Epidermal Growth Factor Receptor Inhibitors for Lung Cancer and the Risk of Keratitis

Importance

Epidermal growth factor receptor inhibitors (EGFRis) have been reported to be associated with cutaneous and ocular side effects; however, there is limited evidence of an association between EGFRi treatment and keratitis.

Objective

To determine the association between EGFRi treatment and agents and the risk of new-onset keratitis among patients with lung cancer.

Design, Setting, and Participants

This US population-based cohort study examined TriNetX data of patients with lung cancer treated with or without EGFRis between May 1, 2003, and October 30, 2023.

Exposures

Treatment with EGFRis, including the first-generation agents gefitinib and erlotinib, the second-generation agent afatinib, and the third-generation agent osimertinib.

Main Outcomes and Measures

The risk of new-onset keratitis among patients with lung cancer receiving EGFRi treatment was determined using logistic and Cox proportional hazards regression.

Results

Among 1 388 108 patients with lung cancer, 22 225 received EGFRis (mean [SD] age, 69.7 [10.6] years; 62.8% females and 37.2% males). Patients treated with EGFRis had a higher risk of keratitis than nonexposed patients (hazard ratio [HR], 1.520; 95% CI, 1.339-1.725). Subtypes of EGFRi-associated keratitis included keratoconjunctivitis (HR, 1.367; 95% CI, 1.158-1.615), superficial keratitis (HR, 1.635; 95% CI, 1.306-2.047), and corneal ulcer (HR, 2.132; 95% CI, 1.515-3.002). Patients taking afatinib had a higher risk of keratitis (HR, 2.229; 95% CI, 1.480-3.356).

Conclusions and Relevance

These findings suggest that patients with lung cancer treated with EGFRis may have an increased risk of new-onset keratitis, especially with the second-generation EGFRi afatinib, supporting the need for prompt diagnosis and management of EGFRi-associated ocular issues to prevent serious complications or treatment disruptions.

Recent Development in the Search for Epidermal Growth Factor Receptor (EGFR) Inhibitors based on the Indole Pharmacophore

The signal transduction and cell proliferation are regulated by the epidermal growth factor receptor. The proliferation of tumor cells, apoptosis, invasion, and angiogenesis is inhibited by the epidermal growth factor receptor. Thus, breast cancer, non-small cell lung cancer, cervical cancer, glioma, and bladder cancer can be treated by targeting the epidermal growth factor receptor. Although third-generation epidermal growth factor receptor inhibitors are potent drugs, patients exhibit drug resistance after treatment. Thus, the search for new drugs is being continued. Among the different potent epidermal growth factor receptor inhibitors, we have reviewed the indole-based inhibitors. We have discussed the structure-activity relationship of the compounds with the active sites of the epidermal growth factor receptor receptors, their synthesis, and molecular docking studies.

Structure-Activity Relationship Studies Based on Quinazoline Derivatives as EGFR Kinase Inhibitors (2017-Present)

The epidermal growth factor receptor (EGFR) plays a critical role in the tumorigenesis of various forms of cancer. Targeting the mutant forms of EGFR has been identified as an attractive therapeutic approach and led to the approval of three generations of inhibitors. The quinazoline core has emerged as a favorable scaffold for the development of novel EGFR inhibitors due to increased affinity for the active site of EGFR kinase. Currently, there are five first-generation (gefitinib, erlotinib, lapatinib, vandetanib, and icotinib) and two second-generation (afatinib and dacomitinib) quinazoline-based EGFR inhibitors approved for the treatment of various types of cancers. The aim of this review is to outline the structural modulations favorable for the inhibitory activity toward both common mutant (del19 and L858R) and resistance-conferring mutant (T790M and C797S) EGFR forms, and provide an overview of the newly synthesized quinazoline derivatives as potentially competitive, covalent or allosteric inhibitors of EGFR.

Untargeted Lipidomics of Non-Small Cell Lung Carcinoma Demonstrates Differentially Abundant Lipid Classes in Cancer vs. Non-Cancer Tissue

Lung cancer remains the leading cause of cancer death worldwide and non-small cell lung carcinoma (NSCLC) represents 85% of newly diagnosed lung cancers. In this study, we utilized our untargeted assignment tool Small Molecule Isotope Resolved Formula Enumerator (SMIRFE) and ultra-high-resolution Fourier transform mass spectrometry to examine lipid profile differences between paired cancerous and non-cancerous lung tissue samples from 86 patients with suspected stage I or IIA primary NSCLC. Correlation and co-occurrence analysis revealed significant lipid profile differences between cancer and non-cancer samples. Further analysis of machine-learned lipid categories for the differentially abundant molecular formulas identified a high abundance sterol, high abundance and high m/z sphingolipid, and low abundance glycerophospholipid metabolic phenotype across the NSCLC samples. At the class level, higher abundances of sterol esters and lower abundances of cardiolipins were observed suggesting altered stearoyl-CoA desaturase 1 (SCD1) or acetyl-CoA acetyltransferase (ACAT1) activity and altered human cardiolipin synthase 1 or lysocardiolipin acyltransferase activity respectively, the latter of which is known to confer apoptotic resistance. The presence of a shared metabolic phenotype across a variety of genetically distinct NSCLC subtypes suggests that this phenotype is necessary for NSCLC development and may result from multiple distinct genetic lesions. Thus, targeting the shared affected pathways may be beneficial for a variety of genetically distinct NSCLC subtypes.

