In vitro and in vivo evaluation of combined calcitriol and cisplatin in dogs with spontaneously occurring tumors

PURPOSE: Calcitriol potentiates cisplatin-mediated activity in a variety of tumor models. We examine here, the effect of calcitriol and cisplatin pre-clinically and clinically in canine spontaneous tumors through in vitro studies on tumor cells and through a phase I study of calcitriol and cisplatin to identify the maximum-tolerated dosage (MTD) of this combination in dogs with cancer and to characterize the pharmacokinetic disposition of calcitriol in dogs. METHODS: Canine tumor cells were investigated for calcitriol/cisplatin interactions on proliferation using an MTT assay in a median-dose effect analysis; data were used to derive a combination index (CI). Cisplatin was given at a fixed dosage of 60 mg/m(2). Calcitriol was given i.v. and the dosage was escalated in cohorts of three dogs until the MTD was defined. Serum calcitriol concentrations were quantified by radioimmunoassay. RESULTS: In vitro, CIs < 1.0 were obtained for all combinations of calcitriol/cisplatin examined. The MTD was 3.75 mug/kg calcitriol in combination with cisplatin, and hypercalcemia was the dose-limiting toxicosis. The relationship between calcitriol dosage and either C (max )or AUC was linear. Calcitriol dosages >1.5 mug/kg achieved C (max) >/= 9.8 ng/mL and dosages >1.0 mug/kg achieved AUC >/= 45 h ng/mL. CONCLUSIONS: Calcitriol and cisplatin have synergistic antiproliferative effects on multiple canine tumor cells and high-dosages of i.v. calcitriol in combination with cisplatin can be safely administered to dogs. C (max) and AUC at the MTD 3.75 mug/kg calcitriol exceed concentrations associated with antitumor activity in a murine model, indicating this combination might have significant clinical utility in dogs.     

A phase I and pharmacokinetics study of intravenous calcitriol in combination with oral dexamethasone and gefitinib in patients with advanced solid tumors

Purpose

The primary objective of this study was to determine the maximum tolerated dose (MTD) of intravenously (i.v.) calcitriol administered in combination with a fixed oral dose of dexamethasone and gefitinib in patients with refractory solid tumors.

Methods

A fixed oral dose of dexamethasone of 4 mg/day was given every 12 h × 3 doses starting 12 h prior to i.v. calcitriol administration. Calcitriol was administered i.v. over 1 h on weeks 1, 3, and weekly thereafter. The starting calcitriol dose level was 57 μg and escalation occurred in cohorts of three patients until the MTD was defined. Gefitinib was given at a fixed oral daily dose of 250 mg starting at week 2 (day 8). Serum calcitriol PK studies were performed on day 1 (calcitriol + dexamethasone) and on day 15 (calcitriol + dexamethasone + gefitinib).

Results

A total of 20 patients were treated. Dose-limiting hypercalcemia was observed in two out of the four patients receiving 163 mcg/week of calcitriol. Mean (±SE) peak serum calcitriol concentration (C _max) at the MTD (125 μg/week calcitriol) was 11.17 ± 2.62 ng/ml and the systemic exposure (AUC_0–72 h) of 53.30 ± 10.49 ng h/ml. The relationship between calcitriol dose and either C _max or AUC was linear over the 57–163 μg dose range.

Conclusions

The addition of a low dose of dexamethasone allowed the safe escalation of calcitriol to the MTD of 125 μg/week. This dose level resulted in serum calcitriol concentrations that are associated with pre-clinical antitumor activity. However, no antitumor activity was noted clinically in patients with solid tumors.     

Gefitinib (ZD1839) combined with weekly epirubicin in patients with metastatic breast cancer: a phase I study with biological correlate.

