EGFR and non-small cell lung carcinoma: In any case, the current indication for afatinib includes NSCLC-patients with exon 19dels or with the uncommon G719X, S768I or L861Q EGFR-substitutions, though patients with these mutations, over time, can become resistant to afatinib by acquiring a secondary T790M mutation or more rarely other substitutions in exon 20 [89,91].