Pharmacokinetic-pharmacodynamic modeling of the anticancer effect of erlotinib in a human non-small cell lung cancer xenograft mouse model

Aim： Erlotinib is used to treat non-small-cell lung cancer （NSCLC）, which targets epidermal growth factor receptor （EGFR） tyrosine kinase. The aim of this study was to investigate the relationship between erlotinib plasma concentrations and phosphorylated EGFR （pEGFR） levels, as well as the relationship between pEGFR levels and tumor growth inhibition in a human non-small-cell lung cancer xenograft mouse model. Methods： Female BALB/c nude mice were implanted with the human NSCLC cell line SPC-A-1. The animals were given via gavage a single dose of erlotinib （4, 12.5, or 50 mg/kg）. Pharmacokinetics of erlotinib was determined using LC-MS/MS. Tumor volume and pEGFR levels in tumor tissues were measured at different time points after erlotinib administration, The levels of pEGFR in tumor tissues was detected using Western blotting and ELISA assays. Results： The pharmacokinetics of erlotinib was described by a two-compartment model with first order extravascular absorption kinetics. There was a time delay of approximately 2 h between erlotinib plasma concentrations and pEGFR degradation. The time course of pEGFR degradation was reasonably fit by the indirect response model with a calculated IC~o value of 1.80 pg/mL. The relationship between pEGFR levels and tumor volume was characterized by the integrated model with a Kbio value of 0.507 cm3/week which described the impact of pEGFR degradation on tumor growth. Conclusion： The pharmacokinetic/pharmacodynamic properties of erlotinib in a human tumor xenograft model were described by the indirect response model and integrated model, which will be helpful in understanding the detailed processes of erlotinib activity and determining an appropriate dosing regimen in clinical studies.     

Erlotinib: a new therapeutic approach for non-small cell lung cancer

Although treatment with cytotoxic agents has produced modest survival improvement in patients with stage III and IV non-small cell lung cancer (NSCLC), it appears that a plateau has been reached with currently available chemotherapeutic regimens. Increasing knowledge regarding the properties of malignant neoplasms has identified a number of potential therapeutic targets. The epidermal growth factor receptor (EGFR) is one of these targets. Preclinical models have revealed that tumour growth can be inhibited by monoclonal antibodies directed against EGFR and EGFR-specific tyrosine kinase inhibitors. Erlotinib (Tarceva?; OSI Pharmaceuticals, Genentech and Roche), a quinazoline derivative with good oral absorption, is one of several EGFR tyrosine kinases that has been studied in clinical trials. In a Phase I study, mild diarrhoea and mild rash were the most common toxicities. At a dose of 200 mg/day, diarrhoea was the dose-limiting toxicity. The observation that EGFR overexpression is relatively common in NSCLC led to a Phase II trial of erlotinib at the maximum-tolerated dose (150 mg/day) in previously treated NSCLC patients. Erlotinib produced a 12% response rate and there was no apparent relationship between response and tumour EGFR levels. More recent reports suggest that patients who develop a rash have higher responses. Based on its single agent activity, erlotinib has been evaluated in two Phase III trials which compared erlotinib plus chemotherapy to chemotherapy alone in previously untreated NSCLC patients. Erlotinib has also been compared to placebo in a Phase III trial which was limited to advanced stage NSCLC patients whose disease had progressed after two previous chemotherapy regimens. The optimum use of erlotinib in NSCLC will be determined by the results of the completed and future Phase III trials.     

