1232PD - Lung Cancer Harboring Her2 Mutation: Epidemiological Characteristics and Therapeutic Perspectives

Abstract

ABSTRACT Introduction HER2 oncogene is a member of the EGFR family, encoding a transmembrane receptor that drives and regulates cell proliferation. HER2 mutations are identified in about 2% of non small cell lung cancer (NSCLC), mainly located in exon 20, and appear to be critical for lung cancer carcinogenesis. Very scarce data are available to define a clinical profile of the patients harboring HER2 mutated NSCLC. We aimed to study clinicopathological characteristics and therapeutic outcomes of patients harboring HER2 mutation in a large European series. Results We retrospectively identified 46 NSCLC patients diagnosed with HER2 exon 20 mutation. HER2 mutation was mainly exclusive as only one concomitant KRas mutation was described. Our population was characterized by a median age of 60 yr (31 to 86 yr), a high proportion of women (30 vs. 16 men, 65%), and of never smokers (24, 52%). All tumors were adenocarcinomas (two with lepidic features). Half of the patients had stage IV disease at the time of diagnosis. HER2 targeted treatment was delivered after conventional chemotherapy. A total of 20 anti-Her2 treatments were evaluable. We observed 4 progressive diseases, 7 disease stabilizations and 9 partial responses according to RECIST 1.1 (overall response rate ORR = 45%; disease control rate DCR = 80%). Specifically, we observed a DCR of 92% for trastuzumab-based therapies (n = 14), 100 % for afatinib (n = 3) but no response to lapatinib (n = 2) and to a multiTKI (n = 1). Median survival was of 68.2 months and 22.9 months for respectively early stage and stage IV patients. Conclusion This study, the largest to date dedicated to HER2 mutated NSCLC, reinforces the importance of an HER2 screening strategy in lung adenocarcinomas. HER2-targeted drugs should be tested further, ideally within large collaborative clinical trials. Disclosure All authors have declared no conflicts of interest.