AZD9291 (osimertinib) is a potent irreversible inhibitor of both the single epidermal growth factor receptor sensitising mutation positive (EGFRm+) (tyrosine kinase inhibitor [TKI] sensitivity-conferring mutation) and dual EGFRm+/T790M+ (TKI resistance-conferring mutation) receptor forms of EGFR. AZD9291 therefore has the potential to provide clinical benefit to patients with advanced non-small cell lung cancer (NSCLC) harbouring both the single sensitivity mutations and the resistance mutation following prior therapy with an EGFR TKI. AZD9291 (osimertinib) was awarded FDA accelerated approval in November 2015, followed by conditional approval in the EU, full approval in Japan and additional markets in 2016, for the treatment of patients with EGFR T790M+ NSCLC who have progressed on or after EGFR TKI therapy.