Erlotinib: a new therapeutic approach for non-small cell lung cancer

Although treatment with cytotoxic agents has produced modest survival improvement in patients with stage III and IV non-small cell lung cancer (NSCLC), it appears that a plateau has been reached with currently available chemotherapeutic regimens. Increasing knowledge regarding the properties of malignant neoplasms has identified a number of potential therapeutic targets. The epidermal growth factor receptor (EGFR) is one of these targets. Preclinical models have revealed that tumour growth can be inhibited by monoclonal antibodies directed against EGFR and EGFR-specific tyrosine kinase inhibitors. Erlotinib (Tarceva trade mark; OSI Pharmaceuticals, Genentech and Roche), a quinazoline derivative with good oral absorption, is one of several EGFR tyrosine kinases that has been studied in clinical trials. In a Phase I study, mild diarrhoea and mild rash were the most common toxicities. At a dose of 200 mg/day, diarrhoea was the dose-limiting toxicity. The observation that EGFR overexpression is relatively common in NSCLC led to a Phase II trial of erlotinib at the maximum-tolerated dose (150 mg/day) in previously treated NSCLC patients. Erlotinib produced a 12% response rate and there was no apparent relationship between response and tumour EGFR levels. More recent reports suggest that patients who develop a rash have higher responses. Based on its single agent activity, erlotinib has been evaluated in two Phase III trials which compared erlotinib plus chemotherapy to chemotherapy alone in previously untreated NSCLC patients. Erlotinib has also been compared to placebo in a Phase III trial which was limited to advanced stage NSCLC patients whose disease had progressed after two previous chemotherapy regimens. The optimum use of erlotinib in NSCLC will be determined by the results of the completed and future Phase III trials.     

非小细胞肺癌靶向治疗新药——厄洛替尼

厄洛替尼是一种口服、高选择性、可逆的表皮生长因子受体(EGFR)酪氨酸激酶(TK)抑制剂,它通过抑制EGFR-TK的自磷酸化反应,抑制信号转导,从而达到抑制肿瘤生长作用。一项Ⅲ期安慰剂对照临床研究结果表明,厄洛替尼每日口服150 mg单药治疗,可显著延长晚期复发性非小细胞肺癌(NSCLC)病人的生存期、延缓疾病进展和症状恶化,且耐受性较好,最常见的不良反应为皮疹和腹泻。本文对厄洛替尼的药动学和药效学特性、临床疗效和药物相互作用以及难治性晚期NSCLC病人的耐受性等作一综述。     

Erlotinib in non-small-cell lung cancer

Epidermal growth factor receptor (EGFR) plays an essential role in normal cell growth and differentiation, and is involved in tumour proliferation and survival. EGFR overexpression is a common feature in solid malignancies, including non-small-cell lung cancer (NSCLC), and is associated with poor clinical prognosis. Erlotinib is a small-molecule inhibitor of EGFR tyrosine kinase, showing a significant improvement in median survival, quality of life and related symptoms in an unselected population of advanced NSCLC patients in the second- or third-line setting. Erlotinib is well tolerated (with common toxicities including rash and diarrhoea) when administered at a standard oral daily dose of 150 mg. Further investigations are ongoing to contribute to our understanding of the role of erlotinib in NSCLC treatment.     

Erlotinib in non-small-cell lung cancer

Epidermal growth factor receptor (EGFR) plays an essential role in normal cell growth and differentiation, and is involved in tumour proliferation and survival. EGFR overexpression is a common feature in solid malignancies, including non-small-cell lung cancer (NSCLC), and is associated with poor clinical prognosis. Erlotinib is a small-molecule inhibitor of EGFR tyrosine kinase, showing a significant improvement in median survival, quality of life and related symptoms in an unselected population of advanced NSCLC patients in the second- or third-line setting. Erlotinib is well tolerated (with common toxicities including rash and diarrhoea) when administered at a standard oral daily dose of 150 mg. Further investigations are ongoing to contribute to our understanding of the role of erlotinib in NSCLC treatment.     

Reviewing the safety of erlotinib in non-small cell lung cancer

Importance of the field: Erlotinib, a potent inhibitor of EGFR activity, is approved as a monotherapy for the treatment of advanced NSCLC and in combination with gemcitabine for advanced pancreatic cancer. The oral administration and manageable toxicity of erlotinib, along with its similar efficacy to chemotherapy, make it an important option as either maintenance therapy or in second-/third-line for patients with NSCLC who have previously received first-line chemotherapy. It is also an emerging option in other treatment settings in NSCLC.