PURPOSE: Epidermal growth factor receptor (EGFR) is overexpressed in approximately 50% of invasive breast carcinomas and it is correlated with hormone resistance and poor prognosis. EGFR suppression by gefitinib, a quinazoline derivative that inhibits phosphorylation of the specific receptor, represents a novel therapeutic strategy. A dose-finding study was performed to evaluate the combination of gefitinib with weekly epirubicin in patients with pretreated metastatic breast cancer. METHODS: Fifteen patients were enrolled at four sequential dose levels. Gefitinib was administered orally, at the fixed daily dose of 250 mg. The starting dose of epirubicin was 20 mg/m2. Escalating dose levels of epirubicin were planned by increments of 5 mg/m2 per level, up to the maximum tolerated dose (MTD). Pharmacodynamic studies were performed by determining serum and tissue ERBB2 and EGFR. RESULTS: At the first three dose levels tested no patient experienced a dose-limiting toxicity (DLT). In cohort 4, two patients experienced DLTs (grade 4 dyspnea and asthenia, grade 3 diarrhea and thrombocytopenia) identifying the MTD of epirubicin as 35 mg/m2. Of the 14 cases assessable for response, partial response was documented in two patients, and stable disease in seven, giving an overall disease control rate of 64.2%. The comparison of pre- and post-therapy ERBB2 and EGFR values was not statistically significant between the subgroups of patients regarding responsiveness to treatment. CONCLUSIONS: The recommended dose of epirubicin for phase II studies is 30 mg/m2 in combination with gefitinib at the daily dose of 250 mg. Pharmacodynamic studies did not identify any biomarker predictive of response.     

Better survival with EGFR exon 19 than exon 21 mutations in gefitinib-treated non-small cell lung cancer patients is due to differential inhibition of downstream signals

Somatic mutations in the epidermal growth factor receptor (EGFR) kinase domain are associated with sensitivity to tyrosine kinase inhibitors (TKIs) in patients with non-small cell lung cancer (NSCLC). Our clinical data showed NSCLC patients with exon 19 deletions survived longer following gefitinib treatment than those with exon 21 point mutations. We aimed to investigate whether these two mutations produced differences in phosphorylation of EGFR and downstream signals. Two stable cell lines expressing these mutations were obtained by transfection. Inhibition of phosphorylation of EGFR, Akt, and Erk by gefitinib was detected using Western blotting, and cell inhibition tests were conducted to evaluate the bio-behavior. Gefitinib inhibited the phosphorylation of EGFR, Akt, and Erk to a greater degree in exon 19 deletion cells than in L858R cells. Gefitinib produced G1 arrest in more of the cells with exon 19 deletion than with L858R. This might be attributable to patient selection in TKIs therapy.     

Vitamin D-related therapies in prostate cancer

Calcitriol or 1,25-dihydroxycholecalciferol (vitamin D) is classically known for its effects on bone and mineral metabolism. Epidemiological data suggest that low vitamin D levels increase the risk and mortality from prostate cancer. Calcitriol is also a potent anti-proliferative agent in a wide variety of malignant cell types including prostate cancer cells. In prostate model systems (PC-3, LNCaP, DU145, MLL) calcitriol has significant anti-tumor activity in vitro and in vivo. Calcitriol's effects are associated with an increase in cell cycle arrest, apoptosis, differentiation and in the modulation of growth factor receptors. Calcitriol induces a significant G₀/G₁ arrest and modulates p21^Waf1/Cip1 and p27^Kip1, the cyclin dependent kinase inhibitors. Calcitriol induces PARP cleavage, increases the bax/bcl-2 ratio, reduces levels of phosphorylated mitogen-activated protein kinases (P-MAPKs, P-Erk-1/2) and phosphorylated Akt (P-Akt), induces caspase-dependent MEK cleavage and up-regulation of MEKK-1, all potential markers of the apoptotic pathway. Glucocorticoids potentiate the anti-tumor effect of calcitriol and decrease calcitriol-induced hypercalcemia. In combination with calcitriol, dexamethasone results in a significant time- and dose-dependent increase in VDR protein and an enhanced apoptotic response as compared to calcitriol alone. Calcitriol can also significantly increase cytotoxic drug-mediated anti-tumor efficacy. As a result, phase I and II trials of calcitriol either alone or in combination with the carboplatin, paclitaxel, or dexamethasone have been initiated in patients with androgen-dependent and -independent prostate cancer and advanced cancer. Patients were evaluated for toxicity, maximum tolerated dose (MTD), schedule effects, and PSA response. Data from these studies indicate that high-dose calcitriol is feasible on an intermittent schedule, the MTD is still being delineated and dexamethasone or paclitaxel appear to ameliorate toxicity. Studies continue to define the MTD of calcitriol which can be safely administered on this intermittent schedule either alone or with other agents and to evaluate the mechanisms of calcitriol effects in prostate cancer.     

