Luca Toschi

Preexistence and Clonal Selection of MET Amplification in EGFR Mutant NSCLC

MET amplification activates ERBB3/PI3K/AKT signaling in EGFR mutant lung cancers and causes resistance to EGFR kinase inhibitors. We demonstrate that MET activation by its ligand, HGF, also induces drug resistance, but through GAB1 signaling. Using high-throughput FISH analyses in both cell lines and in patients with lung cancer, we identify subpopulations of cells with MET amplification prior to drug exposure. Surprisingly, HGF accelerates the development of MET amplification both in vitro and in vivo. EGFR kinase inhibitor resistance, due to either MET amplification or autocrine HGF production, was cured in vivo by combined EGFR and MET inhibition. These findings highlight the potential to prospectively identify treatment naive, patients with EGFR-mutant lung cancer who will benefit from initial combination therapy.

Increased MET Gene Copy Number Negatively Affects Survival of Surgically Resected Non–Small-Cell Lung Cancer Patients

PURPOSE To investigate the prognostic role of genomic gain for MET and epidermal growth factor receptor (EGFR) genes in surgically resected non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS This retrospective study included 447 NSCLC patients with available tumor tissue from primary lung tumor and survival data. EGFR and MET status was evaluated by fluorescent in situ hybridization (FISH) in tissue microarray sections. RESULTS EGFR FISH results were obtained in 376 cases. EGFR gene amplification and high polysomy (EGFR FISH+) were observed in 10.4% and 32.4% of cases, respectively. EGFR FISH-positive patients had a nonsignificant shorter survival than EGFR FISH-negative patients (P = .4). Activating EGFR mutations were detected in 9.7% of 144 stage I-II disease with no impact on survival. MET FISH analysis was performed in 435 cases. High MET gene copy number (mean > or = 5 copies/cell) was observed in 48 cases (MET+, 11.1%), including 18 cases with true gene amplification (4.1%). MET+ status was associated with advanced stage (P = .01), with grade 3 (P = .016) and with EGFR FISH+ result (P < .0001). No patient with activating EGFR mutation resulted MET+. In the whole population, MET-positive patients had shorter survival than MET-negative patients (P = .005). Multivariable model confirmed that MET-negative patients had a significant reduction in the risk of death than MET-positive patients (hazard ratio, 0.66; P = .04). CONCLUSION MET increased gene copy number is an independent negative prognostic factor in surgically resected NSCLC. EGFR gene gain does not impact survival after resection.

Prospective study of gefitinib in epidermal growth factor receptor fluorescence in situ hybridization-positive/phospho-Akt-positive or never smoker patients with advanced non-small-cell lung cancer: the ONCOBELL trial.

PURPOSE In non-small-cell lung cancer (NSCLC), clinical and biologic predictors for epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor sensitivity have been identified in retrospective studies, and there is urgent need to validate these results in prospective trials. The ONCOBELL trial is a prospective phase II study evaluating gefitinib sensitivity in NSCLC patients who never smoked or have increased EGFR gene copy number or activation of the antiapoptotic protein Akt. PATIENTS AND METHODS EGFR gene copy number was evaluated using fluorescence in situ hybridization (FISH), and presence of phospho-Akt was evaluated using immunohistochemistry. Additional tests included immunohistochemistry analysis of EGFR, FISH analysis of HER2, and mutation analysis of EGFR, HER2, and K-ras. RESULTS From November 2004 to February 2006, 183 patients were screened, and 42 patients were enrolled onto the trial. We observed one complete and 19 partial responses, for an overall response rate (RR) of 47.6% (95% CI, 32.5% to 62.7%). Median duration of response was 6.1 months, median time to progression (TTP) was 6.4 months, 1-year survival rate was 64.3%, and median survival time was not reached. EGFR FISH-positive patients, compared with negative patients, had higher RR (68.0% v 9.1%, respectively; P < .001), longer TTP (7.6 v 2.7 months, respectively; P = .02), and a trend for longer survival (median survival not reached v 7.4 months, respectively; P = .3). Therapy was well tolerated, and there were no drug-related deaths. Median follow-up time was too short for significance tests of differences in survival outcomes. CONCLUSION Gefitinib is active and well tolerated in patients with trial characteristics, and EGFR FISH analysis is an accurate predictor for such therapy.

