Is there still any role for afatinib (or first generation TKIs) in the management of EGFR mutated metastatic lung adenocarcinoma?   

Yes, there is still a role for Afatinib for certain uncommon mutations, especially exon 18 deletions, E709X, G719A, and S768I, where the IC50's are sometimes 10X better for Afatinib than osimertinib. I have seen clinical responses to Afatinib in tumors with these mutations progressing on osimertinib...