Second-line Chemotherapy in the Treatment of Advanced Non-Small Cell Lung Cancer (NSCLC)

An increasing number of patients with advanced non-small cell lung cancer (NSCLC) progressing after front-line chemotherapy are still in good performance status and willing to receive further treatment. Several drugs have been tested in this setting of treatment, but the only agent registered world-wide for second-line chemotherapy of advanced NSCLC is docetaxel. This drug, at dose of 75 mg/m2 every three weeks, has been the standard of care as second-line chemotherapy since 2000, based on two trials that reported improved survival times and quality of life when comparing with best supportive care (TAX 317) and with ifosfamide or vinorelbine (TAX 320). Docetaxel, given at this dose and schedule, resulted in significant haematological toxicity, with many patients at risk for neutropenic fever. Pemetrexed is a novel multitargeted antifolate agent with single-agent activity in first- and second-line treatment of NSCLC. In a phase III study in 571 patients pemetrexed, comparing with docetaxel in second-line chemotherapy, demonstrated clinically equivalent therapeutic outcomes, but a more favourable haematological toxicity profile, with fewer episodes of neutropenia, neutropenic fever, and infections and less use of granulocyte colony-stimulating factor support. Others several agents have been evaluated for the second-line treatment of patients with non-small cell lung cancer, but no comparative phase III studies with docetaxel has been carried out. The epidermal growth factor receptor-tyrosine kinase inhibitors gefitinib (ZD1839, Iressa) and erlotinib (OSI 774, Tarceva) have been evaluated in the second- and third-line setting. Both drugs have demonstrated interesting response rates and toxicity profile and, in particular, erlotinib evidenced a survival advantage of 2 months respect placebo in recent phase III trial. Future developments are likely to value poli-chemotherapy or combination chemotherapy with EGFR tyrosine kinase inhibitors in second-line treatment of advanced NSCLC.

Mechanisms of acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors gefitinib and erlotinib are effective therapies for non-small cell lung cancer patients whose tumors harbor somatic mutations in EGFR. All patients, however, ultimately develop resistance to these agents. Thus, there is a great need to understand how patients become resistant to develop effective therapies for these cancers. Studies over the last few years have identified two different EGFR tyrosine kinase inhibitor resistance mechanisms, a secondary mutation in EGFR, EGFR 790M, and amplification of the MET oncogene. These findings have led to clinical trials using newly designed targeted therapies that can overcome these resistance mechanisms and have shown promise in laboratory studies. Ongoing research efforts will likely continue to identify additional resistance mechanisms, and these findings will hopefully translate into effective therapies for non-small cell lung cancer patients.

Role of erlotinib in the management of pancreatic cancer

Pancreatic cancer is a largely chemo-resistant disease with a poor prognosis. Despite the adoption of gemcitabine monotherapy as a standard of care, outcomes remain poor. Until recently randomized phase III studies have not demonstrated superiority of various cytotoxic combinations or a number of the newer biologic targeted drugs. The situation has changed with capecitabine and erlotinib, either of which in combination with gemcitabine produces a small increase in survival. Erlotinib is a small molecule tyrosine kinase inhibitor against epidermal growth factor receptor which has an important role in the molecular pathogenesis of pancreatic cancer. In both pre-clinical and early clinical evaluation it has shown anti-tumor activity against pancreatic cancer in combination with gemcitabine. A randomized phase III study in locally advanced and metastatic pancreatic cancer has shown a survival advantage for the combination of gemcitabine plus erlotinib over gemcitabine alone. The rationale for the clinical development of erlotinib in combination with gemcitabine in pancreatic cancer culminating in this randomized trial, together with pharmacologic, toxicity and patient selection considerations form the focus of this review.

Effects of smoking on the pharmacokinetics of erlotinib

PURPOSE

To compare the pharmacokinetic variables of erlotinib in current smokers with nonsmokers after receiving a single oral 150 or 300 mg dose of erlotinib.

EXPERIMENTAL DESIGN

This was a single-center, open-label pharmacokinetic study in healthy male subjects. Subjects were enrolled into two treatment cohorts based on smoking status (current smokers and nonsmokers). The pharmacokinetic profile for erlotinib and its metabolite, OSI-420, was determined for each subject following each treatment.

RESULTS

Current smokers achieved significantly less erlotinib exposure following a single 150 or 300 mg dose than nonsmokers. Following the 150 mg dose, the geometric mean erlotinib AUC(0-infinity) in smokers was 2.8-fold lower than in nonsmokers and similar to that of nonsmokers at the 300 mg dose. C(max) in smokers was two-thirds of that in nonsmokers, and C(24h) in smokers was 8.3-fold lower than in nonsmokers. The median C(24h) of smokers at the 300 mg dose was slightly less than the C(24h) of smokers at the 150 mg dose. The median C(max) was greater in smokers at the 300 mg dose than in nonsmokers at the 150 mg dose.

CONCLUSION

This study confirms that the pharmacokinetics of erlotinib is different in current smokers and nonsmokers. The observation that AUC(0-infinity) and C(24h) were significantly decreased in smokers compared with nonsmokers, and a smaller decrease in C(max) was observed, is consistent with increased metabolic clearance of erlotinib in current smokers.

Different Responses to Gefitinib in Lung Adenocarcinoma Coexpressing Mutant- and Wild-Type Epidermal Growth Factor Receptor Genes

Response to gefitinib is strongly associated with the status of the epidermal growth factor receptor gene. Here we report the different treatment responses in a case of lung adenocarcinoma coexpressing mutant-type gene in the primary lung mass and a wild-type gene in the metastatic bone lesions. This case demonstrated that at least two strains of tumor cells were present in a single patient. This may be one of the mechanisms of gefitinib resistance.

Novel kinase inhibitors in renal cell carcinoma: progressive development of static agents

The rapidly expanding knowledge regarding neoplastic diseases is providing a plethora of new targets for drug discovery and development as exemplified by recent data in renal cell carcinoma. The initial experience with molecularly "targeted" agents has demonstrated that development of the newer non-cytotoxic agents will provide unique challenges requiring modification of many traditional drug development concepts and methods. We discuss recently reported data from a few renal cell carcinoma trials with putative cytostatic agents and highlight issues that need to be addressed for efficient development of cytostatic agents during various phases of clinical development.

