20 patients will be required in the phase II period. In the expansion phase, 10 patients with T790M and 10 patients without T790M will be enrolled. It is assumed that 20% response rate is the target of clinical interest. If the true response rate is 20%, the probability of observing no responses in a random sample of 10 patients is 0.107. The false negative rate for detecting a true 20% response rate in each cohort is approximately 10%. Each cohort will be enrolled 10 patients to evaluate the efficacy; therefore 20 patients will be enrolled in dose expansion part. Patients treated at the MTD and/or RP2D during the phase Ib will be considered as part of the required number of patients in the phase II. Patients at the MTD or RP2D cannot contribute to the 20 patients require for phase II part.