Phase 1 study of twice weekly pulse dose and daily low-dose erlotinib as initial treatment for patients with EGFR-mutant lung cancers

Background

Patients with EGFR-mutant lung cancers treated with EGFR tyrosine kinase inhibitors (TKIs) develop clinical resistance, most commonly with acquisition of EGFR T790M. Evolutionary modeling suggests that a schedule of twice weekly pulse and daily low-dose erlotinib may delay emergence of EGFR T790M. Pulse dose erlotinib has superior central nervous system (CNS) penetration and may result in superior CNS disease control.

Methods

We evaluated toxicity, pharmacokinetics, and efficacy of twice weekly pulse and daily low-dose erlotinib. We assessed six escalating pulse doses of erlotinib.

Results

We enrolled 34 patients; 11 patients (32%) had brain metastases at study entry. We observed 3 dose-limiting toxicities in dose escalation: transaminitis, mucositis, and rash. The MTD was erlotinib 1200 mg days 1-2 and 50 mg days 3-7 weekly. The most frequent toxicities (any grade) were rash, diarrhea, nausea, fatigue, and mucositis. 1 complete and 24 partial responses were observed (74%, 95% CI 60-84%). Median progression-free survival was 9.9 months (95% CI 5.8-15.4 months). No patient had progression of an untreated CNS metastasis or developed a new CNS lesion while on study (0%, 95% CI 0-13%). Of the 18 patients with biopsies at progression, EGFR T790M was identified in 78% (95% CI 54-91%).

Conclusion

This is the first clinical implementation of an anti-cancer TKI regimen combining pulse and daily low-dose administration. This evolutionary modeling-based dosing schedule was well-tolerated but did not improve progression-free survival or prevent emergence of EGFR T790M, likely due to insufficient peak serum concentrations of erlotinib. This dosing schedule prevented progression of untreated or any new central nervous system metastases in all patients.

Inclusion of RBD improves the diagnostic classification of dementia with Lewy bodies

OBJECTIVE

To determine whether adding REM sleep behavior disorder (RBD) to the dementia with Lewy bodies (DLB) diagnostic criteria improves classification accuracy of autopsy-confirmed DLB.

METHODS

We followed 234 consecutive patients with dementia until autopsy with a mean of 4 annual visits. Clinical diagnoses included DLB, Alzheimer disease (AD), corticobasal syndrome, and frontotemporal dementia. Pathologic diagnoses used the 2005 DLB consensus criteria and included no/low likelihood DLB (non-DLB; n = 136) and intermediate/high likelihood DLB (DLB; n = 98). Regression modeling and sensitivity/specificity analyses were used to evaluate the diagnostic role of RBD.

RESULTS

Each of the 3 core features increased the odds of autopsy-confirmed DLB up to 2-fold, and RBD increased the odds by 6-fold. When clinically probable DLB reflected dementia and 2 or more of the 3 core features, sensitivity was 85%, and specificity was 73%. When RBD was added and clinically probable DLB reflected 2 or more of 4 features, sensitivity improved to 88%. When dementia and RBD were also designated as probable DLB, sensitivity increased to 90% while specificity remained at 73%. The VH, parkinsonism, RBD model lowered sensitivity to 83%, but improved specificity to 85%.

CONCLUSIONS

Inclusion of RBD as a core clinical feature improves the diagnostic accuracy of autopsy-confirmed DLB.

Nomogram to predict the presence of EGFR activating mutation in lung adenocarcinoma

Epidermal growth factor receptor (EGFR) tumour genotyping is crucial to guide treatment decisions regarding the use of EGFR tyrosine kinase inhibitors in nonsmall cell lung cancer (NSCLC). However, some patients may not be able to obtain tumour testing, either because tissue is limited and/or tests are not routinely offered. Here, we aimed to build a model-based nomogram to allow for prediction of the presence of EGFR mutations in NSCLC. We retrospectively collected clinical and pathological data on 3,006 patients with NSCLC who had their tumours genotyped for EGFR mutations at five institutions worldwide. Variables of interest were integrated in a multivariate logistic regression model. In the 2,392 non-Asian patients with lung adenocarcinomas, the most important predictors of harbouring EGFR mutation were: lower tobacco smoking exposure (OR 0.41, 95% CI 0.37-0.46), longer time interval between smoking cessation and diagnosis (OR 2.19, 95% CI 1.71-2.80), advanced stage (OR 1.58, 95% CI 1.18-2.13), and papillary (OR 4.57, 95% CI 3.14-6.66) or bronchioloalveolar (OR 2.84, 95% CI 1.98-4.06) histologically predominant subtype. A nomogram was established and showed excellent discriminating accuracy: the concordance index on an independent validation dataset was 0.84. As clinical practices transition to incorporating genotyping as part of routine care, this nomogram could be highly useful to predict the presence of EGFR mutations in lung adenocarcinoma in non-Asian patients when mutational profiling is not available or possible.

