Although these developments remain at an early stage, published data suggest that these compounds may have significant clinical activity in NSCLC patients harboring exon 20 insertion mutations in EGFR and HER2. In this section, we will discuss the latest pre-clinical evidence that supports the evaluation of these EGFR exon 20 insertion selective inhibitors in lung cancer patients. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.