Robert A. Kratzke

ERCC1 Isoform Expression and DNA Repair in Non-Small-Cell Lung Cancer

BACKGROUND The excision repair cross-complementation group 1 (ERCC1) protein is a potential prognostic biomarker of the efficacy of cisplatin-based chemotherapy in non-small-cell lung cancer (NSCLC). Although several ongoing trials are evaluating the level of expression of ERCC1, no consensus has been reached regarding a method for evaluation. METHODS We used the 8F1 antibody to measure the level of expression of ERCC1 protein by means of immunohistochemical analysis in a validation set of samples obtained from 494 patients in two independent phase 3 trials (the National Cancer Institute of Canada Clinical Trials Group JBR.10 and the Cancer and Leukemia Group B 9633 trial from the Lung Adjuvant Cisplatin Evaluation Biology project). We compared the results of repeated staining of the entire original set of samples obtained from 589 patients in the International Adjuvant Lung Cancer Trial Biology study, which had led to the initial correlation between the absence of ERCC1 expression and platinum response, with our previous results in the same tumors. We mapped the epitope recognized by 16 commercially available ERCC1 antibodies and investigated the capacity of the different ERCC1 isoforms to repair platinum-induced DNA damage. RESULTS We were unable to validate the predictive effect of immunostaining for ERCC1 protein. The discordance in the results of staining for ERCC1 suggested a change in the performance of the 8F1 antibody since 2006. We found that none of the 16 antibodies could distinguish among the four ERCC1 protein isoforms, whereas only one isoform produced a protein that had full capacities for nucleotide excision repair and cisplatin resistance. CONCLUSIONS Immunohistochemical analysis with the use of currently available ERCC1 antibodies did not specifically detect the unique functional ERCC1 isoform. As a result, its usefulness in guiding therapeutic decision making is limited. (Funded by Eli Lilly and others.).

Gefitinib in Patients with Malignant Mesothelioma: A Phase II Study by the Cancer and Leukemia Group B

Purpose: The Cancer and Leukemia Group B conducted a phase II study of gefitinib, an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, in patients with previously untreated malignant mesothelioma. Experimental Design: Eligible patients had unresectable pleural or peritoneal mesothelioma, measurable disease, no prior therapy, and performance status 0-1 by Cancer and Leukemia Group B criteria. Gefitinib (500 mg p.o.) was administered once a day for 21 days. Patients underwent restaging after every two cycles. Therapy was continued until disease progression or unacceptable toxicity. Results: The most common grade 3 toxicities were diarrhea (16%) and nausea (12%). Of 43 patients enrolled, 1 patient (2%) had a complete response, 1 patient (2%) had a partial response, 21 (49%) had stable disease lasting two to eight cycles, 15 (35%) had progressive disease, and 5 (12%) had early deaths. One-year survival was 32% [95% confidence interval (CI), 21-50%]. Median survival and failure-free survival were 6.8% (95% CI, 3.5-10.3) and 2.6 months (95% CI, 1.5-4.0), respectively. The 3-month failure-free survival was 40% (95% CI, 25-56%). EGFR expression score by immunohistochemistry done in 28 patients was categorized as low (EGFR 1+ or 2+) or high (EGFR 3+) expression: 97% had EGFR overexpression (2+ or 3+). The median and 3-month failure-free survival were 3.6 months and 40% for those patients with low EGFR expression compared with 8.1 and 40% for those with high EGFR expression. Conclusions: Although 97% of patients with mesothelioma had EGFR overexpression, gefitinib was not active in malignant mesothelioma. EGFR expression does not correlate with failure-free survival.

Functional analysis of c-Met/hepatocyte growth factor pathway in malignant pleural mesothelioma

c-Met receptor tyrosine kinase (RTK) has not been extensively studied in malignant pleural mesothelioma (MPM). In this study, c-Met was overexpressed and activated in most of the mesothelioma cell lines tested. Expression in MPM tissues by immunohistochemistry was increased (82%) in MPM in general compared with normal. c-Met was internalized with its ligand hepatocyte growth factor (HGF) in H28 MPM cells, with robust expression of c-Met. Serum circulating HGF was twice as high in mesothelioma patients as in healthy controls. There was a differential growth response and activation of AKT and extracellular signal-regulated kinase 1/2 in response to HGF for the various cell lines. Dose-dependent inhibition (IC50 < 2.5 micromol/L) of cell growth in mesothelioma cell lines, but not in H2052, H2452, and nonmalignant MeT-5A (IC50 > 10 micromol/L), was observed with the small-molecule c-Met inhibitor SU11274. Furthermore, migration of H28 cells was blocked with both SU11274 and c-Met small interfering RNA. Abrogation of HGF-induced c-Met and downstream signaling was seen in mesothelioma cells. Of the 43 MPM tissues and 7 cell lines, we have identified mutations within the semaphorin domain (N375S, M431V, and N454I), the juxtamembrane domain (T1010I and G1085X), and an alternative spliced product with deletion of the exon 10 of c-Met in some of the samples. Interestingly, we observed that the cell lines H513 and H2596 harboring the T1010I mutation exhibited the most dramatic reduction of cell growth with SU11274 when compared with wild-type H28 and nonmalignant MeT-5A cells. Ultimately, c-Met would be an important target for therapy against MPM.