Areas covered in this review: This review summarizes safety data from major clinical trials of erlotinib in patients with advanced NSCLC, as well as post-marketing data obtained in the 5 years since this drug was first approved.

What the reader will gain: An understanding of the common toxicities expected with erlotinib in patients with advanced NSCLC.

Take home message: Erlotinib is a well-tolerated treatment option for patients with advanced NSCLC. The main adverse events of rash and diarrhea are typically mild or moderate in severity, and rarely lead to treatment withdrawal. When necessary, rash and diarrhea can be easily managed prophylactically, by active intervention or through dose reduction.     

Erlotinib and vinorelbine in advanced malignant solid tumors: a phase I study

Summary Background Erlotinib is an oral epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI). Vinorelbine, a vinca alkaloid, interferes with microtubule assembly inhibiting mitosis during metaphase. Both drugs are commonly used as single agents in the treatment of advanced non small cell lung cancer (NSCLC). Given their efficacy in NSCLC and their non-overlapping toxicity profile, we conducted a phase I study of erlotinib and vinorelbine to establish the feasibility and safety of the combination and to determine the maximum tolerated dose (MTD). Patients and methods Patients with advanced solid tumors were treated with vinorelbine intravenously on day 1 and 8 and erlotinib orally daily on a 21 day schedule. The dose levels of vinorelbine/erlotinib were 25 mg/m²/100 mg, 25/150 and 30/150. Results Sixteen patients were enrolled. Five patients were chemo-na?ve; 11 had one prior therapy. The majority of patients had NSCLC (n = 7). Dose limiting toxicities included febrile neutropenia (4 patients) and grade 5 infection (1 patient). Non-hematologic grade 3/4 toxicities included diarrhea, hypokalemia, infection, dyspnea and mucositis. Of 12 patients assessable for radiologic response, there were no objective responses; eight had stable disease. Conclusions (1) The MTD was vinorelbine 25 mg/m² day 1 and 8 with erlotinib 100 mg/day every 21 days. (2) The combination was associated with high rate of febrile neutropenia (25%). (3) Due to subsequent data demonstrating a lack of efficacy of erlotinib in combination with platinum doublets in advanced NSCLC, this combination has not been explored further. Supported in part by University of California Davis Cancer Center Support Grant, Genentech and Glaxo-Smith Kline.     

Evaluation of the mTOR inhibitor, everolimus, in combination with cytotoxic antitumor agents using human tumor models in vitro and in vivo

The aim was to determine the potential of the allosteric mammalian target of rapamycin inhibitor, everolimus, to act in combination with cytotoxic anticancer compounds in vitro and in vivo. A concomitant combination in vitro showed no evidence of antagonism, but enhanced the antiproliferative effects (additive to synergistic) with cisplatin, doxorubicin, 5-fluorouracil, gemcitabine, paclitaxel, and patupilone. Everolimus (1-5 mg/kg/d orally) was evaluated for antitumor activity in vivo alone or in combination with suboptimal cytotoxic doses using athymic nude mice bearing subcutaneous human H-596 lung, KB-31 cervical, or HCT-116 colon tumor xenografts. Everolimus monotherapy was very well tolerated and caused inhibition of tumor growth, rather than regression, and this was associated with a dose-dependent decline in tumor pS6 levels, a key downstream protein of mammalian target of rapamycin. At the doses used, the cytotoxics inhibited tumor growth and caused tolerable body-weight loss. Concomitant combinations of cisplatin, doxorubicin, paclitaxel, or patupilone with everolimus produced cooperative antitumor effects, in some cases producing regressions without clinically significant increases in toxicity. In contrast, combinations with gemcitabine and 5-fluorouracil were less well tolerated. Alternative administration schedules were tested for cisplatin, gemcitabine, or paclitaxel combined with everolimus: these did not dramatically affect cisplatin or gemcitabine activity or tolerability but were antagonistic for paclitaxel. Everolimus showed promising maintenance activity after treatment with doxorubicin or paclitaxel ceased. Overall, the results confirm that everolimus is an effective, well-tolerated suppressor of experimental human tumor growth, and although it did not show strong potentiation of efficacy, antitumor activity in vivo was increased without marked increases in toxicity, supporting clinical use of everolimus as a partner for conventional cytotoxics.     