MET increased gene copy number and primary resistance to gefitinib therapy in non-small-cell lung cancer patients

BACKGROUND MET amplification has been detected in approximately 20% of non-small-cell lung cancer patients (NSCLC) with epidermal growth factor receptor (EGFR) mutations progressing after an initial response to tyrosine kinase inhibitor (TKI) therapy. PATIENTS AND METHODS We analyzed MET gene copy number using FISH in two related NSCLC cell lines, one sensitive (HCC827) and one resistant (HCC827 GR6) to gefitinib therapy and in two different NSCLC patient populations: 24 never smokers or EGFR FISH-positive patients treated with gefitinib (ONCOBELL cohort) and 182 surgically resected NSCLC not exposed to anti-EGFR agents. RESULTS HCC827 GR6-resistant cell line displayed MET amplification, with a mean MET copy number >12, while sensitive HCC827 cell line had a mean MET copy number of 4. In the ONCOBELL cohort, no patient had gene amplification and MET gene copy number was not associated with outcome to gefitinib therapy. Among the surgically resected patients, MET was amplified in 12 cases (7.3%) and only four (2.4%) had a higher MET copy number than the resistant HCC827 GR6 cell line. CONCLUSIONS MET gene amplification is a rare event in patients with advanced NSCLC. The development of anti-MET therapeutic strategies should be focused on patients with acquired EGFR-TKI resistance.

Primary resistance to cetuximab therapy in EGFR FISH-positive colorectal cancer patients

The impact of KRAS mutations on cetuximab sensitivity in epidermal growth factor receptor fluorescence in situ hybridisation-positive (EGFR FISH+) metastatic colorectal cancer patients (mCRC) has not been previously investigated. In the present study, we analysed KRAS, BRAF, PI3KCA, MET, and IGF1R in 85 mCRC treated with cetuximab-based therapy in whom EGFR status was known. KRAS mutations (52.5%) negatively affected response only in EGFR FISH+ patients. EGFR FISH+/KRAS mutated had a significantly lower response rate (P=0.04) than EGFR FISH+/KRAS wild type patients. Four EGFR FISH+ patients with KRAS mutations responded to cetuximab therapy. BRAF was mutated in 5.0% of patients and none responded to the therapy. PI3KCA mutations (17.7%) were not associated to cetuximab sensitivity. Patients overexpressing IGF1R (74.3%) had significantly longer survival than patients with low IGF1R expression (P=0.006), with no difference in response rate. IGF1R gene amplification was not detected, and only two (2.6%) patients, both responders, had MET gene amplification. In conclusion, KRAS mutations are associated with cetuximab failure in EGFR FISH+ mCRC, even if it does not preclude response. The rarity of MET and IGF1R gene amplification suggests a marginal role in primary resistance. The potential prognostic implication of IGF1R expression merits further evaluation.

Role of gemcitabine in cancer therapy.

Gemcitabine, a pyrimidine nucleoside antimetabolite, is one of the most promising new cytotoxic agents. The drug has shown activity in a variety of solid tumors, and has been approved for the treatment of non-small cell lung cancer, pancreatic, bladder, and breast cancer. Recent data showed that gemcitabine is also active against ovarian cancer. Gemcitabine has a good toxicity profile, with myelosuppression being the most common side effect, while non-hematological events are relatively uncommon. The low toxicity profile makes the drug a valid option for unfit and elderly patients. Due to the synergistic activity with other chemotherapeutic compounds, mainly cisplatinum, several trials have been conducted to evaluate the efficacy and tolerability of gemcitabine in combination with other cytotoxic agents. Current clinical trials are evaluating the role of gemcitabine in combination with new targeted therapies.

Single-Agent and Combination Therapeutic Strategies to Inhibit Hepatocyte Growth Factor/MET Signaling in Cancer

Receptor tyrosine kinases are often aberrantly activated in human malignancies and contribute to cancer development and progression. Specific receptor tyrosine kinase inhibitors have been shown to be clinically effective therapies in subsets of cancer patients with either hematologic or solid tumors. Activation of the hepatocyte growth factor (HGF)/MET signaling pathway has been found to play a critical role in oncogenesis, cancer metastasis, and drug resistance. These observations have led to the development of agents that can effectively inhibit HGF/MET signaling through direct inhibition of the receptor (anti-MET antibodies), through inactivation of its ligand HGF (AMG102, L2G7), by interfering with HGF binding to MET (NK4), or by inhibiting MET kinase activity (PHA-665752 and SU11274). Moreover, the combination of anti-MET therapeutic agents with either signal transduction inhibitors (ERBB family or mTOR inhibitors) or with cytotoxic chemotherapy has been evaluated in preclinical models. These studies provide insight into the rational development of combination therapeutic strategies that can be evaluated in clinical trials. This review will discuss different strategies of MET inhibition with a specific focus on combination therapeutic approaches.