Identification of driver mutations in tumor specimens from 1,000 patients with lung adenocarcinoma: The NCI’s Lung Cancer Mutation Consortium (LCMC)

CRA7506

Background: The ability to detect driver mutations like EGFR and EML4-ALK in tumor specimens from patients with lung cancer and administer agents targeting those molecular lesions has revolutionized the management of adenocarcinoma of the lung. The availability of multiplexed assays to detect mutations permits the identification of multiple driver mutations from tumors at diagnosis. The number of molecular lesions and new agents to target them continues to grow. To exploit this, we created the LCMC to determine 10 driver mutations in tumors from 1,000 patients and to give the results to clinicians for care and entry onto targeted therapeutic trials based on these findings. Methods: The 14 member LCMC is prospectively enrolling patients to test tumors from patients with lung adenocarcinoma in CLIA laboratories for KRAS, EGFR, HER2, BRAF, PIK3CA, AKT1, MEK1, and NRAS using standard multiplexed assays and fluorescence in situ hybridization (FISH) for ALK rearrangements and MET amplifications. All are stage IIIB/IV, PS 0-2, have available tissue, and signed consent. Results: 830 patients have been registered with 50 enrolling monthly. We detected a driver mutation in 60% (252/422, 95% CI 55 to 65%) of tumors thus far. Mutations found: KRAS 107 (25%, 95% CI 21 to 30%), EGFR 98 (23%, 95% CI 19 to 27%), ALK rearrangements 14 (6%, 95% CI 4 to11%), BRAF 12 (3%, 95% CI 1 to 5%), PIK3CA 11 (3%, 95% CI 1 to 5%), MET amplifications 4 (2%, 95% CI 0.5 to 5%), HER2 3, (1%, 95% CI 0.1 to 2%), MEK1 2 (0.4%, 95% CI 0.1 to 2%), NRAS 1 (0.2%, 95% CI 0.01 to 1%), AKT1 0 (0%, 95% CI 0 to 1%). 95% of molecular lesions were mutually exclusive. Conclusions: We detected an actionable driver mutation in 60% of tumors from prospectively studied patients with lung adenocarcinoma. Results of EGFR mutation testing are given to treating physicians to select erlotinib as initial treatment per NCCN and ASCO guidelines. Patients with other driver mutations are offered participation in LCMC-linked trials of agents targeting the mutation identified, e.g. crizotinib with EML4-ALK. At half of LCMC sites, multiplexed testing for all mutations is now routine practice in their pathology departments. Supported by 1RC2CA148394-01.

An integrated genomic analysis of lung cancer reveals loss of DUSP4 in EGFR-mutant tumors

To address the biological heterogeneity of lung cancer, we studied 199 lung adenocarcinomas by integrating genome-wide data on copy number alterations and gene expression with full annotation for major known somatic mutations in this cancer. This revealed non-random patterns of copy number alterations significantly linked to EGFR and KRAS mutation status and to distinct clinical outcomes, and led to the discovery of a striking association of EGFR mutations with under-expression of DUSP4, a gene within a broad region of frequent single-copy loss on 8p. DUSP4 is involved in negative feedback control of EGFR signaling and we provide functional validation for its role as a growth suppressor in EGFR-mutant lung adenocarcinoma. DUSP4 loss also associates with p16/CDKN2A deletion and defines a distinct clinical subset of lung cancer patients. Another novel observation is that of reciprocal relationship between EGFR and LKB1 mutations. These results highlight the power of integrated genomics to identify candidate driver genes within recurrent broad regions of copy number alteration and to delineate distinct oncogenetic pathways in genetically complex common epithelial cancers.

Rebiopsy of patients (pts) with acquired resistance to epidermal growth factor tyrosine kinase inhibitors (EGFR-TKIs) in non-small cell lung cancer (NSCLC)