Erlotinib induces mitochondrial-mediated apoptosis in human H3255 non-small-cell lung cancer cells with epidermal growth factor receptorL858R mutation through mitochondrial oxidative phosphorylation-dependent activation of BAX and BAK

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib shows potent antitumor activity in some non-small-cell lung cancer (NSCLC) cell lines and is approved by the Food and Drug Administration as second and third line treatment for NSCLC. However, the molecular mechanisms by which erlotinib induces apoptosis remain to be elucidated. Here, we investigated the effect of erlotinib on apoptotic signal pathways in H3255 cells with the EGFR(L858R) mutation. Erlotinib induces apoptosis associated with the activation of caspases in a dose- and time-dependent manner. Erlotinib did not alter the expression of apoptotic receptors FAS and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), although it induced caspase-8 activation and BID cleavage. In addition, cell death caused by erlotinib was not prevented by coincubation with FAS and TRAIL antagonists, ZB-4 monoclonal antibody and TRAIL/Fc recombinant, suggesting that erlotinib-induced apoptosis is not associated with receptor-mediated pathways. Erlotinib induces loss of mitochondrial membrane potential and release of cytochrome c and second mitochondria-derived activator of caspases/direct IAP binding protein with low pI from mitochondria. Furthermore, erlotinib causes BAX translocation to mitochondria, BAX and BAK conformational changes, and oligomerization. Erlotinib did not induce reactive oxygen species generation, and cotreatment with antioxidants did not alter erlotinib-induced activation of BAX and BAK and apoptosis. However, cotreatment with inhibitors of mitochondrial oxidative phosphorylation significantly blocked erlotinib-induced activation of BAX and BAK and cell death. Benzyloxycarbiny-VAD-fluoromethyl ketone had no effect on erlotinib-induced BAX and BAK activation but effectively prevented apoptosis. Overexpression of BCL-2 caused a significant attenuation of erlotinib-induced cell death, but no effect on BAX and BAK activation. Down-regulation of BAX and BAK gene expression with small interfering RNA led to an effective reduction of erlotinib-induced apoptosis. Our data indicate that activation of BAX and BAK plays a critical role in the initiation of erlotinib-induced apoptotic cascades.     

Erlotinib resistance is altered after gemcitabine chemotherapy for recurrent non-small-cell lung cancer

We report the case of a male Mongolian lifelong non-smoker with recurrent non-small-cell lung cancer (NSCLC) who developed resistance to the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib after initially responding to this agent but then subsequently had another response to a second course of erlotinib treatment after intervening gemcitabine chemotherapy. Sixteen months after the patient received chemoradiotherapy with gemcitabine/cisplatin plus radiotherapy, his recurrent mediastinal metastases were found to have progressed. Treatment with erlotinib was followed by an initial, partial response but evidence of progression was again observed 6 months later. The patient was then treated with gemcitabine chemotherapy, which resulted in a reduction in tumour volume. One month later, progression of mediastinal metastases was again observed and the patient received a second course of erlotinib. Another partial response occurred and the patient's disease remained stable at the 9-month follow-up visit (and with no reported symptom progression at an 11-month telephone follow-up). Genetic examination of tumour tissue collected at the time of the original diagnosis and during the second course of erlotinib therapy revealed activating exon 19 mutation in the EGFR gene. This case suggests that resistance to erlotinib may change following chemotherapy and that repeat erlotinib therapy may be worth considering after chemotherapy in NSCLC patients who initially respond positively to erlotinib treatment but subsequently experience recurrence of disease.     

