Extrait

Lung cancer is the leading cause of cancer deaths in France, Europe and the world. 50% of lung cancers are of the adenocarcinoma subtype. 60% of patients present with a metastatic disease (stage IV) at the time of diagnosis. Approximately 10% of patients present with a mutation of the epidermal growth factor receptor (EGFR) requiring an EGFR tyrosine kinase inhibitor (EGFR-TKI), namely erlotinib, gefitinib or afatinib. For the majority of chemotherapy-naïve patients without addictive mutation, platinum-based chemotherapy, frequently the platinum - pemetrexed doublet, provides disease control rate of up to 70% and improves survival from approximately 4.5 with best supportive care alone to 15 months. However, patients with non-small cell lung cancer (NSCLC) usually relapse within 4 to 6 months and benefit from a second-line chemotherapy. Authorized drugs in this setting are pemetrexed, docetaxel and erlotinib. The prescription of erlotinib for unselected patients whose tumor does not harbor an EGFR mutation is questionable . In the second line setting, docetaxel provides less than 10% of partial responses and progression-free survival of 10 to 12 weeks. There are no standard options following failure of two previous lines of standard chemotherapy. In view of these modest results, new agents and therapeutic strategies are greatly needed for this patient population. Neurotensin (NTS) is a 13 amino acids peptide, present and biologically active in the central nervous system and in periphery. At the peripheral level, NTS is released by the endocrine cells of the intestinal mucosa after meals and acts as an endocrine hormone involved in the postprandial regulation of the motor functions of the gastrointestinal tract. The effects of NTS are mediated by three subtypes of receptor: NTSR1 and NTSR2 exhibit high and low affinity for NTS, respectively, and belong to the family of G protein receptors; NTSR3 is a single transmembrane domain receptor. Exogenous activation of NTSR1 leads to cell proliferation, survival, mobility and invasion in cancer cells from diverse origin. These effects are the result from the activation of kinases and effectors, such as PKC, MAPK, FAK, RHO-GTPase, RAS and Src. The PKC activation may induce MAPK by direct stimulation of Raf-1, or by transactivation of the EGFR. The activation of MAPK via NTSR1 is mainly associated with uncontrolled cell growth. Both NTS and NTSR1 are expressed in 40% of lung tumors, whereas they are never expressed in the normal tissue. NTSR1 high expression is a negative prognostic factor in stage I to III operated lung adenocarcinomas. Sustained stimulation of NTSR1 results in the activation of MMP1, the release of EGF "like" ligands such as HB-EGF as well as neuregulin 1 NGR1 (a specific ligand for HER3) followed by EGFR, HER2 and HER3 overexpression and activation. Accordingly, xenografted tumors expressing NTS and NTSR1 show a positive response to erlotinib, whereas tumors void of NTSR1 expression have no detectable response. Afatinib (BIBW2992) is a small molecule, selective and irreversible erbB family blocker. In preclinical models it effectively inhibits EGFR, HER2 and HER4 phosphorylation resulting in tumour growth inhibition and regression of established subcutaneous tumours derived from four human cell-lines known to co-express ErbB receptors. Our claim is that patients harbouring the NTS/NTSR complex, without EGFR mutation, will respond to afatinib due to the sustained activation of EGFR/HER2 under neurotensin activation. Presently, only EGFR mutated tumors are eligible to receive EGFR TKI representing 10% of all lung cancer patients. The aim of this study is to evaluate the efficacy of afatinib, an EGFR TKI, on lung adenocarcinomas, EGFR wild-type, bearing the NTS/NTSR1 complex with a high level of expression. This subpopulation of patients represents approximately 20% of lung adenocarcinomas.

Critère d'inclusion

• Small Cell Lung Carcinoma

Liens

• nct