Activated Src and Ras induce gefitinib resistance by activation of signaling pathways downstream of epidermal growth factor receptor in human gallbladder adenocarcinoma cells

Purpose: Although gefitinib, a selective inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase, has been demonstrated to exhibit its antitumor activity by the blockade of EGF receptor, the role of signaling pathways downstream of EGFR in gefitinib sensitivity remains unknown. In this study, we investigated the mechanistic role of Src and Ras, major oncogene products implicated in the pathogenesis of many human cancers in gefitinib sensitivity. Methods: Using parental and v-src- or c-H-ras-transfected HAG-1 human gallbladder adenocarcinoma cell lines, effects of gefitinib on cytotoxicity, cell cycle purtubation and apoptosis, and tyrosine phosphorylation of EGFR, Akt, and Erk were determined by WST-1 assay, flow cytometry, and Western blots, respectively. Results: Activated Ras and Src conferred a strong resistance to gefitinib by nearly 30-fold and 200-fold, respectively. Gefitinib induced accumulation of cells in the G0/G1 phase of the cell cycle at 24-h, with progressive expansion of apoptotic cell population in parental HAG-1 cells, but these effects were completely abolished in v-src- or c-H-ras-transfected cell line. Upon gefitinib treatment, EGFR activation and subsequent downstream activation through Erk and Akt were significantly inhibited in HAG-1 cells. By contrast, gefinitib failed to inhibit the activation of both Akt and Erk in v-src-transfected cells and Erk, but not Akt in c-H-ras-transfected cells, despite the blockade of EGFR activation in these respective cell lines. Treatment of v-src-transfected cells with herbimycin A, a Src tyrosine kinase inhibitor, partially reversed the gefitinib resistance, with concomitant inhibition of Akt and Erk. Conclusion: Our results suggest that activated Ras and Src could induce gefitinib resistance by activating either or both of Akt and Erk signaling pathways, thus providing a strategic rationale for assessment of these specific signaling molecules downstream of EGFR to customize treatment.Baoli Qin and Hiroshi Ariyama contributed equally to this work.     

Enhanced cytotoxicity induced by gefitinib and specific inhibitors of the Ras or phosphatidyl inositol-3 kinase pathways in non-small cell lung cancer cells

In this study, we have characterized a panel of NSCLC cell lines with differential sensitivity to gefitinib for activating mutations in egfr, pik3ca, and k-ras, and basal protein expression levels of PTEN. The egfr mutant NSCLC cell line H1650 as well as the egfr wild type cell lines H292 and A431 were highly sensitive to gefitinib treatment, indicating that other factors determine gefitinib-sensitivity in egfr wild type cells. Activating k-ras mutations were specifically detected in gefitinib-resistant cells, suggesting that the occurrence of k-ras mutations is correlated with resistance to EGFR antagonists. No pik3ca mutations were detected within the panel of cell lines, and PTEN protein expression levels did not correlate with gefitinib sensitivity. Gefitinib effectively blocked Akt and Erk phosphorylation in two gefitinib-sensitive NSCLC cell lines, further supporting our previous findings that persistent activity of the PI3K/Akt and/or Ras/Erk pathways is associated with gefitinib-resistance of NSCLC cell lines. Gefitinib-resistant NSCLC cell lines, showing EGFR-independent activity of the PI3K/Akt or Ras/Erk pathways, were treated with gefitinib in combination with specific inhibitors of mTOR, P13K, Ras, and MEK. Additive cytotoxicity was observed in A549 cells co-treated with gefitinib and the MEK inhibitor U0126 or the farnesyl transferase inhibitor SCH66336 and in H460 cells treated with gefitinib and the PI3K inhibitor LY294002, but not in H460 cells treated with gefitinib and rapamycin. These data suggest that combination treatment of NSCLC cells with gefitinib and specific inhibitors of the PI3K/Akt and Ras/Erk pathways may provide a successful strategy.     

A Phase I trial of pulse calcitriol in patients with refractory malignancies: pulse dosing permits substantial dose escalation.