Targeting growth factors and angiogenesis; using small molecules in malignancy

Targeted biologic therapy for cancer has evolved from the laboratory to active clinical protocols and applied clinical practice in selected patients. Major targets include epidermal growth factor, and vascular endothelial growth factor receptors which are commonly expressed in gastro-intestinal cancers head & neck and lung cancers, and to some degree breast and gynecologic malignancy. Down stream signal transduction pathway inhibition of B-raf and N-ras mutations are examined in melanoma. New approaches involving re-packaging of chemotherapeutic agents are being exemplified in the nanoparticle formulation of paclitaxel which provides increased access to endothelial and tumor cells with potential enhanced therapeutic efficacy compared to the conventional version solubilized in a cremophor.

EGFR tyrosine kinase inhibitors decrease VEGF expression by both hypoxia-inducible factor (HIF)-1-independent and HIF-1-dependent mechanisms

Epidermal growth factor receptor (EGFR) inhibitors can decrease vascular endothelial growth factor (VEGF) expression and tumor angiogenesis. In the current study, we investigate the molecular pathways by which this occurs using two drugs that have been used in the clinic, gefitinib (Iressa) and erlotinib (Tarceva). The decrease in VEGF expression by gefitinib in SQ20B squamous cell carcinoma cells was opposed by adenoviral expression of Akt in these cells. The hypoxia-inducible factor-1 (HIF-1) binding site located at approximately -1 kbp in the VEGF promoter was not required for down-regulation of promoter activity by gefitinib under normoxia. Furthermore, the drug decreased activity of a reporter containing the -88/+54 region. In a gel shift assay, gefitinib led to decreased retardation of a labeled DNA oligonucleotide probe corresponding to the -88/-66 region of the VEGF promoter, which contains Sp1 binding sites. These effects of gefitinib on VEGF promoter activity and DNA binding were both reversed by Akt expression. Phosphorylation of Sp1 was decreased in the presence of gefitinib. Gefitinib also decreases VEGF expression by decreasing HIF-1alpha expression. This occurs due to decreased protein translation without any change in the level of HIF-1alpha mRNA. Together, these results suggest that gefitinib decreases VEGF expression both by decreasing Sp1 binding to the proximal core VEGF promoter and by down-regulating HIF-1alpha expression. Similar results were obtained with erlotinib in SQ20B and gefitinib in HSC3 squamous carcinoma cells. These results indicate that there are at least two separate mechanisms by which EGFR inhibitors decrease VEGF expression.

Randomized phase II trial of different schedules of administration of rebeccamycin analogue as second line therapy in non-small cell lung cancer

Rebeccamcyin analogue (RA) is an antitumor antibiotic that results in DNA intercalation and topoisomerase I and II inhibition. Phase I trials of the daily x 5 schedule and once every 3 week schedule have been completed. Antitumor activity was observed during the phase I trials. The purpose of this study is to primarily determine the response rate of 2 different schedules of administration of RA in patients with advanced non-small cell lung cancer (NSCLC) who had progressed on one prior chemotherapy regimen. Secondary endpoints were median and 1-year survival rates. A two-stage Simon design was employed for both arms of the study. Patients were randomly assigned to either of two RA treatment schedules of 500 mg/m(2) as a 1 hr infusion repeated every 3 weeks (Arm A) or 140 mg/m(2)/day x 5 days repeated every 3 weeks (Arm B). Forty-two patients were randomized. No confirmed objective responses were seen. Stable disease was seen in 52% of patients on arm A and 37% on arm B. Median survival and 1 year survival rates were 5.6 months and 33.3% for arm A, 9.7 months and 42.1% for arm B respectively. Cox regression model demonstrated increased risk of death in patients younger than the age of 61 and for patients treated on arm A. RA failed to demonstrate a significant response rate in this disease setting, although the proportion of patients with stable disease and 1-year survival were encouraging and similar to other published studies of approved single agents for second-line therapy of NSCLC.

Targeted therapies for esophageal cancer

Esophageal cancer is a highly aggressive neoplasm. In 2005, 14,520 Americans will be diagnosed with esophageal cancer, and more than 90% will die of their disease. On a global basis, cancer of the esophagus is the sixth leading cause of cancer death worldwide. In fact, gastric and esophageal cancers together accounted for nearly 1.3 million new cases and 980,000 deaths worldwide in 2000-more than lung, breast, or colorectal cancer. Although esophageal squamous cell carcinoma cases have steadily declined, the incidence of gastroesophageal junction adenocarcinoma has increased 4%-10% per year among U.S. men since 1976, more rapidly than for any other cancer type, and parallels rises in population trends in obesity and reflux disease. With advances in surgical techniques and treatment, the prognosis of esophageal cancer has slowly improved over the past three decades. However, the 5-year overall survival rate (14%) remains poor, even in comparison with the dismal survival rates (4%) from the 1970s. The underlying reasons for this disappointingly low survival rate are multifold: (a) ineffective screening tools and guidelines; (b) cancer detection at an advanced stage, with over 50% of patients with unresectable disease or distant metastasis at presentation; (c) high risk for recurrent disease after esophagectomy or definitive chemoradiotherapy; (d) unreliable noninvasive tools to measure complete response to chemoradiotherapy; and (e) limited survival achieved with palliative chemotherapy alone for patients with metastatic or unresectable disease. Clearly, additional strategies are needed to detect esophageal cancer earlier and to improve our systemic treatment options. Over the past decade, the field of drug development has been transformed with the identification of and ability to direct treatment at specific molecular targets. This review focuses on novel targeted treatments in development for esophageal squamous cell carcinoma and distal esophageal and gastroesophageal junction adenocarcinoma.