Increasing-dose gemcitabine plus low-dose cisplatin in metastatic non-small cell lung cancer

Gemcitabine, a pyrimidine analog active in non-small cell lung cancer (NSCLC), is widely used with cisplatin. The potential activity of the combination has not been fully assessed: gemcitabine is not used at its maximum tolerated dose (MTD) and cisplatin shows a clearly dose-related toxicity. This trial was designed to assess the MTD and dose-limiting toxicity (DLT) of low-dose cisplatin and increasing gemcitabine dose. CHEMOTHERAPY: cisplatin 50 mg/m2 on day 1, gemcitabine starting at 1400 mg/m on days 1 and 8 every 21 days. Subsequent levels were increased by 200 mg/m2. Forty-two patients with metastatic NSCLC were enrolled (37 males; median age 61 years; squamous cell carcinoma 19 patients; performance status 2, in 13 patients; 18 patients had significant weight loss). MTD was found to be 2600 mg/m2 because of DLT in three of six patients: two neutropenic fever and one massive bleeding. Overall toxicity was generally mild consisting mainly of neutropenia. Asthenia was the most common non-hematological effect. Overall response rate was 19 out of 41 patients (46.3%) and median survival was 31 weeks. We conclude that the recommended dose for a phase II dose is gemcitabine 2400 mg/m2 days 1 and 8 as a 30-min infusion when given with cisplatin 50 mg/m2.     

厄洛替尼对非小细胞肺癌脑转移放疗后复发/进展的疗效观察

目的 评价厄洛替尼治疗非小细胞肺癌(NSCLC)脑转移放疗后复发/进展的疗效和不良反应. 方法回顾性分析37例NSCLC脑转移放疗后复发/进展患者的临床资料. 全部患者均接受厄洛替尼 150 mg&#8226;d-1口服治疗,8周后评价疗效和不良反应. 结果 携带EGFR基因外显子19/21突变者13例,状态不详者24例. 全部患者颅内转移灶的疾病控制率为56.7%,其中部分缓解5例(13.5%),稳定16例(43.3%);突变组部分缓解、稳定分别为3,8例,状态不详组部分缓解、稳定分别为2,8例. 全部患者全身病变的疾病控制率为40.5%,其中部分缓解3例(8.1%),稳定12例(32.4%);突变组部分缓解、稳定分别为2,7例,状态不详组部分缓解、稳定分别为1,5例. 突变组较状态不详组疗效差异有统计学意义(P<0.05). 不良反应主要表现为Ⅰ或Ⅱ度的乏力24例(64.9%)、皮疹16例(43.2%)与腹泻8例(21.6%),突变组较状态不详组皮疹发生率差异有统计学意义(P<0.05). 结论 厄洛替尼对NSCLC脑转移放疗后复发/进展患者有一定的疗效,对EGFR突变患者疗效更佳,且不良反应较轻,可以作为NSCLC脑转移放疗后复发/进展者的一种治疗选择.     

Antitumor activity of a novel EGFR tyrosine kinase inhibitor against human lung carcinoma in vitro and in vivo

Summary  Treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) has led to dramatic clinical improvement in selected patients with non-small cell lung cancer (NSCLC). However, intrinsic and acquired resistance to EGFR-TKI remains a common phenomenon. Novel EGFR-TKI, structurally different with erlotinib or gefitinib might be beneficial for patients with NSCLC. In this study, we examined the antitumor effect of a newly synthesized novel EGFR tyrosine kinase inhibitor (Zhao260054). In vitro studies in a panel of four different human lung cancer cell lines revealed that Zhao260054 inhibited cell proliferation with high potency and induced G₀/G₁ arrest of cell cycle and apoptosis. Zhao260054 markedly reduced phosphorylation of EGFR and inhibited activation of ERK1/2 and AKT. Oral administration of Zhao260054 (200 mg/kg/day) to BALB/c nude mice bearing SPC-A1 xenografts significantly retarded tumor growth. In conclusion, Zhao260054 has potent antitumor activity on human lung cancer in vitro and in vivo.     