Eicosanoid Modulation in Advanced Lung Cancer: Cyclooxygenase-2 Expression Is a Positive Predictive Factor for Celecoxib + Chemotherapy—Cancer and Leukemia Group B Trial 30203

PURPOSE Increased expression of eicosanoids in cancer has been associated with adverse prognosis. We performed a randomized phase II trial to test the hypothesis that inhibitors of two eicosanoid pathways (cyclooxygenase-2 [COX-2], celecoxib and 5-lipoxygenase [5-LOX], zileuton) added to chemotherapy would improve outcome in advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS Patients with advanced NSCLC, a performance status of 0 to 2, and no prior therapy were eligible. All patients received carboplatin area under the curve (AUC) 5.5 mg/mL x min day 1 + gemcitabine (1,000 mg/m(2)) days 1 and 8. Patients were randomly assigned to: (a) zileuton 600 mg PO qid, (b) celecoxib 400 mg PO bid, or (c) celecoxib and zileuton at the same doses. Immunohistochemical staining for COX-2 and 5-LOX was performed without knowledge of outcomes. RESULTS One hundred forty patients were entered and 134 were eligible and treated. There was no survival difference between the arms. COX-2 expression was a negative prognostic marker for overall survival (OS; hazard ratio [HR] = 2.51, P = .019 for index >or= 4; HR = 4.16, P = .005 for index = 9) for patients not receiving celecoxib. Patients with increased COX-2 expression (index >or= 4), receiving celecoxib had better survival than did COX-2-expressing patients not receiving drug (HR = .342, P = .005 for OS; HR = .294, P = .002 for failure-free survival). Multivariate analysis confirmed the interaction of COX-2 and celecoxib on survival. 5-LOX expression was neither prognostic nor predictive. CONCLUSION This study failed to demonstrate the value of dual eicosanoid inhibition or benefit from either agent alone in addition to chemotherapy. However, a prospectively defined subset analysis suggests an advantage for celecoxib and chemotherapy for patients with moderate to high COX-2 expression.

Pooled Analysis of the Prognostic and Predictive Effects of KRAS Mutation Status and KRAS Mutation Subtype in Early-Stage Resected Non–Small-Cell Lung Cancer in Four Trials of Adjuvant Chemotherapy

PURPOSE We undertook this analysis of KRAS mutation in four trials of adjuvant chemotherapy (ACT) versus observation (OBS) to clarify the prognostic/predictive roles of KRAS in non-small-cell lung cancer (NSCLC). METHODS KRAS mutation was determined in blinded fashion. Exploratory analyses were performed to characterize relationships between mutation status and subtype and survival outcomes using a multivariable Cox model. RESULTS Among 1,543 patients (763 OBS, 780 ACT), 300 had KRAS mutations (codon 12, n = 275; codon 13, n = 24; codon 14, n = 1). In OBS patients, there was no prognostic difference for overall survival for codon-12 (mutation v wild type [WT] hazard ratio [HR] = 1.04; 95% CI, 0.77 to 1.40) or codon-13 (HR = 1.01; 95% CI, 0.47 to 2.17) mutations. No significant benefit from ACT was observed for WT-KRAS (ACT v OBS HR = 0.89; 95% CI, 0.76 to 1.04; P = .15) or codon-12 mutations (HR = 0.95; 95% CI, 0.67 to 1.35; P = .77); with codon-13 mutations, ACT was deleterious (HR = 5.78; 95% CI, 2.06 to 16.2; P < .001; interaction P = .002). There was no prognostic effect for specific codon-12 amino acid substitution. The effect of ACT was variable among patients with codon-12 mutations: G12A or G12R (HR = 0.66; P = .48), G12C or G12V (HR = 0.94; P = .77) and G12D or G12S (HR = 1.39; P = .48; comparison of four HRs, including WT, interaction P = .76). OBS patients with KRAS-mutated tumors were more likely to develop second primary cancers (HR = 2.76, 95% CI, 1.34 to 5.70; P = .005) but not ACT patients (HR = 0.66; 95% CI, 0.25 to 1.75; P = .40; interaction, P = .02). CONCLUSION KRAS mutation status is not significantly prognostic. The potential interaction in patients with codon-13 mutations requires validation. At this time, KRAS status cannot be recommended to select patients with NSCLC for ACT.