Phase I and pharmacologic study of PKI166, an epidermal growth factor receptor tyrosine kinase inhibitor, in patients with advanced solid malignancies

PURPOSE

This phase I study was conducted to assess the tolerability, pharmacokinetics, and antitumor activity of the oral, selective epidermal growth factor receptor tyrosine kinase inhibitor PKI166 in patients with advanced solid malignancies.

EXPERIMENTAL DESIGN

PKI166 was first given once daily continuously and in the second part of the study once daily for 2 weeks every 4 weeks to establish the maximum tolerated dose (MTD). Ten additional patients were studied at MTD to acquire additional safety information and characterize the effect of food intake on PKI166 pharmacokinetics. Pharmacokinetics of PKI166 were characterized after single and multiple doses at all dose levels.

RESULTS

Fifty-four patients received a total of one hundred sixteen 28-day cycles of PKI166. Dose-limiting transaminase elevations were observed in two of seven and two of eight patients using 50 and 100 mg PKI166 continuously. In the second part with PKI166 once daily for 2 weeks every 4 weeks, MTD was set at 750 mg. Dose-limiting toxicity consisted of diarrhea, skin rash, and transaminase elevations. Pharmacokinetic analysis revealed fast absorption, a linear dose-response relationship without drug accumulation after multiple doses. At MTD, no significant influence of food intake on PKI166 pharmacokinetics was observed. Stable disease for more than two cycles was observed in 11 patients.

CONCLUSIONS

PKI166 given once daily for 2 weeks every 4 weeks is well tolerated with linear pharmacokinetics, compatible with once daily dosing, and without significant effect of food intake on absorption. The recommended dose for further studies is 750 mg once daily for 2 weeks every 4 weeks.

Epithelial versus mesenchymal phenotype determines in vitro sensitivity and predicts clinical activity of erlotinib in lung cancer patients

Significant improvements in the outcome of non-small cell lung carcinoma (NSCLC) have been reported in patients treated with the epidermal growth factor receptor (EGFR) inhibitor, erlotinib. To discover biomarkers for the enrichment of patients who might benefit from treatment, a pharmacogenomic approach was used to identify gene signatures that may predict erlotinib activity using in vitro model systems. Erlotinib sensitivity in a panel of 42 NSCLC cell lines was determined by EGFR-mediated proliferative potential, EGFR mutations, and/or EGFR gene amplification, thus supporting an underlying biological mechanism of receptor activation. A strong multigene signature indicative of an epithelial to mesenchymal transition (EMT) was identified as a determinant of insensitivity to erlotinib through both supervised and unsupervised gene expression approaches. This observation was further supported by expression analysis of classic EMT marker proteins, including E-cadherin and vimentin. To investigate the clinical relevance of these findings, we examined expression of the epithelial marker E-cadherin by immunohistochemistry on primary tumor samples from subjects enrolled in a randomized NSCLC clinical trial in which erlotinib in combination with chemotherapy previously failed to show clinical activity. The majority (75%) of the 87 subjects tested showed strong E-cadherin staining and exhibited a significantly longer time to progression (hazard ratio, 0.37; log rank P=0.0028) and a nonsignificant trend toward longer survival with erlotinib plus chemotherapy treatment versus chemotherapy alone. These data support a potential role for EMT as a determinant of EGFR activity in NSCLC tumor cells and E-cadherin expression as a novel biomarker predicting clinical activity of the EGFR inhibitor erlotinib in NSCLC patients.

Approval summary for erlotinib for treatment of patients with locally advanced or metastatic non-small cell lung cancer after failure of at least one prior chemotherapy regimen

PURPOSE

To describe the Food and Drug Administration (FDA) review and approval of erlotinib (Tarceva, OSI Pharmaceuticals, Melville, NY) for treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) after failure of at least one prior chemotherapy regimen.

EXPERIMENTAL DESIGN

The FDA reviewed raw data in electronic format from a randomized controlled clinical trial comparing erlotinib with placebo in patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen.

RESULTS

Patients were randomized in a 2:1 ratio (erlotinib, n = 488 and placebo, n = 243). Erlotinib was superior to placebo for survival, progression-free survival, and tumor response rate. Exploratory analyses indicate that epidermal growth factor receptor status may be an important predictor of the erlotinib survival effect. Rash (75% versus 17%) and diarrhea (54% versus 18%) in the erlotnib and placebo group respectively were the most common adverse events. Severe rash occurred in 9% and severe diarrhea in 6% of erlotinib-treated patients and each resulted in study discontinuation in 1% of patients. Dose reductions were required for 10% of patients with rash and 4% of patients with diarrhea.

CONCLUSIONS

On November 18, 2004, the FDA granted erlotinib regular approval for treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen. The applicant has committed to conduct post-marketing clinical trials to assess further the effect of epidermal growth factor receptor expression, measured with immunohistochemical staining, on erlotinib treatment effect.

Blockade of epidermal growth factor receptor (EGFR) activity

The rapidly expanding knowledge of the pathogenesis of cancer at the molecular level is providing new targets for drug discovery and development. The key role that EGFR plays in the intracellular transduction of environmental variations and the maintenance of cellular homeostasis explains the dependence that many tumor types have on this pathway, and the pivotal role that it plays in the development of malignant features such as uncontrolled proliferation, augmented invasion, and the ability to escape apoptosis. An enormous body of knowledge has been gathered in the past 20 years that has enabled the development of rationally designed EGFR-targeted therapies, and the results of their clinical evaluation are now becoming available. The lack of positive results of some of these trials has highlighted the need for a robust preclinical knowledge in order to efficiently select patients for therapy, and have prompted the implementation of novel trial designs with rational endpoints.

Increased HER2 gene copy number is associated with response to gefitinib therapy in epidermal growth factor receptor-positive non-small-cell lung cancer patients

PURPOSE

In non-small-cell lung cancer (NSCLC), response to tyrosine kinase inhibitors (TKIs) is significantly associated with the presence of increased copy number and/or activating mutations of the epidermal growth factor receptor gene (EGFR). Preclinical data indicate that HER2, a member of the EGFR family, could enhance TKI sensitivity.