8025

Background: The EGFR-TKIs erlotinib and gefitinib produce dramatic regressions of tumor in ∼ 70% of NSCLC patients with activating mutations in the EGFR-TK domain. After a median time to progression of ∼1 year, most pts have progressive disease. We undertook this study to search for mechanisms of “acquired resistance” to EGFR-TKIs, to determine the spectrum and frequency of secondary EGFR mutations which arose, and to determine the feasibility of rebiopsy in this setting. Methods: All pts had metastatic or recurrent NSCLC and prior treatment with EGFR-TKI and progressive disease while on EGFR-TKI. Pts must also have had an activating EGFR mutation OR radiographic response (RECIST or WHO) to EGFR-TKI OR significant and durable improvement in cancer-related symptoms as judged by patient's physician. Core biopsies were performed and studied for EGFR mutation (exons 18–21 including PCR-based test for T790M) and MET amplification. Results: From 8/04–12/08 98 pts were consented for rebiopsy and 85 underwent the procedure. Demographics Female/Male=59/39; median age 62 (range 28–88); smoking: never=59, former/current=39. Primary EGFR mutation was exon 19 del-39; exon 21 L858R-11, other/WT-28, pending-7. Median time on EGFR-TKI before biopsy was 12 months (7–28 months). Secondary EGFR mutations: T790M-33, other-2, none detected-31, indeterminate-10, pending-9. MET amplification in 2/16 studied to date. Conclusions: 1) Rebiopsy of patients with NSCLC and acquired resistance to EGFR TKIs is feasible and well-received by pts. 2) Knowledge of EGFR genotype including EGFR T790M and MET status can inform clinical trials of targeted therapies in this population 3) More complete annotation of MET status and exploratory analyses of profiles of specimens by metastatic sites and prior EGFR-TKI versus chemo and EGFR-TKI is ongoing. Supported by the Doris Duke Foundation, the LaBrecque Foundation, Steps for Breath, NIH, and an anonymous donor.

No significant financial relationships to disclose.

A phase II trial of salirasib in patients with stage IIIB/IV lung adenocarcinoma enriched for KRAS mutations

8012

Background: KRAS mutations are present in 30% of lung adenocarcinomas and are associated with primary resistance to erlotinib and gefitinib. Salirasib severs RAS proteins from the membrane, decreasing function of all RAS isoforms. Salirasib inhibits KRAS-dependent growth in cell lines and xenograft models. This phase II study was designed to determine the activity of salirasib in patients (pts) with advanced NSCLC enriched for KRAS mutations. Methods: Two cohorts of pts with stage IIIB/IV NSCLC were eligible. Group A: pts with KRAS mutations previously treated with chemotherapy. Group B: previously-untreated pts with ≥15 pack-year smoking history. Salirasib was given orally, for days 1–28 of a 35 day cycle, with response assessment on day 28, day 63, and every 10 weeks (wks) thereafter. The primary endpoint was rate of RECIST non-progression at 10 wks. Secondary endpoints were response rate (RR), time to progression (TTP), overall survival (OS) and toxicity. Results: From August 2007-December 2008, 33 pts were enrolled (20 women); median age 68 (range 46–79). Pts in Group A had received a median of 2 lines of prior chemotherapy. All 23 pts in Group A and 7/10 pts in Group B had KRAS mutations. Of the 30 pts with KRAS mutations, 7 were never smokers or smoked ≤15 pack-years. Three pts withdrew due to drug-related diarrhea in the first 10 wks of therapy. Four pts have not reached 10 wks of therapy. After 10 wks of salirasib, 5/18 (28%) previously treated pts with KRAS mutations and 3/8 (38%) previously untreated pts showed no progression. The RR in pts was 0/18 for Group A and 0/8 in Group B. For all pts with KRAS mutations, the RR was 0/23. The median TTP was 1 month (mo) and 2 mo in Groups A and B, respectively. The median OS was 13 mo for Group B and not reached in Group A (median follow-up 3 mo). Grade 3 diarrhea and fatigue were the most common toxicities. Conclusions: After 10 wks of salirasib, 28% of previously treated pts with KRAS mutations and 38% of untreated pts had stable disease. No partial or complete responses were seen in pts with KRAS mutations. The successful enrollment over 15 months of 29 pts with tumors with known KRAS mutations demonstrates that trials of a KRAS-specific genotype in lung cancer are feasible, and should be standard in future studies targeting the KRAS pathway.

[Table: see text]

Expression levels of total IGF-1R and sensitivity of NSCLC cells in vitro to an anti-IGF-1R antibody (R1507)