厄洛替尼治疗全脑放疗后复发／进展的非小细胞肺癌脑转移的疗效观察

目的对全脑放疗后复发／进展的非小细胞谛癌脑转移患者应用厄洛替尼治疗的疗效及不良反应进行观察。方法回顾性分析30例全脑放疗后复发／进展的非小细胞肺癌脑转移患者的,隘床资料。全部患者均接受厄洛替尼150mg,日1次口服,2个月后评价疗效和不良反应。结果携带EGFR外显子19／21突变者12例,状态不详者18例。全部患者颅内转移病灶的疾病控制率为56．7％,部分缓解4例（13．3％）,稳定13例（43．3％）,其中突变组部分缓解3例,稳定7例;状态不详组,部分缓解1例,稳定6例。全部患者全身病变的疾病控制率为43.3％,部分缓解3例（10％）,稳定10例（33.3％）,其中突变组部分缓解2例,稳定7例;状态不详组,部分缓解1例,稳定3例。比较两组的有效率、疾病控制率,均有统计学意义（均P〈0．05）。主要不良反应包括乏力20例（66．7％）、皮疹14倒（46．7％）、腹泻6例（20％）等,多为I度或II度。突变组较状态不详组皮疹发生率差异有统计学意义（均P〈0．05）。结论厄洛替尼对于全脑放疗后复发／进展NSCLC脑转移患者治疗有效,对EGFR基因突变者疗效更好,不良反应较轻,耐受性好。     

Comparison of the antitumor activity of gemcitabine and ara-C in a panel of human breast, colon, lung and pancreatic xenograft models

Summary Gemcitabine is a new deoxycytidine analog that exhibits significant cytotoxicity against a variety of cultured murine and human tumor cells. The cytotoxic action of gemcitabine appears to be due to the inhibition of DNA synthesis by inhibition of ribonucleotide reductase and by competition with dCTP for incorporation into DNA. We have previously shown that gemcitabine, but not cytosine arabinoside (ara-C), has a broad spectrum of antitumor activity against 7 different types of murine solid tumors. The activity of gemcitabine was schedule dependent. To further characterize its activity, gemcitabine was tested against 12 human carcinoma xenografts. When given on an every 3 day × 4 schedule, the following percent inhibitions (at maximally tolerated doses [MTD]; MTD/2) in tumor growth were seen: MX-1 mammary (93%; 80%), CX-1 colon (92%; 82%), HC-1 colon (96%; 92%), GC3 colon (98%; 94%), VRC5 colon (99%; 100%), LX-1 lung (76%; 61%), CALU-6 lung (75%; 38%), NCI-H460 lung (45%; 46%), HS766T pancreatic (73%; not tested), PaCa-2 pancreatic (69%; 40%), PANC-1 pancreatic (70%; 60%), and BxPC-3 pancreatic (9%; 19%). In contrast, only the LX-1 lung carcinoma xenograft was responsive to ara-C treatment, which inhibited tumor growth by a marginal 62 percent. Thus, like its activity against murine solid tumors, gemcitabine has excellent antitumor activity against a broad spectrum of human solid tumors.     

替吉奥和吉西他滨分别联合顺铂一线治疗EGFR野生型的晚期非小细胞肺癌的临床观察

目的:比较替吉奥联合顺铂方案和吉西他滨联合顺铂方案一线治疗表皮生长因子受体(EGFR)基因野生型的晚期非小细胞肺癌的疗效和安全性。方法:选取2010年7月-2011年12月收治的68例符合入组标准的EGFR基因野生型的晚期非小细胞肺癌患者,将其随机分为2组,观察组采用替吉奥联合顺铂方案进行一线化疗;对照组采用吉西他滨联合顺铂方案进行一线化疗。比较2组患者的近期疗效、无进展生存期和不良反应。结果:替吉奥联合顺铂组(观察组)和吉西他滨联合顺铂组(对照组)的总有效率分别为41.2%和38.2%,差异无统计学意义(P>0.05);中位无进展生存期分别为5.4个月和5.1个月,差异无统计学意义(P=0.088);不良反应中替吉奥组的血小板降低发生率(11.8%)低于吉西他滨组,差异有统计学意义(P<0.05)。结论:替吉奥联合顺铂方案一线治疗EGFR基因野生型的晚期非小细胞肺癌具有较好疗效,且不良反应较轻。     