PATIENTS AND METHODS

HER2 gene copy numbers per cell were evaluated by fluorescent in situ hybridization (FISH) in 102 NSCLC patients treated with gefitinib, and previously evaluated for EGFR status by FISH, immunohistochemistry, and presence of mutations.

RESULTS

Patients with HER2 high copy number (high polysomy and gene amplification [HER2 FISH positive]) represented 22.8% of patients, and compared with patients with no or low gain (HER2 FISH negative), had significantly better objective response (OR, 34.8% v 6.4%; P = .001), disease control rate (DCR, 56.5% v 33.3%; P = .04), time to progression (TTP, 9.05 v 2.7 months; P = .02), and a trend toward longer overall survival (OS, 20.8 v 8.4 months; P = .056). HER2 protein expression investigated by immunohistochemistry was positive in only five of 72 (7%) patients analyzed and all 89 patients tested by DNA sequencing were negative for mutations in HER2 exon 20. Patients with HER2 FISH-positive tumors displaying increased expression of EGFR protein, gene gain, or mutations (EGFR positive) had a significantly better OR, DCR, TTP, and OS than patients negative for both receptors.

CONCLUSION

Increased copy number of the HER2 gene is associated with gefitinib sensitivity in EGFR-positive patients, supporting use of HER2 FISH analysis for selection of patients for TKI therapy.

HER1/EGFR inhibitor-associated rash: future directions for management and investigation outcomes from the HER1/EGFR inhibitor rash management forum

Skin rash associated with HER1/epidermal growth factor receptor (EGFR) inhibitors is common. The lack of clinical and patient guidance for this often chronic and sometimes distressing side effect makes rash management and etiology investigation high priorities. To address this, oncologists and dermatologists with experience with HER1/EGFR inhibitors attended the HER1/EGFR Inhibitor Rash Management Forum. Recommendations include continued analysis of the correlation between rash and clinical outcome and improving the accuracy and reproducibility of terminology and grading systems. Because acne vulgaris has a unique pathology, and the pathology and etiology of rash are unclear yet distinct from acne vulgaris, using such terms as acne, acne-like, or acneiform should be avoided. Until there is a specific dermatological definition, rash is best described using phenotypic terms for its appearance and location. It is currently unknown which agents are best for treating rash. Clinical trials of rash treatments are urgently required, and suggestions for agents to consider are made based on current knowledge. The effect of dose reduction or interruption on rash should also be investigated. Secondarily infected rash may be more frequent than has been previously recognized, and some investigators favor empiric use of an oral antibiotic if this appears to be the case. Suggestions for patients include makeup to camouflage the rash and an emollient to prevent and alleviate skin dryness. The increasing use of HER1/EGFR-targeted agents makes managing rash important. We hope the outcomes from this Forum provide background for future studies.

Combination Treatment with Erlotinib and Pertuzumab against Human Tumor Xenografts Is Superior to Monotherapy

In many solid tumors, overexpression of human epidermal growth factor receptors (e.g., HER1/EGFR and HER2) correlates with poor prognosis. Erlotinib (Tarceva) is a potent HER1/EGFR tyrosine kinase inhibitor. Pertuzumab (Omnitarg), a novel HER2-specific, recombinant, humanized monoclonal antibody, prevents heterodimerization of HER2 with other HERs. Both mechanisms disrupt signaling pathways, resulting in tumor growth inhibition. We evaluated whether inhibition of both mechanisms is superior to monotherapy in tumor cell lines expressing different HER levels. Human non-small cell lung cancer (NSCLC) cells (Calu-3: HER1/EGFR 0+, HER2 3+; QG56: HER1/EGFR 2-3+, HER2 0+) and breast cancer cells (KPL-4: HER1/EGFR 2-3+, HER2 3+) were implanted into BALB/c nu/nu mice and severe combined immunodeficient beige mice, respectively. Tumor-bearing mice (n = 12 or 15 per group) were treated with vehicle (Captisol or buffer), erlotinib (orally, 50 mg/kg/d), pertuzumab (i.p. 6 mg/kg/wk with a 2-fold loading dose), or erlotinib and pertuzumab for 20 (QG56), 27 (KPL-4), or 49 (Calu-3) days. Drug monotherapy had antitumor activity in all models. Tumor volume treatment-to-control ratios (TCR) with erlotinib were 0.36 (Calu-3), 0.79 (QG56), and 0.51 (KPL-4). Pertuzumab TCR values were 0.42, 0.51, and 0.64 in Calu-3, QG56, and KPL-4 models, respectively. Combination treatment resulted in additive (QG56: TCR 0.39; KPL-4: TCR 0.38) or greater than additive (Calu-3: TCR 0.12) antitumor activity. Serum tumor markers for NSCLC (Cyfra 21.1) and breast cancer (soluble HER2) were markedly inhibited by combination treatment (80-97% in Calu-3 and QG56; 92% in KPL-4), correlating with decreased tumor volume. Overall, erlotinib and pertuzumab are active against various human xenograft models, independently of HER1/EGFR or HER2 expression. A combination of these HER-targeted agents resulted in additive or greater than additive antitumor activity.

Study Design Issues and Early Stage Non-Small Cell Lung Cancer

The most common type of clinical trial in oncology enrolls patients with advanced disease. End points for phase II trials in advanced disease typically include response rate or time to progression, based upon the presumption that these may serve as surrogates for the ultimate end point of improved survival. Unique problems arise with the design of adjuvant trials, for which response rates clearly are not appropriate end points. In addition, survival is much longer, making rapid completion of phase III trials difficult. For lung cancer, the proportion of patients with stage I and II disease is much lower than with other types of cancer, and the absolute number of these patients is relatively low. To conduct large adjuvant trials in lung cancer more efficiently, we need to optimize our trials as much as possible. "Targeted therapies," by definition, inhibit a specific target, thus offering the theoretical advantage of enriching the patient population by restricting enrollment to patients whose tumor expresses the target of interest. Education of health care professionals regarding the benefits of adjuvant therapies, to decrease a sense of nihilism and to increase referrals, and international collaborations may also be necessary to increase accrual.