Long-Term Follow-up Results of the DANTE Trial, a Randomized Study of Lung Cancer Screening with Spiral Computed Tomography

RATIONALE Screening for lung cancer with low-dose spiral computed tomography (LDCT) has been shown to reduce lung cancer mortality by 20% compared with screening with chest X-ray (CXR) in the National Lung Screening Trial, but uncertainty remains concerning the efficacy of LDCT screening in a community setting. OBJECTIVES To explore the effect of LDCT screening on lung cancer mortality compared with no screening. Secondary endpoints included incidence, stage, and resectability rates. METHODS Male smokers of 20+ pack-years, aged 60 to 74 years, underwent a baseline CXR and sputum cytology examination and received five screening rounds with LDCT or a yearly clinical review only in a randomized fashion. MEASUREMENTS AND MAIN RESULTS A total of 1,264 subjects were enrolled in the LDCT arm and 1,186 in the control arm. Their median age was 64.0 years (interquartile range, 5), and median smoking exposure was 45.0 pack-years. The median follow-up was 8.35 years. One hundred four patients (8.23%) were diagnosed with lung cancer in the screening arm (66 by CT), 47 of whom (3.71%) had stage I disease; 72 control patients (6.07%) were diagnosed with lung cancer, with 16 (1.35%) being stage I cases. Lung cancer mortality was 543 per 100,000 person-years (95% confidence interval, 413-700) in the LDCT arm versus 544 per 100,000 person-years (95% CI, 410-709) in the control arm (hazard ratio, 0.993; 95% confidence interval, 0.688-1.433). CONCLUSIONS Because of its limited statistical power, the results of the DANTE (Detection And screening of early lung cancer with Novel imaging TEchnology) trial do not allow us to make a definitive statement about the efficacy of LDCT screening. However, they underline the importance of obtaining additional data from randomized trials with intervention-free reference arms before the implementation of population screening.

EGFR and HER2 Gene Copy Number and Response to First-Line Chemotherapy in Patients with Advanced Non-small Cell Lung Cancer (NSCLC)

Background: A critical point in designing clinical trials comparing chemotherapy with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in patients with non-small cell lung cancer (NSCLC) is the expected benefit with standard chemotherapy in presence of biological features indicative of TKI sensitivity. The aim of this study was to assess whether EGFR and HER2 gene copy number and Akt activation are associated with response to first-line chemotherapy. Methods: Tumor samples from 190 patients with NSCLC were analyzed. EGFR and HER2 gene copy number were evaluated by fluorescence in situ hybridization in 185 and 184 cases, respectively. Akt activation was assessed by immunohistochemistry (n = 176). Additional biomarkers included EGFR DNA sequencing (n = 65), and EGFR immunohistochemistry (n = 185). Results: Response rate was not associated with EGFR, HER2, and P-Akt status, irrespective of the method used for biomarker assessment. Among patients with EGFR gene mutations, response to chemotherapy was observed only in individuals with exon 19 deletion (response rate: 46.6% versus 0%, p = 0.02). Among the 190 patients analyzed, 123 received a treatment with a TKI as second- or third-line therapy. When assessed by fluorescence in situ hybridization or DNA sequencing, EGFR-positive patients seemed to be more sensitive to TKIs than to chemotherapy in terms of response rate and time to progression, whereas in EGFR-negative patients, response rate and time to progression favored chemotherapy. Conclusion: This study suggested that EGFR expression and gene copy number, HER2 gene copy number, and P-Akt expression are not associated with response to first-line chemotherapy in NSCLC. Prospective phase III trials should compare standard chemotherapy with a TKI in selected NSCLC.

Insulin-like growth factor receptor 1 (IGF1R) expression and survival in surgically resected non-small-cell lung cancer (NSCLC) patients

BACKGROUND The purpose of this study is to investigate the prognostic role of insulin-like growth factor receptor 1 (IGF1R) expression in surgically resected non-small-cell lung cancer (NSCLC). Patient characteristics and methods: This retrospective study was conducted in 369 stage I-II-IIIA, surgically resected, NSCLC patients. Patients exposed to anti-epidermal growth factor receptor (EGFR) agents were excluded. IGF1R expression was evaluated by immunohistochemistry in tissue microarray sections. RESULTS A positive IGF1R expression (score > or = 100) was observed in 282 cases (76.4%) and was significantly associated with squamous cell histology (P = 0.04) and with grade III differentiation (P = 0.02). No difference in survival was observed between the positive and negative group when score 100 was used as cut-off for discriminating a positive versus a negative IGF1R result (52 versus 48 months, P = 0.99) or when median value of IGF1R expression was used (45 versus 55 months, P = 0.36). No difference in survival was observed between IGF1R-positive and -negative patients in a subgroup of stage I-II adenocarcinoma (n = 137) with known EGFR mutation and copy number status. CONCLUSIONS IGF1R expression does not represent a prognostic factor in resected NSCLC patients. Patients with squamous cell carcinoma overexpress IGF1R more frequently than patients with nonsquamous histology, justifying the different sensitivity to anti-IGF1R agents observed in clinical trials.