BACKGROUND: Calcitriol is the principal biologically active metabolite of vitamin D. Calcitriol's activity against many neoplasms is well documented, but calcitriol's therapeutic application has been hampered by predictable hypercalcemia when it is given daily. Because laboratory data has suggested that intermittent exposure to high levels of calcitriol may be sufficient to produce antiproliferative effects, the authors developed a Phase I trial to determine the maximal tolerated dose, dose-limiting toxicity, and the pharmacokinetic profile of calcitriol given weekly by mouth. METHODS: Patients with refractory malignancies were enrolled for 4 weeks of treatment followed by 4 weeks of observation. Reenrollment at a higher dose level was permitted for patients who had evidence of response or stable disease and no Grade 3 or greater toxicity. The starting dose was 0.06 microg/kg. RESULTS: Fifteen patients received 20 cycles of therapy. Doses up to 2.8 microg/kg of calcitriol weekly produced no dose-limiting toxicity. While peak levels and the area under the serum concentration-time curve of calcitriol increased in a linear fashion at lower doses, saturable absorption was observed at doses above 0.48 microg/kg. Doses of 0.48 microg/kg and above produced mean peak calcitriol levels of 1625 pg/mL, approximately 25-fold greater than top normal levels and well within the therapeutic range suggested by in vitro experiments. Eight patients experienced self-limiting Grade 1 hypercalcemia. CONCLUSIONS: Weekly dosing of oral calcitriol permitted substantial dose escalation with minimal toxicity. Peak serum calcitriol levels were in the predicted therapeutic range. A dose of 0.5 microg/kg was selected for evaluation in Phase II studies.     

Gefitinib and chemotherapy combination studies in five novel human non small cell lung cancer xenografts. Evidence linking EGFR signaling to gefitinib antitumor response

The epidermal growth factor receptor (EGFR) signaling pathway is often activated in NSCLC, and thus represents a promising therapeutic target. We studied the antitumor activity of gefitinib (Iressa), an orally active EGFR-tyrosine kinase inhibitor, alone and in combination with standard chemotherapy in 5 recently established human NSCLC xenografts with wild-type EGFR. Mice were treated with 2 protocols of chemotherapy based on cisplatin (CDDP) combined with either gemcitabine (GEM) or vinorelbine (VNR). Gefitinib alone significantly inhibited tumor growth (TGI) in 4 of the 5 tumor xenografts (mean TGI of 58%, range: 25-70%). CDDP+VNR alone failed to achieve any significant responses, while CDDP+GEM achieved significant responses in 2 xenografts (TGI of 93 and 47%). Addition of gefitinib to CDDP+GEM potentialized chemotherapy in the 3 CDDP+GEM-resistant xenografts, but did not potentialize the CDDP+VNR combination. The effect of gefitinib treatment on the activity of extra cellular-regulated kinase (Erk), Akt, JNK and p38 kinases was assessed in IC9LC11 and IC1LC131, two NSCLC xenografts selected for their sensitivity and resistance to gefitinib, respectively. In IC9LC11, gefitinib strongly inhibited Erk, Akt and Jnk phosphorylation, but P38 remained active. Inversely, in IC1LC131, Erk and Akt pathways remained active, while Jnk and P38 pathways were inhibited by gefitinib. The data indicate that the antitumor activity of gefitinib in NSCLC, alone or in combination with chemotherapy, is tumor-dependent and is influenced by downstream signaling events independent of EGFR status.     

Phase I study of weekly DN-101, a new formulation of calcitriol, in patients with cancer

Background DN-101 is a new, high-dose, oral formulation of calcitriol under investigation for the treatment of cancer. We sought to evaluate the tolerability and pharmacokinetics (PK) of weekly doses of DN-101 in patients with advanced cancer. Methods Patients who completed a previously reported single dose escalation study of DN-101 [Beer et al. (2005) Clin Cancer Res 11:7794–7799] were eligible for this continuation weekly dosing study. Cohorts of 3–10 patients were treated at doses of 15, 30, 45, 60, and 75 μg calcitriol. Once 45 μg was established as the maximum tolerated dose (MTD), this cohort was expanded to include 18 patients. Dose limiting toxicity (DLT) was defined as ≥grade 2 hypercalcemia or ≥grade 3 persistent treatment-related toxicities. Results Thirty-seven patients were recruited. DLT of transient reversible grade 2 hypercalcemia (serum calcium of 11.6–12.5 mg/dL) occurred in two of six patients treated with 60 μg of DN-101. No DLT was observed in the 18 patients who received DN-101 weekly at 45 μg. Overall, DN-101 was well tolerated. The most frequent adverse events were fatigue (27%), hypercalcemia (19%, including five grade 1, two grade 2, and no grade 3 or 4 events), and grade 1 nausea (16%). PK parameters following repeat dosing were comparable to those for the initial dose (n = 4). Conclusion The MTD for weekly DN-101 was established as 45 μg. The DLTs observed were two episodes of rapidly reversible grade 2 hypercalcemia in two of the six patients treated at 60 μg weekly. Repeat doses of DN-101 at 45 μg weekly are well tolerated and this dose is suitable for studies of weekly DN-101 in cancer patients. OHSU and Dr. Beer have a significant financial interest in Novacea, Inc., a company that may have a commercial interest in the results of this research and technology. This potential conflict was reviewed and a management plan approved by the OHSU Conflict of Interest in Research Committee and the Integrity Program Oversight Council was implemented.     

