P50.08 Targeting HER2 or EGFR Exon 20 Insertion Mutation in Lung Cancer - A Case Series from India

Abstract

Around 4% of EGFR mutated Non Small Cell Lung Cancers (NSCLC) harbour exon 20 in-frame insertions. 2-4% of patients with NSCLC also have HER2 mutations, out of which 90% are exon 20 insertions. Insertion mutations at EGFR and HER2 both occur at analogous positions in exon 20. These mutations confer intrinsic resistance to most of the Tyrosine Kinase inhibitors(TKI's). Clinical trials are underway to estimate treatment benefits for novel molecules to target EGFR or HER2 exon 20 mutations. In this study, we provide the data of four patients with NSCLC associated with EGFR or HER2 exon 20 mutations. We also report the clinical benefit in an Indian setting. We collected Next Generation Sequencing-based Comprehensive Genomic Profile (CGP) testing data from medical oncologists across India. We collated data from the test reports along with clinical information. Here, we describe the results of EGFR or HER2 exon 20 targeting in our retrospective cohort. We collated 297 CGP test reports from 12 medical oncologists. Four patients had EGFR or HER2 exon 20 insertion mutation. Three had HER2 mutation and one person had EGFR mutation. One mutation was detected through liquid biopsy and the remaining ones were identified through tissue biopsy. Two patients were on Poziotinib outside of a clinical trial, one was on Osimertinib and the fourth person was on Trastuzumab emtansine. Two patients are having ongoing treatment responses at 6 months. One person on Poziotinib was on the medicine for 2 months. One person on Trastuzumab emtansine took the drug for 7 months. EGFR or HER2 exon 20 insertion mutation in NSCLC provides a promising target for novel molecules. Even in an Indian setting, clinically meaningful responses are observed.