Study of Dacomitinib and Osimertinib for Patients With Advanced EGFR Mutant Lung Cancer

Dose level 1 Dacomitinib, Dose level 2 Dacomitinib, Dose level 3 Dacomitinib. Three patients will need to be enrolled at each dose level and assessed for DLT for 1 full cycle (28 days for cycle 1) before dose escalation decision is made.

Dose level 1, 2 and 3 Osimertinib 40mg daily. Three patients will need to be enrolled at each dose level and assessed for DLT for 1 full cycle (28 days for cycle 1) before dose escalation decision is made.