Gefitinib inhibits the growth and invasion of urothelial carcinoma cell lines in which Akt and MAPK activation is dependent on constitutive epidermal growth factor receptor activation.

PURPOSE: Abnormally high levels of epidermal growth factor receptor (EGFR) protein are associated with advanced tumor stage/grade. The objective of this study was to evaluate the effects of the specific EGFR tyrosine kinase inhibitor gefitinib on activation of the Akt and mitogen-activated protein kinase (MAPK) pathways in human urothelial cell carcinoma (UCC) cell lines and to identify potential markers of gefitinib responsiveness in biopsy samples of UCC. EXPERIMENTAL DESIGN: Changes in markers of UCC growth and invasion after exposure to gefitinib were studied in six human UCC cell lines expressing various levels of EGFR. The findings were related to activation of Akt and MAPK. We studied the influence of gefitinib on intraepithelial expansion of the responsive 1207 cell line. EGFR, Akt, and MAPK activation was studied by Western blot analysis of a panel of 57 human UCC. RESULTS: Gefitinib had a growth-inhibitory and anti-invasive effect in two of six UCC cell lines (i.e., 647V and 1207). Gefitinib was also able to block the expansion of 1207 at the expense of normal urothelial cells. These effects did not depend on the level of expression of EGFR but they were associated with the down-regulation of MAPK and Akt activity; in 1207 cells, gefitinib activity was associated with p27 up-regulation and p21 and matrix metalloproteinase-9 down-regulation. Similarly, the Akt and MAPK pathways were found to be strongly phosphorylated in association with EGFR activation in a subset of human UCC specimens. CONCLUSIONS: Activation of EGFR, Akt, and MAPK defines a subset of UCC which might provide information for the identification of gefitinib responders.     

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.     

Epidermal growth factor receptor as a potential therapeutic target in triple-negative breast cancer

BackgroundNo proven targeted therapy is currently available for the treatment of triple-negative breast cancer (TNBC). Epidermal growth factor receptor (EGFR) is frequently overexpressed in TNBC. We studied the activity of EGFR antagonists alone, and in combination with chemotherapy, in TNBC cell lines.Materials and methodsEGFR and phosphorylated EGFR were measured by enzyme-linked immunosorbent assay. Sensitivity to EGFR inhibitors alone and in combination with chemotherapy was assessed. Effects of gefitinib on EGFR signalling and cell cycle were also examined.ResultsEGFR was overexpressed in the TNBC compared with the human epidermal growth factor receptor 2 (HER-2)-positive cell lines. Phosphorylation of EGFR was detected in the TNBC cells in response to epidermal growth factor stimulation and was blocked by gefitinib treatment. However, the TNBC cell lines were less sensitive to EGFR inhibition than the HER-2-positive cell lines. Response to gefitinib was associated with reduced phosphorylation of both mitogen activated protein kinase (MAPK) and Akt and induction of G₁ arrest. Gefitinib enhanced response to both carboplatin and docetaxel in the TNBC cells, and the triple combination of gefitinib, carboplatin and docetaxel was synergistic.ConclusionsAlthough the TNBC cells are less sensitive to EGFR inhibition than the HER-2-positive cell lines, gefitinib enhanced response to chemotherapy. Gefitinib combined with carboplatin and docetaxel warrants further investigation in TNBC.     