The Role of Targeted Agents in Adjuvant Therapy for Non-Small Cell Lung Cancer

The recent survival benefit of adjuvant chemotherapy in early stage non-small cell lung cancer provides optimism for the future success of targeted therapy in this setting. It is important that we begin to explore molecularly targeted agents in the adjuvant arena, but how best to accomplish this in the face of these new findings presents a challenge. Criteria for selecting promising targeted therapies and optimal trial designs to evaluate them expeditiously in the adjuvant setting are clearly needed.

Epidermal growth factor receptor gene and protein and gefitinib sensitivity in non-small-cell lung cancer

BACKGROUND

Gefitinib is a selective inhibitor of the epidermal growth factor (EGFR) tyrosine kinase, which is overexpressed in many cancers, including non-small-cell lung cancer (NSCLC). We carried out a clinical study to compare the relationship between EGFR gene copy number, EGFR protein expression, EGFR mutations, and Akt activation status as predictive markers for gefitinib therapy in advanced NSCLC.

METHODS

Tumors from 102 NSCLC patients treated daily with 250 mg of gefitinib were evaluated for EGFR status by fluorescence in situ hybridization (FISH), DNA sequencing, and immunohistochemistry and for Akt activation status (phospho-Akt [P-Akt]) by immunohistochemistry. Time to progression, overall survival, and 95% confidence intervals (CIs) were calculated and evaluated by the Kaplan-Meier method; groups were compared using the log-rank test. Risk factors associated with survival were evaluated using Cox proportional hazards regression modeling and multivariable analysis. All statistical tests were two-sided.

RESULTS

Amplification or high polysomy of the EGFR gene (seen in 33 of 102 patients) and high protein expression (seen in 58 of 98 patients) were statistically significantly associated with better response (36% versus 3%, mean difference = 34%, 95% CI = 16.6 to 50.3; P<.001), disease control rate (67% versus 26%, mean difference = 40.6%, 95% CI = 21.5 to 59.7; P<.001), time to progression (9.0 versus 2.5 months, mean difference = 6.5 months, 95% CI = 2.8 to 10.3; P<.001), and survival (18.7 versus 7.0 months, mean difference = 11.7 months, 95% CI = 2.1 to 21.4; P = .03). EGFR mutations (seen in 15 of 89 patients) were also statistically significantly related to response and time to progression, but the association with survival was not statistically significant, and 40% of the patients with mutation had progressive disease. In multivariable analysis, only high EGFR gene copy number remained statistically significantly associated with better survival (hazard ratio = 0.44, 95% CI = 0.23 to 0.82). Independent of EGFR assessment method, EGFR+/P-Akt+ patients had a statistically significantly better outcome than EGFR-, P-Akt-, or EGFR+/P-Akt- patients.

CONCLUSIONS

High EGFR gene copy number identified by FISH may be an effective molecular predictor for gefitinib efficacy in advanced NSCLC.

Epidermal Growth Factor Receptor Mutations in Non–Small-Cell Lung Cancer: Implications for Treatment and Tumor Biology

The epidermal growth factor receptor (EGFR) has emerged as an attractive therapeutic target for patients with non–small-cell lung cancer (NSCLC). However, despite its almost universal presence in NSCLC tumors, therapeutic inhibition of EGFR has resulted in significant tumor regressions in only 10% to 20% of patients. Several investigations over the last 12 months have uncovered somatic mutations in EGFR that underlie the sensitivity to EGFR inhibitors. NSCLC tumors and cell lines with EGFR mutations are exquisitely sensitive to the EGFR tyrosine kinase inhibitors (TKIs), erlotinib and gefitinib, and are biologically distinct from other forms of NSCLC. Somatic mutations in EGFR are found more frequently in patients with adenocarcinomas, nonsmokers, patients of Asian ethnicity, and in females. EGFR mutation detection is now becoming clinically available and is being incorporated into clinical treatment decisions and into the design of future clinical trials. Mutations in K-ras, a mediator of EGFR signaling, are mutually exclusive with EGFR mutations, and are associated with resistance to EGFR TKIs. In addition, secondary mutations, conferring resistance to EGFR TKIs, in patients with primary EGFR mutations once sensitive to EGFR TKIs, are beginning to be identified. The frequency of EGFR mutations, their impact on NSCLC biology, clinical treatment, and clinical trial design, as well as methods and limitations for mutation detection, will be reviewed.

Treatment of Advanced Non–Small-Cell Lung Cancer in the Elderly: Results of an International Expert Panel

The best treatment for elderly patients with advanced non–small-cell lung cancer (NSCLC) is still debated. To guide clinical management of these patients and suggest the priorities for clinical research in this field, an International Expert Panel met in Naples, Italy, on April 19 to 20, 2004. Results and conclusions based on a review of evidence available in the literature to date are presented in this article. A comprehensive geriatric assessment is recommended to better define prognosis and to predict tolerance to treatment. In the first randomized study dedicated to elderly NSCLC patients, single-agent vinorelbine showed superiority over supportive care alone, both in terms of survival and quality of life. In a large randomized trial, gemcitabine plus vinorelbine failed to show any advantage over either agent alone. Subset analyses suggest that the efficacy of platinum-based combination chemotherapy is similar in fit older and younger patients, with an acceptable increase in toxicity for elderly patients. These data should be interpreted cautiously because retrospective subgroup analyses are encumbered by selection bias; hence, randomized trials dedicated to platinum-based chemotherapy for nonselected elderly patients are warranted. Several promising biologic therapies are under investigation; however, with present data, target-based agents as first-line treatment for elderly NSCLC patients are not yet recommended. Clinical research, with trials specifically designed for elderly patients, is mandatory. With the current evidence, single-agent chemotherapy with a third-generation drug (vinorelbine, gemcitabine, a taxane) should be the recommended option for nonselected elderly patients with advanced NSCLC. Platinum-based chemotherapy is a viable option for fit patients with adequate organ function. Best supportive care remains important, in addition to chemotherapy or as the exclusive option for patients who are unsuitable for more aggressive treatment.