Randomized phase II trial of erlotinib alone or with carboplatin and paclitaxel in patients who were never or light former smokers with advanced lung adenocarcinoma: CALGB 30406 trial.

PURPOSE Erlotinib is clinically effective in patients with non-small-cell lung cancer (NSCLC) who have adenocarcinoma, are never or limited former smokers, or have EGFR mutant tumors. We investigated the efficacy of erlotinib alone or in combination with chemotherapy in patients with these characteristics. PATIENTS AND METHODS Patients with advanced NSCLC (adenocarcinoma) who were epidermal growth factor receptor tyrosine kinase inhibitor and chemotherapy naive never or light former smokers (smokers of > 100 cigarettes and ≤ 10 pack years and quit ≥ 1 year ago) were randomly assigned to continuous erlotinib or in combination with carboplatin and paclitaxel (ECP) for six cycles followed by erlotinib alone. The primary end point was progression-free survival (PFS). Tissue collection was mandatory. RESULTS PFS was similar (5.0 v 6.6 months; P = .1988) in patients randomly assigned to erlotinib alone (arm A; n = 81) or to ECP (arm B; n = 100). EGFR mutation analysis was possible in 91% (164 of 181) of patients, and EGFR mutations were detected in 40% (51 of 128) of never smokers and in 42% (15 of 36) of light former smokers. In arm A, response rate (70% v 9%), PFS (14.1 v 2.6 months), and overall survival (OS; 31.3 v 18.1 month) favored EGFR-mutant patients. In arm B, response rate (73% v 30%), PFS (17.2 v 4.8 months), and OS (38.1 v 14.4 months) favored EGFR-mutant patients. Incidence of grades 3 to 4 hematologic (2% v 49%; P < .001) and nonhematologic (24% v 52%; P < .001) toxicity was greater in patients treated with ECP. CONCLUSION Erlotinib and erlotinib plus chemotherapy have similar efficacy in clinically selected populations of patients with advanced NSCLC. EGFR mutations identify patients most likely to benefit.

Randomized Phase II Study of Pemetrexed, Carboplatin, and Thoracic Radiation With or Without Cetuximab in Patients With Locally Advanced Unresectable Non–Small-Cell Lung Cancer: Cancer and Leukemia Group B Trial 30407

PURPOSE Cancer and Leukemia Group B conducted a randomized phase II trial to investigate two novel chemotherapy regimens in combination with concurrent thoracic radiation therapy (TRT). PATIENTS AND METHODS Patients with unresectable stage III non-small-cell lung cancer (NSCLC) were randomly assigned to carboplatin (area under the curve, 5) and pemetrexed (500 mg/m(2)) every 21 days for four cycles and TRT (70 Gy; arm A) or the same treatment with cetuximab administered concurrent only with TRT (arm B). Patients in both arms received up to four cycles of pemetrexed as consolidation therapy. The primary end point was the 18-month overall survival (OS) rate; if the 18-month OS rate was ≥ 55%, the regimen(s) would be considered for further study. RESULTS Of the 101 eligible patients enrolled (48 in arm A and 53 in arm B), 60% were male; the median age was 66 years (range, 32 to 81 years); 44% and 35% had adenocarcinoma and squamous carcinoma, respectively; and more patients enrolled onto arm A compared with arm B had a performance status of 0 (58% v 34%, respectively; P = .04). The 18-month OS rate was 58% (95% CI, 46% to 74%) in arm A and 54% (95% CI, 42% to 70%) in arm B. No significant difference in OS between patients with squamous and nonsquamous NSCLC was observed (P = .667). The toxicities observed were consistent with toxicities associated with concurrent chemoradiotherapy. CONCLUSION The combination of pemetrexed, carboplatin, and TRT met the prespecified criteria for further evaluation. This regimen should be studied further in patients with locally advanced unresectable nonsquamous NSCLC.