8095

Background: The IGF-1R (IGF receptor type 1) pathway is frequently deregulated in human tumors and has become a target of interest for anti-cancer therapy. We investigated predictive biomarkers of response to an anti-IGF-1R antibody (Ab) in vitro in NSCLC. Methods: We examined the growth inhibitory effects of R1507, a fully-humanized IgG1 anti-IGF-1R monoclonal Ab (Roche), against a panel of 22 NSCLC cell lines using CellTiter Blue assays. Phospho-receptor tyrosine kinase (pRTK) arrays and ELISAs were used to determine the status of IGF-1R and other RTKs. SNP arrays were used to determine IGF-1R copy number. Immunohistochemical (IHC) staining of total IGF-1R was performed with G11 (an anti-total IGF-1R Ab; Ventana) on a tissue microarray (TMA) containing 77 independent NSCLC tumor samples. Staining intensity was scored on a scale of 0 to 3+ by a pathologist (JF). Results: 5 of 22 NSCLC cell lines were moderately sensitive (25–50% growth inhibition) to R1507 alone. ELISA and pRTK array analysis demonstrated that pIGF-1R levels in the presence or absence of serum did not correlate with drug sensitivity. However, 4 of 5 sensitive lines displayed high levels of total IGF-1R vs 1/17 resistant lines (p=0.003 Fisher's Exact). SNP array analysis showed that sensitive lines also harbor relatively higher copy numbers of IGF-1R. There was no correlation with EGFR/KRAS mutational status. 48% of TMA NSCLC tumors had scores of 2+ or greater, while 5% were scored as 3+. Addition of erlotinib or paclitaxel to R1507 led to further growth inhibition in sensitive but not resistant lines. In one EGFR mutant lung adenocarcinoma cell line, R1507 and erlotinib co-treatment induced apoptosis, whereas treatment with either drug alone induced only cell cycle arrest. Apoptosis was mediated, in part, by the survival-related AKT pathway, as pAKT was significantly downregulated by R1507 but not erlotinib. Conclusions: In NSCLC cell lines, high levels of total IGF-1R are associated with moderate sensitivity to R1507. These results suggest a possible enrichment strategy for clinical trials with anti-IGF-1R therapy.

[Table: see text]

Use of an Internet-based protocol to collect clinical information and blood from patients with lung cancer who never smoked cigarettes

e19064

Background: At least 10% of patients develop lung cancer despite smoking <100 cigarettes in a lifetime. These “never smokers” with lung cancer have a unique clinical course and likely represent a subgroup genetically distinct from lung cancer patients with a history of cigarette smoking. Few genes associated with the development of lung cancer in this population have been found. To identify genetic risk factors, we plan to perform genome-wide association studies (GWAS) but need to study a large group of cases - more than that seen at a single institution in a reasonable timeframe. To speed accrual, we hypothesized that we could use the internet to collect clinical information and blood from never smokers with lung cancer. Methods: We established an IRB- approved protocol to collect prospectively clinical information and blood samples from patients recruited via the internet. Interested patients enroll via the website ( www.mskcc.org/neversmokerswithlungcancer ), or by email ( neversmokerswithlungcancer@mskcc.org ). Eligibility criteria: age ≥18 yo, pathologic diagnosis of lung cancer, smoking history <100 cigarettes in a lifetime, resident of the U.S. Study materials (information packet, screening questionnaire, consent form, and tissue sample collection kit) are directly sent to patients. Bloods are drawn at routine local doctor visits and returned to study investigators by free overnight shipping. All data are kept confidential. Results: The website went online on 14 Sept 2008. As of 5 Jan 2009, 70 patients from 25 states contacted us via the internet. 33 patients signed the consent form, 27 were eligible, and 19 sent blood samples. For those who sent blood, the median time between first email contact and receipt of blood was 29 days. Conclusions: Collection of clinical information and blood samples from cancer patients is feasible over the internet. We are expanding efforts to connect with individuals appropriate to this study, with a target of 2000 patients. The identification of risk variants associated with lung cancer through GWAS can facilitate the development of new strategies for prevention, diagnosis, and treatment.

No significant financial relationships to disclose.

Smoking history and frequency of somatic KRAS mutations in adenocarcinoma of the lung

7573

Background: Somatic mutations in the epidermal growth factor receptor (EGFR) gene are more common in patients with adenocarcinoma, especially those who smoked < 15 pack years (py). KRAS mutations are found in ∼25% of lung adenocarcinomas, most commonly in codons 12 and 13 of exon 2 (∼85%) and have been associated with poor prognosis in resected disease [Winton NEJM 2005] and resistance to EGFR tyrosine kinase inhibitors [Pao PLoS Med 2005]. KRAS mutations are uncommon in non-small cell lung cancer histologies other than adenocarcinoma. We sought to determine the association between quantitative measures of cigarette smoking and presence of KRAS mutations in lung adenocarcinomas. Methods: Standard direct sequencing techniques were used to identify KRAS codon 12 and 13 mutations in lung adenocarcinoma specimens from surgical resections between 2001 and 2006 and tumor specimens sent for KRAS molecular analysis in 2006. Surgical specimens were obtained from an institutional tumor bank. Detailed smoking history (age at first cigarette, packs per day, years smoked, years since quitting smoking) was obtained from the medical record and a patient-completed smoking questionnaire. Results: KRAS mutational analysis was performed on 408 lung adenocarcinomas from 242 women and 166 men. Median age was 68 (range 33–89). KRAS mutations were present in 19% (78/408, 95% CI 15 to 23%). The frequency of KRAS mutation was not associated with age or gender. The presence of KRAS mutations was not related to smoking history with 15% (9/61) of never smokers having KRAS mutations compared with 19% (51/275) of former smokers. When compared with never smokers, there was no significant difference in frequency of KRAS mutations for tumors from patients with 1–5 py (5%, p=0.44), 6- 10 py (12%, p=0.99), 11–15 py (25%, p=0.45), 16–25 py (16%, p=0.99), 26–50 py (25%, p=0.129), 51–75 py (20%, p=0.48), >75 py (20%, p=0.47) history of cigarette smoking. Conclusions: While the incidence of EGFR mutations has a strong inverse relationship with the amount of cigarettes smoked, allowing the selective molecular testing for EGFR mutations, the frequency of KRAS mutations cannot be predicted by age, gender, or smoking history. KRAS mutational analysis of all adenocarcinomas is required to reliably identify patients with KRAS mutations.