Gefitinib as a First-Line Therapy of Advanced or Metastatic Adenocarcinoma of the Lung in Never-Smokers

PURPOSE

A subset of patients with adenocarcinoma of the lung who had never smoked cigarettes showed excellent tumor responses to gefitinib therapy. To evaluate the efficacy of gefitinib as a first-line therapy in this subgroup of patients, we conducted a phase II study.

EXPERIMENTAL DESIGN

Eligible patients had no smoking history, stage IIIB or IV adenocarcinoma, Eastern Cooperative Oncology Group performance status 0 to 2, and adequate organ functions. Treatment consisted of daily oral administration ofF 250 mg gefitinib for 28 days until disease progression. Responses were assessed after every two cycles of therapy.

RESULTS

Of 37 patients enrolled, 36 were assessed for response. Twenty-five patients (69%) had partial response, 4 (11%) had stable disease, and 7 (19%) had progressive disease. Of 10 patients with evaluable brain metastases, 7 had objective responses in both intracranial and extracranial lesions, 1 had stable disease in the brain and dramatic response in the extracranial lesions, and 2 had progressive disease in both sites. After a median follow-up of 48 weeks (range, 4-70 weeks), 26 patients had disease progression, with median progression-free survival of 33 weeks, and 9 patients died, all due to disease progression. The median survival time has not been reached yet but the estimated 1-year survival rate was 73%. Common toxicities were skin rash and mild diarrhea but there was no significant hematologic toxicity.

CONCLUSIONS

Gefitinib showed very dramatic antitumor activity, even in the brain, with unprecedented survival outcome in never-smoker adenocarcinoma patients. These data support the use of gefitinib as a first-line therapy in this particular subgroup.

Mechanisms of enhanced radiation response following epidermal growth factor receptor signaling inhibition by erlotinib (Tarceva)

Erlotinib (Tarceva) is an orally available HER1 (epidermal growth factor receptor, EGFR) tyrosine kinase inhibitor advancing through clinical trials for the treatment of a range of human malignancies. In this study, we examine the capacity of erlotinib to modulate radiation response and investigate specific mechanisms underlying these interactions in human tumor cell lines and xenografts. The impact of erlotinib on cell cycle kinetics was analyzed using flow cytometry, and the impact on apoptosis was evaluated via fluorescein-labeled pan-caspase inhibition and poly(ADP-ribose) polymerase cleavage. Radiation-induced EGFR autophosphorylation and Rad51 expression were examined by Western blot analysis. Radiation survival was analyzed using a clonogenic assay and assessment of in vivo tumor growth was done using a mouse xenograft model system. Microarray studies were carried out using 20 K human cDNA microarray and select genes were validated using quantitative reverse transcription-PCR (RT-PCR). Independently, erlotinib and radiation induce accumulation of tumor cells in G(1) and G(2)-M phase, respectively, with a reduction of cells in S phase. When combined with radiation, erlotinib promotes a further reduction in S-phase fraction. Erlotinib enhances the induction of apoptosis, inhibits EGFR autophosphorylation and Rad51 expression following radiation exposure, and promotes an increase in radiosensitivity. Tumor xenograft studies confirm that systemic administration of erlotinib results in profound tumor growth inhibition when combined with radiation. cDNA microarray analysis assessing genes differentially regulated by erlotinib following radiation exposure identifies a diverse set of genes deriving from several functional classes. Validation is confirmed for several specific genes that may influence radiosensitization by erlotinib including Egr-1, CXCL1, and IL-1beta. These results identify the capacity of erlotinib to enhance radiation response at several levels, including cell cycle arrest, apoptosis induction, accelerated cellular repopulation, and DNA damage repair. Preliminary microarray data suggests additional mechanisms underlying the complex interaction between EGFR signaling and radiation response. These data suggest that the erlotinib/radiation combination represents a strategy worthy of further examination in clinical trials.

Epidermal growth factor receptor mutations, small-molecule kinase inhibitors, and non-small-cell lung cancer: current knowledge and future directions

PURPOSE

Gefitinib and erlotinib are small molecules that selectively inhibit epidermal growth factor receptor (EGFR) tyrosine kinase activity. When these drugs were introduced into the clinic, the specific targets affected in human tumors were unknown. In April 2004, two groups reported that mutations in the tyrosine kinase domain of EGFR are strongly associated with gefitinib sensitivity in patients with non-small-cell lung cancer (NSCLC). We subsequently extended these findings and showed that such mutations are also associated with sensitivity to erlotinib. Here, we present current knowledge about EGFR mutations in the context of clinical trials involving gefitinib and erlotinib in NSCLC.

DESIGN

This article reviews the rationale for targeting EGFR, the development of gefitinib and erlotinib, the discovery of EGFR mutations, and subsequent studies to define the incidence, spectrum, and functions of EGFR mutations.

RESULTS

The discovery of EGFR mutations promises to alter the ways in which we consider and treat NSCLC.

CONCLUSION

This information can guide practitioners and help them inform their patients about EGFR mutations and their impact on the treatment of NSCLC.

