards, enabled quantification and structural identification of metabolites. On incubation with pooled human liver microsomes, [(14)C]-gefitinib underwent rapid and extensive metabolism to a number of metabolites, although M523595 was only a minor microsomal product. Formation of most metabolites was markedly decreased by ketoconazole, but M523595 production was inhibited only by quinidine. Gefitinib was metabolized extensively by expressed CYP3A4, producing a similar range of metabolites to liver microsomes, but M523595 was not formed. CYP1A2, 2C9 and 2C19 produced no measurable metabolism of gefitinib, while CYP3A5 produced a range of metabolites similar to CYP3A4, but to a much lower degree. In contrast, CYP2D6 catalysed rapid and extensive metabolism of gefitinib to M523595. While formation of M523595 was CYP2D6 mediated, the overall metabolism of gefitinib was dependent primarily on CYP3A4, and this was not obviously diminished in liver microsomes from CYP2D6 poor metabolizers.

Cells, Cultured↗
PubMedDate not supplied

Evaluation of gefitinib for treatment of refractory solid tumors and central nervous system malignancies in pediatric patients.

Gefitinib (ZD1839, Iressa), a member of the 4-anilinoquinazoline class of compounds, has the chemical name 4-quinazolinamine, N-(3-chloro-4-flurophenyl)-7-methoxy-6-[3-(4-morpholinyl)propoxy]. Gefitinib often is referred to as a "specific" or "selective" inhibitor of epidermal growth factor receptor (EGFR). EGFR expression has been noted in neuroblastoma and rhabdomyosarcoma cell lines and in tumor specimens from children with Wilms tumor, osteosarcoma, and glioma. Thus, gefitinib, the first marketed EGFR tyrosine kinase inhibitor, was chosen for study in children with refractory solid tumors and central nervous system (CNS) malignancies. This review discusses findings from 3 clinical trials of gefitinib in children with refractory solid tumors and CNS malignancies, focusing on the clinical pharmacology of the compound. To date, gefitinib has been studied in children as a single agent and in combination with irinotecan. Overall, the compound has been well tolerated in children and has a safety profile similar to that observed in adults. The clinical pharmacokinetics of gefitinib in children are similar to those observed in adults. Finally, the future for the use of gefitinib in pediatrics is similar to that of other molecularly targeted agents and awaits definition of tumors and patient populations in which it will be most advantageous.

Adult↗
PubMed2004

Gefitinib as a last treatment option for non-small-cell lung cancer: durable disease control in a subset of patients.

BACKGROUND: We describe 16 months' single-institution experience with gefitinib ("Iressa", ZD1839) used as "ultimum refugium" for pretreated non-small-cell lung cancer (NSCLC) patients. PATIENTS AND METHODS: Toxicity, response and survival data of NSCLC patients participating in a compassionate-use program with gefitinib were reviewed. Documented disease progression and confirmation of the absence of other treatment options were requested. Oral gefitinib at a dose of 250 mg/day was given until disease progression, unacceptable toxicity or death. Cox's proportional hazards model was used to analyze relationships between factors and probability of survival. RESULTS: Rapid disease precluded treatment in eight cases. Of 92 evaluable patients, one-third had a baseline performance status (PS) of > or =2. The main side-effects of gefitinib were grade 1-2 diarrhea and skin rash. A disease control rate of 46% (objective response rate 8.7%) and 1-year survival of 29% were documented. Histology (adenocarcinoma) and a "never-smoking" history were predictive of response. Number of previous chemotherapy regimens, gender, time since diagnosis and time since last chemotherapy lacked such an association. Radiotherapy during gefitinib treatment was well tolerated and was associated with prolonged survival in a patient with multiple brain metastases. Multivariate analyses revealed a significant impact of PS on survival. A "never-smoking" history, adenocarcinoma/bronchoalveolar-cell carcinoma and female gender showed a trend towards better survival outcomes. CONCLUSION: Gefitinib's single-agent activity in a group consisting of pretreated NSCLC patients is confirmed. Side-effects of gefitinib were mild. Prolonged survival was associated with good PS and less significantly with a never-smoking history, female gender and histology. Additional studies on mechanisms of tumor control and selection of target populations for this remarkable new drug are warranted.

Administration, Oral↗
PubMed2005

The EGFR mutation and its correlation with response of gefitinib in previously treated Chinese patients with advanced non-small-cell lung cancer.

BACKGROUND: The aim of the study was to evaluate the efficacy of gefitinib and the epidermal growth factor receptor (EGFR) mutation to gefitinib response in a series of Chinese patients with pretreated advanced non-small-cell lung cancer (NSCLC). METHODS: A total of 98 patients who had failed at least one platinum-based regimen received gefitinib 250 mg once daily. The mutation analysis of the EGFR kinase domain was performed for 30 patients using paraffin-embedded tumor tissue. RESULTS: The response rate was 31.6% and the disease control rate was 67.3%. Objective response was correlated with adenocarcinoma, female gender and non-smokers. Median progress free survival (PFS) was 7.0 months, median overall survival (OS) was 12.0 months and 1-year survival was 53.1%. The median PFS and OS were improved among patients with adenocarcinoma, gefitinib responders and non-smokers. Active gene mutation was detected in 12 patients. Mutation rates were higher among gefitinib responders, non-smokers, patients with adenocarcinoma and female patients. OS was longer for patients with gene mutation than for patients without mutation. CONCLUSION: Gefitinib demonstrated significant antitumor activity with a favorable toxicity profile for pretreated Chinese patients with advanced NSCLC. The active mutation of the EGFR kinase domain was strongly associated with response to gefitinib and prolonged overall survival.

Adenocarcinoma↗
PubMed2004

Prediction of sensitivity of advanced non-small cell lung cancers to gefitinib (Iressa, ZD1839).

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.

Adult↗