No significant financial relationships to disclose.

Mutational analysis of EGFR signaling pathway genes in lung adenocarcinomas

7584

Background: About fifty percent of lung adenocarcinomas harbor somatic mutations in six genes that encode signaling proteins in the EGFR signaling pathway, i.e. EGFR, HER2/ERBB2, HER4/ERBB4, PIK3CA, BRAF, and KRAS. We performed mutational profiling of a large cohort of lung adenocarcinomas to uncover other somatic mutations that could contribute to lung tumorigenesis. Methods: We analyzed genomic DNA from 261 resected, clinically well-annotated non-small cell lung cancer (NSCLC) specimens. 90% of tumors were adenocarcinomas, and 10% were squamous cell carcinomas. The coding sequences of 39 genes, encoding proteins mostly in the EGFR signaling cascade and FGFR1–4, were screened for somatic mutations via high-throughput dideoxynucleotide sequencing of PCR-amplified gene products. Mutations were considered to be somatic only if they were found in an independent tumor-derived PCR product but not in matched normal tissue. Results: First-pass analysis of 9 MB of tumor sequence identified 199 distinct types of genetic variants that differed from published reference sequences. At least one variant was found in each gene analyzed. In addition to 6 variants found in RAS genes, we further examined the 94 variants localized to exons encoding the kinase domain of respective proteins. We have thus far identified known somatic mutations in EGFR, KRAS, BRAF, and PIK3CA, in addition to a number of previously unreported single nucleotide polymorphisms (SNPs). Conclusions: Mutational profiling of genes that encode for components of the EGFR signaling pathway has revealed multiple putative genetic variants in lung adenocarcinomas. Further analysis of potential somatic mutations is in progress.

No significant financial relationships to disclose.

Combined inhibition of mTOR and EGFR with everolimus (RAD001) and gefitinib in patients with non-small cell lung cancer who have smoked cigarettes: A phase II trial

7575

Background: Most non-small cell lung cancers (NSCLC) are primarily resistant to the EGFR tyrosine kinase inhibitor gefitinib. One strategy to overcome resistance is to block parallel or downstream effectors that maintain tumor growth and proliferation. Preclinical data supports this hypothesis as inhibition of the PIK3CA/Akt/mTOR pathway restores gefitinib sensitivity in resistant cells. In a phase I study, gefitinib (250 mg) and the mTOR inhibitor everolimus (5 mg) were safely administered orally once-a-day (Milton Proc ASCO 2005). This combination induced regressions in patients with NSCLC. To assess the efficacy of this regimen, we designed this phase II trial. Methods: Two cohorts of patients with measurable stage IIIB/IV NSCLC were entered: (1) untreated with chemotherapy and (2) previously treated with cisplatin or carboplatin and docetaxel. A Simon two-stage design proposed to enroll up to 31 patients in each cohort. Response was assessed after 1 month then every 2 months. Pretreatment tumor specimens were collected on all patients. Results: To date, 25 patients have entered, 11 untreated and 14 previously treated. The median age was 66 years and KPS 80%. 52% were women, 68% had adenocarcinoma, and all were current (n=1) or former smokers. Partial responses (RECIST) have been observed in 4 of 23 evaluable patients (17%, 95% CI 5 to 39%) One of these 4 tumors harbored a KRAS mutation and one an EGFR exon 19 deletion. Responses lasted 3, 4, 9+, and 16+ months. Responses were observed in 2 of 13 untreated and 2 of 10 previously treated individuals. Toxicities: Grade 2/3 diarrhea in 13%, Grade 2 pustular rash in 25%, and Grade 2 mucosal ulcerations in 38%. 8% had dose reductions. There were no Grade 4 toxicities or treatment-related deaths. Conclusions: The combination of everolimus and gefitinib produced a 17% partial response rate in smokers with NSCLC, a group less likely to benefit from gefitinib. Enough responses have been seen in both untreated and previously treated cohorts to complete enrollment according to the two stage design of this trial. We plan to correlate outcomes with the molecular profile of tumors. Supported by Novartis, USA

No significant financial relationships to disclose.