Phase I/II trial evaluating the anti-vascular endothelial growth factor monoclonal antibody bevacizumab in combination with the HER-1/epidermal growth factor receptor tyrosine kinase inhibitor erlotinib for patients with recurrent non-small-cell lung cancer

PURPOSE

Bevacizumab (Avastin; Genentech, South San Francisco, CA) is a recombinant, humanized anti-vascular endothelial growth factor monoclonal antibody. Erlotinib HCl (Tarceva, OSI-774; OSI Pharmaceuticals, New York, NY) is a potent, reversible, highly selective and orally available HER-1/epidermal growth factor receptor tyrosine kinase inhibitor. Preclinical data in various xenograft models produced greater growth inhibition than with either agent alone. Additionally, both agents have demonstrated benefit in patients with previously treated non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

A phase I/II study in two centers examined erlotinib and bevacizumab (A+T) in patients with nonsquamous stage IIIB/IV NSCLC with > or = one prior chemotherapy. In phase I, erlotinib 150 mg/day orally plus bevacizumab 15 mg/kg intravenously every 21 days was established as the phase II dose, although no dose-limiting toxicities were observed. Phase II assessed the efficacy and tolerability of A+T at this dose. Pharmacokinetic parameters were evaluated. ResultsForty patients were enrolled and treated in this study (34 patients at phase II dose); the median age was 59 years (range, 36 to 72 years), 21 were female, 30 had adenocarcinoma histology, nine were never-smokers, and 22 had > or = two prior regimens (three patients had > or = four prior regimens). The most common adverse events were mild to moderate rash, diarrhea, and proteinuria. Preliminary data showed no pharmacokinetic interaction between A + T. Eight patients (20.0%; 95% CI, 7.6% to 32.4%) had partial responses and 26 (65.0%; 95% CI, 50.2% to 79.8%) had stable disease as their best response. The median overall survival for the 34 patients treated at the phase II dose was 12.6 months, with progression-free survival of 6.2 months.

CONCLUSION

Encouraging antitumor activity and safety of A + T support further development of this combination for patients with advanced NSCLC and other solid tumors.

Critical update and emerging trends in epidermal growth factor receptor targeting in cancer

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase of the ErbB receptor family that is abnormally activated in many epithelial tumors. The aberrant activation of the EGFR leads to enhanced proliferation and other tumor-promoting activities, which provide a strong rationale to target this receptor family. There are two classes of anti-EGFR agents: monoclonal antibodies (MAbs) directed at the extracellular domain of the receptor and small molecule, adenosine triphosphate-competitive inhibitors of the receptor's tyrosine kinase. Anti-EGFR MAbs have shown antitumor activity in advanced colorectal carcinoma, squamous cell carcinomas of the head and neck, non-small-cell lung cancer (NSCLC) and renal cell carcinomas. The tyrosine kinase inhibitors (TKIs) have a partially different activity profile. They are active against NSCLC, and a specific EGFR inhibitor has shown improvement in survival. Recently, mutations and amplifications of the EGFR gene have been identified in NSCLC and predict for enhanced sensitivity to anti-EGFR TKIs. In addition to specific anti-EGFR TKIs, there are broader acting inhibitors such as dual EGFR HER-2 inhibitors and combined anti-pan-ErbB and antivascular endothelial growth factor receptor inhibitors. Current research efforts are directed at selecting the optimal dose and schedule and identifying predictive factors of response and resistance beyond EGFR gene mutations and/or amplifications. Finally, there is a need for improved strategies to integrate anti-EGFR agents with conventional therapies and to explore combinations with other molecular targeted approaches including other antireceptor therapies, receptor-downstream signaling transduction inhibitors, and targeted approaches interfering with other essential drivers of cancer, such as angiogenesis.

Aberrant Epidermal Growth Factor Receptor Signaling and Enhanced Sensitivity to EGFR Inhibitors in Lung Cancer

Epidermal growth factor receptor (EGFR) is occasionally amplified and/or mutated in non–small cell lung cancer (NSCLC) and can be coexpressed with other members of the HER receptor family to form functional heterodimers. We therefore investigated lung cancer cell lines for alterations in EGFR gene copy number, enhanced expression of EGFR and other HER family members, and EGFR coding sequence mutations and correlated these findings with response to treatment with the EGFR inhibitors and the kinetics of ligand-induced signaling. We show here that somatic deletions in the tyrosine kinase domain of EGFR were associated with increased EGFR gene copy number in NSCLC. Treatment with the specific EGFR tyrosine kinase inhibitors (TKI) gefitinib or erlotinib or the EGFR inhibitory antibody cetuximab induced apoptosis of HCC827, a NSCLC cell line with EGFR gene amplification and an exon 19 deletion. H1819, a NSCLC cell line that expresses high levels of EGFR, ErbB2, and ErbB3 but has wild-type EGFR, showed intermediate sensitivity to TKIs. In both cell lines, ligand-induced receptor tyrosine phosphorylation was delayed and prolonged and AKT was constitutively phosphorylated (but remained inhibitable by EGFR TKI). Thus, in addition to EGFR mutations, other factors in NSCLC cells, such as high expression of ErbB family members, may constitutively activate AKT and sensitize cells to EGFR inhibitors.

Targeting ErbB receptor signaling: A pan-ErbB approach to cancer

The ErbB receptors are localized to the cell membrane where they are activated by ligand to trigger a network of signaling pathways. In some cancer cells, dysregulation of ErbB-mediated signaling confers a growth advantage, resulting in cellular transformation and increased metastatic potential. Several agents that inhibit individual ErbB receptors have recently been approved for the treatment of human malignancies, validating ErbB receptors as therapeutic targets. One strategy to improve the efficacy of ErbB-targeted therapies is to inhibit multiple ErbB receptors, thereby interfering with the cooperation that exists between receptors. This minireview addresses the approaches being developed to concurrently inhibit multiple ErbB receptors.