Combination with liposome-entrapped, ends-modified raf antisense oligonucleotide (LErafAON) improves the anti-tumor efficacies of cisplatin, epirubicin, mitoxantrone, docetaxel and gemcitabine

Raf-1 protein serine/threonine kinase plays an important role in cell proliferation and cell survival. We have previously described a novel cationic liposome-entrapped formulation of raf antisense oligodeoxyribonucleotide (LErafAON) and its use as a radiosensitizer. The aim of this study was to examine the effect of combination of LErafAON and a chemotherapeutic agent on growth of human prostate (PC-3) and pancreatic tumor xenografts in athymic mice (Aspc-1 and Colo 357). In PC-3 tumor-bearing mice, administration of a combination of LErafAON (i.v., 25 mg/kg/dose, x10/16) and cisplatin (i.v., 11.0 mg/kg/dose, x3), epirubicin (EPI) (i.v., 9.0 mg/kg/dose, x3) or mitoxantrone (MTO) (i.v., 2.5 mg/kg/dose, x3) led to enhanced tumor growth inhibition as compared with single agents (LErafAON+cisplatin versus cisplatin, p<0.0002, n=8; LErafAON+EPI versus EPI, p<0.0001, n=6; LErafAON+MTO versus MTO, p<0.05, n=5). In prostate or pancreatic tumor-bearing mice, combination of LErafAON (i.v., 25 mg/kg/dose, x10/13) with docetaxel (Taxotere) (i.v., 5, 7.5 or 10 mg/kg/dose, x2/4) led to tumor regression or enhanced growth inhibition as compared with single agents (PC-3: LErafAON+Taxotere versus Taxotere, p<0.02, n=7; Aspc-1: LErafAON+Taxotere versus Taxotere, p<0.03, n=5; Colo 357: LErafAON+Taxotere versus Taxotere, p<0.04, n=7). Combination of LErafAON (i.v., 25 mg/kg/dose, x10/13) with gemcitabine (i.v., 75 mg/kg/dose, x4/6) also caused a significant tumor growth inhibition in the two pancreatic carcinoma models studied (Aspc-1: LErafAON+gemcitabine versus gemcitabine, p<0.0001, n=7; Colo 357: LErafAON+gemcitabine versus gemcitabine, p<0.002, n =5). LErafAON treatment (i.v., 25 mg/kg/dose, x10) caused inhibition of Raf-1 protein expression in these tumor tissues (around 25-60%, n=4-7). Interestingly, Taxotere treatment per se also led to decreased steady state level of Raf-1 protein in PC-3 and Aspc-1 tumor tissues (i.v., 10 mg/kg/dose, x1 or 7.5 mg/kg/dose, x2; around 25-80%, n=2/6). Present studies demonstrate enhanced tumor growth inhibition or regression in response to a combination of a chemotherapeutic drug and LErafAON. These data provide a proof-of-principle for the clinical use of LErafAON in combination with chemotherapy for cancer treatment.     

Role of erlotinib in the treatment of non-small cell lung cancer: clinical outcomes in wild-type epidermal growth factor receptor patients

Erlotinib is an orally administered small molecule inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase. Erlotinib at the standard oral daily dose of 150 mg is approved for the treatment of unselected chemorefractory advanced non-small cell lung cancer patients as well as maintenance therapy after first-line chemotherapy. The European Medicines Agency has recently also approved erlotinib as the first-line therapy in patients with EGFR mutations. Although recent studies have identified higher response rates and improved survival with erlotinib in a subset of patients with EGFR mutations, the survival benefit from single agent erlotinib in chemorefractory patients and in the maintenance setting is well observed in EGFR wild-type patients. The role of single agent erlotinib in the first-line setting in special subsets of EGFR wild-type patients (elderly, poor performance status, non-smokers) needs to be further determined. The combination of erlotinib with other targeted therapies has shown promising results and warrants further studies in EGFR wild-type patients.