Integrated genomic analysis of lung adenocarcinomas identifies loss of the MAPK phosphatase gene DUSP4 in most EGFR mutant tumors

7686

Background: Genomic analyses of lung adenocarcinoma have yielded striking advances that are already impacting on clinical management. Further advances in understanding the biological heterogeneity of this disease will require integration of multiple types of genomic data. To this end, we have assembled a large integrated genomics dataset of lung adenocarcinomas. Here, we highlight one of the novel findings emerging from its initial analysis. Methods: 173 primary lung adenocarcinomas were included in this analysis. Profiling of genomic gains and losses was done by array comparative genomic hybridization (aCGH) on Agilent 44K arrays. Expression profiling was based on Affymetrix U133A arrays. The dataset was annotated for EGFR mutations (exon 19 deletion and L858R) by sensitive PCR-based assays and for KRAS mutations by sequencing. Results: By unsupervised analysis of the aCGH data, the 173 tumors clustered robustly into two or three patterns of co-occurring gains and losses. One aCGH cluster was strongly associated with EGFR mutation (p<10−4) and was characterized by 7p gains (in the EGFR region) and 8p losses. Remarkably, by expression profiling the most consistently underexpressed gene (p<10−9) in EGFR mutant cases compared to EGFR wild type cases was a MAPK phosphatase gene at 8p12, DUSP4 (MKP-2). The DUSP4 region showed genomic loss in 27/35 EGFR mutant cases vs 47/138 non-mutated cases (p<10−4). A limited screen (n=11) has so far revealed no DUSP4 mutations. Western blotting shows low DUSP4 in most EGFR mutant lines, compared to KRAS mutant lines. Conclusions: EGFR mutations in lung adenocarcinomas are strongly associated with genomic loss and low expression of DUSP4. DUSPs are known to be transcriptionally upregulated by MAPK signaling as a negative feedback mechanism and DUSP family members are emerging as putative tumor suppressors in other cancers. We hypothesize that DUSP4 loss cooperates with EGFR mutation to allow full oncogenic activation of the MAPK pathway. Functional studies of DUSP4 in lung adenocarcinoma cell lines are in progress. Our data highlight the value of large, integrated, highly annotated genomic datasets in generating novel insights and hypotheses.

No significant financial relationships to disclose.

Oncogenes come of age

Mutations of proto-oncogenes are common events in the pathogenesis of cancers, as shown in a wide range of studies during the 30 years since the discovery of these genes. The benefits of novel therapies that target the products of mutant alleles in human cancers, and the demonstrated dependence of cancers in mouse models on continued expression of initiating oncogenes, are especially promising signs that revolutionary improvements in cancer care are possible. Full realization of the promise of targeted therapies, however, will require better definitions of the genotypes of human cancers, new approaches to interrupt the biochemical consequences of oncogenic mutations, and a greater understanding of drug resistance and tumor progression. In this paper, we summarize recent efforts toward these goals in our laboratory and others.

EGFR mutation and copy number, EGFR protein expression and KRAS mutation as predictors of outcome with erlotinib in bronchioloalveolar cell carcinoma (BAC): Results of a prospective phase II trial

7003

Background: Erlotinib produces dramatic responses in a subset of patients with NSCLC. Mutations in the EGFR tyrosine kinase domain, EGFR amplification or polysomy and EGFR overexpression on immunohistochemistry have all been associated with sensitivity and benefit; pts with KRAS mutation are commonly resistant to this agent. These correlative studies were prospectively undertaken to characterize the ability of these markers to predict response rate, time to progression and survival in pts with BAC treated with the EGFR-TKI, erlotinib. Methods: One hundred and two patients received erlotinib as part of a phase II trial in BAC (Kris, Proc ASCO 2005); 84 had one or more correlative studies completed. Analysis of EGFR exons 19 and 21 (n=82) (Pao, et al PNAS 2004), EGFR IHC (n=62) (DAKO) was performed and EGFR copy number was determined by chromogenic in situ hybridization (CISH) (n=74) (Zymed); detection of ≥ 4 signals per cell was considered evidence of amplified copy number. KRAS exon 2 (n=79) testing was performed by direct sequencing. Fisher’s exact test was used to study the association of each feature in pts with partial response or no partial response. Time to progression and survival were analyzed with log-rank test. Results: See table below. Conclusions: 1) EGFR exon 19 or 21 mutation is a powerful predictor of response and TTP but not OS in pts with BAC treated with erlotinib. 2) CISH ≥4 is associated with response and improved TTP but not OS. 3) Patients with both EGFR mutation and amplification fare well supporting the concept of “oncogene addiction”; erlotinib should be considered as initial therapy in this population. 4) EGFR amplification without mutation is uncommon. 5) There is no clear utility of EGFR IHC in clinical decision making. 6) The presence of KRAS mutation predicts resistance to erlotinib. Supported, in part, by Genentech.

