Would you consider first line osimertinib to patients with an EGFR Exon 18 G719X mutation?  

Yes, there is some retrospective data that osi (or afatinib) are reasonable options here

Yes, I would consider osimertinib. Afatinib is the only EGFR TKI that is FDA-approved for the rare sensitizing EGFR mutations based on pooled data from LUX-Lung 2/3/6. These studies included 18 patients with G719X mutations with a RR 78%, PFS 14 mo., and OS 27 mo. (Yang et al., PMID 26051236) Other ...