Results from a pilot Phase I trial of gefitinib combined with docetaxel and estramustine in patients with hormone-refractory prostate cancer

BACKGROUND: Gefitinib, which is an orally active epidermal growth factor receptor tyrosine kinase inhibitor, has demonstrated activity against hormone-refractory prostate cancer (HRPC) in preclinical studies. In this pilot Phase I trial, the authors evaluated the tolerability, efficacy, and pharmacokinetics of gefitinib combined with estramustine and docetaxel in patients with HRPC. METHODS: Patients received gefitinib (at a dose of 250 mg/day or 500 mg/day) on each day of a 21-day treatment cycle. Docetaxel (at a dose of 60 mg/m(2)) was administered on Day 1, and estramustine (at a dose of 280 mg) was administered 3 times daily on Days 1 through 5. RESULTS: Fifteen patients were recruited at each gefitinib dose level. The most common adverse events observed were consistent with the known profiles of gefitinib, docetaxel, and estramustine. No dose-limiting toxicity was observed. Adverse events considered to be gefitinib related included diarrhea (n = 23 patients), rash (n = 8 patients), nausea (n = 7 patients), dry skin (n = 6 patients), and emesis (n = 6 patients). Overall, 9 of 22 evaluable patients (40.9%) experienced a pain response. and 9 of 30 patients (30%) had a prostate-specific antigen response. A partial objective tumor response was demonstrated in 1 of 13 evaluable patients (7.7%) in each dose group; the median time to progression for both doses combined was 185 days (range, 28-233 days). Data comparisons within individual patients suggested that docetaxel and estramustine had no effect on gefitinib steady-state levels. Gefitinib had no effect on docetaxel exposure at the 250-mg dose but decreased exposure at the 500-mg dose. However, gefitinib may increase exposure to estramustine, particularly at the 500 mg/day dose. CONCLUSIONS: The results of the current study demonstrated that gefitinib combined with estramustine and docetaxel had acceptable and predictable tolerability. However, it is unclear whether gefitinib provides an additional clinical benefit over docetaxel and estramustine alone.     

Gefitinib therapy for non-small cell lung cancer

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

Mutations of the epidermal growth factor receptor gene predict prolonged survival after gefitinib treatment in patients with non-small-cell lung cancer with postoperative recurrence.

PURPOSE: To evaluate the relationship between mutations of the epidermal growth factor receptor (EGFR) gene and the effectiveness of gefitinib treatment in patients with recurrent lung cancer after pulmonary resection. PATIENTS AND METHODS: We sequenced exons 18-21 of the EGFR gene using total RNA extracted from 59 patients with lung cancer who were treated with gefitinib for recurrent lung cancer. Gefitinib effectiveness was evaluated by both imaging studies and change in serum carcinoembryonic antigen (CEA) levels. RESULTS: EGFR mutations were found in 33 patients (56%). Of these mutations, 17 were deletions around codons 746-750 and 15 were point mutations (12 at codon 858, three at other codons), and one was an insertion. EGFR mutations were significantly more prevalent in females, adenocarcinoma, and never-smokers. Gefitinib treatment resulted in tumor shrinkage and/or CEA decrease to less than half of the baseline level in 26 patients, tumor growth and/or CEA elevation in 24 patients, and gefitinib effect was not assessable in nine patients. Female, never-smoking patients with adenocarcinoma tended to respond better to gefitinib treatment. Gefitinib was effective in 24 of 29 patients with EGFR mutations, compared with two of 21 patients without mutations (P < .0001). Of note, del746-750 might be superior to L858R mutations for prediction of gefitinib response. Patients with EGFR mutations survived for a longer period than those without the mutations after initiation of gefitinib treatment (P = .0053). CONCLUSION: EGFR mutations were a good predictor of clinical benefit of gefitinib in this setting.     

Tolerability of gefitinib in patients receiving treatment in everyday clinical practice

Gefitinib ("Iressa", ZD1839), an epidermal growth factor receptor tyrosine kinase inhibitor, has recently been approved in several countries for use in advanced or metastatic non-small-cell lung cancer (NSCLC). In contrast to chemotherapies, which are generally used at or near their maximum-tolerated dose (MTD), gefitinib is used at an optimal biological dose (250 mg day(-1)), which is substantially below its MTD, minimising the risk of adverse events without compromising efficacy. Tolerability data from the compassionate use of gefitinib in the "Iressa" Expanded Access Programme support the favourable safety profile of the agent reported in Phase I and II trials. In both settings, the majority of adverse drug reactions were mild/moderate and consisted mainly of grade 1/2 diarrhoea and skin rash. Although skin rash has been suggested to predict response to gefitinib, available data do not support this hypothesis. Overall, these tolerability data demonstrate that gefitinib has a relatively benign side-effect profile and is a well-tolerated treatment option for patients with previously treated NCSLC, who currently have few alternatives.     