[Table: see text]

[Table: see text]

Molecular analysis of NSCLC patients with acquired resistance to gefitinib or erlotinib

7078

Background: We previously reported that in 2 of 5 non-small cell lung cancer (NSCLC) patients with acquired resistance to the tyrosine kinase inhibitors (TKIs), gefitinib and erlotinib, tumors biopsied after disease progression contained a second site mutation (T790M) in the epidermal growth factor receptor (EGFR) kinase domain, in addition to a primary drug-sensitive mutation (exon 19 deletion (del) or exon 21 point mutation (L858R)) (Pao et al, PLoS Med ‘05). No patients had KRAS mutations, which are associated with primary resistance to these TKIs. We sought to determine the frequency of second site EGFR kinase domain and KRAS mutations in tumors from patients with acquired resistance to TKIs, administered either as monotherapy or with chemotherapy. Methods: 18 patients with NSCLC who responded to either TKI alone (n = 14) or TKI plus chemotherapy (n = 4) and then progressed were re-biopsied. Genomic DNA samples from tumors were examined for EGFR (exons 18–24) and KRAS (exon 2) mutations. Results: Sequence analysis was successfully performed on tumors from 17 patients. The T790M EGFR mutation was detected in 6 of 13 (46%, 95% CI 19–75%) on TKI monotherapy, and in 0 of 4 (0%, 95% CI 0–53%) on TKI plus chemotherapy. In one autopsy case, the T790M mutation was detected in 5 of 5 sites, which all harbored the same exon 19 del. No other EGFR or KRAS mutations were detected. Conclusions: Secondary EGFR T790M but not KRAS mutations are commonly associated with acquired resistance to TKI monotherapy. More patients are being studied, and we are trying to elucidate determinants of acquired resistance in the absence of T790M mutations. New therapies are needed to treat and/or suppress the development of acquired resistance to gefitinib or erlotinib. Support: Joan’s Legacy, DDCF, K08-CA097980, R21-CA115051.

[Table: see text]

Prospective FDG-PET and CT assessment of discontinuation of erlotinib (E) or gefitinib (G) in patients with EGFR TKI sensitive non-small cell lung cancer (NSCLC) who subsequently progress radiographically on E or G (“acquired resistance”) followed by re-initiation of E or G and the subsequent addition of everolimus (RAD001)

7065

Background: About 10% of patients (pts) with NSCLC have a radiographic response to E or G. A dependence on signaling through the epidermal growth factor receptor (EGFR) is thought to underlie this response. Despite initial regression, these pts invariably develop acquired resistance to E or G. Optimal management of these patients is unknown. In patients with acquired resistance, we sought to evaluate changes in tumor metabolism by PET and size by CT after discontinuation of E or G, resumption of E or G, and then the addition of the mTOR inhibitor everolimus to E or G. Methods: Pts with stage IV NSCLC with exon 19 or 21 EGFR mutation or previous radiographic response after treatment with E or G and then radiographic progression after > 6 months of treatment were eligible. All pts had 4 FDG-PET/CT and helical CT scans: baseline, 3 weeks after discontinuation of E or G, 3 weeks after restarting E or G, and 3 weeks after combined treatment with everolimus (5 mg daily) and E or G. CT measurements were uni-dimensional. Results: To date, 9 pts (5 on G, 4 on E) have enrolled with 6 pts completing all 4 PET/CT and CT assessments. Within 3 weeks of discontinuation of E or G, 7 of 9 (77%, 95% CI 40–97%) developed symptomatic disease progression. Three of 6 pts had an increase in SUV of >50% and increase in CT measurements >15% 3 weeks after discontinuation of E or G. Three of 6 pts had decrease in SUV of >10% 3 weeks after resumption of E or G. Two of 6 pts had further reduction of SUV > 50% and >10% decrease in CT measurements 3 weeks after everolimus was added to E or G. Conclusions: In EGFR TKI-sensitive patients who develop acquired resistance: 1) Discontinuation of E or G results in rapid symptomatic progression and increases in SUV on PET of indicator lesions. 2) Both symptoms and SUV values improve on re-initiation of E or G, suggesting that some tumor cells remain sensitive to EGFR blockade. 3) We saw further improvement when everolimus was combined with E or G. Based on these data we now recommend continuing E or G in similar patients. Support: Novartis, CA05826, MSKCC “Steps for Breath.”