Re-expression of p16 INK4a in mesothelioma cells results in cell cycle arrest, cell death, tumor suppression and tumor regression

Absence of expression of the p16IKN4a gene product is commonly observed in mesothelioma tumors and cell lines, while wild-type pRB expression is maintained. We have examined the biologic and potential therapeutic role of re-expressing p16INK4a gene product in mesothelioma cells and tumors. Following transduction with a p16INK4a expressing adenovirus (Adp16), over-expression of p16INK4a in mesothelioma cells resulted in cell cycle arrest, inhibition of pRB phosphorylation, diminished cell growth, and eventual death of the transduced cells. Expression of p16INK4a protein was accompanied by decreased expression of pRB as detected by immunoblot and immunohistochemistry. Experiments in mesothelioma xenografts demonstrated inhibition of tumor formation, tumor growth arrest and diminished tumor size and spread. p16INK4a gene product expression was also demonstrated in intraperitoneal xenografts of human mesothelioma cells. These results demonstrate that p16INK4a gene transfer may play a therapeutic role in the treatment of mesothelioma.

Thoracoscopic Versus Thoracotomy Approaches to Lobectomy: Differential Impairment of Cellular Immunity

BACKGROUND Video-assisted thoracoscopic surgery (VATS) for patients with early-stage non-small-cell lung cancer is associated with lower stress responses and potentially improved outcomes, as compared with thoracotomy. The goal of our study was to examine the cellular components of the postoperative immune response. Specifically, we assessed the cytotoxic capacity of peripheral blood mononuclear cells (PBMCs) of patients undergoing lobectomy for non-small-cell lung cancer by either VATS or thoracotomy. METHODS We performed a prospective cohort study of lobectomy patients undergoing either VATS or thoracotomy. We isolated PBMCs from perioperative blood samples, and performed cytokine analysis on plasma fractions. Using flow cytometry, we analyzed PBMC phenotype (CD3, CD16/56, CD4, CD8) and T-cell activation markers (CD25, CD69, HLA-DR). Using a chromium release assay, we quantified cellular cytotoxicity. To assess gene expression differences, we used Affymetrix messenger ribonucleic acid microarray and polymerase chain reaction analysis. RESULTS A total of 13 patients enrolled in our study: 6, VATS; 7, thoracotomy. On postoperative day 1, interleukin-6 and matrix metalloproteinase-9 were significantly different between the two groups. On day 2, cellular cytotoxicity (0.34) was significantly greater (p < 0.05) after VATS, as compared with thoracotomy (0.18). In both groups, cytotoxicity returned to baseline and was equivalent at first follow-up (VATS, 29.4 days versus thoracotomy, 29.3 days; p > 0.05). We noted minimal yet significant differences in PBMC phenotype, but no differences in T-cell activation makers. A 9-gene polymerase chain reaction-validated subset clustered the two groups with complete concordance. CONCLUSIONS Video-assisted thoracoscopic surgery lobectomy for non-small-cell lung cancer is associated with less impairment of cellular cytotoxicity, as compared with thoracotomy. We found that this difference was not accounted for by PBMC phenotypic changes. Instead, PBMC gene expression changes likely represent the molecular basis of this differential immune response.

Oncolytic measles viruses encoding interferon β and the thyroidal sodium iodide symporter gene for mesothelioma virotherapy

Mesothelioma usually leads to death within 8–14 months of diagnosis. To increase the potency of oncolytic measles viruses (MVs) for mesothelioma therapy, we inserted the interferon β (IFNβ) gene alone or with the human thyroidal sodium iodide symporter (NIS) gene into attenuated MV of the Edmonston lineage. The corresponding mouse IFNβ (mIFNβ) viruses, MV-mIFNβ and MV-mIFNβ-NIS, successfully propagated in human mesothelioma cells, leading to intercellular fusion and cell death. High levels of mIFNβ were detected in the supernatants of the infected cells, and radioiodine uptake was substantial in the cells infected with MV-mIFNβ-NIS. MV with mIFNβ expression triggered CD68-positive immune cell infiltration 2–4 times higher than MV-GFP injected into the tumor site. The numbers of CD31-positive vascular endothelial cells within the tumor were decreased at day 7 after intratumoral injection of MV-mIFNβ or MV-mIFNβ-NIS, but not after MV-GFP and PBS administration. Immunohistochemical analysis showed that MV-mIFNβ changed the microenvironment of the mesothelioma by increasing innate immune cell infiltration and inhibiting tumor angiogenesis. Oncolytic MVs coding for IFNβ effectively retarded growth of human mesotheliomas and prolonged survival time in several mesothelioma tumor models. The results suggest that oncolytic MVs that code for IFNβ and NIS will be potent and versatile agents for the treatment of human mesothelioma.