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/m² as a 90 min intravenous (i.v.) infusion, 5-FU 400 mg/m² bolus i.v. and leucovorin 20 mg/m² 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/m² and 5-FU to 500 mg/m². 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.     

Phase 1 trial of everolimus and gefitinib in patients with advanced nonsmall-cell lung cancer

BACKGROUND: Preclinical studies have demonstrated that the inhibition of the PI3K/Akt/mTOR pathway restores gefitinib sensitivity in resistant cancer cell lines. A phase 1 study was conducted of the combination of everolimus, an mTOR inhibitor, and gefitinib to determine a daily dose of everolimus with gefitinib in patients with advanced nonsmall-cell lung cancer (NSCLC). METHODS: Oral everolimus and gefitinib were both administered daily to patients with progressive NSCLC. Patients were enrolled in 3-patient cohorts at everolimus dose levels of 5 and 10 mg daily. All patients received gefitinib 250 mg daily. RESULTS: Ten patients were enrolled. The maximum tolerated dose of everolimus was 5 mg when administered daily with gefitinib 250 mg. Two patients who were treated at the 10 mg dose level of everolimus experienced dose-limiting toxicity, including grade 5 hypotension and grade 3 stomatitis. Pharmacokinetic studies demonstrated no consistent, significant interaction on the t(max), C(max), and AUC(0-8h) of either agent. Two partial radiographic responses were identified among the 8 response-evaluable patients. CONCLUSIONS: For further study, everolimus at a dose of 5 mg daily in combination with daily gefitinib 250 mg is recommended. The 2 radiographic responses identified are encouraging. A phase 2 trial in patients with NSCLC is under way.     

Evaluation of the therapeutic potential of the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib in preclinical models of bladder cancer.

The epidermal growth factor receptor (EGFR) is associated with aggressive phenotypes and is an independent predictor of stage progression and mortality in bladder cancer. Gefitinib ('Iressa,' ZD1839) is an orally active EGFR-tyrosine kinase inhibitor. The objective of this study was to evaluate the in vitro and in vivo effects of gefitinib in the EGFR-expressing human bladder cancer cell lines 253J B-V, RT-112, and T24. EGFR expression was 3- and 2-fold higher in 253J B-V and RT-112, respectively, compared with T24 cells. Ten microm gefitinib inhibited EGFR, p42/44 extracellular signal-regulated kinase (ERK), and Akt/protein kinase B phosphorylation in all three of the cell lines. Inhibition of ERK by gefitinib was significantly greater in 253J B-V compared with RT-112 and T24 cells (9:2:1 in 253J B-V:RT-112:T24), whereas inhibition of Akt phosphorylation was less in 253J B-V compared with RT-112 and T24 cells (1:9:30 in 253J B-V:RT-112:T24). When cultured in serum-free medium supplemented with epidermal growth factor, 10 microm gefitinib inhibited DNA synthesis in T24 and RT-112 cells, whereas 1 microm gefitinib was sufficient to inhibit DNA synthesis in 253J B-V cells. Similarly, in the presence of serum, 10 microm gefitinib induced a significant reduction in S-phase and viable cell number in T24 and RT-112 cells, whereas 1-10 microm gefitinib caused a dose-dependent effect on these phenotypes in 253J B-V cells. Gefitinib significantly enhanced the ability of ionizing radiation to reduce colony forming ability in 253J B-V and RT-112 cells. In nude mice, a daily oral dose of 150 mg/kg gefitinib induced regression of tumors produced by 253J B-V cells growing at s.c. sites and suppression of tumors produced by these cells at orthotopic sites but had no effect on tumors produced by RT-112 cells growing at s.c. sites. The data indicates that gefitinib has potential therapeutic value, alone or in combination with ionizing radiation, in a subset of EGFR-expressing bladder cancers. However, there is a differential response to gefitinib in these EGFR-expressing bladder cancer cell lines. Although gefitinib can inhibit phosphorylation of EGFR, ERK, and Akt, and inhibit growth of bladder cancer cells in vitro, it does not necessarily inhibit growth of bladder cancer cells in vivo. It is likely that optimized therapy approaches will require an accurate "molecular" diagnosis allowing effective, selective, tailored therapeutic strategies to be designed.