[Table: see text]

Prospective trial with preoperative gefitinib to correlate lung cancer response with EGFR exon 19 and 21 mutations and to select patients for adjuvant therapy

7021

Background: Induction therapy provides a unique opportunity for the objective assessment of therapies in patients with NSCLC to facilitate care and advance research. We designed this 40 patient prospective trial to measure gefitinib’s ability to induce regressions preoperatively in individuals with NSCLC and to simultaneously correlate response with mutations in EGFR exons 19 and 21. Patients with ‘in-vivo‘ gefitinib sensitivity and/or mutations receive gefitinib postoperatively as well. To facilitate our goals, we enriched the population studied to select individuals with tumors more likely to harbor mutations in EGFR. Methods: At diagnosis, patients with stage I or II NSCLC had baseline chest CT imaging and a core-needle biopsy to detect EGFR mutations. All participants smoked cigarettes ≤ 10 pack years and/or had tumors with bronchioloalveolar features. All received gefitinib 250 mg daily. After 21 days, CT imaging was repeated and resection followed. Surgical specimens were agained assayed for EGFR mutations. Patients with mutation and/or a ≥ 25% regression (WHO) were given gefitinib 250 mg for 2 years. Results: 20 patients enrolled to date. EGFR mutations were detected in both pre and post gefitinib specimens in 4/19 tested (21%). Five of 19 (26%) had a ≥ 25% bidimensional tumor reduction after 3 weeks. Regressions ≥ 25% were seen in 2/4 (50%) with exon 19 and 21 EGFR mutations and 3/15 (20%) with WT EGFR. The other 2 patients with mutations had 11% and 23% tumor regressions. The 6 patients who had either a ≥ 25% lesion reduction and/or mutation received gefitinib postoperatively. No perioperative complications related to gefitinib occurred. All patients are relapse free. Conclusions: In this ongoing trial, 1) Our ‘enrichment strategy‘ resulted in the detection of twice the expected number of EGFR mutations in USA patients with NSCLC. 2) Gefitinib sensitivity can be assessed by CT in 3 weeks. 3) Results of mutation detection were identical in pre- and post-treatment specimens. 4) The rate of response is numerically higher in patients with EGFR mutations in exons 19 and 21. 5) We are using the surgical specimens to elucidate determinants of gefitinib sensitivity in the absence of EGFR mutation. Support: CA05826, CA113653.

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Simple purification methods for an alphagalactose-specific antibody from chicken eggs

For many applications avian antibody from egg yolk (IgY) offers advantages over the well-known mammalian antibodies. Different experimental techniques for the purification of IgY from chickens immunized with an alphagalactose-containing antigen (alphaGal-trisaccharide) were compared. These included ammonium sulfate precipitation, filtration with diatomaceous earth, treatment with deoxycholate, and thiophilic and affinity chromatography. Samples were tested for overall purity, protein and lipid content, and specific activity. Evaluated on the basis of these results and the simplicity of the process, the favored purification method is ammonium sulfate precipitation of diluted egg yolk directly followed by affinity chromatography. The high lipid content of IgY preparations is greatly reduced by either thiophilic or affinity chromatography. Affinity purification of ammonium sulfate precipitated material resulted in anti-alphaGal-trisaccharide IgY preparations with approximately 1% of the original protein content but approximately 100-fold higher specific activity for the alphaGal-trisaccharide epitope.

Simple purification methods for an alphagalactose-specific antibody from chicken eggs

For many applications avian antibody from egg yolk (IgY) offers advantages over the well-known mammalian antibodies. Different experimental techniques for the purification of IgY from chickens immunized with an alphagalactose-containing antigen (alphaGal-trisaccharide) were compared. These included ammonium sulfate precipitation, filtration with diatomaceous earth, treatment with deoxycholate, and thiophilic and affinity chromatography. Samples were tested for overall purity, protein and lipid content, and specific activity. Evaluated on the basis of these results and the simplicity of the process, the favored purification method is ammonium sulfate precipitation of diluted egg yolk directly followed by affinity chromatography. The high lipid content of IgY preparations is greatly reduced by either thiophilic or affinity chromatography. Affinity purification of ammonium sulfate precipitated material resulted in anti-alphaGal-trisaccharide IgY preparations with approximately 1% of the original protein content but approximately 100-fold higher specific activity for the alphaGal-trisaccharide epitope.